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Author: 
 
 Roe, Joseph Wickham 
 
 Title: 
 
 The mechanical 
 equipment 
 
 Place: 
 
 New York 
 
 Date: 
 
 [1 922] 
 
COLUMBIA UNIVERSITY LIBRARIES 
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 Roe, Joseph Wickham. 
 
 The mechanical equipment, by Joseph W. Eoe . . . New 
 York, Industrial extension institute, incorporated t*i918i 
 
 ^ xviii,"^5l3 p. illus. 19i"°. (Factory management course, -r; 3 ^^^^ / 
 
 Added t.-p. : Factory management course and service ... written for the 
 Industrial extension institute ... 
 
 I. Machinery. i. Title. 
 
 Library of Congress 
 Copy 2. 
 
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 Columliia Winti^txiity 
 
 in tbt dtp of ^etD f^orfc 
 
 LIBRARY 
 
 School of Business 
 
FACTORY MANAGEMENT 
 COURSE AND SERVICE 
 
 A Series of Interlocking Text Books Written for the 
 Industrial Extension Institute by Factory Man- 
 agers and Consulting Engineers as Part 
 of the Factory Management 
 Course and Service 
 
 INDUSTRIAL EXTENSION INSTITUTE 
 
 INCORPORATED 
 
 NEW YORK 
 
ADVISORY COUNCIL 
 
 Nicholas Thiel Ficker, Pres., 
 
 Charles E. Funk, Secy., 
 
 Chas. a. Bbockaway, Treas., 
 
 Alwin von Auw, 
 
 Oen, Mgr. Boorum-Peaae Co, 
 
 Charles C. Goodrich, 
 
 Ooodrich-Lockhart Co, 
 
 WiLLARD F. HiNE, 
 
 Consulting Appraisal Engi- 
 neer, Chief Gas Engr., 
 Public Service Comm, 
 N. Y, 
 
 Charles P. Steinmetz, 
 
 Chdef Consulting Engineer^ 
 General Electric Co. 
 
 Jervis R. Harbeck, 
 
 Vice-Pres. American Can Co. 
 Benj. a. Franklin, 
 
 Vice-Pres, Strathmore Paper 
 Co., Lieut. Col. Ord- 
 nance Dept. 
 
 Charles B. GIoing, 
 
 Formerly Editor, The Engi- 
 neering Magazine, Con- 
 sulting Industrial Engi- 
 neer, 
 
 THE 
 MECHANICAL EQUIPMENT 
 
 BY 
 
 JOSEPH W. ROE, M.E. 
 
 Assistant Professor Mechanical Engineering Shield 
 Scientific School, Yale University 
 
 STAFF. 
 
 C. E. Knoeppel, 
 
 Prea. C. E. Knoeppel & Co.. 
 Consulting Engineers. 
 Meteb Bloomfield, 
 
 Consultant on Personnel. 
 Geoboe S. Arm strong, 
 
 Consulting Jnausirial Engivkeer, 
 
 H. B. TWYFOED, 
 
 Purchasing Agent, Nichols Cop- 
 per Co. 
 
 Nicholas Thiel Fickeb, 
 
 Consulting Industrial Engineer. 
 
 DwiGHT T. Fabnham, 
 
 Consulting Industrial Engineer. 
 
 Willabd L. Case, 
 
 Pres. Willard L. Case & Co., 
 Consulting Engineers. 
 
 Davh) Moffat Myers, 
 
 Origgs & Myers, Consulting 
 Engineers. 
 
 Joseph W. Roe, 
 
 Prof. Machine Design, Sheffield 
 Bcientiflo School, Yale Univ. 
 Albert A. Dowd, ■ 
 
 Consuting Engineer. 
 
 William P. Hunt, 
 
 Consulting Inaustrial Engineer. 
 Chablis W. MoKat, 
 
 Appraisal Engineer 
 
 Organization and Administba- 
 
 TION. 
 
 Labor and Compensation. 
 Planning and TimetStudy. 
 Purchasing and Storing. 
 
 Industrial Cost Finding, 
 Executive Statistical Control 
 The Factory Building. 
 
 The Power Plant. 
 
 The Mechanical Equipment. 
 
 Tools and Patterns. 
 
 Handling Material in Factor- 
 ies. 
 
 Valuing Industbla.l Pbopebties. 
 
 J . 
 
 VOLUME 9 
 FACTORY MANAGEMENT COURSE 
 
 INDUSTRIAL EXTENSION INSTITUTE 
 
 INCORPORATED 
 
 NEW YORK 
 

 « ^r Q I ^ 
 
 .o„ 
 
 *«'.-,..i«'*~"""° ""^ 
 
 TXT^.,« Copyright, 1922, bv 
 INDUSTRIAL EXTENSION INSTITUTE 
 
 • • INCORPORATED 
 
 3 ^3 5- 
 
 PREFACE 
 
 The purpose of this book is to present the standard ma- 
 chines and mechanical methods used in general manufactur- 
 ing, and to show their proper fields. 
 
 An industrial executive deals with two general classes of 
 problems : those relating to business, accounting and executive 
 management, and those involving the physical equipment and 
 methods of manufacture. It is not necessary that an execu- 
 tive be able to build every machine he uses, or even that he 
 know all its habits, good and bad, as intimately as the skilled 
 mechanic who runs it. But, in order to act intelligently, he 
 must know the types of machines available for the work in 
 hand, their capacity and relation to each other, and the 
 processes and methods involved. 
 
 Modern industrial equipment is almost as varied as the 
 industries themselves, and no single volume could attempt to 
 describe all of it. This book is therefore confined chiefly to 
 the machine shop. As Mr. F. A. Halsey has said: "The ma- 
 chine shop is the center from which all modern industries 
 radiate. From the brickyard to the flying machine, from the 
 sawmill to wireless telegraphy, from the stone quarry to the 
 moving-picture camera, there is no modern industry more 
 than twice removed from the machine shop." Even with the 
 field so narrowed it is necessary to confine the attention to 
 typical machines and to avoid too detailed discussion. 
 
 So far as the writer knows no book has yet presented the 
 subject of machine equipment as a whole, or has pointed out 
 the relations of the standard tools to each other. It is the 
 purpose of this book to do so. It is an outgrowth of a course 
 of lectures and recitations given for a number of years to 
 
vt 
 
 PREFACE 
 
 the students in Mechanical Engineering at the Sheffield 
 Scientific School, Yale University, and presupposes only such 
 technical knowledge or experience as might be possessed by 
 an undergraduate in a technical school or an office man hav- 
 ing a general familiarity with manufacturing. 
 
 While the book deals chiefly with foundry, forge shop, and 
 machine shop equipment, four chapters have been added to 
 point out the more characteristic features of wood-working, 
 paper, shoe, and textile machinery. In the preparation of 
 these four chapters the writer would acknowledge his in- 
 debtedness to Mr. Everett 0. Waters, of the Sheffield Scientific 
 School. 
 
 Sheffield Scientific School, 
 Yale University. 
 
 Joseph Wickham Roe. 
 
 TABLE OF CONTENTS. 
 
 CHAPTER I 
 
 BUILDING AND MANUFACTURING 
 
 PAGE 
 
 "M Distinction Between the Two Systems 1 
 
 The Building Method 2 
 
 The Manufacturing Method 3 
 
 Tools Used in Building 4 
 
 Tools Used in Manufacturing 5 
 
 The Interchangeable System 6 
 
 Combination Methods 11 
 
 CHAPTER II 
 
 THE DRAFTING DEPARTMENT 
 
 Functions 13 
 
 Design of Product 14 
 
 Design of Plant Equipment 14 
 
 Standards, Drawings, and Lists 15 
 
 Record of Work Done 16 
 
 Estimating . 17 
 
 Supplementary Functions 17 
 
 Personnel 18 
 
 Policies 19 
 
 Practice 23 
 
 Tools Available 24 
 
 Checking 24 
 
 Blueprints 25 
 
 Filing 25 
 
 vii 
 
/ 
 
 mil 
 
 TABLE OF CONTENTS 
 
 Changes and Alterations ........ 26 
 
 Equipment V ' ' * ^ 
 
 Location of the Drafting Room ...... * 27 
 
 CHAPTER III 
 
 THE PATTERN SHOP 
 Function and Location qq 
 
 Balance of Pattern Makers' and Holders' Time " 30 
 
 Types of Patterns • • • 
 
 Gated Patterns 04 
 
 Pattern Material • • • . » 
 
 Allowances \ * ^- 
 
 Warping and Splitting ... **''.* * 
 
 Fillets '.'.]''' 38 
 
 Core Prints 
 
 Marking and Painting .....'.*.*'* 30 
 
 Pattern Storage oq 
 
 Index System 
 
 Records ... 
 
 40 
 
 CHAPTER IV 
 
 FOUNDRY METALS AND FOUNDRY BUILDINac- 
 
 Metals 
 
 Grey Iron 
 
 Chilled Iron 
 
 Malleable Iron 
 
 Cast Steel .....*.*.'.* 
 
 Alloys .... 
 
 Foundry Buildings and Equipment 
 
 Storage 
 
 Transportation ... 
 
 41 
 41 
 42 
 43 
 43 
 44 
 45 
 49 
 49 
 
 TABLE OF CONTENTS ix 
 
 CHAPTER V 
 
 FOUNDRY MOLDING METHODS 
 
 PAGE 
 
 Materials 52 
 
 Molding Sands 53 
 
 Loam 54 
 
 Facing 54 
 
 Cores and Core Binders 55 
 
 Cope and Drag 56 
 
 Small Tools . 57 
 
 Making a Mold . 58 
 
 Machine Molding ' . . 60 
 
 Carrier Foundries 63 
 
 CHAPTER VI 
 
 FOUNDRY— MELTING, POURING, CLEANING 
 
 General Methods 65 
 
 The Cupola 65 
 
 The Air Furnace 70 
 
 Open-Hearth Furnace 71 
 
 Oil or Gas Furnaces 71 
 
 Crucible Furnace 72 
 
 Electric Furnace 75 
 
 Ladles 75 
 
 Pouring . 76 
 
 Defects of Castings 76 
 
 Cleaning . 78 
 
 Tumbling 78 
 
 Pickling 79 
 
 Sand Blast 79 
 
 CHAPTER VII 
 
 FORGING METHODS 
 
 Hand Work 80 
 
 The Forge . 81 
 
i 
 
 « TABLE OF CONTENTS 
 
 Tuols ^^^^ 
 
 Operations .*.''* 86 
 
 Welding .* * .* \ \ \ \ \ 37 
 
 Steam Hammer Work .'.'*' 88 
 
 Power Hammers • • • . . 
 
 Headers and Upsetters .*.*!'* 94 
 
 Hydraulic Press .".'.'!* 94 
 
 Rolling \ . \ \ \ 97 
 
 I^rawing 99 
 
 Extrusion Process ...... i * ' * * inn 
 
 Pipe Bending .'.'.'.*.* 100 
 
 CHAPTER VIII 
 
 DROP FORGING 
 
 Utility 102 
 
 Drop Hammer ^qo 
 
 Trimming Press .... ' ' * ' ' * mc 
 T^. lUo 
 
 ^!^« 107 
 
 Die Working ^^q 
 
 Heating .'.*.'.'.'.'* 114 
 
 The Forging Operation .'.''' 114 
 
 Pickling .'.*.'.'.' 115 
 
 Cold Trimming ]]'*'' -^^ 
 
 General Considerations .' 1 ! ' * 116 
 
 CHAPTER IX 
 
 WELDING, SOLDERING AND BRAZING 
 
 General Classes of Welding jj^ 
 
 Pressure Welding by Hammering . . .' .* .' .' ] 119 
 
 Electric Resistance Welding ....!.'.'.* 122 
 
 La Grange-Hoho Process .'.'.*' 127 
 
 Electric-Arc Welding .....'.'.*.'.'* 128 
 
 Gas-Flame Welding • , . .* .* .' .' ,' .' .' 130 
 
 TABLE OF CONTENTS 
 
 x\ 
 
 PAGE 
 
 Advantages 233 
 
 Uses 
 
 133 
 
 Thermit Welding ^33 
 
 Soldering and Brazing 235 
 
 Brazing Process ^36 
 
 CHAPTER X 
 
 HEAT TREATMENTS 
 
 Variability of Steel Properties 133 
 
 Heat Treat Processes 139 
 
 Hardening j^q 
 
 Heating ^^^ 
 
 Quenching ^^ 
 
 Self-Hardening Steels 143 
 
 Taylor-White Steel .'.'!!! 149 
 
 Annealing jcq 
 
 Tempering ^r-. 
 
 The Color Scale .,.!!!.'! .' ] ." \ 151 
 Carbonizing j^q 
 
 CHAPTER XI 
 
 THE TOOL ROOM— FIXTURES AND GAUGES 
 
 The Tool Room a Modern Development 
 
 Relation of Tool Room to Shop 
 
 Functions of the Tool Room 
 
 The Tool Storeroom 
 
 Machine Equipment 
 
 Policies .... 
 
 Fixtures and Jigs . 
 
 Economic Principles 
 
 Mechanical Principles 
 
 Gauging .... 
 
 Types of Gauges 
 
 General Considerations 
 
 155 
 
 155 
 
 156 
 
 158 
 
 159 
 
 160 
 
 160 
 
 161 
 
 162 
 
 164 
 
 165 
 
 169 
 
^** TABLE OF CONTENTS 
 
 CHAPTER XII 
 
 CUTTING TOOLS 
 
 Material ^^^^ 
 
 Carbon Steel . . . ]l\ 
 
 Mushet, or Self-Hardening Steel .79 
 
 High-Speed Steels . . .^^ 
 
 The Lathe-Planer . . ^^^ 
 
 Multiple Tool-Holders . [ :lt 
 
 Single-Edged Forming Tools .70 
 
 Milling Cutters . . ]V: 
 
 Gang Mills .....*.*; JJJ 
 
 Speeds and Feeds '10^ 
 
 Drills ' ' ^^' 
 
 Reamers .... 
 
 Taps . ^^^ 
 
 Dies . . : : ; ^^^ 
 
 Punches . . ^^^ 
 
 Shears . . * ' * ^^^ 
 
 Saws .......'.' ^^^ 
 
 Cutting Lubricants ...*.' l^l 
 
 CHAPTER XIII 
 
 LATHES 
 
 i^evelopment of the Lathe 20O 
 
 Henry Maudslay and Modern Tools onn 
 
 The Speed Lathe .'•'.'*" 203 
 
 The Engine Lathe . . oni 
 
 Head-Stock . f"* 
 
 Speeds ....!.'.' f^ 
 
 Spindle and Tail Stock . .' l^l 
 
 Slide Rest . "^"^ 
 
 210 
 
 Change-Gear Box * ' ' ' ^10 
 
 Single Driving Pulley ....'...*' 012 
 
 4 
 
 TABLE OF CONTENTS 
 
 Xlll 
 
 PAGE 
 
 Mounting the Work 212 
 
 Tool Post 214 
 
 Special Lathes 215 
 
 Lathe Operation 215 
 
 CHAPTER XIV 
 
 TURRET AND AUTOMATIC LATHES 
 
 The Turret Principle 219 
 
 Turret Lathe vs. Engine Lathe .220 
 
 Hand and Automatic Turret Lathes 221 
 
 Multi-Spindle Automatics 222 
 
 Hand-Operated Turret Lathes 223 
 
 Gisholt Lathe 226 
 
 Warner and Swasey Lathe 228 
 
 Hartness Flat-Turret Lathe 229 
 
 Principle of Automatic Lathes 232 
 
 Gridley Automatic Lathe 236 
 
 Multi-Spindle Automatics 238 
 
 Fay Automatic Lathe 240 
 
 Lo-Swing Lathe 243 
 
 Blanchard Lathe 244 
 
 CHAPTER XV 
 
 BORING 
 
 Wilkinson 's Boring Machine 245 
 
 r^>oring Mills Classified * ! ! ! . 246 
 
 Vertical Boring Mill versus Lathe ...... 247 
 
 Vertical Boring Mill versus Planer .....! 249 
 
 Construction of Vertical Boring Mill .... .* 251 
 
 Table, Drive and Tools ! . . . 255 
 
 Bullard Mult-au-matic Vertical Lathe \ , . . . 256 
 
 Horizontal Boring Machine .' .' . 258 
 
 Similarity to the Lathe ....!.*!!.* 260 
 
 X 
 
XIV 
 
 TABLE OF CONTENTS 
 
 An Adaptable Type 260 
 
 Portable Boring Machines 263 
 
 CHAPTER XVI 
 
 DRILLING MACHINERY 
 
 The Sensitive Drill 266 
 
 Upright Drills * 268 
 
 Details of the Drive 269 
 
 Heavy Duty Drill-Presses 270 
 
 Radial Drills ..!!.* 273 
 
 The Column and Drilling Mechanism 274 
 
 Multiple-Spindle Drill ! . . 278 
 
 Drilling Jigs . ! 279 
 
 Work Commonly Done on Drill Press . . . . .* 281 
 
 CHAPTER XVII 
 
 PLANERS, SHAPERS, AND SLOTTERS 
 
 Definition of Field 283 
 
 Early Types of Planers ! ! ! 284 
 
 The Modern Planer .* ! ! 284 
 
 Standard Type of Planer ..." 285 
 
 Rack-and-Pinion Drive 286 
 
 The Uprights . .' 289 
 
 Feed Motions . . . . 290 
 
 Special Types of Planers .'292 
 
 The Shaper and Its Work 297 
 
 Construction and Operation of the Shaper .... 299 
 
 The Traversing Shaper \ 302 
 
 The Vertical Shaper, or Slotter 305 
 
 CHAPTER XVIII 
 
 MILLING MACHINES 
 Some Advantages of the Milling Process . . ... . 308 
 
 The Work of the Milling Machine .308 
 
 TABLE OF CONTENTS xv 
 
 PAGE 
 
 lOrigin and Development of Milling Machine ... ^09 
 
 [The Lincoln Type 313 
 
 JThe Briggs' Type 314 
 
 Modern Development of Lincoln Miller 316 
 
 Column-and-Knee Type 317 
 
 Vertical Miller 3^9 
 
 Profile Milling Machine 322 
 
 Universal Milling Machine 324 
 
 Milling Teeth of Spur Gear 327 
 
 Milling Long Spirals 327 
 
 Control of Rotary Motion 327 
 
 Continuous Rotary Feeding 323 
 
 Planer Type of Milling Machine 329 
 
 Rotary Planer 332 
 
 CHAPTER XIX 
 
 GEAR-CUTTING 
 
 Two Systems of Tooth Forms ........ 334 
 
 Spur Gears 335 
 
 Helical Gears 337 
 
 Bevel Gears 337 
 
 Worm Gears 337 
 
 Formed-Tooth Principle 333 
 
 Template Principle 34^ 
 
 Form-Generating Principle 343 
 
 Spur-Gear-Cutter 345 
 
 Machine Embodying Template Principle .... 346 
 
 Fellows Gear-Shaper 343 
 
 Hobbing Machines ^51 
 
 Cutting Helical (Jears 353 
 
 Cutting Bevel Gears 354 
 
 Machine Embodying Form-Generating Principle . . 357 
 
/ 
 
 ( 
 
 ^^«* TBALE OF CONTENTS 
 
 CHAPTER XX 
 
 SCREW-THREAD-CUTTING 
 
 Early Methods of Cutting Screw Threads .... 360 
 
 Standardization of Screw Threads 361 
 
 Types of Screw Threads 351 
 
 Cutting Screw Threads 354 
 
 Bolt-Threading Machines 355 
 
 Opening Die Heads 355 
 
 Pipe-Threading Machines 359 
 
 Thread-Cutting on Lathes 371 
 
 Milling Screw Threads 374 
 
 Rolling Threads 375 
 
 CHAPTER XXI 
 
 GRINDING, AND GRINDING MACHINERY 
 
 Development of the Grinding Process 377 
 
 Special Advantages 377 
 
 Grinding Abrasives 373 
 
 Grinding Wheels . . . 330 
 
 C^rading 381 
 
 Selection of Wheels 332 
 
 Mounting of Wheels 333 
 
 Types of Grinding Machines ........ 386 
 
 Tool Grinders . 395 
 
 Polishing and Buffing 397 
 
 CHAPTER XXII 
 
 BROACHING AND PRESS WORK 
 
 The Broaching Process ogg 
 
 The Broaching Machine 400 
 
 Broaching Tools ^q2 
 
 Punches and Dies ^5 
 
 TABLE OF CONTENTS 
 
 xvtt 
 
 Types of Presses ^qq 
 
 ^^^'^y •:•••••'.'.*!!.■.* 414 
 
 CHAPTER XXIII 
 
 WOODWORKING MACHINERY 
 
 Types of Machines, Few : Modifications, Many ... 416 
 
 Saws ! . 417 
 
 Band Saw ' .^r. 
 
 Circular Saw ' a^c^ 
 
 Universal Saw Bench aoq 
 
 Swing-Frame Saw " ' 421 
 
 Log Mill ' .... 421 
 
 Gang Saw 423 
 
 Power Consumption of Saws , 424 
 
 Planers, Surfacers, Moulders and Shapers ' * 424 
 
 ^"*^^\ • .*.'.* 430 
 
 Gauge Lathe .09 
 
 Blanchard, or Copying, Lathe .' .' . 432 
 
 Miscellaneous Machines ' .* 434 
 
 CHAPTER XXIV 
 
 PAPER MACHINERY 
 
 Rag Machinery ^ ^^g 
 
 Dusters and Cutters .' .' " 439 
 
 Digesters and Washers .' * 441 
 
 Wood-Pulp Machinery .* . " * 444 
 
 Beaters and Refiners .' .* 447 
 
 Paper Machines .' ' ' 448 
 
 Finishing Machinery .'.'.'. 456 
 
 CHAPTER XXV 
 
 BOOT AND SHOE MAf^HINERY 
 
 General Characteristics 459 
 
 History of Shoe Machinei y ! .* 459 
 
 V 
 
f 
 
 XVll% 
 
 TABLE OF CONTENTS 
 
 f 
 
 PAGE 
 
 Machine Operations 46I 
 
 Arrangement of a Shoe Factory 462 
 
 Types of Shoes 462 
 
 Cutting Room Machinery 464 
 
 Stitching-Room Machinery 468 
 
 Machinery of the Stock-Fitting Room 472 
 
 Bottoming-Room Machinery 474 
 
 Finishing-Room Machinery 473 
 
 CHAPTER XXVI 
 
 TEXTILE MACHINERY 
 
 The Fibres and the Processes 48I 
 
 Cotton-Spinning Machinery 431 
 
 The Comb 434 
 
 Drawing Frame ; Fly Frame ; Spinning Machine . . 485 
 
 Wool-Spinning Machinery 439 
 
 Worsted-Spinning Machinery 490 
 
 Linen and Silk Preparation 493 
 
 Weaving Machinery 494 
 
 Mechanism of the Loom 496 
 
 Weaving Intricate Patterns 499 
 
 Knitting Machines \ .501 
 
 Finishing Machinery 503 
 
 THE MECHANICAL EQUIPMENT 
 
 CHAPTER I 
 BUILDING AND MANUFACTURING 
 
 Distinction Between the Two Systems.— Two well- 
 I defined methods of production are found in the metal 
 .trades, and the principles which differentiate them 
 run through all forms of factory production. No gen- 
 lerally recognized names have been given them, and 
 for want of better terms we will call them ** building" 
 land ** manufacturing." The two systems are sharply 
 differentiated through the entire process of produc- 
 tion, and even to marketing. The use of one or the 
 other affects the nature of the whole plant, its 
 methods, and its equipment; consequently before tak- 
 ing up the equipment in detail we will consider the 
 [two systems and what they involve. 
 
 We shall use the term ''building," to cover the 
 [production of machines or other articles one at a 
 I time, or in numbers so limited that their methods of 
 production are unchanged. By ** manufacturing" we 
 shall mean production in lots to standard designs and 
 usually with the corresponding parts interchangeable. 
 As will be seen later, the term manufacturing usually 
 implies a large output, but the distinction lies rather 
 in the methods used than in the quantities produced. 
 
2 THE MECHANICAL EQUIPMENT 
 
 A firm might build a great many things, or manufac- 
 ture a few. In either case the costs would probably 
 be high. As we shall see, the two systems may be 
 and often are combined in the production of articles 
 where certain details used in great quantities are 
 manufactured, while the larger parts which are not 
 standard are built. This use of the two systems 
 together may often be the wisest and most profitable 
 method of production. 
 
 The Buildings Method. — ^Perhaps the best way to 
 bring out the characteristics of the building method 
 is to follow the course of a large water-works engine. 
 
 The intending purchaser may issue a set of speci- 
 fications laying down the conditions under which the 
 proposed engine is to operate, the quality of materials 
 to be used, and the capacity and economies to be 
 guaranteed. The firms quoting will draw up pre- 
 liminary designs and estimate upon them, taking into 
 account patterns available, machinery required for 
 production, transportation, erecting facilities, and so 
 forth. A public hearing may then be held where the 
 advantages of the various designs submitted are 
 argued. These are considered and the contract 
 finallv let. The successful firm then makes the draw- 
 ings covering the details of the entire machine, the 
 patterns that may be necessary, and casts and ma- 
 chines the various parts and erects the engine within 
 its plant. It is then knocked down, shipped to its 
 destination, erected in place, and finally tested under 
 working conditions. As this process requires a long 
 time and heavy expenditure, partial payments may be 
 made at stated stages; but the engine, even when in 
 
 BUILDING AND MANUFACTURING 3 
 
 place and running, is still in the hands of the builder 
 and is not accepted until the performance guaranteed 
 has been demonstrated. Then and not until then is 
 the transaction closed and the final payment made. 
 
 The Manufacturing Method.— Contrast the above 
 with the production of a new model of sporting rifle. 
 A firm manufacturing rifles may determine that a new 
 type of rifle is called for, or some design may be sub- 
 mitted to them which they recognize as desirable. 
 I Every available expert is consulted, a design evolved, 
 one or more models ** built," and carefullv tested 
 I under every possible condition of use. Any necessary 
 I modification will be made, the details of manufacture 
 carefully studied out, and a sequence of operations 
 determined. A force of tool-makers will be set to 
 work designing jigs, fixtures, gauges, and, if neces- 
 jsary, special machines. The building of these, 
 together with the preliminary work, will run into 
 I thousands or even hundreds of thousands of dollars. 
 When actual production is started a large lot will be 
 I manufactured and placed in stock, an advertising 
 campaign will be inaugurated, and sales begun. In 
 general, the selling department will begin its 
 activities when the goods are finished and placed in 
 [stock. And the marketing of the product is one of 
 [business skill and judgment, involving little or no 
 engineering. In the case of the engine, the sale pre- 
 cedes the building and even much of the designing;, 
 and the engineer is intimately concerned in the selling 
 as he must convince the purchaser of the superiority 
 of his design. The two processes of production from 
 initial sale to final acceptance follow different courses. 
 
V 
 
 4 THE MECHANICAL EQUIPMENT 
 
 Tools Used in Building.— The contrast runs into the 
 tools used, the methods employed, and even to the 
 type of building best adapted. The building system 
 employs what are commonly called the standard tools 
 — the lathe, planer, shaper, slotting machine, boring 
 mill, drilling machine, and so on. The workmen de- 
 termine the dimensions of the work and the adjust- 
 ment of the cutting tools for each piece by direct 
 measurement, and check the work with standard 
 measuring tools and calipers — operations which call 
 for a skilled mechanic. The building used for this 
 large work usually contains a large open bay (see A, 
 Figure 1) with complete crane service, providing room 
 for heavy machine tools, work in progress, erecting 
 floor, etc. On each side of this bay will be one or 
 more floors (B and C) equipped with smaller tools, 
 producing the minor pieces which move out to the 
 
 FIG. 1. TYPE OP BUILDING ADAPTED TO LARGE AND 
 
 SPECIAL WORK 
 
 BUILDING AND MANUFACTURING § 
 
 center as the work is completed. The middle bay 
 may have standard railway tracks and connections, so 
 that the rough castings may be brought in from the 
 foundry or elsewhere and the finished product loaded 
 on cars under cover with the use of the crane equip- 
 ment. 
 
 The type of tools and the building system in general 
 were developed in England a little over a century 
 ago by early English mechanics, such as Maudslay, 
 Roberts, Nasmyth and Whitworth. In later years 
 large special tools, such as armor-plate planers, 
 special drilling machinery, and the forging machinery 
 used in American bridge work, will be found in build- 
 ing plants, but they are special only in so far as they 
 are adapted to a certain type of work. They call for 
 skilled attendants, however, and the size of the work 
 is determined by direct measurement. Most of the 
 standard tools used in building were developed be- 
 fore 1850; since that time they have increased in size, 
 power, and precision, but the essential features of 
 their design remain much the same. 
 
 Tools Used in Manufacturing.— When one turns to 
 manufacturing, an entirely different range of tools is 
 encountered, and different methods prevail. Here the 
 characteristic machines are turret-lathes of the hand- 
 operated, automatic, and single- and multi-spindle 
 types, and the milling machine. With them will be 
 found the stamping press, doing all kinds of work 
 ranging from the roughest to the extremely accurate, 
 m the case of sub-press dies; the precision grinder, 
 the drop hammer, and the broaching machine. On 
 nearly all of these machines the work is done with the 
 
I 
 
 6 THE MECHANICAL EQUIPMENT 
 
 use of jigs, fixtures, and special cutters, which has a 
 profound effect upon the whole working force of the 
 plant. The functions performed by the general me- 
 chanic operating the standard tool have been segre- 
 gated into those of the skilled tool-maker in the tool 
 room and the handy man or operative running the 
 machine. As manufactured products are usually 
 comparatively light, the large crane bay is not needed 
 and the building may be of the usual multi-floored 
 mill type (see Figure 2). As the work is put through 
 in large quantities, it is moved on trucks or specially 
 adapted racks. Much ingenuity has been given to 
 the subject of these trucks and they will be taken up 
 in another volume.* 
 
 The Interchangeable System. — In its application to 
 the metal trades, manufacturing usually implies the 
 use of the interchangeable system of production. The 
 essential elements of the interchangeable system are, 
 first, the use of limit gauges, which are based on the 
 application of the old principle that ** things equal to 
 the same thing are equal to each other." Each part 
 manufactured must fit definite gauges, each of which 
 contains two limits for measuring the operation to be 
 gauged. If it comes within these limits, the piece is 
 known to be usable; if it falls without, it is not usable 
 and is rejected. By this means the individual judg- 
 ment of the workman as to the fitting of parts is 
 almost eliminated. The second element, so closely 
 allied to the first as to be almost inseparable, is the 
 use of jigs, fixtures, and special forms of cutters. By 
 
 BUILDING AND MANUFACTURING 
 
 I 
 
 "m/z/mmm/zm/m)^^ 
 
 *See "Handling Material in Factories," by William F. Hunt, 
 Factory Management Course. 
 
 FIG. 2. TYPE OF BUILDING USED IN MANUFACTURING WORK 
 
 these the workman is also largely relieved of judg- 
 ment in setting the work in the machine and in set- 
 ting the tool in relation to the work. 
 
 The interchangeable system was developed by Eli 
 Whitney a few years after the invention of the cotton 
 gin. Few people realize that Whitney, in addition to 
 making possible the modern cotton industry, de- 
 veloped commercially the interchangeable system of 
 manufacture with its profound and far-reaching 
 effects. It was applied by him to the manufacture of 
 muskets for the United States Government about 
 
^ 
 
 I 
 
 8 
 
 THE MECHANICAL EQUIPMENT 
 
 
 1800 Simeon North, of Middletown, Conn., at almost 
 the ame time applied it to the manufacture of 
 pistols; and in the shops of these two men it was 
 demonstrated that work could be produced commer- 
 cially upon this basis. From the gun makers, the 
 sys em spread to the clock makers, and later, in turn! 
 to the manufacture of sewing machines, typewriters 
 bicycles, automobiles, and the many high-grade ma 
 chine-shop products which have been developed i 
 the last two or three generations. 
 
 Many great advantages are offered by the inter 
 changeable system. The product is much cheape; 
 
 Iln^"^'" /•"" ^^^^^ quantities, is more carefully 
 st.id.ed out, IS usually better made and more uniform 
 Goods may be carried in stock, and immediate dt 
 hveries are possible. Many a sale can be maleof a 
 standard article to be delivered at once from stock 
 tZ\ "^^'T^ "'^^ ""-"^'^ "«"ld require atng 
 liLTin the H r.^r^'r .'"-^ ^'l"^"^ ^'^' «dvantagf 
 
 ZZl^ K i*^ *" '*'*^^° '■^P^''- ?«"•*«; f°r these afe 
 obtamable both promptly and at a low cost from the 
 
 repair stocks carried for this purpose. This advan! 
 tage IS very marked in the case of automobiles and 
 other articles subject to breakage and wear A 
 standard machine of proven design for which repa^ 
 par s may be obtained at conveniently located dt 
 tnbuting centers is much more valuable to a pur- 
 
 Certain limitations more or less offset the above 
 grea advantages, and, hence, the disadvantaels 
 should also be thoroughly understood. Ae Tnve? 
 
 -X 
 
 I 
 
 i 
 
 JBUILDING AND MANUFACTURING 9 
 
 ment in tools, gauges, etc., may be enormous, and be- 
 comes prohibitive when distributed over a small out- 
 put. There is always the balance between the direct 
 savings in manufacture over the building system on 
 the one hand, and the interest charges, maintenance, 
 etc., of the tools required by the interchangeable 
 manufacturing system on the other hand. While the 
 labor costs are relatively high in the building system, 
 they may be curtailed in slack time by the discharge 
 of workmen. Under the manufacturing system, how- 
 ever, the interest charges on the expensive equip- 
 ment go on whether the production is large or small. 
 The total costs, therefore, are much less flexible. It 
 follows that the markets for a manufacturing opera- 
 tion must be more stable than is necessary in a build- 
 ing operation. The great investment in special tools, 
 etc., based on a standard output tends to discourage 
 minor improvements; and these special tools must 
 show a large margin of saving to pay for discarding 
 the old equipment and the building of the new. 
 Standards once adopted may become so inflexible as 
 almost to defy change. 
 
 Another danger in the interchangeable system lies 
 in the possible obsolescence or supersedence of the 
 product. The bicycle industry is a good example of 
 chis. At its height, this industry represented the 
 most refined application of the interchangeable prin- 
 ciple, and millions of dollars were invested in tools 
 and equipment which, in a very few years, became 
 almost valueless with the collapse of the industry. 
 
 It is evident from the elaborate preparations neces- 
 sary that a long time is required to get started; and 
 
10 
 
 THE MECHANICAJj EQUIPMENT 
 
 BUILDING AND MANUFACTURING 
 
 11 
 
 if the preliminary work is slighted or neglected, dis- 
 aster is almost certain. It requires the careful work 
 of trained experts— new and untrained men cannot be 
 trusted to do it. The failure of so many American 
 manufacturers who ** jumped into'' the ammunition 
 business at the outbreak of the European War, is a 
 glaring example. Many firms, which had been build- 
 ing other things successfully, took contracts calling 
 for quick deliveries and were utterly unable to fulfill 
 their guarantees either as to quantities, time prom- 
 ised, or quality of work. Even the older firms, 
 thoroughly familiar with this type of manufacture, 
 fell down when compelled to expand their business 
 many fold in a short time. In one of the large com- 
 panies the inability to build new tools and properly 
 to maintain both the old and the new tools, caused an 
 actual decrease in output from that which obtained 
 before the sudden strain was put upon them, despite 
 an enormous expansion of their plant. 
 
 The advantages of the interchangeable system can 
 be fully realized only when there is a large, stable 
 and homogeneous market, educated to the use of the 
 standardized product. Without doubt, this is one of 
 the reasons why America has led the world in the 
 development of the system. While the United States 
 has a vast number of clever mechanics capable of 
 working to the standards required, it must be borne 
 in mind that it also offers the greatest market in the 
 world with the greatest purchasing power. American 
 manufacturers, operating upon the principle of inter- 
 changeable manufacture, have been notably slow in 
 capturing the foreign market. Articles in demand in 
 
 i 
 
 foreign countries have not been standardized, and the 
 American manufacturers prefer to manufacture for 
 the large and rich home market rather than build for 
 the diverse and scattered foreign market. It is not 
 so much that they have been neglectful of foreign 
 opportunity as that they have preferred to manufac- 
 ture for their own market at greater profit. 
 
 Combination Methods.— Building methods will 
 always have their place and are the only ones pos- 
 sible for large and unstandardized work which must 
 be made to suit individual conditions. Great 
 progress has been made, however, particularly in 
 America, in the partial standardization of such work 
 by standardizing the units employed and obtaining 
 some diversity by the manner of assembling them. 
 Nothing could be more diversified, for instance, than 
 the systems of shafting and power transmission in 
 various plants. The units which are employed have 
 been standardized, and we have standard hangers, 
 pulleys, shafting, etc., which are combined in dif- 
 ferent ways as local conditions require. Another 
 example of this is the machinery for handling ma- 
 terials: the various elements in conveying machin- 
 ery have been reduced to standards, are manufac- 
 tured in lots, and carried in stock; widely diverse 
 installations are made from these units by assembling 
 them in framing suited to meet the conditions. This 
 principle is carried into the design of large ma- 
 chinery, and many factories have standard details of 
 design, such as standard size hubs for shafts, stand- 
 ard arms, and standard dimensions for various parts. 
 This enables them to utilize the patterns, special tools! 
 
t 
 
 12 
 
 THE MECHANICAL EQUIPMENT 
 
 and advantages of manufacturing in what is other- 
 wise a varied line of output. An example of stand- 
 ards in dimensions is found in the distance between 
 the centers of duplex pumps. The large manufac- 
 turers have adopted certain distances between centers, 
 each covering a definite range of sizes, which enables 
 them to machine the pumps on standard double- 
 spindle lathes which finish both cvlinders at once. 
 This principle is of great importance and should be 
 borne in mind in all plants where the output is such 
 that it can be applied. 
 
 From the foregoing considerations it is seen that 
 the two methods of production should be carefully 
 considered in the design of all plant equipment and in 
 the determination of the most desirable methods of 
 production. 
 
 1. 
 
 2. 
 
 CHAPTER II 
 THE DRAFTING DEPARTMENT 
 
 Functions.— The functions, policies, and practice of 
 the drafting department present too large a subject to 
 be considered in detail here. Some only of the prin- 
 ciples involved will be pointed out, and references 
 cited so that special features may be studied else- 
 where. A schedule of the functions is as follows: 
 
 Developing the design of new product which in- 
 volves the making and authorizing of any 
 alterations or improvements in the product. 
 
 Designing plant equipment, special tools, fixtures, 
 and gauges, etc. 
 
 Establishing standards for— 
 Product, and elementary details of the product, 
 such as hubs, key- ways, gears, etc.; 
 
 b. Machines and tools used in production; 
 
 c. Supplies, such as screws, fittings, etc. 
 
 4. Furnishing complete instructions covering the 
 above, which involves — 
 Designs, 
 
 Detail drawings, 
 Tracings, 
 
 Drawing lists and bills of material, 
 Data-sheets, 
 
 13 
 
 3. 
 
 a. 
 
 a. 
 b. 
 c. 
 d. 
 e. 
 
Y 
 
 14 
 
 THE MECHANICAL EQUIPMENT 
 
 DRAFTING DEPARTMENT 
 
 15 
 
 f. Cheeking all of the above items (a) to (e), 
 
 g. Making blueprints. 
 
 5. Maintaining a record of work done. 
 
 6. Sometimes estimating on new work. 
 
 Functions 1 and 6 involve as supplementary work, 
 issuing, indexing, and filing the blueprints, sketches, 
 data-sheets, estimates, etc., and recording changes in 
 design, pattern numbers, issues and recalls of blue- 
 prints, etc. 
 
 Design of Product.— The development of designs 
 for experimental machines and studies of possible im- 
 provements should be done under the supervision of 
 the chief engineer or the chief draftsman with the as- 
 sistance, in the case of very large concerns, of special 
 designers expert in a particular field. Designers 
 should also co-operate with the shop in the testing of 
 these machines-, and make such changes as may be 
 shown desirable in the development of the work. 
 
 Design of Plant Equipment.— In many companies 
 much of the work covered by the second function, 
 instead of being performed in the main drafting 
 office, is done in independent drafting rooms scat- 
 tered through the plant. Many reasons exist why 
 this work should be under the same general control 
 as the design of product. Drawings and designs of 
 some sort, are involved which can be made most effi- 
 ciently in the drafting department, although this 
 work can be separated and placed into the hands of 
 tool specialists who may or may not be in the general 
 drafting room. It is desirable, however, that their 
 work should **head up'' to the official in charge of 
 
 the designing department. If this is done, the de- 
 signs of product are much more likely to be developed 
 with proper reference to the patterns and tools avail- 
 able. Slight changes in design which will enable the 
 utilization of existing tools are more apt to be made 
 and the operations of manufacture to be borne in mind. 
 In interchangeable products no new design should be 
 considered complete until the entire scheme of manu- 
 facturing operations and of gauging each piece has 
 been determined to the last detail. 
 
 Of necessity this work must be done in conjunction 
 with the principal shop executives. To secure the 
 all-round point of view necessary, a ^ design commit- 
 tee has been found useful in some plants, which may 
 consist of the sales manager, chief draftsman, super- 
 mtendent, tool designer, and the leading men con- 
 cerned in the manufacture of the proposed work, such 
 as the foremen of the pattern shop, foundry, and 
 machine shop. Any proposed preliminary design is 
 gone over by this committee from the points of view 
 ot saleabihty, operation, construction, cost of manu- 
 facture and so forth. This results in forestalling 
 many of the difficulties experienced with new work 
 Desirable changes of design for the purpose of cost 
 reduction are brought out, and the product designers 
 have the advantage of the intimate experience of the 
 duTtirn * ""^^ ^'''^'^'''^ ^"""^ operating the tools of pro- 
 Standards Drawings and Lists.-The establish- 
 rm^i well-considered standards covering the de- 
 
 Beve;^!^ "l??^'.l^^.J-z;^^^^^^^^^ PP' ^^^5; John H. Van 
 
f 
 
 16 
 
 THE MECHANICAL EQUIPMENT 
 
 DRAFTING DEPARTMENT 
 
 17 
 
 tails of design of the product, tools, and supplies is 
 of incalculable value in lowering shop costs and in- 
 vestment in shop equipment. 
 
 The fourth function explains itself in the main. 
 Drawings for complicated work should be accom- 
 panied by drawing lists locating the details on the 
 various sheets. Such lists are of great help to the 
 assembling department, stores department, produc- 
 tion, cost, and purchasing departments. Formerly 
 the compiling of bills of material was not considered 
 a part of the work of the drafting room, but this 
 must be done somewhere in the plant sooner or later, 
 and it can be done much more efficiently and ac- 
 curately by the draftsmen who are making the draw- 
 ings. 
 
 Record of Work Done.— The fifth function— main- 
 taining a record of the work done — is of especial im- 
 portance in connection with repair wdrk in a firm 
 ** building" machinery. Prior to 1880, drawings were 
 considered only as instructions for the production of 
 the work. They were made on paper, usually in 
 pencil, and sent out into the shop. Their rough usage 
 soon made them almost illegible and anyone who has 
 had anything to do with repair work in an old firm 
 knows how nearly useless these old drawings are as 
 a record of what was originally sent out. 
 
 With the advent of tracing cloth and the art of 
 blueprinting, it was no longer necessary to send the 
 original drawings into the shop; and the drawings 
 became much fuller in their information, were more 
 carefully studied out, and became complete enough to 
 furnish a record of the work done. This entails 
 
 several things: the first and most obvious is that the 
 work and the drawings should conform, but only 
 constant watchfulness will accomplish this, for there 
 is always a tendency to maKe minor changes in the 
 shop without having them properly recorded on the 
 drawings. It is important that the work should fol- 
 low the drawing exactly or, if minor changes are 
 necessary, that they should be noted on the drawing 
 so that the records will be correct. 
 
 Estimating.— The sixth function— estimating— de- 
 pends largely upon the nature of the business. 
 Where the prices to be quoted, as in the case of large 
 work, are dependent upon the designs submitted, it is 
 evident that the drawing room is involved. The de- 
 gree to which it is involved and the manner of hand- 
 ling the work varies widely and cannot be outlined 
 here. In some cases a committee, similar to the 
 design committee already referred to, can be of great 
 help in this work. 
 
 Supplementary Punctions.- As indicated in the 
 schedule, the work of the drawing room includes the 
 issuing, indexing, and filing of blueprints, sketches, 
 data-sheets, estimates, and other lesser items. The 
 issuing must be done in an orderly manner to avoid 
 leakage of information, and an accurate record must 
 be kept to enable the recall of outstanding prints 
 Blueprints floating around the shop unknown to the 
 drawing room, which are not recalled for alterations, 
 are a fruitful source of trouble. 
 
 In order to provide ready access to the drawings 
 and needed information, the drafting department 
 Should maintain indexes for all of the following- 
 
 AV 
 
! J 
 
 18 
 
 THE MECHANICAL EQUIPMENT 
 
 DRAFTING DEPARTMENT 
 
 19 
 
 Drawings, sketches, data-sheets, estimates, orders, is- 
 sues of prints, etc., alterations, and sometimes, but 
 not usually, tools and patterns. This work will be 
 taken up more in detail later. Proper facilities should 
 be provided for the filing of all drawings and records 
 where they will be protected from loss or fire and will 
 be readily accessible. The functions of issuing, index- 
 ing, filing, and recording are closely related, and much 
 of the efficiency of a drawing room depends upon the 
 business-like way in which it is carried on. 
 
 Personnel. — In a large drawing department there 
 will be a chief engineer, a chief draftsman, and assist- 
 ants, estimators, designers, detailers, checkers, tracers, 
 blueprinters, and clerks who care for drawings, blue- 
 prints, orders and estimates. In small drawing rooms, 
 two or more of these positions may be combined. 
 
 The head of the drafting room should be relieved as 
 much as possible of routine work. He should have 
 time to confer with the sales department, to plan 
 new work, to supervise the activities of the drawing 
 room, and he should also be free to spend consider- 
 able time out in the plant following work in progress. 
 To tie him down too closely to executive routine is a 
 serious mistake. He should be a man of high order 
 and adequate technical training, and have an inti- 
 mate knowledge of the machinery used in the plant 
 as well as of foundry and machine shop methods. 
 His assistants mav be executives who relieve him of 
 most of the detail, or specialists in certain fields in 
 charge of various phases of the work, such as product, 
 tools, etc., with designers working under their im- 
 mediate supervision. 
 
 Draftsmen and detailers are always a problem in 
 the drawing room. It is difficult to keep ambitious 
 young men permanently at this work. College-trained 
 men learn rapidly, but are apt to be deficient in prac- 
 tical information; and if they are good they soon want 
 to move on to other work. In general, shop-trained 
 men, who have partially educated themselves through 
 night work, etc., are more stable and often more satis- 
 factory. Some plants employ women for tracing and 
 detailing. They are admirably adapted for this work 
 as they are careful and accurate and willing to stay * 
 at it. The typical blueprint boy is about in the class 
 of the printer's devil, and a good one is a treasure. 
 Here, too, there is difficulty in keeping a good boy on 
 the job. In some cases this has been settled by util- 
 izing a man past middle life who is glad to do the 
 work and will not be a rover. The problem of the 
 clerical force in the drawing room differs little from 
 the same problem elsewhere. 
 
 Policies.— First and foremost, there should be an 
 open-minded attitude toward ideas from any source, 
 whether from shop and foundry foremen, from drafts- 
 men, from the sales organization, or from competitors. 
 A good chief will be quick to recognize and utilize 
 ideas from any of these sources and will be generous 
 in acknowledging the credit where it is due. A jeal- 
 ous or small-minded man will often close himself from 
 every one of these sources of information and in so 
 domg will limit his own capacity and earning power; 
 m keeping them open and in acknowledging credit 
 where it is due, he will invariably strengthen his own 
 usefulness. 
 
// 
 
 I 
 
 20 
 
 THE MECHANICAL EQUIPMENT 
 
 DRAFTING DEPARTMENT 
 
 Patience and tact are closely allied with this. Fric- 
 tion is almost always latent, at least, between the shop 
 and the drawing room. Human nature is such that 
 the first recourse of the shop is to lay bad work at 
 the door of the drawing room. Unless carefully 
 guarded against this is almost certain to bring about 
 poor team play which will eventually run into steady 
 losses for the company. For example, one chief 
 draftsman whom I knew was a good designer and a 
 good executive so far as his own department was con- 
 cerned, but in his relations with the shop men he be- 
 came so overbearing that they would go out of their 
 way to put him in a hole. When a drafting-room mis- 
 take was discovered in the shop, they would say noth- 
 ing and machine the work exactly as drawn, in order to 
 allow it to run into as much money as possible, know- 
 ing that the expense would be charged against an ac- 
 count covering bad work due to mistakes in design. 
 A new chief draftsman, however, who was a man of 
 tact and familiar with this situation remedied it com- 
 pletely. He was friendly with the shop men and his 
 first act was to go to the various foremen and remind 
 them that, while it was an interesting game, the firm 
 was footing the bills. He agreed that when he found 
 mistakes on the shop he would first take up the mat- 
 ter directly with the foremen, and they, in turn, 
 agreed to report any errors in the drawings to him at 
 once. This new man was less experienced than the 
 first and no better designer, and yet the amount of 
 bad work due to mistakes in the drawing room fell 
 to almost nothing. The foreman, who usually caught 
 these mistakes just as the work was starting, would 
 
 21 
 
 tuck the blueprint under his arm, trudge up to the 
 drawing room and the trouble would be made right 
 with a few changes on the drawing at the expense of 
 some ''jollying'' from the foreman and a cigar from 
 the chief draftsman's desk. Probably just as many, 
 or more, mistakes were made under the new regime 
 as under the old, but they were caught early and not 
 allowed to run into money. 
 
 I have already stated that the processes of manu- 
 facture and the keeping down of pattern and tool ex- 
 pense should always be borne in mind. They should 
 be impressed on every man in the drafting room. The 
 draftsmen should be encouraged to spend their noon 
 hours and such other time as may be available in 
 following their work through the shop, not only for 
 the educative effect upon themselves, but also because 
 they will be able sometimes to catch things which are 
 going wrong on work with which they are familiar. 
 
 Another important policy in drawing-room practice 
 should be the determination of and adherence to 
 standards. There seems to be some inherent quality 
 in human nature which tempts men to depart from 
 standards on the slightest excuse, especially in small 
 details, and unless watched continually the number of 
 hand-wheels, gears, and other units creeps up— and 
 with it shop expense. 
 
 There should be a systematic use of experience to 
 preclude unnecessary repetition of work. Hardly a 
 machine or class of machines exists in which certain 
 units do not recur again and again. Unless prevented, 
 these units are re-designed continually, according to 
 the whim or inspiration of the moment; and the re- 
 
22 
 
 THE MECHANICAL EQUIPMENT 
 
 suit is a variety of patterns, castings, and tools which 
 could be greatly reduced by forethought and stand- 
 ardization. The advantages of studying these units 
 as a class are that interchangeability is increased; in- 
 vestment in patterns, castings, and tools is minimized; 
 assembling work is facilitated, and quicker deliveries 
 are made possible.* This work may take the form of 
 data-sheets covering standard details of design, stand- 
 ard tools, and methods of manufacture which will be 
 available for the entire drafting room and for subse- 
 quent work. 
 
 The work of the department should be planned out 
 and scheduled ahead as far as possible. Bulletin 
 boards, similar to those in a modern planning depart- 
 ment, covering work in hand, work ready to take up, 
 and work ahead, are perfectly applicable to the draft- 
 ing room. In fact, they can be applied there with as 
 great advantage and with very much less trouble than 
 in any other part of the plant. 
 
 All calculations and sketches should be kept. Many 
 drafting rooms do not allow the use of pads or loose 
 pieces of paper but issue numbered books to the 
 draftsmen in which they do all such work. These 
 books are useful in checking mistakes in design, and 
 are the best kind of evidence in patent litigation. 
 
 As soon as a drafting room reaches any size, the 
 principle of the division of labor should*^ be intro- 
 duced, and the work of detailing and tracing separ- 
 ated from that of designing. This keeps the highly 
 paid men on the skilled work. Only the highest 
 
 ♦See "Machine Shop IManagement," pp. 20-27; John H. Van De- 
 venter. McGraw-Hill Book Co. 
 
 DRAFTING DEPARTMENT 
 
 23 
 
 standard of what constitutes a working drawing 
 should be tolerated. It should give complete instruc- 
 tions from the designer to the workman — there is no 
 middle ground. It should be positive, thoroughly 
 definite, clear, and self-sufficient. 
 
 Practice. — The practice of the drawing room as to 
 sizes of drawings, style of dimensioning, sectioning, 
 etc., should be standardized and, in the form of data- 
 sheets, put into the hands of every draftsman and 
 tracer when he enters the drawing room, and strict 
 adherence to the standards should be required. Var- 
 ious codes of practice have been published, one of 
 which has been prepared by the American Society of 
 Mechanical Engineers.* 
 
 There is an increasing tendency in making detail 
 drawings to show only one piece on each sheet. This 
 is highly commendable, for it facilitates work in the 
 order and production departments and also in the 
 shop. It can be carried too far, however, but should 
 be considered and the principle adopted as far as feas- 
 ible. Many drawing rooms specify the limits of ac- 
 curacy, style of finish, allowance for finish on pat- 
 terns, and so on. This, too, can be carried to ex- 
 tremes, but the practice is sound and should be given 
 careful attention. 
 
 For convenience in filing, a standard location and 
 style of title should be insisted upon; and the infor- 
 mation contained in the title should conform in size 
 and em phasis to its relative importance. If the filing 
 
 ♦"Machinery's Reference Series," Numbers 2 and 33, give a very 
 rnnm^^.rl-^"^^?^^'?"^ ^"^ ''"'^•^ Covering many points in drawing 
 S^ akn VnnV'' l"""^ to include here but well worth consulting 
 fcee also \an Deventer; "Machine Shop Management." Section II 
 
24 
 
 THE MECHANICAL EQUIPMENT 
 
 system is based on numbers, the number should be 
 most conspicuous. A title should contain the follow- 
 ing information: 
 
 Name of Company. 
 Name of machine. 
 Name of parts shown. 
 Number of drawing. 
 
 Number of order First used for 
 
 Scale. 
 
 Designed by Date 
 
 Traced by ** 
 
 Checked by '* 
 
 Approved by ** 
 
 Tools Available.— Lists of tools available for work, 
 with such dimensions as concern the drafting room, 
 (such as ranges of sizes, etc.) and lists of standard 
 screws, bolts, and other supplies, may be included in 
 the data-sheets already referred to and are a great 
 help in standardizing the shop practice. 
 
 Checking. — It is often desirable that all designs 
 should be checked twice; once before the drawing is 
 traced to discover any mistakes in design, and again 
 after the tracing is finished to make sure that dimen- 
 sions and other details are correctly copied. Many 
 firms, however, check their work only once — after the 
 tracing has been completed. In either case it should 
 be done in a systematic way and the drawing exam- 
 ined for: 
 
 1. General design, strength, material, method of manu- 
 
 facture. 
 
 2. Dimensions; — their accuracy, sufficiency and arrange- 
 
 ment 
 
 DRAFTING DEPARTMENT 25 
 
 3. Finish and finish marks. 
 
 4. Patterns and pattern numbers. 
 
 5. Molding and foundry work. 
 
 6. Comparison with bill of materials. 
 
 7. Comparison with list of stock parts, tools, etc. 
 
 8. Notes. 
 
 Blueprints. — Blueprints should be issued only with 
 the shop orders or upon signed requisitions from the 
 proper persons, and record should be made of each 
 issuance, giving date and to whom issued. This rec- 
 ord is necessary for the recall of prints in making 
 alterations. Prints that are standard and subjected 
 to considerable use should be mounted on heavy card- 
 board, or other material, and varnished or made 
 waterproof. In some cases it is desirable to bind sets 
 of prints together into books for use in assembling 
 and erecting. 
 
 Filing.— Generally, drawings and tracings are filed 
 in flat drawers which preferably are made of sheet 
 metal and located in a fireproof vault opening into 
 the drawing room. Rolling the tracings and draw- 
 ings cannot be too greatly condemned, for it is diffi- 
 cult to find the right roll and they are troublesome 
 to use when unrolled. If possible only one size of 
 drawing should be filed in one drawer. When large 
 and small drawings are filed together indiscrimi- 
 nately, the small ones are difficult to find as they are 
 apt to get into the back of the drawer and sometimes 
 get lost behind it. A guard across the top at the 
 back of the drawer is a help in lessening this last 
 trouble. 
 
 IV 
 
26 
 
 THE MECHANICAL EQUIPMENT 
 
 DEAFTING DEPARTMENT 
 
 27 
 
 If 
 
 Changes and Alterations.— No deviation from the 
 drawings should be allowed without formal authoriza- 
 tion from the drawing room. This is absolutely es- 
 sential for the maintenance of an accurate record of 
 work done. If any changes or improvements are 
 made, the drawing room should recall outstanding 
 prints and substitute new or corrected ones. Eecord 
 should be made, either upon the drawing itself or 
 elsewhere, of the serial numbers of the machines for 
 which the drawing was used, the date when it ceased 
 to be standard, the drawing by which it was super- 
 seded, and the first machine on which the new draw- 
 ing was used. This record is invaluable in caring 
 for repairs.* 
 
 In making changes and alterations, it is well to fol- 
 low a definite procedure to make sure of covering the 
 various items which require attention. The follow- 
 ing list covers most of them: 
 
 1. General assembly tracings. 
 
 2. Detail tracings. 
 
 3. Drawing lists. 
 
 4. All blueprints outstanding should be recalled and re- 
 
 placed with correct ones. 
 
 5. Patterns involved. 
 
 6. Special tools involved. 
 
 7. Disposition of stock on hand, if any. 
 
 8. Necessary records of the change. 
 
 Equipment.— The general practice in the past has 
 been to use drawing tables large enough for a loose 
 
 ♦For procedure in changes in alterations, see Van Deventer, 
 "Machine Shop Management," pp. 35-37; also "Machinery Reference 
 Series," Nos. 2 and 33. 
 
 drawing board, with room at the side for reference 
 drawings and other papers. In many places the verti- 
 cal board is preferred and for large drawings it is 
 unquestionably more convenient, but when it is used 
 tables should be provided for holding any reference 
 drawings. In either case parallel rulers will be found 
 preferable to T-squares; in large work their use is 
 almost universal. The **Universar' drafting ma- 
 chine," combining a parallel motion, protractor, and 
 scales, is a convenient and time-saving device, well 
 adapted to many forms of drafting work. 
 
 Few modern drafting rooms rely upon sun print- 
 ing for making their blueprints. A number of 
 electric machines are on the market which make 
 prints rapidly, day or night, rain or shine. Many of 
 them^ combine washing and even drying with the 
 printing process, and their convenience and avail- 
 ability at all times make them preferable in every 
 way to the old sun-printing frames wherever there is 
 any large amount of blueprinting to be done. Such a 
 machine is shown in Figure 3. 
 
 Two new machines are now available, the * 'Photo- 
 stat ''and the '^Eectigraph," which will photograph 
 any kmd of record— a drawing, order, printed page- 
 in a few moments' time and at moderate cost. 
 While the machines are expensive, they can be used 
 in a great many ways for saving time and in avoid- 
 ing errors in copying. Their possibilities and avail- 
 ability should be considered in every large drafting 
 room. ^ 
 
 Location of the Drafting Room.— Generally speak- 
 ing, the drafting room should be convenient to the 
 

 DRAFTING DEPARTMENT 29 
 
 office, pattern shop, tool room, and, if possible, cen- 
 trally located with respect to the shop. It should be 
 roomy, well ventilated, and have white or light-toned 
 wal s. The best possible lighting is the cheapest-a 
 north hght for the daytime, and an artificial light 
 I so arranged as to avoid eye strain and eliminate 
 .shadows for evening work. The work calls for close 
 use of the eyes, and few realize the lowering of eT 
 ciency m a drafting room where the light is ooor 
 The expenditure represented by the difference be 
 t^^^^ lighting and the best obtainaMet 
 
 L,.;^^"-^" = "*'"''"'■•'' f-'shtlng." Chap. VI. on Drafting Room 
 
 KG. 3. CONTINUOUS ELECTRIC BLUE PRINTING MACHINE 
 
 C. F. Pease Company. 
 
 28 
 
/ 
 
 DKAFTING DEPARTMENT 2!» 
 
 office, pattern shop, tool room, and, if possible, cen- 
 trally locate,] with respect to the shop. It should he 
 n.on,y, well ve„tilate<l, an,l have white or li«ht-toned 
 «=.l s. Ihe .est possible lighting- is the cheapest-a 
 north light for the <layti,ne, an<l an artificial li.-ht 
 so arranged as to avoid eye strain an,l eliminate 
 shadows tor evening work. The work calls for close 
 »:-■ "I <li<' eyes, a.,,1 few realize th,. lowring of efti- 
 ;•;<•->• in a drariing room when- the light T. poor 
 llH. expen.l,(,ne represented by ,he difference be-' 
 
 "cen (he poorest lighting and the best obtainable s 
 ''^oon [)ai(l lor." ^luauii ks 
 
 *n..\v('ll: -Fju-tory M-htIn-" CJiMn vt . r. 
 
 ftin^' n«K»ni 
 
 FIG. 3. CONTINUOT^S P:T.ECTRIC BLri: I'RINTIMJ MACHINE 
 
 ('. F. Tease Company. 
 
 28 
 
11 
 
 I 
 
 
 CHAPTER III 
 THE PATTEEN SHOP 
 
 Function and Location. — The functions of the pat- 
 tern shop are to make, maintain, and store patterns 
 and core boxes, and to keep the pattern records. As 
 patterns are usually of wood, this involves a wood- 
 working shop with the necessary benches and ma- 
 chinery. Metal patterns may be used in manufac- 
 turing plants where there is repetition work and 
 machine molding; and this would involve, in addi- 
 tion, metal working equipment adapted to the manu- 
 facture of iron patterns, stripping plates, and such 
 articles. The pattern shop is in frequent com- 
 munication with the foundry and with the drafting 
 room. It should be located, therefore, conveniently 
 with respect to these two departments, preferably 
 between the two. 
 
 Balance of Pattern Makers* and Molders' Time. 
 — The cost of a pattern is distributed over all the 
 castings made from it, and when great numbers of 
 castings are made, may become almost negligible; but 
 the molder's time enters into the cost of every mold 
 and increases directly with the number of molds 
 made. If but one casting is wanted, it pays to make 
 the cheapest pattern possible and let the molder 
 spend more time on his work. Where the pattern is 
 to be used for many castings, it will pay to spend 
 much more time upon it, if thereby the molding cost 
 
 30 
 
 PATTERN SHOP 31 
 
 can be cut down, for this saving will appear in every 
 casting made. For illustration, let us assume the 
 pattern maker's *and molder's time each at $4 per 
 day, and compare the total cost in making one cast- 
 ing as against ten castings. 
 
 One casting Ten castings 
 
 Pattern maker's time, 1 day $4.00 $4.00 
 
 Molder's time, 1/2 day to each casting. 2.00 20.00 
 
 Total combined cost $6.00 $24.00 
 
 Combined cost per casting 6.00 2.40 
 
 Suppose now the pattern maker to spend three days 
 making a better type of pattern which will enable the 
 molder to make molds at the rate of ten per day. 
 We then have: 
 
 T^ ,, , , . One casting Ten castings 
 
 Pattern maker's time, 3 days $12.00 $12.00 
 
 Molder's time, 1-10 day to each cast- 
 I'^S 40 4.00 
 
 Total combined cost .$12.40 $16.00 
 
 Combined cost per casting 12.40 1.60 
 
 A comparison of the first columns shows clearly 
 that for one casting it will pay to make a cheap pat- 
 tern and let the molder spend a half day on the 
 mold. For ten castings it will be cheaper to let the 
 pattern maker spend several days in making a better 
 pattern to gain the saving in the molder's time. If 
 similar calculations are made on the basis of two, 
 three, and four castings, it will be found that the 
 cheap pattern is still the more economical. At five 
 castings the combined cost per casting is the same, 
 i^eyond that number the advantage is increasingly in 
 tavor of the more expensive type of pattern. 
 

 ^^ 
 
 32 
 
 THE MECHANICAL EQUIPMENT 
 
 In the above example, both the wage rates and the 
 molder's and pattern maker's time have been assumed 
 arbitrarily, but the principle is the same in any case. 
 Each pattern is a separate problem. Sometimes the 
 simplest, at other times the most expensive, type will 
 be cheapest. From this principle it is obvious that 
 there should be constant and closest co-operation be- 
 tween foundry and pattern-shop foremen to determine 
 the kind of patterns to be made. 
 
 The pattern shop and the drawing room must also 
 work together to utilize existing patterns as far as 
 possible and to reduce the number of patterns by the 
 use of loose pieces for making right- and left-hand 
 castings, etc. 
 
 The facilities for storing patterns should be ade- 
 quate, accessible, fireproof, and capable of expansion. 
 All patterns should be indexed and records kept show- 
 ing their location, condition, etc. 
 
 Pattern making constitutes a highly skilled trade 
 and is too intricate to be dealt with in detail here. 
 Those who would desire even a general knowledge of 
 it are referred to some of the elementary books on 
 the subject. Here, as in the case of the drafting 
 room, we will take up only some of the general fea- 
 tures. 
 
 Types of Patterns. — The simplest form of pattern 
 is the one-piece pattern used only for small castings. 
 Its sole merit is that of being cheap. It throws a 
 great deal of work on the molder, but it is often 
 used for simple work where only one casting or but 
 a few castings are required. 
 
 Where castings are required in moderate number.'. 
 
 PATTERN SHOP 
 
 33 
 
 the pattern would be split, and the two portions dow- 
 eled together, one half forming the drag impression, 
 the other the cope.* This simplifies the work 
 of molding, and, hence, this type is most commonly 
 employed for medium sized work. The parting of the 
 mold generally coincides with the parting of the pat- 
 tern. After the mold is formed, the cope is lifted off 
 the drag, the two halves of the pattern removed and 
 put together again for use on the next mold. 
 
 When the principal surfaces of a casting are plane 
 surfaces or those of translation, a skeleton pattern is 
 used which gives only the outline of the casting. This 
 is set m the mold, and straight-edges or -strike 
 boards are slid along the skeleton to generate the * 
 mtermediate surfaces. This type is very useful for 
 large work, as the saving in the cost of pattern work 
 
 rpSff'^""" K""'^^^ "^^^ ^' ^PP^^^^ t^ surfaces of 
 revolution such as cylinders, wheels, gears, and so 
 
 bLpi.f ^ • ^^^'"^ ^^' ""^^^^^ ^^ the surface to 
 be generated is mounted at the desired radius upon 
 
 an arm swinging on a spindle and used to generate 
 
 IteTs :" "' ''! "^^'- '" "^^^^^ -^1^« f-"ea 
 
 n a s;i;Hl'''T'' ^f'*''^ '^ ^"^ t^^th i« -counted 
 on a spmdle and revolved at the proper pitch radius 
 
 ^om position to position. This principle i's embodle^^ 
 inf n^LY ^^^^^^^ ''""'''^ ^" th^ Mesta mold- 
 
 mli of IT^r "'' ™^^'^ ' ^^^^^^ -i"^ a seg- 
 ment of the pattern carrying the tooth is mounted 
 
 For definitions of drag and cope, see Chapter V. page 56. 
 
Ill 
 
 '< 
 
 34 
 
 THE MECHANICAL EQUIPMENT 
 
 on a cross rail, and the mold revolves under it from 
 position to position until all the teeth are molded. In 
 this way a very accurate mold may be made. In 
 sweeps, the strike board may also be made to ad- 
 vance uniformly along the axis as it is rotated. This 
 generates a spiral surface and is used for molding 
 the spiral grooves in rope sheaves and sometimes for 
 the working faces of screw propellers. 
 
 Gated Patterns. — ^Where small castings are made in 
 great quantity, it is best to make several impressions 
 in one mold. This involves the use of gated pat- 
 terns, — the patterns for a number of pieces being 
 mounted upon a single plate and molded simultane- 
 ously. The patterns are connected by a common gate 
 which leads the molten metal from a single pouring 
 opening to the various impressions. Gated patterns, 
 which are very generally used on molding machines, 
 may be made of wood, but they are more often made 
 of cast iron or brass. Two general types of gated ma- 
 chine patterns are used: in the first, the patterns 
 are permanently secured to the pattern plate; the 
 flask is placed over the pattern, filled with facing and 
 sand which is rammed, squeezed, or jarred, and the 
 mold is then lifted clear of the patterns. In the sec- 
 ond — the stripping-plate type — the patterns are 
 mounted on a separate plate. After the mold is made, 
 the patterns are withdrawn downward clear of the 
 mold through a ** stripping plate" which fits the pat- 
 terns closely at the parting line and supports the sand 
 during the act of withdrawal. This type requires 
 little or no draft, and the molding work is fast. 
 Where cope and drag impressions are necessary, it is 
 
 [ 
 
 r No Finish ^f^rfing L/ne 
 
 'inish 
 and-' 
 Draft: 
 
 Finish- 
 
 6ond .: 
 
 'Draft :'' 
 
 and Finish 
 
 ^'•Finish :\ 
 
 Profty'.'^'ff'^^pir-^^i^r ............ 
 
 but no finish;: "^Sec/ion of /rn/sheaf':':. 
 
 ■ ■•:■::'■■::.■■.'■/■■:■::.■■. /Vece ■.-.■' ^ :•'■!■ 
 
 SOLID PATTERN- SET IN THE DRAG 
 SHOWING VARIOUS ALLOWANCES 
 
 Co/?e '-{f-fnish and Draff. ::^'n'sh on/t/.- : rSand': y-'\ 
 
 ■■^^^■^>^-~^''Dii,ffS:^fiL^^^ 
 
 • • •;./■> 
 
 ■ Drdq^<:,z:-^-Dow^l. '.*. 
 '\HaJfyy.yr:}::Pin-: 
 
 SPLIT PATTERN 
 
 SECTION X-X 
 
 Parfinq line' =:';"-!'i •.••;•: '.••••:•• ••.•.•;.•..•.■ 
 
 of Mo/a::: .■:■>:■: ^^:^.•: : :--;;;-V;- •^;^! 
 
 i: . oano/'Cojfe' ::\ | • - . •:■•.■ 
 
 :■ ;. ■•;."t H; ■.'■ •; "■■ igg fe }. ■ v ^ f ^; ■:•}}. 
 
 .■.'•.••"■•. ijrrrf: -Core /?/-//>/;''; vTT^*;'.*;:" 
 ':• '..'•. ■.'.•.■'•■•■": '.: Sand'Draa- '•:'■ '•'■'.':'. '•: 
 
 rrri. 
 
 " 1 i ! I ^"^ggg fo be cast 
 
 WG. 4. TYPES OF PATTERNS 
 35 
 
36 
 
 THE MECHANICAL EQUIPMENT 
 
 desirable to arrange them on the same pattern plate 
 on opposite sides of a line of symmetry, a cope im- 
 pression on one half matching a drag impression on 
 the other half. If this is done, the cope and drag 
 of the mold will be the same. This saves making 
 two plates, one for cope and one for drag impres- 
 sions, and lessens the amount of work in both pat- 
 tern shop and molding floor. Figure 4 shows a sim- 
 ple gated pattern, not mounted on a plate. The prin- 
 ciple, however, is the same as that just described. 
 
 Patterns for large work, such as that done in loam 
 foundries, are built up of many pieces and are often 
 very complicated. Parts of the pattern— for in- 
 stance, large flat surfaces— may be left open and the 
 mold finished with a strike board; while flanges, 
 bosses, etc., may be made in full and carried on the 
 frame of the pattern. Arms and other projections 
 may be in loose pieces, and the mold may be made in 
 flasks having two or even more parting lines. 
 
 Pattern Material.— The prevailing material for pat- 
 terns is wood— air seasoned and perfectly dry. Pat- 
 terns of a permanent nature and of fair size should 
 be built up of several thicknesses, with the grain re- 
 versed to neutralize the tendency to warp. White 
 pine is most generally used as it is straight grained, is 
 free from knots, works easily, and takes varnish well. 
 For molding large quantities of small castings mahog- 
 any is used. It is much stronger and harder than 
 pine, works less easily, but it stands moisture as well 
 or better, and has little tendency to warp. Bay wood, 
 a species of mahogany, but lighter and softer, is 
 
 PATTERN SHOP 
 
 37 
 
 sometimes used, and, for special purposes, cherry, 
 black walnut, maple, and birch. 
 
 AUowances.— Certain allowances are made in pat- 
 terns that give them a shape slightly different from 
 the casting to be produced from them. Foundry 
 metals shrink in cooling, and if castings are desired 
 of a certain size, the patterns must be made larger 
 by an amount sufficient to allow for this shrinkage 
 The allowance for grey iron is about an eighth of an 
 inch to a foot; for malleable iron and brass, about 
 three-sixteenths inch to a foot, and for cast steel and 
 aluminum, which have a heavy shrinkage, as high as 
 one-fourth inch to a foot. For various reasons this 
 shrinkage is not always equal in all directions and 
 this discrepancy must be cared for by varying the 
 shrinkage allowance. 
 
 Another allowance which must be made in patterns 
 IS that for draft. It is practically impossible to lift 
 the pattern from the mold without breaking the cor- 
 ners if the sides of the pattern are at right angles 
 
 1 1 rT. f^ ^'^'' ^" ^^"^^ *^i«' *hey are made 
 on a shght taper which should be greater on an in- 
 
 FTgure'r ^^^"^ ^""^ ^" '''*'''^' ^'''' ^' '^^^^ i^ 
 
 chZirr *^' T^"' "^ ^^' '^'^""^ ^'' to be ma- 
 chined there must be additional metal added which 
 
 and sLT"^ V" ^^^^^"i"^ operations. On small 
 and simple castings this may be as little as 1-16 inch, 
 m large castings, % or i/^ inch must be allowed, 
 they arP l^.^ P^^^^^^^/f withdrawn from the mold 
 frn T ^^"^ ""^PP^^ by *be molder to free them 
 from the sand. This enlarges the mold slightly and 
 
38 
 
 THE MECHANICAL EQUIPMENT 
 
 PATTERN SHOP 
 
 39 
 
 
 is sometimes taken into account in the dimensions of 
 the pattern. Another advantage of the stripping- 
 plate type of pattern is that it does away with the 
 difficulties introduced by rapping as well as the ne- 
 cessity for draft, which was previously mentioned on 
 
 page 34. 
 
 Waxping and Splitting.— The principal cause of 
 warping in patterns is moisture in the wood. For 
 this reason the lumber used should be thoroughly 
 seasoned and the pattern may be built up as already 
 explained. The second cause of warping is moisture 
 in the mold. To provide against this, patterns are 
 heavily varnished and painted to keep the moisture 
 put. Splitting is usually caused by rapping the pat- 
 tern in the mold. Suitable rapping plates will obviate 
 trouble from this source. 
 
 Fillets.— All corners should be rounded whenever 
 possible. The corners look better, the pattern makes 
 a cleaner mold, the molten metal does not wash away 
 the sand, and the castings are much stronger. For 
 internal corners' in the pattern wood strips may be 
 used, or leather strips— which come especially cut for 
 this purpose— can be secured in the corner with tacks 
 and glue. These leather strips are widely used, as 
 they can be run around curves and irregular places. 
 For cheap patterns intended for temporary use, the 
 fillets may be made of linseed-oil putty. 
 
 Core Prints.— The supports for all cores should be 
 large and well placed. The best practice in modern 
 shops is to standardize the sizes of core prints wher- 
 ever possible. This lessens the cost both in the pat- 
 tern shop and in the core room. 
 
 Marking and Painting.— All patterns should be 
 painted, preferably in two colors— the pattern in 
 black, and the core prints, core parts, and boxes 
 in red. All the loose pieces of both the patterns and 
 core boxes should be so marked as to identify them 
 with the pattern to which they belong. 
 
 Pattern Storage.— The pattern storage should be 
 guarded against fire with the greatest care. It should 
 be so located that it may not be in danger of 
 catching fire from sparks from the foundry or from 
 other buildings; and it should be protected from fire 
 from within by the best possible fire-fighting appa- 
 ratus. Hydrants and hose should be available and, if 
 possible, a sprinkler system. The air should be kept 
 warm and dry to avoid the splitting and warping of 
 the patterns. Obviously, related patterns and their 
 parts should be together. The patterns should not 
 be piled at random; they should be stored according 
 to some well-thought-out, orderly system, with the 
 smaller ones on shelves arranged in aisles. Shelves 
 for patterns should be adjustable, and the whole 
 scheme of arrangement capable of expansion, as the 
 number of patterns to be stored increases steadily 
 and may become very great — some pattern storages 
 in this country house more than a million patterns. 
 Every pattern should have a definite place and should 
 be identified with that place in the pattern index. 
 
 Index System. — A card index should > cover all pat- 
 terns in storage, and each card should contain full 
 information necessary to locate and describe the pat- 
 tern. On each card the following data should be 
 shown; 
 
I 
 
 r II 
 
 i 
 
 
 40 THE MECHANICAL EQUIPMENT 
 
 Pattern number 
 
 Size and name of the part 
 
 Size and name of the machine 
 
 Drawing number 
 
 Order number 
 
 Date made 
 
 Location in loft, section, aisle, and shelf 
 
 Number of pieces in pattern 
 
 Number of pieces in core box 
 
 Record of alterations 
 
 A record of the castings made from pattern and the 
 order numbers covering them may be given in suit- 
 able space on the backs of the cards. 
 
 Records. — Systematic records, usually by a card 
 index, should be maintained of the issuing of pat- 
 terns, as follows: 
 
 Patterns sent to foundry and core room. 
 
 Patterns sent to outside foundries. 
 
 Patterns sent to pattern shop for repairs. 
 In some storerooms provision is made for cards on 
 the shelves, which will give the location of the pat- 
 terns when they are out of storage. This is not al- 
 ways necessary, as the above office records should 
 contain such information. 
 
 CHAPTER IV 
 FOUNDEY METALS AND FOUNDEY BUILDINGS 
 
 Metals. — The principal metals which form the prod- 
 uct of foundries are grey iron, chilled iron, white or 
 malleable iron, cast steel, brass and bronze alloys, and 
 aluminum. 
 
 Grey Iron.— Grey iron is used for machinery cast- 
 ings. Its ultimate tensile strength will run from 
 20,000 to 25,000 pounds per square inch. But for these 
 castings, soundness and ease of machining are of 
 more importance than great strength. A great many 
 mixtures of grey iron are used for special purposes. 
 The chemical composition and strength are more 
 or less influenced by the size of the product, and spe- 
 cial physical properties are sometimes required. Cyl- 
 inder and pump castings, for example, should be 
 dense, close grained and free from shrinkage spots, 
 and as hard as is consistent with machining in order 
 to wear slowly to a high polish. Castings for dynamo 
 frames are made of very soft iron to prevent the re- 
 tention of residual magnetism. 
 
 Stoves, radiators, and ornamental castings, on the 
 other hand, are made from iron with high percentages 
 of phosphorous and silicon. This composition is very 
 fluid in the molten state, flows freely in thin sections, 
 and fills the finest lines of the mold: it is brittle and 
 
 41 
 
42 
 
 THE MECHANICAL EQUIPMENT 
 
 i 
 
 will not machine well, but these castings are not in- 
 tended to be machined. '^Semi-steeP' is made by 
 adding from 10 to 40 per cent of steel scrap, giving 
 a strong iron which can be machined, although with 
 some difficulty. Guij iron is the most reliable and 
 highest grade of grey iron made: It is melted in air 
 furnaces and used for small engine cylinders, fine fin- 
 ishing rolls, and similar precise work. 
 
 Chilled Iron.— When grey iron is poured and al- 
 lowed to cool slowly, the casting is soft and the car- 
 bon content is largely in the free or graphitic state. 
 But if, instead, the pour is cooled suddenly, the sur- 
 face to a depth of one-half inch to an inch becomes 
 exceedingly hard and crystalline, and the carbon re- 
 mains chemically combined with the iron. This prop- 
 erty is utilized in the making of chilled-iron castings. 
 In making the castings the metal is poured into iron 
 molds or, more generally, into sand molds in which 
 iron castings covering the part to be hardened have 
 been set. The metal pieces used for this purpose, 
 ** chills," as they are called, may be solid or, if the 
 mold is large, hollow to permit the passage of steam 
 for drying and of water for the rapid cooling of the 
 pour. 
 
 The process permits castings, known as chilled-iron 
 castings, to be made, of which some parts will have 
 the composition and machining qualities of ordinary 
 grey iron, while the parts that have come in contact 
 with the ** chill" may be almost glass hard. The 
 metal used for the process is usually high grade, hav- 
 ing small contraction, and being melted in air fur- 
 naces. Car wheels and iron rolls furnish examples 
 
 THE FOUNDRY 43 
 
 of such work, and some foundries make this their 
 specialty. 
 
 Malleable Iron.-Malleable or white iron has a 
 strength between that of grey iron and cast steel, or 
 about 30,000 to 35,000 pounds ultimate tensile 
 strength to the square inch. While it cannot be 
 forged It can be bent and twisted, and resists shocks 
 well. It IS cheaper than cast steel and better adapted 
 tor small work. When cast it is known as ^* white 
 iron and is hard, crystalline, and very brittle The 
 cast metal is annealed by heating in scale or iron 
 oxide at a temperature of about 1350 degrees Fahren- 
 heit for several days and then cooled very slowly 
 This process burns out some of the carbon and con^ 
 
 r. tl '''* I''"' *^" '^^^^^^^ *^ the graphitic 
 
 a 'n. ^^r^'^'i'' ^^'^ ^''^ ^^^ i« then known 
 as malleable iron." 
 
 Cast Steel-Cast steel is classified by the way it is 
 melted as electric furnace, crucible, acid open hearth 
 basic open-hearth, and bessemer. The electric fi/ 
 nace and crucible methods are used onrfo %ty 
 
 iSelttl T'*"''! '"^ ''"^" ^«^«"^«- Open-hearth 
 steel IS the cheapest and most used. It is strono- and 
 
 000 pounds per square inch. It requires a high 
 lieat for melting, about 3300 degrees F is mnS 
 
 e mold poorly has a shrinkage nearly double that 
 
 t nls T r .'''""" '" ^""^^'^'l t° r^'ie-e the 
 m ed to /„v ""''^r .'"■"'"^- ^'^^y risers are re- 
 Ztl VT ""^ ^^' shrinkage. Because of these 
 "nd the rough character of the product, steel found! 
 
u 
 
 THE MECHANICAL EQUIPMENT 
 
 ries are still confined to work of medium and large 
 sizes. Cast steel is supplanting large forgings be- 
 cause it is cheaper, and, in general, more reliable, 
 especially where the forgings are built up by welding, 
 such as locomotive and ship frames. The art of cast- 
 ing steel is developing rapidly and it is gradually 
 being utilized for smaller and smaller work. 
 
 Alloys.— The principal metals used in the various 
 alloys are: 
 
 a. Copper: A tough, malleable, ductile, non-corrosive metal 
 
 which is a good conductor of electricity and casts 
 poorly. It is quoted commercially as lake, electrolitic, 
 and casting copper. 
 
 b. Tin: A crystalline metal, malleable at ordinary tempera- 
 
 tures. 
 
 c. Zinc : A hard and weak metal, which oxidizes slowly. In 
 
 the form of sheets it is known as zinc; in ingots as 
 spelter. 
 
 d. Lead: A very malleable, soft, and weak metal; little 
 
 used except in bearing metals, where it is important. 
 
 e. Phosphorus: An element never used in the pure state; 
 
 ordinarily it is used in the form of phosphor-tin which 
 carries about 5 per cent phosphorus. Phosphor-bronze 
 mixtures contain from 90 to 96 per cent of copper, 10 
 to about 3% per cent tin, and about 14 per cent of phos- 
 phorus. They are tough, very strong, and resist cor- 
 rosion. 
 
 f. Aluminum: (See below.) 
 
 There are a great number of foundry alloys differ- 
 ing widely in composition and physical properties. 
 The two principal alloys are brass, which is com- 
 posed of copper, zinc, and tin; and bronze, which is 
 composed mainly of copper and tin. Even these two 
 are subject to wide variation according to the pur- 
 pose for which they are intended. 
 
 THE FOUNDRY 45 
 
 Brass foundries naturally deal with smaller cast 
 mgs than iron foundries, for the material hank^^^^^^ 
 much more valuable; but the number of casdngs s 
 
 ine brass used m small castings is tough, non-cor 
 rosive, and a good ^^body- for plating. Owing to the 
 
 small quantities in crucibles, or by oil or gas fur- 
 
 Ahiminum foundries are of increasing importance 
 particularly in the manufacture of automoXpar s 
 t'T'"'' ?f" characteristics follow those of brass 
 
 S;? if ™"- j« -^t, very ductile, and no" 
 corrosive. It is a good conductor of electricitv h«. 
 
 h«+ ^ . rf^^^'^'^tic quality is its extreme lightness • 
 
 t.e^l^^'^Sest.ft'^^^^^^^ 
 
 flasks Zm It ''''"'' '""^ transportation !t 
 -gh\XireLS„r •"""" ""''-' '^' '' 
 
 walls be?rfil7ed in w^f' ""^ '''^' ^^^'' '^^ «"ter 
 buildinTshouM b. T "Tr'^r ^"•"^- The main 
 
 -reThttr '"? -" -- trwi^dLThtn^t 
 
 CoviL o%?v:tt-Tr\^f "'"^°^ -- '^«"d 
 
 aea to give sufficient light. The lighting, so far 
 
/ '4 
 
 If 
 
 i I 
 
 46 
 
 THE ME( HANICAL EQUIPMENT 
 
 as possible, should come from the side walls, as side 
 windows are easier to clean and will stay clean longer. 
 The best method of heating and ventilating is the in- 
 direct fan system, where fresh air is drawn in from the 
 outside, heated, if necessary, and delivered to all por- 
 tions of the building. Ample provision should be made 
 for the escape of gases and smoke through the clear 
 story at the top of the roof . The floor should consist of 
 molding sand, the depth varying with the class of 
 work to be done* A foundation of clay, well rolled 
 down, will help greatly in keeping the molding floor 
 in good condition and prevents the moisture from 
 draining into the ground. Figures 5 and 6 give a 
 plan and cress section of a foundry for general work. 
 The arrangement will vary widely with different 
 eases, but the one shown will illustrate the relation 
 of the various processes. 
 
 The office. A, should be centrally located, with a 
 good view of the main floor and partitioned off from 
 it by glass to render it as free as possible from dust. 
 It should be on the side nearest the pattern shop. A 
 temporary storage equipped with low tables and 
 shelves for patterns, B, is provided outside of the of- 
 fice. Here the foreman and his assistants can check 
 the patterns as they come in and hold them for issu- 
 ance to the molders. The heavier work will be 
 molded on the floor of the main bay where it can be 
 served by the overhead cranes, which are necessary 
 for handling the large flasks, cores, and pouring 
 ladles, and for lifting the castings from the mold. 
 The large green-sand castings may be made at one 
 end, C, nearest to the flask storage, D, which is in 
 
 THE FOUNDRY 
 
 47 
 
 6fondarJ Ciiuqe\R.R. j 
 
 _ ^t ^'^'^ ^^'"'''9^' or? Cfyorgmg F/oor ^ leye/ 
 
 TOS. 5 AND 6. PLAN AND SECTION 
 
 OF A GRAY IRON FOUNDRY 
 
/ 
 
 I] 4 
 
 \} 'I 
 
 I] . 
 
 ^1^ 
 
 48 
 
 THE MECHANICAL EQUIPMENT 
 
 the yard outside. Flasks for the dry-sand and loam 
 molds may be brought in from the opposite end, but 
 as the loam work is the heaviest it should be so lo- 
 cated as to involve the least transportation. The 
 loam and dry-sand core work should be located con- 
 veniently with respect to the ovens, F, used for dry- 
 ing the cores and molds. The core shop may be in a 
 separate building or, if under the same roof, should 
 also be near the ovens. 
 
 Light floor work and machine molding may be lo- 
 cated in the side bays where the light is good and the 
 transportation problem is less important. The mold- 
 ing machines may be placed to advantage on the side 
 nearest the sand storage to permit the use of over- 
 head belt or bucket conveyors and chutes for deliv- 
 ering the sand directly to the flasks on the machines. 
 The sand mixing should be located between the sand 
 bins and the main floor. Air-operated sifters and 
 mixers facilitate this work. The cupolas should be 
 centrally located, with the bull ladles under the main 
 crane. In large foundries there will be two or more 
 cupolas, in order that different mixtures may be 
 melted simultaneously. Small cupolas are often in- 
 stalled near the floor for light work to serve that 
 floor alone. Blowers should be placed near the cu- 
 polas to avoid long wind pipes. 
 
 The cleaning department should be located either 
 at the end of the foundry or outside. Sufficient space 
 should be provided to pile the castings as they are 
 brought from the floor and to give sufficient room for 
 men to work. Small castings will be cleaned in tum- 
 bling barrels, or in pickling tubs, or by the use of 
 
 THE FOUNDRY 
 
 49 
 
 emery wheels. As this work is of necessity very 
 dirty and involves fumes, it is well to have it in a 
 separate building or room. Very large castings are 
 usually cleaned on the main floor, and air chipping 
 hammers are indispensable in this work. In fact, 
 compressed air has become the handy man of the 
 foundry; it is distributed about the foundry in pipes 
 and flexible hose at about 80 pounds pressure, and is 
 used for operating the molding machines, for blowing 
 out the molds and for lifting the small flask molds 
 and cores. 
 
 Storage.— The pig iron is stored outside— in the 
 illustration it is on an upper level, even with the 
 charging room floor. The topography here allows the 
 use of a standard-gauge railroad spur outside and up 
 to this level, which permits the unloading of the pig 
 iron and coke on that level and the delivery of the 
 sand by gravity into the bins, M, underneath the 
 track on the level of the main floor where it will be 
 used. 
 
 Transportation—The main bay is provided with 
 travelmg cranes which are heavy enough to handle 
 t he largest flasks, ladles, and castings. Lighter trav- 
 elmg cranes may be installed under the bays for simi- 
 lar service on medium-sized work, and it is desirable 
 to have jib cranes in addition. The traveling cranes 
 should be used for general transportation from one 
 part of the building to another; the jib cranes for 
 local work. The setting of heavy cores and molds 
 trequently takes considerable time, and the overhead 
 crane is too valuable a machine to be tied up with this 
 work when other parts of the foundry may be need- 
 
/ 
 
 \ 
 
 It 
 
 I t! 
 
 |M I 
 
 50 
 
 THE MECHANICAL EQUIPMENT 
 
 ing its service. The best practice, therefore, provides 
 a combination of jib and traveling crane service for 
 this heavy work; while for light work, overhead 
 tracks and trolleys combined with air hoists are very 
 efficient. The overhead trolley leaves the floor free 
 from obstructions and clear for setting out the molds. 
 Standard-gauge railway tracks should enter the main 
 foundry floor in order that the overhead cranes may 
 load the larger castings from the floor directly upon 
 railway cars for shipment to other departments or to 
 outside plants. Wherever possible, the molten iron 
 should be distributed by cranes or overhead trolleys; 
 the use of industrial railways for this purpose is in- 
 efficient and dangerous. Industrial railway tracks 
 will provide for bringing in the flasks, patterns, and 
 sand and for transporting patterns and cores. Turn- 
 tables are preferable to curves on industrial railways 
 inside of a building, for they are more economical of 
 space and the nuisance caused by cars jumping the 
 tracks on sharp curves is avoided. However, the sub- 
 ject of transportation is handled elsewhere in this 
 series, and the reader is advised to consult that vol- 
 ume for full information.* 
 
 Clean, sanitary lockers and washrooms are a part 
 of modern foundry equipment. Foundry work at best 
 is dirty; but foundry workmen are as self-respecting 
 as any others, and haphazard washing facilities and 
 dirty clothes hanging along the walls are neither san- 
 itary nor conducive of self respect. 
 
 In the arrangement shown in Figure 5, the patterns 
 
 ♦See "Handling Material in Factories," by William F. Hunt, 
 Factory Management Course. 
 
 THE FOUNDEY 
 
 51 
 
 come in from one side of the foundry, the supplies 
 from the other, and the flasks from one end, E. The 
 general movement of material is from right to left 
 and out on the railway tracks at the left end. The 
 foundry shown is for general work suitable for han- 
 dling light and heavy grey-iron castings. In brass 
 foundries where the work is light and in steel foun- 
 dries where it is heavy, there would naturally be a 
 somewhat different arrangement, although many of 
 the features would be similar. 
 
 \ 
 
CHAPTER V 
 FOUNDRY MOLDING METHODS 
 
 Materials. — Foundry molding is divided into four 
 well recognized branches — green sand work, dry sand 
 work, loam work, and core work. The first three give 
 their names to corresponding types of foundries, ac- 
 cording to the type of molding which prevails. Core 
 work is common to all three. 
 
 In green sand foundries the molds may be poured 
 as soon as they are made, and because of the quick- 
 ness and cheapness of the process this is the common- 
 est method of making castings. 
 
 In dry sand molding a core sand mixture is used 
 next to the pattern and the mold is baked after the 
 removal of the pattern. The baking drives off all 
 moisture and leaves a hard, clean surface. It is used 
 where the rush or bulk of metal would spoil a green 
 sand mold. 
 
 Loam work consists of building up a mold of brick 
 on which a facing of mortar is placed. The correct 
 form is sometimes given to the mold by a full pattern, 
 more often by a skeleton pattern or a sweep, after 
 which the entire mold is baked. Loam work is used 
 for heavy castings where the pieces are few, and calls 
 for more skill than any other form of molding. 
 
 The principal supplies used in molding are sands, 
 
 52 
 
 FOUNDRY MOLDING METHODS 53 
 
 loam, facings, fire clay, parting dust, and core 
 binders. 
 
 Moldingr Sands.— Good molding sand may be light, 
 medium or heavy. It must be porous enough to al- 
 low the_ escape of air, steam, and the gases generated 
 in pouring, and at the same time compact enough to 
 hold Its shape and withstand the rush of metal It 
 must be refractory to withstand the high tempera- 
 tures and It must not have any chemical reaction 
 with the molten metal. It must be readily removed 
 from the casting and leave a clean, smooth surface. 
 The selection of proper sand is of vital importance: 
 It IS largely a matter of experience and one of the 
 essential elements in a foundryman's skill 
 wS f °'* ™P«^tant element in the sand is siUca, 
 which forms about 85 per cent and gives the requi- 
 
 r 1 Al rf '.? *^"^?^- ^^ ^^' percentage of silica 
 luns too high, the sand will crack in drying and the 
 mold w,l not pack and will not be impervious to the 
 metal. Alumina, or clay, the other important element 
 comprises about 8 or 9 per cent of the composition- 
 1 furnishes the bonding quality and renders the sand 
 pks^c and cohesive. Magnesia also acts as a bo^d 
 
 be lost. The lime and metallic oxides that are nres- 
 
 h uM Tf ""'; r ^^™^"^- Th« -etalliT ox' des 
 should not exceed 4 per cent nor the lime 1 per cent 
 Sand used in brass foundries runs about 10 per cent 
 
 ower in silica and is higher in iron oxide. For smTu 
 cas ings, as there is less need of venting I ZT 
 
 flTLlo '' ""''' ^f''' -*-"-e%rumta' 
 tiian the coarser-gramed sand required for heavy 
 
if 
 
 Ni 
 
 
 54 
 
 THE MECHANICAL EQUIPMENT 
 
 castings; since the heat is less the sand need not be so 
 refractory and may contain less silica. 
 
 Free sands contain about 98 per cent of silica and 
 have less than 2 per cent of alumina. There are two 
 kinds, river and beach sand. River sand is made up 
 of sharp, chipped grains and makes a very strong 
 core. Beach sand is smooth grained and used only 
 for small cores and for parting sand. 
 
 Loam. — Loam is a soil composed chiefly of silica 
 sand, clay, and carbonate of lime, with some oxide 
 of iron and magnesia, and decayed animal and vege- 
 table matter. Next to molding sand it is the most im- 
 portant material used in the foundry. It parts with 
 its water at red heat, and at the temperature of 
 molten iron the carbonate of lime will fuse and be- 
 come vitrified. Black loam is a cheap variety, hav- 
 ing strong binding properties and is used for setting 
 the brick work in loam molds. 
 
 Facing. — Facing is usually some form of carbon 
 such as graphite, charcoal or coke. It is used to give 
 a smooth surface to the face of the mold and, as it 
 burns slowly under the heat of the metal, it forms a 
 thin film of gas between the iron and the sand, pre- 
 venting the sand from burning into the casting and 
 causing it to separte from the casting when cold. 
 Facing should be very finely ground; it must not burn 
 too easily, and must adhere firmly to the face of the 
 mold so that it will not be washed away by the 
 molten iron. Blacking, as it is called, is a mixture 
 of facing with a clay wash or molasses water which 
 is applied to the finished surface of a mold or core. 
 Facing sand is a combination of molding sand and 
 
 FOUNDRY MOLDING METHODS 
 
 55 
 
 coal dust, used next the pattern on large work. Part- 
 ing sand, which may be burnt sand, charcoal, or 
 manufactured preparations, is used between the flask 
 and the cope. It must be absolutely non-tenacious, so 
 that there will be no adherence between the two 
 pieces. 
 
 Cores and Core Binders.— Cores are sand shapes 
 which partially fill the impression in the mold and 
 thereby form the holes or hollows in the castings. 
 They are generally supported by extensions, known 
 as core prints, which extend into the body of the 
 mold. The conditions required of cores are exacting. 
 They must be strong to resist flotation and being 
 washed away; they must be highly refractory be- 
 cause they are almost completely surrounded with 
 molten metal, and yet after the casting has cooled, it 
 must be possible to remove them completely and eas- 
 ily. To accomplish these purposes they are made of 
 free sand containing little or no alumina which would 
 cause them to cake and make them hard to remove. 
 The core sand is mixed with binder, a vegetable 
 compound of ordinary wheat flour with rosin, linseed 
 oil and molasses. When the cores are formed they 
 have little or no strength and are too weak for use 
 m the mold. To give the necessary strength they 
 are heated in ovens to bake the binder and give it 
 the strength required. When the mold is poured, 
 the high temperature of the molten metal burns out 
 the binder and reduces the core to a mass of loose 
 sand which can be dug out with ease. As it takes 
 time for the binder to burn and the gases to escape, 
 the core retains its strength long enough for the metal 
 
 .1 
 
 i .. 
 
56 
 
 THE MECHANICAL EQUIPMENT 
 
 to set. Cores are frequently strengthened with iron 
 rods, pipe, and, at times, with specially east core 
 irons. Where these are not sufficient, chaplets, which 
 are small supports made in many varieties and shapes 
 are used. It is intended that they fuse into the cast- 
 ing, but they are at best a necessary evil as they 
 weaken the casting in three ways — ^by the introduc- 
 tion of a foreign metal, by the formation of porous 
 spots about the chaplet, and sometimes by a failure 
 to fuse. They are necessary, however, in many 
 classes of work. 
 
 Cope and Drag. — Molds are made in flasks consist- 
 ing of two or more rectangular frames of the same 
 length and breadth, the upper one known as the cope 
 and the lower one as the drag or nowel. When there 
 are three parts, the middle one is known as the cheek. 
 The frames are used to hold the sand while the im- 
 pression of the pattern is being made. They are 
 made of wood, cast iron, or pressed steel. Iron and 
 steel flasks should be used for standard work ; wooden 
 flasks are much cheaper, but they deteriorate rapidly 
 and must be handled with care. The copes of large 
 flasks usually have crossbars to help in holding the 
 sand in place. The cope and drag are made to reg- 
 ister with each other by means of guide pins and 
 sockets. In the ordinary type of flask the mold re- 
 mains in the flask while the casting is being poured, 
 necessitating the use of as many flasks as there are 
 molds. 
 
 ''Snap flasks" resemble ordinary flasks except for 
 the fact that they are hinged at one corner and are 
 provided on the diagonal corner with latches, so that 
 
 FOUNDRY MOLDING METHODS 57 
 
 StedTiLt' T?^ 'r^^ ^'^'' ^^' ^^^^ i« f«™^d and 
 hfted clear of it. They are used for small work 
 
 where the mold is strong enough to stand the pres 
 
 a mold IS in place on the floor, the flask is taken off 
 
 snaV flask i" "'"''5 ?^ "^^^ ^^^- ^--' ^^t one 
 
 T''ro^^L''H"'''T "^^'^"^ '^'^' ^--tities. 
 
 mold A ^^ ^^.T,1 ?^''''" ^'' P^^^^^ i^ "taking the 
 I ter of pT '\' ''™ "^^^^ '' '^-^^ -1^ or 
 
 mai^^J^thP ^ ^'""V^. '' "^^^ ^« a «^old board for 
 making the cope. Sand matches are used only where 
 a few castings are needed, while the plaster of Paris 
 matches may be used indefinitelv. Matches are made 
 m shallow frames the size of thJ flask tole used and 
 
 arp «mon 6 ^»A excess sand and slicks, which 
 
 withdrawn In LT ^^""^ ^^^ P^"«™ has been 
 Dl 1 rV '^'''*'*'" *" th^^e there will be snrue 
 plugs which are cylindrical nia<,«.o t -, ^ 
 
 "•aking the runneV th^ugh"^ wh eh T "f? '" 
 
 poured; draw sDikes and hT ,1 **" ™^*^' ^« 
 injr ihl 7/ ^ '^^^^ plates to help in lift 
 
 'ug the pattern, and vent rnHo f,^^ i • ^ 
 
 for the escape ^f gases ''''"^ ^^''^^'' 
 
 It,'. '■• 
 
 )■ 
 
 
 jvii'^ 
 
/ 
 
 58 
 
 THE MECHANICAL EQUIPMENT 
 
 ii 
 
 Making a Mold. — The first operation of importance 
 in making a mold is the preparation of the sand — that 
 is, mixing the proper proportions of old and new sand 
 and tempering the mixture. Too much new sand 
 causes the mold to crack, as it will not vent properly; 
 not enough causes the cutting or washing away of 
 the mold. 
 
 Tempering is done by moistening the sand with 
 water until a handful of it can be squeezed into a 
 firm, egg-shaped lump that will break cleanly with- 
 out crumbling. Too little tempering gives a weak 
 mold; too much tempering produces an excess of 
 gases. 
 
 The next operation is the ramming of the drag 
 and then the cope, that is, sand is shoveled into the 
 flask and is packed around the pattern. If the sand 
 is rammed too hard, blow-holes may result because 
 the natural vents or air cavities are filled up; and if 
 it is not rammed hard enough it will sink under 
 the weight of the metal or be washed away. The 
 joint of the mold where the two parts come together 
 should be rammed hard, as it is exposed to handling. 
 In general, the mold should be as soft as possible and 
 still retain its shape. Gaggers, which are L-shaped 
 pieces of iron, may be set in the mold, when neces- 
 sary, to give it the requisite strength. 
 
 When the mold is formed, it is vented. This is ac- 
 complished by opening up passages for the escape of 
 gas, air and steam. If this is not done, the mold may 
 explode, or some parts may not be filled with iron on 
 account of the pocketing of gas which cannot get 
 away. New sand needs a good deal of venting. Af- 
 
 FOUNDEY MOLDING METHODS 59 
 
 ter venting the mold, an opening is formed through 
 
 Lslh J: "''f 'V '""''^ ^^^ ^''^' This opening 
 has three parts, known as the pouring basin, the 
 
 runner or sprue, and the gate. Making it proper^ 
 
 sible for many bad castings. The gates should be 
 large enough to fill the whole mofd quickly, and 
 should be located so that the metal will rise into the 
 
 Tound'off^R'^' ''^ ''''''' ^^' ^^ machined 
 
 frZthf^rr. '? ""''^''^^ "P^"^^^« ^^tending 
 
 s r^e XZT^T" '" '^' *^P '^ '^' --Id; they 
 
 Sland r TT''' ^' " "^'^^^ ^« ^ skimming 
 
 .ate, and as a supply for additional metal to make ud 
 the shrinkage in cooling ^ 
 
 nefd^'o'ml'^'jfv '" ^' ^"^^^ ^^^ ^''^ -i" often 
 Zl I 1! P^*"^^«^' ^«d ^ good molder will repair 
 
 done with the fingers wherever possible. The mold 
 
 is aTd :::'' ^r rr' ^^^^^^ ^^^^^-^ ---^e 
 
 ^as and causes blow holes; too little facing results in 
 
 nalt and the mold is ready for pouring 
 
 exS S ""''^^"^ i' .'™^^"' *^ ^^^^^ «-^d work 
 except that core sand is used next to the pattern 
 
 rml'r;''t l^^^ ^^^^^^^ --d- After the S 
 IS made It is baked or dried and is then given a coat 
 
 to ! ' ^fi: .^'^ '"^^ "^^^^^ ^'^ -^-de in iron flasks 
 permit their being placed in the oven. It is neces 
 ary vent dry sand molds also, not because therp 
 s moisture in them, but the gase from the burnrn^ 
 
 facing must be parnpH «fF *« • ourning 
 
 s «iu&i oe cdiiied oif to xnsure a sound casting 
 
 [*'i 
 
 ^'-i.. 
 
/ 
 
 60 
 
 THE MECHANICAL EQUIPMENT 
 
 Machine Molding.— Molding machines are used 
 with great advantage in green sand foundries wher- 
 ever there is repetition work. Not only do they in- 
 crease production, but they materially improve the 
 quality of the castings, which, in turn, decreases the 
 cost of the machining operations. They have the fur- 
 ther advantage that they may be operated by com- 
 paratively unskilled labor. They may be classified 
 under four general types, stripping-plate machines, 
 squeezers, roll-over machines, and jarring or jolt ram- 
 ming machines. 
 
 The stripping-plate type of machine is used for 
 work which offers difficulties in drawing the pattern 
 from the sand. The stripping plate itself is sup- 
 ported rigidly on the machine, the patterns being 
 mounted on a drop plate working in guides. The 
 stripping plate is cast to leave openings about one 
 inch wide around the pattern. When the stripping 
 plates and the patterns are properly set, this space 
 is filled in with Babbitt metal, so as to form a close 
 fit around the patterns at the parting line. In opera- 
 tion, the flask is placed on the machine, is rammed, 
 vented, and struck off on the top; the pattern is then 
 withdrawn downward through the stripping plate by 
 a hand lever or an air-operated cylinder, and the 
 mold is removed and set out on the floor. As pointed 
 out in Chapter III, the impressions in gated patterns 
 may be so arranged as to make one plate serve for 
 both the cope and drag parts of the mold. Stripping- 
 plate machines are well adapted to the manufacture 
 of gears, pulleys, etc., having straight or nearly 
 straight sides. 
 
 FOUNDRY MOLDING METHODS 61 
 
 The squeezer type of machine may be operated by 
 hand and merely packs the sand. In it the patterns 
 may be carried on the two sides of a plate which is 
 set between the cope and drag. Both boxes are filled 
 with sifted sand and set on the machine. A lever or 
 air cylinder is used to compress the sand against 
 the plates. The cope is then lifted from the plate, 
 the plate is lifted from the drag, and the two parts 
 of the mold are set on the floor ready for pouring. 
 Ihis type of machine is used chiefly for thin work 
 which vents easily and cools quickly, for the outer 
 surfaces of the mold are apt to be rammed so hard 
 that they would choke the venting of heavy castings 
 In another type of squeezer the cope and drag flasks 
 are side by side, and the patterns, instead of being 
 carried on two sides of the plate, are arranged on 
 the same side, the cope impression being over the 
 flS ^^^^ ^""^ *^^ ^""^^ impression over the drag 
 
 In the roll-over machine the pattern is carried on 
 the top of a match plate; a flask is placed over it and 
 the mold IS rammed by hand or squeezed. The mold 
 and pattern are then rolled over and the pattern is 
 
 time. The match plate with the pattern is then rolled 
 back into its original position ready for making the 
 next mold. (See Figure 7.) All three of the above 
 ypes may be operated by hand or by power, and 
 snap flasks are generally used. The production of a 
 power squeezer will exceed that of a hand squeezer 
 
 will handle a mold weighing 1000 pounds or more 
 
 
 
 % 
 
 
 :/■ 
 
'I 
 
 I 
 
 j 
 
 PIG. 7. HAND-OPERATED ROCK OVER MOLDING MACHINE 
 
 Henry E. Pridmore. 
 
 il 
 
 FIG. 8. MOLDING MACHINE AND SECTIONAL VIEW 
 
 American Molding Machine Co. 
 
 62 
 
 FOUNDRY MOLDING METHODS 63 
 
 foTl'Jl''' jolt-ramming machine, Figure 8, is used 
 for al classes of work up to the largest floor work 
 made in green sand; the only limit is the capacity 
 of the machine itself, which varies from a few hun- 
 
 moltiH "T ^''""'^"^ P°""^«- The patterns are 
 mounted on heavy pattern or match plates; the flask 
 IS put in place, filled with sand, and clammed to the 
 pattern plate. It is then lifted and placed on the 
 jarring table which, in large machines, is on the , eve 
 of the tmmdry floor, the working parts being below 
 on a rigid concrete foundation. The table is "joS- 
 
 2ut thoM ^^"^ L"" ^" ^°^"' ^^'^^S the sand 
 about the pattern. The number of blows required is 
 de ermined by experience, but the time needed s 
 onb- --11 fraction of that consumed by hand ram! 
 
 are made, and many of their operations are automatic 
 Some are better adapted to certain classes of To k 
 
 han others and intelligent selection of the type best 
 suited to the work in hand should be made. 
 
 earner Poundries.-The full capacities of machine 
 mo Iding are best realized in carrier foundriesTa sne 
 
 r sot n °' 'T '''' '^-^'^y^ where thi'm^^; 
 passes bvt^e "I"' '•' ^''"'^ "P*^" ^ ''^"•^er which 
 
 Hoor In tt 7 "' T^'^^ °* "^'"^ '^^ «»t^ on the 
 noor. In the ordinary type of foundry the mold« «r« 
 
 ^Z^ ""^ ''"•^^f '^^'' -^ towVrd the e'nV 
 e day the pounng is done by the molders who brine 
 l>e molten iron to the molds. In the carrier founZ 
 the pouring is done continuously througho. ZZl 
 
 .:.!)! 
 
I 
 
 FKi. 7. Il\SI>-<>l'i:iiATKn ROCK OVKK MOT.DlNci MA<'mNE 
 
 llflliv K. I'liillllolc'. 
 
 FIG. 8. 
 
 >101.[)IN(i MACHINE AND SECTIONAL VIEW 
 AiiuTiitin Miildinj: Macirnic ('". 
 •52 
 
 FOUNDRY MOLniNO METHODS 
 
 63 
 
 foJ''.ir'"i'' "*'■ J"'V""'"""« '""^''''"^ f''ig"'-e 8, is used 
 fo. all classes of work up to ti.e largest floor work 
 
 nade ,n green sand; the only limit is tl.e capacity 
 of the machine itself, which varies from a few hun- 
 .Ired to many thousand pounds. The patterns are 
 ."«.„, ed on heavy pattern or match plates; the flask 
 - put ,n place, filled with sand, and damped to the 
 
 "•'«>.'■'"/";*"• ,.It is then lifte<I and placed on tie 
 
 arnng fal.le wh ch, in large machines, is on the level 
 "f the loundry floor, the working parts being I.elow 
 <"' a n«id concret,. foundation. The table is "jolteii" 
 
 nd'drr^ ;7';'"'<".- «•''-•'' W-ts it about four''inches 
 
 . ''out the pattern. The number of blows required is 
 .1-' ertnined by experience, but the time needed is 
 -ly^a small fraction of that consumed by hll .t" 
 
 \arioMs combinations of these tvpes of machines 
 -e nuKle. and many of their operations are au o a i ' 
 Nome ar<. better adapted to certain classes of 4 S 
 "'! " others, and intelligent selection of the tvpe bes 
 M.de<l ,0 the work in hand .should be made 
 
 '"«> ding aie best realized in carrier foundries (a sne 
 
 ;;r ;:; irr; ■' 't ■•■•"",' '•"""^"•>'> -»'«- tuiinX; 
 
 •'■ ><>on as It IS made, is placed upon a carrier which 
 .™ y the machine, instead of ling set ::t ^ 
 "• I ' the ordinary type of foun.lrv the molds -.re 
 
 .■r,;;^'■'•"^'•^ ''';'''"-•• -"'toward thee: 
 
 'la> the pouring is .lone by the mohlers who bri,,..- 
 
 '"■ niolten iron to (he uiohls In fl. »'«i>iing 
 
 tlic i)(,ii,in<r ;. I - *''*^ carrier fonm rv 
 
 l'o""ng IS done continuously throughonl (he day 
 
II 
 
 < 
 
 t 
 
 1 
 
 1 
 
 64 
 
 THE MECHANICAL EQUIPMENT 
 
 by men who do nothing else, the carrier bringing the 
 molds from the machines to a portion of the floor near 
 the cupola where the pouring is done. After the 
 molds are poured, the castings cool as the carrier 
 progresses; and after a few moments they are 
 knocked out of the mold and run across a set of shak- 
 ing bars which delivers the castings into a cooling 
 crib, while the sand falls through the bars into the 
 hopper of an elevator and is carried up overhead. 
 New sand is then added, and is tempered and deliv- 
 ered by conveyors to chutes which open directly over 
 the molding machines. The snap flasks used by the 
 molder remain at the machines, and the molds are 
 poured either without flasks or with only light steel 
 bands around them to prevent shifting. This type of 
 foundry is very efficient for long runs of small stand- 
 ard castings, such as pipe fittings, which cool quickly, 
 but is not applicable for general work. 
 
 CHAPTER VI 
 FOUNDRY— MELTING, POUEING, CLEANING 
 
 General Methods.— Three ways are employed for 
 forming metals for industrial purposes: 
 
 First, by melting the metal and casting it in sand 
 or other molds. This forms the basis of foundry 
 work. 
 
 Second, by pressing the metal into the desired 
 form. This may be performed while the metal is 
 either hot or cold, either by blows under a hammer 
 or by steady pressure. Forming the metal while hat 
 is known as forging; forming it cold, as press-work 
 or stamping. 
 
 Third, by cutting the metal with tools having single 
 or multiple cutting edges. Grinding is simply a form 
 of cutting. This method is usually used as a supple- 
 ment to the others for machining castings or forgings 
 accurately. The first two methods are most useful 
 for giving the material its general form, but the work 
 must usually be finished by the last method if it is to 
 be close to size. 
 
 The Cupola.— Foundry metals are melted in the 
 cupola, in the air furnace, in the open hearth fur- 
 nace, in oil or gas furnaces, in crucibles, and in the 
 electric furnace. 
 
 Of these, the cupola is the most widely used and is 
 
 66 
 
 > 1 
 
 rH 
 
 
 ■1 'I: 
 I i 
 
 I, 
 
i 
 
 66 THE MECHANICAL EQUIPMENT 
 
 the one generally employed for melting cast iron. It 
 has the highest fuel economy and is the easiest to 
 manipulate. The metal may be melted continuously 
 throughout the day and be drawn off as desired. 
 Figure 9 shows a section of a typical cupola. It con- 
 sists essentially of a vertical iron shell, A, lined with 
 fire brick, into which is charged alternate layers of 
 pig iron and fuel. The shell and lining are carried 
 on a plate, B, supported by four out-spreading legs 
 at a height sufficient to allow the two bottom doors, 
 C, to swing clear of the floor. The doors which form 
 the bottom of the melting chamber are held up in 
 place by a prop, D, while the cupola is in operation, 
 and are protected during the heat by a bed of sand. 
 When the run is over, and the cupola is to be cleaned, 
 the prop is knocked out, the doors swing down, and 
 the sand bed, with what remains of the charge, drops 
 to the floor and is cleaned away. 
 
 Just above the bottom of the melting chamber is a 
 large opening called the breast, filled with fire-clay, 
 and through this is a smaller one, E, called the tap 
 hole, which is used in drawing off the molten metal. 
 This is closed by a plug of fire-clay while the charge 
 is being held in the cupola. Wheii it is drawn off, 
 the plug is removed and a spout lined with a fire- 
 sand mixture carries the stream of metal to the bull 
 ladle. Above the level of the tap hole and on the 
 opposite side is another hole, F, termed the slag hole, 
 which is used to draw off the slag which floats at the 
 top of the molten metal. Several inches above the 
 slag hole are a series of large openings, G, called 
 tuyeres, extending all around the melting chamber, 
 
 Charging . ■ » 
 Door ' 8 
 
 Charg/n q F/oor 
 
 L.m\\m\ss\s^^^^^^ 
 
 ■W/ffcf BoK 
 
 
 Sane/ 
 
 Bed 
 
 .1 ■ i T 
 -t '* i ' I 
 
 .*l 
 
 • ' .'. I •■ "J^* 
 
 •'•:-:-p=ri 
 
 ,1,11! ' V^^v^f-- 
 
 TTT 
 
 FIG. 9. SECTION OF A CUPOLA 
 67 
 
 
 i , 
 
in 
 
 l» 
 
 111 
 
 68 
 
 THE MECHANICAL EQUIPMENT 
 
 which connect the melting chamber with the wind 
 box which surrounds it. These openings, which are 
 usually oblong, direct the air blast into the fuel bed. 
 Peep-holes in the outer side of the wind box opposite 
 the tuyeres enable the melter to look directly into the 
 furnace. The height of the tuyeres above the bed 
 varies with the class of work. Where the metal is 
 being drawn off continually they may be as low as 
 8 or 10 inches above the sand bed. For large cast- 
 ings it is necessary to collect a large body of metal 
 in the cupola and the tuyeres must be higher. For 
 the largest work they may be five or six feet up. 
 
 The air blast through the tuyeres is furnished by 
 fan or pressure blowers, and the quantity of air 
 handled is very large, as it takes about 30,000 cubic 
 feet of air to melt one ton of iron. The table, page 
 69, gives the average melting rate per hour for the 
 various sizes. In large cupolas there are two sets 
 of tuyeres, the upper row provides for the loss of 
 wind should the lower row become partially clogged 
 by slag. The fuel bed should extend above the top 
 of these. The upper tuyeres have a smaller area 
 than the lower as they are intended to give only extra 
 air to burn the cupola gases and not to start a new 
 melting zone. The combined cross-sectional area of 
 the lower tuyeres runs from one-fifth of that of the 
 cupola area for small cupolas down to one-tenth on 
 large ones. The melting zone ranges from about one 
 foot to four feet above the tuyeres. The fire-brick 
 lining is supported at various heights by rings, L, 
 riveted to the inside of the shell. This permits the 
 separate renewal of the lining around the melting 
 
 MELTING, POURING, (LEANING 69 
 
 zone, where the wear is most rapid, without disturb- 
 mg the balance of the lining. 
 
 At a considerable height above the tuyeres is the 
 charging door through which iron and fuel are 
 charged m alternate layers. The width of the charg- 
 mg door for various sized cupolas is given in the 
 accompanying table. 
 
 General Dimensions of Cupolas 
 
 Capacity 
 in 
 
 tons 
 
 per 
 
 hour 
 
 Ito 
 
 3 to 
 
 6 to 
 
 9 to 10 
 12 toll 
 18 to 21 
 24 to 27 
 
 1 
 2 
 5 
 
 7 
 
 Inside 
 diam- 
 eter 
 of 
 lining 
 
 Inches 
 
 23 
 27 
 32 
 42 
 48 
 60 
 72 
 84 
 
 Diam- 
 eter 
 of 
 Shell 
 
 Inches 
 
 Thickness of 
 Lining 
 
 Below 
 Charg- 
 ing 
 Door 
 Inches 
 
 32 
 36 
 46 
 56 
 66 
 78 
 90 
 102 
 
 4K 
 
 4^ 
 
 7 
 
 7 
 
 9 
 
 9 
 
 9 
 
 9 
 
 Above 
 Charg- 
 ing 
 Door 
 Inches 
 
 Charging Doors 
 
 4K 
 4^ 
 
 4^ 
 
 No. 
 
 1 
 1 
 1 
 1 
 2 
 2 
 2 
 2 
 
 Height 
 Inches 
 
 Width 
 Inches 
 
 16 
 20 
 24 
 27 
 27 
 27 
 27 
 27 
 
 16 
 20 
 24 
 30 
 30 
 36 
 36 
 36 
 
 The efficiency of the cupola type of furnace is very 
 ^igh, as the melting ratio averages about one pound 
 ot fuel to ten of iron. This arises from the fact 
 tliat the fuel and the iron are intimately in contact. 
 Ihis close contact has the disadvantage of exposing 
 the iron to impurities, such as sulphur, which may 
 be m the fuel, and therefore the cupola furnace can- 
 not be used for many of the higher grades of cast- 
 
 
 \4' 
 
I 
 
 70 
 
 THE MECHANICAL EQUIPMENT 
 
 ings. Yet on account of its cheapness of operation, 
 its convenience, flexibility of control, and great capac- 
 ity, it is used wherever possible. 
 
 The Air Furnace. — In the air furnace, shown in 
 Figure 10, the metal is charged into the furnace 
 through a charging door at the side; the fuel is 
 burned in a separate chamber, A, and the gases are 
 directed over a bridge wall and across the surface 
 of the charge, B, which lies on the sand bed, C, and 
 are carried off by the chimney at the left. As the 
 gases in their passage cling to the top of the furnace, 
 the metal is heated more by radiation from the in- 
 candescent top and side walls than by direct contact. 
 Since there is no direct contact between the metal 
 and the fuel, fuel impurities in the latter are less 
 troublesome than in the cupola, and a better qual- 
 
 riG. 10. SECTION OF AN AIR FURNACE 
 
 MELTING, POURING, CLEANING 71 
 
 ity of metal is obtained. But the qualities which give 
 the air furnace a purer output decrease its melting 
 efficiency, and the melting ratio, which in the cupola 
 will run from one of fuel to eight or ten of metal, in 
 the air furnace will not do more than one to four. 
 It will, however, give a large amount of high-grade 
 metal at one tap, and heavy pieces of scrap may be 
 used which are difficult to handle in the cupola. 
 
 Open-Hearth Furnace—The open-hearth furnace is 
 used principally for melting steel, and, to some extent, 
 malleable iron. It is somewhat similar to the air fur- 
 nace except that it has two gas chambers, A and A' 
 and two chambers, C C (Figure 11), so arranged that 
 the direction of the flame can be reversed. The 
 checkered brick-work in C and C is used for pre- 
 heating the air so that it enters the furnace at nearly 
 1000 degrees Fahrenheit. This furnace gives a high- 
 grade product and has a heating ratio of about one 
 to SIX By-product or producer gas is generally used 
 as tueL The gas from the chamber. A, and heated air 
 trom C unite as they enter the furnace, pass over 
 the top of the charge, B, and then out through 
 checkered brickwork, C, which absorbs a large part 
 of the remaining heat. When the gases are re- 
 versed, the checkerwork, C, takes up the pre-heat- 
 ing and the waste gases heat the brickwork, C 
 on the other side which was cooled down during the 
 previous run. The direction of the gases is reversed 
 about three times, an hour. 
 
 Oil or Gas Furnaces—Figure 12 shows an oil fur- 
 nace of the type used in a brass foundry. These are 
 mounted on trunnions to permit tilting and pouring 
 
 
 }• I 
 
 ■4 
 
 !•! 
 
 7" «. 
 
 .il 
 
11 
 
 I 
 
 72 
 
 THE MECHANICAL EQUIPMENT 
 
 Z5w 
 
 Froni Gas 
 
 From B/omncf 
 £rfgine or/o sfack 
 
 From Gas 
 
 J 
 
 FIG. 11. DIAGRAMMATIC VIEW OF OPEN-HEARTH FURNACE 
 
 WITH REGENERATORS 
 
 and the fuel is supplied through one of the trunnions 
 at one end. The flame plays across the charge and 
 out at the top. The metal to be charged is first laid 
 on top of the furnace while the fire is on, where it is 
 gradually warmed and finally is pushed into the 
 chamber as required. When oil is used for the fuel, 
 it may be fuel oil, crude oil, distillate, or kerosene. 
 Gas may be used in the form of natural gas, water 
 gas, or city gas. Producer gas is not suitable, since 
 it is too low in calorific value to maintain the temper- 
 atures required. The capacity of these furnaces var- 
 ies from 500 to 1250 pounds at a charge, and about 
 1% to 3 gallons of oil are required to melt 100 pounds 
 of steel. 
 
 I ' 
 
 id 
 
 :!^) 
 
 li 
 
w 
 
 I 
 
 \\ lil) 
 
 74 
 
 THE MECHANICAL EQUIPMENT 
 
 Crucible Furnace. — The crucible furnace is shown 
 in Figure 13. It is used chiefly for melting small 
 special mixtures in brass foundries. The metal does 
 not come into direct contact with the fuel but is 
 placed in refractory crucibles which are covered and 
 set in the furnace. Graphite is the principal ingredi- 
 ent used in the construction of the crucibles, bonded 
 with fire clay, as they must be strong and tough even 
 at a high temperature. They should be brought 
 slowly to a red heat before using, and the charge 
 should be carefully packed, in order to allow expan- 
 sion of the metals inside before they melt, otherwise 
 the crucible may break. The fuel may be hard coal 
 
 ^ 
 
 BuHding .. 
 Wall 
 
 .Jib Cron€ 
 
 ^m^i 
 
 >^ 
 
 tr- 
 
 ie: fe 
 
 ^ys^g 
 
 TTT 
 
 TtT 
 
 I=Z 
 
 1=1 
 
 S 
 
 S 
 
 ^ 
 
 ^ 
 
 rzi 
 
 TTT 
 
 lEi 
 
 cS^ 
 
 rrr 
 
 P^ 
 
 ^ 
 
 -4^ 
 
 V///////////////M 
 
 Air Main 
 
 m 
 
 ,1 ii ■ 
 
 T-'T — 1 
 
 1 Chimnetf \ • { 
 
 
 -^m 
 
 -I- 
 
 i 
 
 
 ps^S^^^w^^j:!^^^ 
 
 JIG. 13. CRUCIBLE FURNACE FOR MELTING BRASS 
 
 MELTING, POURING, CLEANING 76 
 
 or coke, sometimes gas or oil. When the charge is 
 melted, the crucibles are lifted out by means of tongs 
 and emptied into serving ladles. Closed crucibles 
 are used in brass foundries because alloy metals, es- 
 pecially zinc and tin, burn if exposed to the air while 
 melting. If the casting is so large that one crucible 
 Will not suffice, several furnaces must be used and 
 their crucibles discharged into one large ladle. 
 
 Electric Furnace.— Electric furnaces are very ex- 
 pensive in operation and little used except for making 
 high-grade steel in small quantities. Their advan- 
 tage lies in the accurate control of the chemical con- 
 stituents during melting. 
 
 Ladles.— The molten metal is transported from the 
 furnace to the mold in ladles. These range in capac- 
 ity from 25 or 30 pounds up to 60 tons. The large 
 ladle that is located permanently at a cupola into 
 which the spout discharges is called the bull ladle. It 
 is mounted on trunnions and is tilted to pour metal 
 into serving ladles which are brought to it. Serving 
 ladles may be carried by crane, overhead trolley, or 
 by hand. Hand ladles may be single or double, de- 
 pending upon whether they are carried by one or 
 two men. All ladles are made of metal, with a re- 
 fractory lining to protect them from burning. The 
 smaller ladles are provided with a lip or spout from 
 which the metal is poured. Large ladles are carried 
 by cranes and are controlled by gears to facilitate 
 pouring and to prevent accidents from too rapid 
 turning. Very large ladles, such as those used 
 m steel foundries, are not turned in pouring but are 
 provided with u tap hole in the bottom. The lining 
 
 I 
 
 :\:M. 
 
 i 
 
 
 U 
 
 
I 
 
 76 
 
 THE MECHANICAL EQUIPMENT 
 
 in small and medium sized ladles will vary from 
 three-fourths inch to two inches in thickness accord- 
 ing to size. Large ones are lined, first, with fire brick 
 and then daubed with a clay mixture similar to a 
 cupola lining. Ladles must be well dried before using. 
 
 Pouring. — In pouring the molds care must first be 
 taken to skim off the slag. With large ladles, this 
 should be done before leaving the cupola and again as 
 the metal is poured. A skimmer, which is a long 
 iron rod, is used for this purpose; the end of it rests 
 across the top of the ladle near the pouring spout to 
 hold back the slag while the metal runs free. 
 
 Great skill is required in pouring molds, as the 
 speed with which the metal should be poured varies 
 with the character of the work. It should be done 
 slow enough to allow the gases to escape and yet fast 
 enough to keep the metal from chilling in the mold 
 and forming ** cold-shuts,'' as they are called. Care 
 must be exercised to keep the stream steady and not 
 to ** spill" into the mold; the basin at the gate of the 
 mold should be just kept full. It is of vital impor- 
 tance that the pourer gauge correctly the amount of 
 metal required, for if he has not enough metal in his 
 ladle to fill the mold and must use the second one, he 
 is practically certain to lose his casting. Any metal 
 remaining after pouring should not be allowed to chill 
 or freeze in the ladle, but should be poured into a 
 larger ladle or emptied on the floor. Pig beds are 
 usually provided near the cupola for this purpose. 
 
 Defects of Castings.— The accompanying table 
 shows the principal defects of castings, with their 
 causes and cures: 
 
 MELTING, POUEING, CLEANING 77 
 
 Poured Short: 
 
 ^TolTnoTmieV^ """^^^ '"^ *^' ^^^^ misjudged and the 
 Cure— Have enough metal. 
 Blow Holes: 
 
 ^Ztr^^''/ P^^^^ted in the mold, sand packed too 
 
 tight sand too wet, or poor venting. 
 Lure— Provide adequate venting. 
 
 Cold Shut: 
 
 Cause-Two streams of metal meeting in the mold 
 
 which are too cold to fuse together 
 Cure— Use hotter metal or have a thicker section. 
 Sand Holes: 
 
 Cause—Loose sand washing into the cavity and fusing 
 into the metal. Too little facing ^ 
 
 Cure— Have a stronger mold, use more facing If 
 necessary, use dry sand mold. ^' 
 
 Lifts: 
 
 Cure— Weighting or clamping the cope. 
 Shifts : 
 
 ^T^^A^ """"P^ ^'""^ misplaced sidewise with respect 
 
 Cure-Proper registering between cope and draff 
 Core Shifts: ^' 
 
 cT^^'"'^^ breaking or becoming misplaced. 
 Cure— Stronger cores and more careful setting. 
 
 ^''^' c2S) r"""'*^'^' projections on the surf ace ' of the 
 Cause— Mold washing off and being carried awav 
 Cure-Stronger mold, better rammld, and mo^'^^acing. 
 
 Swells (Bulges in the casting) : 
 Cause — Too soft ramming. 
 Cure — Proper ramming. 
 
 
 
78 
 
 THE MECHANICAL EQUIPMENT 
 
 M- I 
 
 Shrinkage (cracks) : 
 
 Cause — Unequal cooling or mold too firm to give as the 
 
 metal cools. 
 Cure — Re-design of the part or lighter packing in the 
 
 mold. 
 
 Warping : 
 
 Cause — Pattern may have warped; casting may have 
 lugs on one side retarding the shrinkage, or sand may 
 be packed harder on one side than on the other. 
 
 Cure — Correcting the pattern or relief of the strain. 
 
 Cleaning. — After th<^ castings are poured sufficient 
 time should be allowed for the metal to set. In small 
 castings this may be a matter of a few moments; in 
 very large ones, it may take a week or even more. 
 If castings are knocked out too soon, shrinkage 
 strains and cracks result. When the castings are 
 removed from the sand, the gates are broken off and 
 turned into the scrap pile for remelting and the cast- 
 ings are collected and carried to the cleaning room 
 as molding floor space is too valuable to be tied up 
 with work which can be done elsewhere. The cores 
 and core irons are dug out and the fins (thin sheets 
 of metal which seep out between the cope and drag) 
 are chipped off. In large work much of the cleaning 
 is done by hand, but it is greatly facilitated by the 
 use of air chipping-hammers, and for very large work, 
 especially large steel castings, the oxy-acetylene flame 
 or the electric torch is used to cut off risers, etc. 
 
 Tumbling. — Tumbling is the most effective way of 
 cleaning small castings which are fairly uniform in 
 size and, in general, not over 50 to 100 pounds in 
 weight. Tumbling barrels are made of steel plate 
 and lined with chilled-iron bars to protect the shell. 
 
 MELTING, POURING, CLEANING 79 
 
 Tlie bearings of these barrels are sometimes hollow 
 and connected with an exhaust system to draw off the 
 dust. As the barrels revolve, the castings tumble 
 
 ZZu Z'"' '^T'"^ '^'^ °*^«'- •" t^«°ty minutes 
 or half an hour. To facilitate the cleaning, shot iron 
 and hardened stars are thrown in and revolved with 
 the castings When removed from the barrel iron 
 
 fact "^F 1 "T ^ "'"""' ^•""^t^' grey-colored sur- 
 face From he tumbling barrels the castings may 
 be taken to the dry emery wheels for grinding off 
 
 i'lCJiIing.— Where much machining is to be done 
 the presence of sand and scale on the surLe of the 
 casting plays havoc with the cutting tools. Such 
 par leles may be removed by the proc:ss of pickUng 
 This consists in washing the castings in dilute 
 
 r ati^f^^ f'r'^f'' ^'''^ ^""^^'^ -ith watert 
 a ratio of 1 to 8 or 1 to 10. They are left in this 
 bath long enough to cut out the sand and the hid 
 skin of iron oxide, which is formed when the iron 
 
 the casting. After removal from the pickling bath 
 
 enough to heat them so that they will dry ranidlv 
 Sand Blast-Small and delicate castings whLh can 
 
 sand blast. Sharp, clean sand is blown against the 
 surface by compressed air at about 10 pounds pres! 
 ure, giving the casting a beautiful finish The work 
 requires a considerable apparatus and invoir a 
 separate room. The operators must be protic Id bv 
 helmets and supplied with fresh air througla Ce 
 
 p'i 
 
 V4 
 
 'hi 
 
 > I 
 
 I 
 
 pf 
 
 A 
 

 
 CHAPTER VII 
 FOKGING METHODS 
 
 Hand Work.— Many metals may be formed or 
 shaped either hot or cold, but the term forging is 
 confined to the working of heated metal under blows 
 or heavy pressure. The forming of cold metal by 
 press work, or cold stamping, requires more power, 
 because of the higher resistance of the metal to a 
 change of shape; but it is more accurate than hot 
 work, as the uncertainties of shrinkage are elimi- 
 nated, and is faster than forging because the work 
 may be manipulated by hand instead of by tongs. 
 Pressing and stamping machines form an entirely 
 different class from those used with hot work and are 
 located in a different department. Hence, hot work, 
 or forging, only will be taken up in this chapter. 
 
 In the past fifty years the work of the forge shop 
 has been undergoing gradual changes. Hand 
 methods have been supplemented by forging ma- 
 chinery, and the field has extended in two directions: 
 Steam hammers and hydraulic presses have permitted 
 an enormous increase in the size of forgings, while 
 drop hammers and the various other forms of power 
 hammers have introduced manufacturing methods in 
 a refined form. On the other hand, the foundry has 
 been cutting into the field of the forge shop through 
 
 80 
 
 FORGING METHODS . ffl 
 
 the increasing production of steel and malleable iron 
 castings now used for many articles which formerly 
 were forgings. 
 
 The principal materials which are forged com- 
 mercially are machinery steel, tool steel, wrought 
 iron, bronze, copper, and aluminum. Bough stock 
 IS usually m the form of merchant bars for small and 
 medium sized work and of billets for large forgings 
 
 follows •^''''''' '^^^^''^^ ""^ ^'"''^''^ ""^^ ^^ ^^^^P^^ ^' 
 
 Hand work 
 
 Welding 
 
 Steam hammer work 
 
 Drop forging and power hammer work 
 
 Heading and upsetting 
 
 Hydraulic press work 
 
 Rolling 
 
 Drawing 
 
 Extrusion work 
 
 Pipe bending. 
 
 Hand forging will always have its place for all 
 small and special work, for making the special cut- 
 ing tools used in every machine shop, and for the 
 Hand tools, special rivets, bolts, etc., on large en- 
 gmeenng operations. But little tool equipment is re- 
 qmred which can be easily moved from place to 
 
 The Forge.— The equipment for hand forging in- 
 volves a forge fire. This may be either a pemanent 
 Sr '? ?' ''^'' °^ blacksmith shops in manufac- 
 
 anvi! ^ ' "'■ ,P*'J*^*'^^ '" ^^^^ " ™^y be set up 
 anywhere-on a platform, on an engineering structure 
 
 mm 
 
 
 .1* 
 
 \y, 
 
w 
 
 
 82 
 
 THE MECHANICAL EQUIPMENT 
 
 tinder erection, or in a shanty by a railroad track. 
 The usual fuel for small fires is soft coal, but occa- 
 sionally charcoal, coke, or hard coal is used. It 
 should*^ break easily and burn freely with little 
 clinker. The necessary air is furnished from beneath 
 through tuyeres. In permanent forges the tuyeres 
 are connected with a general blower system serving 
 the forge shop. For portable forges the bellows 
 used from time immemorial are giving place to 
 small, hand-operated, rotary blowers. The fires 
 should be kept as small as possible, but should be 
 deep enough to make sure that the air blast is dis- 
 tributed evenly through the coal and does not strike 
 open spots. This is necessary for even heating, for 
 the hottest part of the fire follows the blast. A 
 blacksmith will often stir the bar he is heating to 
 loosen it from the coals and to allow the air freer 
 access to the coal immediately around it. Fuel is 
 usually added to the fire at the side and is gradually 
 worked in toward the center of heating. Fires may 
 be either oxidizing or reducing, according as there 
 is or is not an excess supply of oxygen through the 
 air blast. An oxidizing fire should be avoided, as 
 it produces scale or iron oxide which wastes the 
 metal and interferes with forging. When the right 
 amount of air is admitted the iron will come out 
 bright and clean. 
 
 For permanent forges, such as are used for tool 
 dressing in machine shops, gas or oil are the best 
 fuels as they are cleaner and afford easy and accurate 
 control of the heat. They are generally used on drop 
 forging and large work for similar reasons. Care 
 
 FORGING METHODS 83 
 
 must be used to heat large forges slowly and uni- 
 formly and to avoid oxidation. If the surface is too 
 hot and the interior too cold, transverse cracks will 
 appear on the surface of the work being forged. If 
 
 tiLThp 7 -r T''''^ "^^ '^' ^^«id^ i' hotter 
 than the outside, longitudinal cracks will appear 
 
 Steel should be forged with as few heats a poSle 
 There is more danger of injuring the stock by work- 
 
 Sel :Z ^^ r^' '^"" "^^" " - --heated 
 Steel should not be allowed to remain in the for^e 
 
 fire longer than is necessary, or the material wi 1 re' 
 
 carbonize. For very large work a reverberatory or 
 
 2 f™ " T^ "'^^' ^^ ^^"^^^^* similar to the 
 air furnace shown in Figure 10. These are not 
 
 economical of fuel, but they provide means for S^e 
 
 uniform heating of large work. The billets, or ma! 
 
 the'nd' }T\ '" '""''^''^ ^^-"^h -^-r at 
 rom'thV^l/'' .''''i"^ " '^^^ ^^ ^^^ -d-tion 
 
 The fir I ^""^ f ^'' "^ *^^ ^^^^^^^ chamber. 
 J he fuel most used for these furnaces is soft bitu- 
 
 «s coal, and the furnaces are used in connecdl„ 
 
 Ce Si:;.'""' '"""°™ "— "■• "»* - 
 
 cat"n^* r'^^'"^ ^'' '"^•^'"'* *^ shrinkage, as in the 
 
 T:\t:Ttc'^^' TT "^^' ^^^--ssar; 
 
 Tools.— The important tools in hand work are th^ 
 
 -5L aboul n/ '''"i ''T""'' '•'"^ ^"<* ^ head 
 g'ung about 11/2 pounds. Figure 14 shows some 
 
. > 
 
 84 
 
 THE MECHANICAL EQUIPMENT 
 
 of the more common forms of heads. The eye of the 
 head is usually set so that the greater weight is on 
 the face side, as heavier and more accurate blows 
 may be struck than if the weight were evenly 
 balanced. Sledges, which are heavy hammers used 
 by a helper and swung with both hands, vary in 
 weight from 5 to 20 pounds; they average about 12 or 
 15 pounds. 
 
 The first requirement of a blacksmith's anvil is 
 weight. It should be able to absorb its own shocks, 
 and any anvil which has to be braced is practically 
 useless. The next requirement is that it have a hard 
 face, for it must be able to withstand the roughest 
 kind of use. Modern anvils usually have a wrought 
 iron body to which is welded a hardened steel face. 
 The well-known shape of an anvil is a gradual de- 
 velopment through miany generations. At one end is 
 a tapering horn, at the other a wedge-shaped projec- 
 tion having a square hole into which auxiliary tools 
 may be set. It is mounted on a heavy wooden block, 
 about 20 inches high, to give it a firm but elastic 
 foundation, and its weight usually runs from 150 to 
 300 pounds. 
 
 The tongs, some varieties of which are shown in 
 Figure 14, are made of steel and vary in size and 
 shape to meet the needs of the various articles 
 handled. The handles are long and often are pro- 
 vided with a slip ring which can be slid along to 
 clamp the tongs upon the work. 
 
 Some other auxiliary tools are set hammers for 
 working into corners and narrow places, flatters for 
 smoothing out high surfaces, swages for finishing 
 
 FORGING METHODS 
 
 m 
 
 TOP BOTTOM HOT CUTTER BOTTOM TOP 
 FULLER FULLER SWAGE, SWA6E 
 
 COUNTERSINK 
 
 CAPE CHISEL 
 
 CHIPPING CHISEL 
 
 ROUND 
 ■PUNCH 
 
 t^ 
 
 STRAIGHT LIP TONGS 
 
 a 
 
 HARDIE 
 
 GAD TONGS 
 
 SINGLE PICK-UP TONGS 
 
 CENTER PUNCH 
 
 BAND TONGS 
 
 SQUARE 
 FLATTER 
 
 ANGLE JAW 
 
 2*= 
 
 RIVET TONGS 
 ^ '"^ HOOK AND HANDLE RULE 
 
 SET HAMMER 
 
 ENGLISH PATTERN SLEDGE 
 
 BALL PEIN 
 HAMMER 
 
 AMERICAN PATTERN 
 
 FIG. 14. HAND FORGING TOOLS 
 
 J 
 
 
 I, ;,„il 
 
 I H 
 
 i 
 
 71 , 'i 
 
 '■l-\ 
 
86 
 
 THE MECHANICAL EQUIPMENT 
 
 i 
 
 round and convex surfaces, fullers for working 
 grooves or hollows into shape, swage blocks which 
 contain holes of various sizes and shapes, steel 
 calipers for measuring the work, and the necessary 
 
 fire tools. 
 
 Operations.— The operations of hand forging cover 
 almost every type of forging work. The principal 
 ones are drawing, upsetting, riveting, bending, shrink- 
 ing, and welding. 
 
 Drawing consists of hammering the piece on the 
 side and rotating it at the same time between each 
 blow. Under the influence of the hammering the 
 metal spreads in all directions, but the metal forced 
 sidewise by one blow is driven back by the next, 
 while the displacement of the metal endwise is unob- 
 structed. The effect is to work the metal longitudi- 
 nally, and a short piece of large diameter may be 
 drawn out into a long one of small section. 
 
 Upsetting is the reverse of drawing; a long, thin 
 piece is forged from the end and spread out sidewise 
 to form a head (as in the case of bolts), or sometimes 
 a bulge in the middle. 
 
 Eiveting is a special form of upsetting where heads 
 are formed in place on rivets to secure two pieces of 
 
 metal together. 
 
 Bending, which needs no explanation, is usually 
 done over the edge of the anvil or around the horn. 
 
 Shrinking is the setting of forged rings tightly on a 
 solid core or bar. The ring is forged hot to a sliding 
 fit, slipped over the core, and allowed to cool. The 
 shrinkage causes the ring to grip the core with tre- 
 mendous force. 
 
 FORGING METHODS gl 
 
 Welding.-Welding is the process of joining two 
 pieces of heated iron or steel by placing them together 
 and hammenng the joint. It is one of the mosf skil- 
 ful branches of the blacksmith's art. The heating 
 must be done evenly and cleanly in a reducing firel 
 too high a temperature is sure to form scale, and at 
 too low a heat the metal will not weld. The proper 
 s3 "VT^^^^^^^^V^^^^tituting what the black- 
 smith calls -welding heat,- is therefore narrow 
 
 evil of welding It may be formed in the fire and will 
 collect on the heated metal from contact with the air 
 The process of welding is a mechanical one, and there 
 is no direct chemical action. It is facilitated by the 
 
 TA ^^7' Tf^ '^^^ "^ ^^^^^ «« the surface 
 to be welded which unites with the scale and forms a 
 
 slag that melts at less than welding heat and is forced 
 out m the hammering. In -scarfing,- or preparing 
 the pieces for welding, the surfaces to be joined 
 should be convex so that they will touch first in the 
 center. This facilitates forcing out the slag. If the 
 surtaces are concave, some of the slag is likely to be 
 pocketed in the joint and cause an imperfect weld 
 
 Dissimilar metals, such as steel and wrought iron * 
 or tool and machinery steels, may be welded together! 
 but they require skilful handling as the welding heats 
 ot the two metals are not the same. Imperfect welds 
 21 ri /.''•'^ Fr!'''" '^"*^'*' insufficient hammering, 
 ttt r V". '^' •*'^^'' ^^"^ insufficient fluxing, so 
 hat the scale is not all cared for; from too high or 
 
 Whe n. \ '^^ ^''"^ ™P"^^*^^^ ^^ the metal. 
 >Vhere the carbon in steel runs over 1.1 per cent it is 
 
 Ml' 
 
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^ 
 
 .. 
 
 I 
 
 88 
 
 THE MECHANICAL EQUIPMENT 
 
 difficult to make a weld; and cast iron which contains 
 2 per cent or 3 per cent of carbon cannot be welded 
 at all by the ordinary methods. Silicon, phosphorus, 
 sulphur, and manganese all lower the welding quali- 
 ties of iron. The purest and softest steels weld the 
 best. For these reasons the efficiency of a weld is 
 uncertain; it will average from 70 per cent to 80 per 
 cent but may be as low as 50 per cent. Welds made 
 with a steam hammer are stronger than hand welds 
 of the same size. The art of welding has received 
 enormous development in recent years and methods 
 other than the use of a forge fire and hammering will 
 be discussed later. 
 
 Steam Hammer Work. — Steam hammer work is a 
 development from hand forging and differs from it 
 only in the size of the work handled. Three types of 
 steam hammers are used: one where the hammer is 
 lifted by steam and drops of its own weight; one 
 where exhaust steam is admitted above the piston 
 and by its expansion increases the force of the blow, 
 and a third where live steam is used above the piston 
 throughout the downward stroke. 
 
 The first class is used for very large work and the 
 weight of the hammer ranges from 25 to 125 tons. 
 Its disadvantage lies in the fact that the height of the 
 piston in the cylinder from the lower cylinder head 
 varies with the thickness of the work and forms a 
 clearance space which must be filled with live steam. 
 In the second class the consumption of steam is less, 
 the force of blow is greater and a larger number of 
 blows are given in a minute, but the reliability of 
 operation is more or less uncertain. The third 
 
 FORGING METHODS 8!l 
 
 class IS the most widely used: here the weight of 
 
 )TrVT^ ^'"^ "^' *" ^^ ^^^«^ the number and 
 
 orce of blows can be regulated by throttling the 
 
 steam, and the control is such that the weight of 
 
 the hammer only may be used for light blows, while 
 
 ^P^w. T '^!f ^'' *^' ^^"^^^^ ^^^^«- These ham. 
 mers work rapidly and are provided with automatic 
 reversmg gears, so that as many as 350 blows a 
 mmute may be obtained. 
 
 The frames of steam hammers may be single or 
 l'?he^i^""' 15 and 16). The douWe frame! used 
 on the larger sizes are stronger than the single frame 
 
 In boirf'"' "I'T' "'^"' ^^^ ^-" - -^trict'd! 
 In both types the hammer head usually is guided by 
 
 aTXv ;^'"in '^^' ^''^- ^P^^ frame Lmmers! 
 as hey are called, are used for certain classes of 
 
 work where slides would be troublesome In 5e„,t 
 
 large piston rod and small head in one piece le 
 
 rrarsr ^"*' '"■ »" '- -- «» •"« 
 
 The anvil of a steam hammer is a large casting 
 
 ftm tre re^^^^^^^^^^^^ ™' ^^ ^ -P-^te foundS 
 trom the rest of the hammer to lessen the shock on 
 
 he working parts. In good practice the weight of 
 
 hltTthfh'^' '^ r ^^ ^^^^ '^^ - twelv^tim 
 hat of the hammer head; the heavier the better for 
 
 ^ImT^ '' -f'^ '™^^ ^^ increased as ' the 
 ^v eight of the anvil is increased. 
 
 requiredt 'tf X^T'"'''^ '""^ ^'^ ^^ hammer 
 inlT .!. ™"'*'P''' *^^ ''^^s section, in square 
 ■nches of the work to be forged by 80 for steeJ and 
 by 60 for wrought iron. For example, a steel forgtng 
 
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 •n. 
 
 i')i 
 
 •J 
 
 
 
 % 
 
 t ' 
 
90 
 
 FOEGING METHODS 91 
 
 5 by 5 inches would call for a 2000-pound hammer. 
 The question is often asked, "What is the force of the 
 blow?" It is impossible to tell, if by this is meant the 
 pressure produced. The energy, represented by the 
 weight and velocity of the moving parts as they 
 strike the work, is determinable; but the pressure 
 which IS exerted varies inversely with the distance 
 m which they are brought to rest after they strike 
 the work. Thus, while the forging is hot and soft, 
 the hammer sinks into the metal some distance and 
 the pressure is comparatively low; and as the forging 
 cools, the metal grows harder and the pressure in- 
 creases rapidly. There is, therefore, no feasible way 
 of rating hammers other than by the weight of their 
 falling parts. 
 
 The field of the steam hammer is that of general 
 torging on large and special pieces. Sometimes dies 
 are used, but if so, they are only of the simplest 
 character. Steam hammer work has been cut into in 
 recent years from two directions. The hydrauUc 
 press IS preferable for very large work, as it produces 
 sounder forgings and has th6 further advantage of 
 quietness of action; while the heavy blows of a large 
 steam hammer may often cause so much vibration and 
 noise as to be objectionable to an entire neighborhood. 
 Ihe other restriction of field comes from the increas- 
 ing use of steel castings which do away with the 
 necessity of uncertain welds' in built-up work, such as 
 tne side frames of locomotives. 
 
 Power Hammers—Drop hammers are confined to 
 small and medium sized work and are used where 
 many pieces of the same kind are needed. Drop 
 
 11 ■« 
 
 
 
 !■ 
 
 ?■••::(• 
 
 J'' ■^- 
 ■.J;.'.., . 
 
f 
 
 •M 
 
 FUliUliNU .METHODS yj 
 
 5 by 5 iiK-hcs would call for n ^dOO-jioujid liainmcr. 
 The riuostion is oltcn askocl, "Wliat is tlu- l'o.v«. of the 
 hiow?" It is iini)()ssil)|,. to tell, it l)y this is meant the 
 pressure j.roduced. The energy, represented hv the 
 w<-islit and veloeity of tlie moving pai-fs as"tliev 
 Mrdvo the work, is determinable; but the pressure 
 yhieli IS exerted varies inversely with the distance 
 in wjiieli tliey are ])rought to rest after thev strike 
 the woi'k. TJius, wliilo tlio forging is hot and soft, 
 the hammer sinks into the metal some distance and 
 the pressure is comparatively low; and as the forging 
 cools, the metal grows liai-der and tlio pressure in- 
 creases rapidly. There is, therefore, no feasible wav 
 "I rating hammers other than by the -n-eiglit of their 
 i ailing parts. 
 
 The tield of tlio steam liammer is that of general 
 lorgmg on largv and special pieces. Sometimes dies 
 "'•<• nsed, but if so, they are only of the simplest 
 '•liaracfer. Steam hammer Avork has been cut into in 
 '•'■cent years from two dir(..-tions. The hvdraulic 
 press ,s pivferable for very large Avork, as it produces 
 sounder- lorgmgs and lias the further advantage of 
 qmelness of action; while the heavy blows of a large 
 M.;ani JiamnHu- may often cause so much vibration and 
 iioise as to bo objectionable to an entire neighborhood. 
 I he other restri<-tion of field comes from the increas- 
 "IK use of steel castings which do awav with the 
 "'■cess.ty of uncertai.i w<>lds in built-up woric, such as 
 liio side frames of locomotives. 
 
 Power Hammers.-l),op hannuers are confined to 
 ■"lall and medium sized work and are used where 
 inany pieces of the same kind are needed. Drop 
 
92 
 
 THE MECHANICAL EQUIPMENT 
 
 forging is becoming an art in itself and is so im- 
 portant that it will be taken up separately. 
 
 Power hammers other than drop hammers are used 
 in a wide variety of types. The oldest, the helve 
 hammer, now largely obsolete, consists of an oscillat- 
 ing wooden beam pivoted at one end and carrying at 
 the free end the upper half of a pair of dies, the 
 lower half, being carried in an anvil below. The 
 beam is lifted by a rotating shaft carrying a series 
 of cams, each of which raises the hammer and allows 
 it to drop suddenly. This type has been used from 
 mediaeval times. The modern development of the 
 helve hammer is seen in the Bradley hammer. Figure 
 17. In this the beam is operated by a swinging 
 frame driven from a rotating shaft. Between the 
 frame and the beam rubber cushions are interposed, 
 the effect of which is to soften the action on the 
 driving mechanism and to give a quick blow. 
 
 The Beaudry hammer, Figure 18, which is a crank- 
 operated power hammer, is also widely used. The 
 head of this hammer has an internal curve or track. 
 Two steel arms, acting as springs, carry hardened 
 rollers which bear on the curved surface and trans- 
 mit the power from the rotating shaft to the hammer 
 head. The action gives a quick stroke and allows 
 a rebound the instant the blow is made. 
 
 Another type of power hammer is the pneumatic 
 hammer operated by compressed air supplied by an 
 air compressor integral with the frame. The pur- 
 pose in all of these types of hammers is to give a 
 quick, sharp blow. They are started and stopped by 
 a foot treadle: by varying the pressure on the treadle 
 
 93 
 
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 f^^^^ 
 
 LiJ'J^^^^H 
 
 
 v„:^'^^| 
 
 i'^^'i^H 
 
 1 ' I^^^^^^^^^H 
 
 ^n^^l 
 
 
 
 
 
 - . ) 
 
 ^^^^Hi 
 
1)2 
 
 THE ME( HANK AL KQl'IPMENT 
 
 foruiii^' is 1)tvomin.i»- an art in itscll' and is so im- 
 portant that it will he taken n|) s('[)arat('ly. 
 
 Power hanuners other than drop hanuners are used 
 in a wide variety of tyi)es. The oldest, tlie helve 
 lianuner, now largely obsolete, consists of an oseillat- 
 in.i;- wooden Leani i)ivoted at one end and ejirrying at 
 the free end the upper half of a pair of dies, the 
 lower half hein.i;- carried in an anvil l)eh)W. The 
 heani is lirte(l hy a rotating shaft carrying a series 
 of cams, each of Avliich raises the hammer and allows 
 it to drop suddenly. This type has heen used from 
 mediaeval times. The uiodern development of tlie 
 helve hammer is seen in the Bradley hammer, Figure 
 17. In this the ])eam is operated by a swinging 
 frame driven from a rotating shaft. Between the 
 frame and the l)eam rul)l)er cushions are interposed, 
 the elTect of which is to soften the action on the 
 driving mechanism and to give a ({uick blow. 
 
 The Beaudry hannner, Figure 18, which is a crank- 
 operated j)ower hannner, is also widely used. The 
 head of this haiinnei- has an int(Mnal cui've or track. 
 Two steel arms, acting as s])rings, carry liardened 
 rollers which beai' on the curved surface and trans- 
 mit the power from the rotating shaft to the hammer 
 head. Tin* action gives a (piick stroke and allows 
 a rebound the instant the blow is made. 
 
 Another ty])e of power hammer is the pneumatic 
 hannner operated by comy)ressed air supplied by an 
 air compressoi- integral with the frame. The pur- 
 pose in all of these types of hannners is to give a 
 cpiick, shar]) blow. They are started and stopped l)y 
 a foot treadle: by varying the pressure on the treadle 
 
 i 
 
 93 
 
7 
 
 I I' 
 
 94 
 
 THE MECHANICAL EQUIPMENT 
 
 t* II 
 
 any desired speed or force of blow within the capacity 
 of the machine may be obtained. They are used with 
 and without dies for drawing out handles and for sur- 
 facing round work. Hammering is continued until 
 the work is cold. The work is rotated meantime and 
 a heavy stream of water is played upon it, which 
 cracks off the scale and turns out a smooth forging 
 very close to size and requiring little or no machining. 
 
 Headers and Upsetters. — For upsetting heads on the 
 ends of long thin stock, heading and upsetting ma- 
 chines are used. The dies for the purpose are usually 
 in three parts, one on the movable head of the ma- 
 chine (see A, Figure 19), and the other two, B and 
 B', carried by the main frame. These two dies, B, B', 
 in the main frame separate to allow the introduction 
 of the heated bar. They are then closed together, 
 and the third portion of the die. A, on the movable 
 head, advances and drives the hot metal into the im- 
 pression in the other two. This type of machine is 
 used for forging bolt heads, automobile valves, and so 
 forth. 
 
 Hydraulic Press. — The hydraulic press. Figure 20, 
 consists essentially of a heavy frame, an anvil, and a 
 moving head which may or may not be provided with 
 dies. The head is operated by a hydraulic cylinder 
 which creates the pressure used in the forging. The 
 supply of water for the cylinder is controlled by a 
 valve and is furnished by a high-pressure water 
 pump. This type of machine works, not by blows, 
 but by dead pressure. It is used for all sizes, but 
 more especially for large work. The effect of a ham- 
 mer blow is greater along the surface immediately 
 
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114 
 
 THE MECHANICAL EQUIPMENT 
 
 any dt'sirod spoed or force of l)l()\v within tlic capaoity 
 of \\\v niMchine iiiav he ohtaiiied. Thev are used with 
 and without dies foi' drawini;' out handh's and for sur- 
 facing' round work, llannneriiii;- is coutinuiHl until 
 the work is cold. Tlie work is rotated meantime and 
 a heavy strcuim of water is phiyed upon it, which 
 cracks off the scah' and turns out a siuooth for.n'ini;- 
 very ch)se to size and rvquirini;- litth' or no maciiining'. 
 
 Headers and Upsetters. — For uj)settini; iieads on the 
 ends of h)nu' thin stock, headini; and ui)setting ma- 
 chines are used. The dies for tiie puipose are usually 
 ill three parts, one on the movable head of the ma- 
 cliine (see A, Fi,i;ure 19), and the other two, 1> antl 
 IV, carried hy the main frame. These two dies, I>, IV, 
 in the main frame se])arate to allow the intioduction 
 of the heated bar. They are then closed together, 
 and the third portion of the di(\ A, on tin* movable 
 head, advances and drives the hot metal into the im- 
 pression in the other two. This ty])e of machine is 
 used for forging holt heads, automobile valves, and so 
 forth. 
 
 Hydraulic Press. — The hydraulic press. Figure 20, 
 consists essentially of a heavy frame, an anvil, and .i 
 moving- head which mav or mav not l)e ])r()vided with 
 dies. The head is operated by a hydraulic cylinder 
 which cnnites the pressure used in the forging. Th*' 
 sup])ly of water for the cylinder is controlled by a 
 valve and is furnished by a high-pressure watrr 
 [)ump. This type of machine works, not by blow-, 
 but by dead |)ressur(\ It is used for all sizes, but 
 more esf)ecially for large work. The effect of a liai i- 
 mer blow is greater along the surface immediate y 
 
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 FORGING METHODS 97 
 
 SdrkuHe L* %f '*'^' '•^^orseless action of the 
 
 with die forgrn/fLmhrf/^rr^^' ^" connection 
 be used AH^ l^, ^^""^ *^^* ^^^t i^n dies may 
 
 hLTer; fhe'T *^'^ '"'^ '^'^^ ^^^ "^^ in drop 
 verTuTc'ertain .f ""* ^'"^^^' ^"^ their life I 
 
 tuany gSwav r'' "'''' crystallizes and even- 
 nari V usid • T/" ^""^^'^"^""y' steel dies are ordi- 
 
 be dLSill^r ^tLr y : StTri^ns'tr^^ 
 
 tsioTi: Jhld^^^^^"^^^^^^^^^^^ ^^ 
 of die forJnf fl ,f '* ^""^ *^"« P^™its the use 
 
 Justified S'sttl dTes t •""'''!" *'^" "^'^'^ ''^ 
 already pointed^, t: acZ^ofleTySr. ^^ 
 
 a n^ ::i;-f pSi {~^^^ 
 
 high-pressure iX ^d ? LLl ^ t "/"^ 
 capacity of 14,000 ton"™ '^"'"P""' ''«' « 
 
 »< r„i„i "■;, r:i°" o tT;"a; '.r'' "*"" 
 
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 97 
 
 w 
 
 '-^^S* while the ^\ 
 
 •••''»y;MMs ;n.<i tlHMnetal tends to ivork side. 
 
 Iiydnuilic press allows 11 
 
 <>^v^ remorseless action of the 
 
 P'ii'< of the t 
 
 rounder woi*k. It j 
 
 ^>^".i^ni.i; iind, thorel 
 
 Willi die foroino. jVoni ll 
 •<^ ii'^od. Allhoiioh (I 
 
 O'O 
 
 1 1 an 
 
 liners. 
 
 th 
 
 <*n- nse is not 
 
 o pressuri^ to reaeli every 
 'ons it ])roduces 
 in connection 
 may- 
 op 
 
 ''«'^ an advanta 
 
 •<' Hict tlial cast 
 
 n-on dies 
 
 very unecM'lain. 
 
 Iiiall 
 nai'il 
 
 as 11 
 
 niay also he us(m1 in di 
 f^iioral and their life is 
 
 ^Jves way. C^onsc 
 y \\^('^\\ III 
 
 ic metal crvstall 
 
 izes 
 
 quently, steel d 
 
 and 
 
 ev(»n- 
 
 ics are ordi- 
 
 ^'•^y are expensive to make, hnt wher 
 
 ;;uniy piece. ar<. |o he made, XX,, ehar^e f^ 
 
 he distrihuled 
 
 II 
 
 lere a 
 
 ^•<' I ml a few j) 
 
 ov(T I hem and is not 
 
 r dies 
 
 may 
 
 leces. 
 
 'Senons. Where 
 
 IHvssion l()W(M-s the die cost and W 
 
 the ahility to cast W 
 
 le im- 
 
 <>r di(^ foi 
 
 o 
 
 '"^' for small 
 
 us permits the use 
 
 .lustilied with sttH'I dies I 
 >''-^;a<ly pointed ont, the .ictioTorihe 
 
 quantities tlian would be 
 impressions. As 
 
 iavin.2- cut 
 
 '-^ very quiet and it 
 ^•cry large work, suci 
 
 hydraulic press 
 
 ^Iiaftf 
 
 'hid 
 
 > and so forth. The plant 
 
 IS now used almost entirelv for 
 I as armor plate foi 
 
 
 liiiii 
 
 f's not onlv tl 
 
 i(> 
 
 i-pressure pumps and 
 
 Pivss \U(M, hnt tl 
 
 i-oquired— whic] 
 
 eavy 
 1 in- 
 
 P<'"sive, and this form; 
 
 connections 
 
 10 uiH'essarv 
 -IS verv ex- 
 
 '^'le hydraul 
 
 serious limitation to it 
 
 H' \M'^^^, however, is tind 
 
 )een 
 
 avor, and j)lants have 1 
 i^e^one us(hI in the Bethlehem'steel 
 apacty of 14,000 ton 
 Rolling".— A 
 
 s use. 
 
 ing increasing 
 
 installed of enormous 
 
 Con 
 
 U^any has a 
 
 -AS 
 
 II 
 
 o 
 
 ol 
 
 roll 
 roll 
 
 '*' ^''''"^^ i^lpli(^s Ihis |)roee 
 
 '".^' the metal out hetw 
 n is used for lo 
 
 ess consists 
 
 i'V^. 
 
 ^^'ork usually of unifoi 
 
 <'»'n the eurved surf 
 ".i^- and thin. 
 
 ni cro 
 
 :ices 
 
 or narrow 
 
 ss 
 
 section, such as flat 
 
98 
 
 THE MECHANICAL EQUIPMENT 
 
 II' 
 
 plates, steel rails, I-beams, channels, and angles, as 
 well as for merchant shapes, which are bars in stand- 
 ard sizes of round, square, and rectangular section. 
 The rolling process forms the backbone of the steel 
 mill industry and is also important in the brass in- 
 dustry. Eolling mills, vary in size from small ones 
 which are operated by hand or gear-driven from 
 shafting, to the largest sizes which, with their auxili- 
 ary equipment, driving engines, etc., fill the whole of 
 a large building and represent an enormous invest- 
 ment. 
 
 Rolls producing bars and shapes fall under two 
 classes, which are known as the two-high and three- 
 high rolls. In the two-high roll it is necessary to 
 reverse the direction of the roll for the return pass or 
 to send the material back for the next rolling. The 
 material is usually put through the roll a number of 
 times; each pass through a smaller groove in the rolls 
 reduces the section of the bar and increases its length. 
 The distance between the centers of the rollers is ad- 
 justable, so that the size of the section to be rolled 
 may be varied. The three-high roll is similar to the 
 two-high, except for the addition of a third roll. All 
 three rolls revolve continuously, so that adjacent sur- 
 faces of the first and second rolls are moving in one 
 direction while those of the second and third are 
 moving in the reverse direction. The material, there- 
 fore, which has been passed between the lower and 
 middle rolls may be returned between the middle and 
 upper roll with a consequent saving of time in 
 handling. 
 
 The rolling process is used not only for continuous 
 
 FORGING METHODS 99 
 
 work of uniform section, but also for forging separate 
 pieces which are relatively long and narfow^and va^^^^^ 
 m cross section such as axles, sword blades, knife 
 blades wrench handles, etc. Figure 21 shows k forg- 
 ing rolof this type. Th. dies, with the impressions 
 cut m their surfaces, do not extend entirely around 
 he rolls; hence, when the free sections of the upper 
 and lower dies are opposite each other, there is an 
 opening between the rolls into which the stock is in- 
 
 w^ ^ Z "^ ''' ^^' ^^"^^- The rolling motion is 
 
 toward the operator, so that when he reaches forward 
 and inserts material between the rolls, it is caught by 
 th dies and is rolled back toward him. In this man^ 
 
 hands in fl!' """ ?"^'' "^ '^' ^P^^^*^^ '^''^^S his 
 hands m the machine. As in other rolls, there may be 
 
 a series of impressions, each approaching the desired 
 
 t)e needed to forge an article broadside 
 Drawing.-The drawing process is used for the 
 
 bars until the section is small enough to be handled 
 in sectior'7-^^^^^^ ?"' '"^ '^ '''' ^^' i« -^d^^ed 
 the desired size and shape in a hardened die The 
 end IS seized and the rod drawn through the* open 
 ing reducing its cross section to the size of Jhe h'oTe" 
 
 eac T^^r"^^ "^'^ *^^^^^^ --^--e dies,' 
 each of which reduces the section a certain amount 
 
 tney will harden and become brittle after a certain 
 percentage of reduction. Ductility may be reared 
 
100 
 
 THE MECHANICAL EQUIPMENT 
 
 by annealing, that is, by heating and subsequent 
 cooling, and the process may then be repeated with 
 alternate drawing and annealing down to the manu- 
 facture of the finest wire. 
 
 Extrusion Process.— This is the reverse of drawing 
 and might be compared to a potato ricer on a large 
 scale. The metal is passed through dies of the re- 
 quired size and shape, but it is forced or extruded 
 through instead of being pulled through as in the 
 drawing process. This method is used in the manu- 
 facture of brass bars and shapes. It requires 
 enormous power which is usually supplied by a large 
 hydraulic press. An ingot is placed in an enclosed 
 space and a ram coming forward drives the hot metal 
 through the holes in the die at the other end. By 
 this process an ingot six or eight inches in diameter 
 and several feet long may be reduced to a number of 
 bars one-half inch or so in diameter, which may be 
 taken to draw benches and finished by the more ac- 
 curate process of drawing. The extrusion process 
 can be used for the production of fairly intricate 
 shapes, such as stair railings, which cannot be made 
 by the drawing process. 
 
 Pipe Bending. — Another form of forging which may 
 be done either hot and cold is known as the pipe 
 bending process. Any one who has bent a paper roll 
 knows that a tube will collapse at the point of bend- 
 ing unless the sides are prevented from coming 
 together. A metal pipe which is to be bent is filled 
 with sand or other resistent material which will stand 
 heat. Then, since the pipe cannot collapse, the fibres 
 on the outside of the bend are stretched, those on the 
 
 FORGING METHODS loi 
 
 used L^Idi^g llLTZ Tofr '^^^ "^^^ '' 
 
 of the weld V^iV ^ ^ ^^ ^"^ ^^^^ "P t^^ joint 
 bent ;^^1,e^;irn Ti^t^'^^^ 
 
 Z fend " °f '" ^"^^^^"^ "- decreas d a„7wLr 
 used to give the desired radius of curvature- fnr 
 
 a core tor large pipmg, such as steam mains efr- 
 
 endroft?'"^ "* ^° ' ''''' floor-plarand the 
 tackle! '''^' '" ^""^'^ ^^°-d *'y -«dla.s and 
 
 1 I 
 
 
 E'Wii 
 
! '»l 
 
 CHAPTER VIII 
 DROP FORGING 
 
 Utility.— Drop forging is an application of manu- 
 facturing methods to the forging process, developed 
 by the American gun manufacturers about the middle 
 of the last century. It consists of hammering the 
 material between two dies, one of which is carried on 
 the anvil and one on the face of the hammer, and 
 forcing the material into accurately registered im- 
 pressions cut in the faces of the dies. Drop forgings 
 are produced in an almost infinite variety of shapes 
 and can be made close to size and in great quantities. 
 
 Great advancement has been made in the art and 
 its scope and usefulness are being steadily widened. 
 It is now an important element in the manufacture of 
 many types of interchangeable products, such as fire 
 arms, sewing machines, automobiles, machine tools, 
 and so on. The field of the drop forging process is 
 confined chiefly to smaller forgings, not so much from 
 any mechanical limitation of the process itself as 
 from the fact that few large forgings are produced in 
 quantities sufficient to warrant the expense of the 
 necessary dies. Automobile steering parts, crank 
 shafts and axles represent about the limit of drop 
 forging at the present time, but there is no reason 
 why the process may not be extended to larger work 
 if occasion requires. 
 
 102 
 
 DROP FORGING 
 
 103 
 
 Two auxiliary processes accompany or follow the 
 work of forging. During the forging a small amount 
 of material, called ** flash,'' is forced out of the im- 
 pression into a thin space provided between the face 
 of the dies. This is trimmed off either during or 
 after the forging process. During the forging, also, 
 a thin scale of iron oxide* is formed which is removed 
 later by pickling or in the sand blast. 
 
 The drop forging process is subject to some limita- 
 tions. Forging dies correspond roughly to the cope 
 and drag of the sand mold used in the foundry, and 
 impressions in the dies to the impressions left in the 
 molds when the pattern has been removed. In foun- 
 dry work the sand mold is temporary and is de- 
 stroyed after the casting has been poured, therefore, 
 the casting may have any shape. In drop forging 
 the dies are practically permanent; consequently the 
 forgmg must have no enlargements or bosses which 
 would prevent its being lifted freely out of the im- 
 pressions in the die. Furthermore no cores are pos- 
 sible, as in the case of foundry work, on account of 
 the heavy hammering, of the obstruction they would 
 offer to the distribution of the metal, and of the in- 
 ability to get them out of the finished forging. 
 
 Drop Hammer.— The drop hammer consists essen- 
 tially of a heavy steel ram sliding between two verti- 
 cal guides mounted on an anvil or block which forms 
 a base. The upper die is keyed to the hammer head 
 and the lower die, in accurate register with the upper, 
 js keyed to the base. In the early form of drop 
 hammers, used in the Colt Armory about 1860, the 
 l^oads were lifted by a vertical rotating screw to a 
 
 '1,.;^ 
 
if 
 
 104 
 
 THE MECHANICAL EQUIPMENT 
 
 definite height which was determined by an adjust- 
 able trip. This method was slow and has long since 
 been superseded. For light work, such as jewellers' 
 hammers, the head is lifted by a strap which runs up 
 over a pulley and down to the floor where it is 
 operated by foot power. For slightly larger hammers 
 the belt may be operated from above by a pulley with 
 various forms of release mechanism to allow the 
 hammer to fall. While a few belt and rope drops re- 
 main, the board drop has, in the East, practically 
 superseded all others for medium-sized work and the 
 steam drop for large work. In the Middle West, the 
 steam drop is used for light and medium work also. 
 In the board drop. Figure 22, one or more boards 
 are keyed into the top of the hammer head, and two 
 rollers at the top of the hammer are pressed together 
 and roll the board upward. When the head has 
 reached the height desired, a trip on the side of the 
 hammer head operates a latch rod which, in turn, 
 spreads the rollers apart and allows the hammer and 
 board to fall freely on to the work below. As the 
 hammer reaches the bottom of its stroke the latch rod 
 throws the rolls together again, and they roll the 
 board up to the top of the stroke. The operation is 
 controlled by a foot lever. If a single blow is desired, 
 the treadle is depressed and released at once; the 
 hammer will then fall, rise to its top position and 
 stop. If a succession of blows is desired, the treadle 
 is held down and the hammer will continue to operate 
 automatically until the treadle is released. Clear, 
 straight-grained maple, free from all knots, is the 
 only material which will stand up under the severe 
 
 t • 
 
 FIG. 22. MEDIUM-SIZED BOARD DROP HAMMER 
 
 Cliamoersburg Engineering Co. 
 
 105 
 
104 
 
 THE MECHANICAL EQlIPMExNT 
 
 (h'iiiiito ]HM<;lit which was di'tiM'iniiH'd by an ad,iust- 
 abh^ trip. This iiietliod was slow and has h)n^- since 
 been suporseded. For light work, such as jewellers' 
 haniniers, the head is lifted l)y a stra]) which runs up 
 over a pull(»y and down to the floor where it is 
 operated l)y foot j)owcr. Foi- sli<;htly lari^er hammers 
 the belt may be ()p(M-at<Ml from above by a ])ulley with 
 various forms of release mechanism to allow the 
 hauunei- to fall. While a f(^w belt and rope drops re- 
 main, the board drop has, in the Fast, practically 
 superseded all others for medium-sized work and the 
 steam drop for lari»e woi'k. In the Middle West, the 
 steam drop is used for li^ht and medium work also. 
 In the board drop. Figure 22, one or more boards 
 are keyed into the top of the hanuner head, and two 
 rollers at the top of the hammer are pressed together 
 and roll the ])oard upward. AVhcn the head has 
 reached the heiglit desired, a trip on the side of the 
 hanmier head operates a latch rod which, in turn, 
 spreads the rollers apart and allows the hammer and 
 })oard to fall freely on to the work below. As the 
 hammer reaches the bottom of its stroke the latch rod 
 throws the rolls together again, and they roll the 
 board up to the top of the stroke. The operation is 
 controlled bv a foot lever. If a single blow^ is desired, 
 the treadle is depressed and released at once; the 
 liannufM* will then fall, rise to its top position and 
 stop. If a succession of blows is desired, the treadle 
 is held down and the hammer will continue to operate* 
 automatically until the treadle is released. Clear, 
 straight-gi-ained maple, free from all knots, is the 
 only material which will stand up under the severe 
 
 PIG. 22. iviEnir:ir-sizED board drop hammer 
 
 Chain iiershiir;; IOnsineeriii«,' Co. 
 105 
 
 L 
 
106 
 
 THE MECHANICAL EQUIPMENT 
 
 crushing pressure of the rolls. It is expensive and 
 difficult to obtain, and many attempts have been made 
 to substitute paper, fibre, and other materials, but 
 nothing has as yet proven satisfactory. One of the 
 rolls in the head is carried in fixed bearings and the 
 other roll is mounted on an eccentric bearing oper- 
 ated by a latch rod. The raising or lowering of the 
 latch rod rotates the eccentric and presses the 
 movable roller in and out against the board. The 
 rollers are driven by pulleys and rotate continuously. 
 
 The weight of the base of a drop hammer should 
 be from 12 to 20 times that of the head, as a heavy 
 base will increase the size of the forging work which 
 inay be done for a given weight and fall of hammer 
 head. Board drops, as in the case of steam ham- 
 mers, are rated by the weight of the head, which runs 
 from 200 up to about 3,000 pounds. The board and 
 friction rollers are not practicable for weights beyond 
 this, and the larger sizes of drop hammers, which 
 range from 3,000 as high as 12,000 pounds, are 
 operated by steam. The steam drop hammer is es- 
 sentially the same as the board drop except for the 
 lifting mechanism. It corresponds to the first type of 
 steamer hammer mentioned on page 88, except for 
 the general design of the frame which conforms to 
 that of the board hammer. 
 
 Trimming Press. — ^It is impractical to guage 
 exactly the amount of metal necessary to fill the im- 
 pression. To make sure that it is filled, an excess of 
 stock is always provided which is allowed to go off 
 sidewise into a space provided between the surface 
 of the dies. The fin, or flash, which results must be 
 
 DROP FORGING 107 
 
 the whole run has been made, but this can only be 
 done on small work, as the flash is thin and chills 
 quickly and retards forging. For large work, there- 
 fore to allow the hammer to expend its energy on 
 
 I'n T^V'l''''^/'^ ^^' ^^^^' ^ *^™^i^^ press is in- 
 stalled at the side of the hammer and the forger will 
 
 step over to the press and trim the forging once or 
 twice during the progress of the work. 
 
 Dies—The dies for drop hammers are rectangular 
 bbcks which, for general all-around work, are made 
 of 60-point open-hearth steel. By -60-point steel- is 
 meant one having six-tenths of one per cent of car- 
 
 . i on ^""^^ ''''"''^^^ ^^ *^^^ steel forgings are 
 wanted 80 to 90-point tool steel is better; and for the 
 severest use 3% per cent nickel steel may be Led 
 
 here are not many pieces. It has been considered 
 
 treacherous material for dies and is only used- because 
 
 the impression could be cast in the face and little 
 
 finishing work is required. 
 
 Recent experiments have shown cast iron dies in a 
 
 mSriA^^^^ ^^ ^^^^^^^' ''^ -ore is 
 
 wetht of ft ?^P'^^T P"''"'^ '' ^^*^«^^«d the 
 weight of the iron and consequent crumbling, which 
 
 ordinary sand could not do. The molding flasks are 
 m three parts-the Mrag,' containing the core and 
 
 pattern, and the 'cope,' the wood pattern of the 
 
 llT.i:\tT''^ '"^^^' '' P^^™^ '^^ -^te« iron 
 through the top, a special inlet is made through the 
 
 ■I •<t^\ 
 
 .'I/ 
 
108 
 
 THE MECHANICAL EQUIPMENT 
 
 sand and to one side of the mold, allowing the iron to 
 run out gently over the core instead of falling onto it. 
 In this way the mold is filled from the bottom up, 
 making possible the easting of delicate impressions 
 without fear of breaking the sharp corners. A riser 
 is left in the top of the mold providing for th-e 
 shrinkage of the cooling iron and for bringing the 
 *slag' to the surface. All that remains to be done to 
 prepare the castings for the hammer is to clean out 
 the impressions with a brush or die and to stamp 
 them with their designating numbers."* The reports 
 of these dies show a saving in time and expense. 
 **The maximum time required to turn out cast-iron 
 dies ready for the hammer is four days; the average 
 time for steel dies is between one and four weeks. 
 * * * In many cases the life of the dies nearly 
 equals the average duration of steel dies. Even if 
 cast-iron dies did not produce one-third as many 
 forgings as steel dies, the saving in cost would be 
 sufficient to justify their use, letting alone the time 
 saved." 
 
 The backs of dies, where they are secured to the 
 base and to the hammer head, are provided with 
 dovetailed shanks which slide into corresponding 
 grooves and are then tightened with a taper key 
 driven in by a sledge. In selecting the size of the 
 die blocks sufficient metal should be left around the 
 impressions to make sure that the die will not split. 
 For ordinary work 1^2 inches is enough. The depth 
 of the blocks runs from about the same as the width 
 to about % or 2-3 of the width; for wider blocks the 
 
 ♦American Machinist, October 12, 1916. 
 
 DROP FORGING 
 
 109 
 
 depth increases. A die 14 inches wide would be 
 about 8 inches deep. The length varies with the 
 forging to be made. 
 
 Die Working.— The first operation in preparing the 
 blocks IS that of planing the edges square and true, 
 as the impressions are located from the edges. The 
 blocks are then turned over and the shanks cut. So 
 far as possible the size of shanks should be standard- 
 ized to insure interchangeability of use in the various 
 hammers available. 
 
 Before laying out the impressions one or more tem- 
 plates are made of sheet steel, the principal one 
 giving the contour of the forging along the parting 
 Ime of the dies. Other templates are made of the 
 cross sections at various points. These templates 
 must allow for the shrinkage of the forging, for any 
 extra stock to be machined off later, and for draft 
 Draft IS a taper of not less than 7 degrees on all 
 straight sides of the forging so that it may be freely 
 hfted out of the die. Without this draft the forging 
 IS liable to stick and give trouble. If possible the 
 draft is put on surfaces which are to be machined, as 
 It then disappears in the finished piece. More draft 
 should be allowed for an internal surface, as shown 
 m Figure 23, than for an outside one, as the 
 metal in shrinking tends to seize the sides of a pluR 
 in the die while it tends to free itself from outside 
 surfaces. The choice of the best parting line is a 
 matter of skill and experience. Often a curved sur- 
 face IS used which follows an available line in the 
 torgmg, as the butt plate for a rifle shown in Figure 
 ^% and the receiver shown in Figure 26. This is 
 
 I 
 
no 
 
 iliii 
 
 TKB MECHANICAL EQUIPMENT 
 
 •Spof^ Centering 
 
 ^P''"^ j^^ Flash 
 
 w///////////y/////////. 
 
 Outside Praf/ 
 
 Inside Dfaff 
 
 Oufside ■■ 
 Prarf 
 
 flash 
 
 FIG. 23. LONGITUDINAL SECTION OF A DROP FORGING FOR A 
 CONNECTING ROD PRIOR TO THE TRIMMING OPERATION 
 
 necessary in bent pieces, as the forging must in all 
 cases lift out of both dies freely. 
 
 Having determined the parting line, the faces of the 
 die are planed, and the impressions are laid out with 
 the aid of the templates. The impressions in the two 
 dies are right and left-handed, so that they will match 
 when the two faces are brought together. The num- 
 ber of impressions required depends on the size and 
 
 FIG. 24. DIE BLOCKS FOR THE BUTT PLATES OF A RIFLE 
 SHOWING INTERLOCKED DIE 
 
 DROP FORGING jij 
 
 S'afd ^^^^^ '" ^^^-^^ th-e is a rough- 
 
 ing and a finishing impression, and an -ed^'- or 
 side breakdown Tho loof • . *^ugei or 
 
 function irfl^./! !i, ' ^^""^ important, as its 
 
 ine sme ot the blocks, are used for drawing out th^ 
 stock. In Fia-nrA ')'^ th<. «„ * • "'"wing out tJie 
 
 the original b^s oef Ld Ihrslcfn^ T"^ "' 
 after the fuller has drawn itttTudlh? X^'Z 
 readvin l\ ""t' " *'^" substantially i/plaee 
 
 Alter the forging impressions have been or^^ fi. 
 surface of the die is mi^lArl «ff + \ ^ *' ^^^ 
 1/32-inch for a w'dth ZTvi^y" \^T^ '^ ^''""t 
 it may be deepened t ilf \ '^ "'?' ''^^°°** ^^^^^^ 
 
 "®" the forging is completed. Where th^./ 
 
 tlefac ';r;^ tT^ ™P--ions may be eft on 
 race and are used progressively. The last im- 
 
 
 
il 
 
 ■:| 
 
 ?* ^ S 
 « 52 * •* 
 
 3^Q .2 
 0, -^ c 3 
 
 SEC 
 
 M 
 
 
 9> 
 
 bfii 
 
 =1 _ 03 
 
 V V 9) o 
 
 M -g - u 
 
 to 
 
 X .2 2 
 
 ^ 
 
 2£ 
 
 O. bO 
 
 22 .E 
 
 D, go 
 
 * to 
 
 •2 * £ ~ 
 OS 
 
 i 
 
 « E 7 
 
 0, C J, 
 
 _ ^ 
 
 
 alE 
 E *- 
 
 o 
 
 ■2 « 
 
 .g-S 
 
 111 
 
 « 
 
 •O "O 
 
 i-s:s 
 
 FIG. 25. STAGES OF A DROP FORGING 
 
 112 
 
 DROP FORGING 
 
 113 
 
 FIG. 26. DIE BLOCKS FOR A SHOT GUN RECEIVER, 
 SHOWING INTERLOCKED DIES 
 
 pression is used only to give the final blow and bring 
 the work to size. Letters may be cut in this im- 
 pression so that the forging bears some desired mark- 
 ing, such as the maker's name, the size, or part num- 
 ber. By the time the forging has reached this last 
 impression it has assumed almost its final shape and 
 the only work to be done is to bring out sharply the 
 details, such as the lettering referred to. By this 
 succession of impressions the last one retains its ac- 
 curacy a long time. The side impressions used for 
 the preliminary work are called the "breaking down" 
 impressions, and the upper ones "finishing" impres- 
 sions. The impressions will, of course, wear out 
 lias appears by the rounding off of corners, and the 
 gradual widening of the impression and loss of definite- 
 ness. ihe dies may sometimes be re-faced and re-cut 
 
114 
 
 THE MECHANICAL EQUIPMENT 
 
 Often they fail by cracking or splitting, which 
 precludes their further use. After dies are cut they 
 are usually hardened on the face and shanks, as these 
 are the two portions subject to wear. Some makers, 
 however, have the shanks soft and claim better re- 
 sults against breakage. It is desirable that the main 
 portion should be as tough as possible and conse- 
 quently these are left unhardened. In order to in- 
 sure the registering of the two impressions they are 
 accurately located with reference to the planed edg«s. 
 When the dies are set in the hammer they are lined 
 up by these edges and it is then known that the 
 position of the impressions is correct. 
 
 Heating. — In heating steel for forgings, the tem- 
 perature should be raised slowly to about 600 degrees 
 Fahrenheit, and after that it can be raised as quickly 
 as desired to the welding temperature. This is due 
 to the fact that steel is not ductile below about 600 
 degrees Fahrenheit, and is not fitted to resist the 
 strains imposed upon it by the differential expansion 
 of an unevenly heated metal. 
 
 By heating suddenly, the outer shell becomes red 
 before the core has had an opportunity to absorb any 
 heat, and great strains are thus caused by the ex- 
 pansion of the outer shell. Due to these changes 
 when heating up cold steels and especially the high- 
 grade alloys, many poor forgings are turned out by 
 raising the temperature of the metals too suddenly. 
 
 The Forging Operation. — Drop forgings are made 
 from forging bar stock cut into convenient lengths 
 to make a certain number of forgings and heated 
 usually in gas or oil furnaces. When ready for forg 
 
 DROP FORGING 115 
 
 ing the heated end of the bar is placed under the 
 hammer, drawn out, if necessary, on the fuller, and 
 bent into the approximate shape on the edger. It is 
 then laid over on the face of the die on the forging 
 mipression and the forging work is performed. As 
 the metal is brought to size the flash begins to appear 
 and, in the case of large forgings, is trimmed off as 
 the work progresses. 
 
 The number of blows required varies with the size 
 and shape of the work. Small and simple work may 
 be forged in one or two blows, while large work will 
 require many. Thin sections require a larger ham- 
 mer and more blows than a thick or chunky one, as 
 the hot metal is exposed to the cold surface of 'the 
 dies and chills quickly. When the forging is finished 
 It IS cut off at the sprue and drops out on the floor, 
 while the bar is returned to the fire for reheating 
 
 Pickling.— After the forgings are made they are 
 pickled by dipping in dilute sulphuric or hydrochloric 
 acid and rinsed off in hot water. This operation is 
 similar to that already described for castings in 
 foundry work. 
 
 Cold Trimming.-Small forgings are always 
 trimmed cold, as it is much faster and cheaper than 
 hot trimming. This work is done in stamping presses 
 and the forgings may be handled by hand. Trim- 
 ming dies have the form of the forging around its 
 parting line. For ordinary work thev are flat with 
 their cutting edges in one plane. The trimming dies 
 tor forgings having an irregular parting line must be 
 oent to conform with the surface of the forging dies. 
 If the piece is to have a hole in it, the flash which 
 
116 
 
 THE MECHANICAL EQUIPMENT 
 
 closes this hole must be trimmed separately from the 
 flash on the outside. Forgings, like castings, are sub- 
 ject to shrinkage, and consequently the size of hot 
 trimming dies must be larger than the finished work 
 for they do their work before the shrinking has 
 taken place, and the parting template used to lay out 
 the forging dies may be used to lay out the trim- 
 ming die. Cold trimming dies are the size of the 
 finished forging. The steel for the trimming dies is 
 usually 60 to 70-point carbon tool steel, hardened and 
 tempered, while the punch may be low carbon steel 
 as it has merely to push the forging through the die, 
 the lower end being shaped to fit over the forging 
 like a saddle. Trimming dies are usually sectional- 
 ized or made in a number of pieces fitted together 
 and mounted on a plate. This is to permit regrinding 
 when necessary. Otherwise the size when once lost 
 could not be restored. 
 
 On account of the shrinkage forgings will 
 inevitably distort somewhat in cooling. If they are 
 restruck when cold, in dies accurately cut for that 
 purpose, certain dimensions may be brought to 
 within .001 or .002-inch of specified size. Conse- 
 quently this work is sometimes done when great ac- 
 curacy is required, or to straighten forgings bent 
 during the trimming. 
 
 General Considerations.— The range in size of drop 
 forgings is from small pieces the size of a thimble to 
 pieces weighing 100 or 200 pounds. The process is 
 limited in its application by the cost of making dies, 
 and these are justified only for a comparatively large 
 number of pieces. Where forgings are to be drilled 
 
 DROP FORGING ny 
 
 later at right angles to the parting plane, the holes 
 may be located quite accurately in the drop for^in^ 
 by what IS known as -spot centering,- whereby 
 conical depressions are formed at the spot where the 
 hole IS to be drilled, acting as a starting point for 
 guiding the nose of the drill. Frequently drop for^- 
 mgs are forged in one plane and then bent in a sub- 
 sequent operation. A conspicuous example of this is 
 that of six-throw cranks for automobile engines. 
 
 the shaft IS then twisted in a subsequent operation so 
 that the cranks will stand at the required angles. 
 Frequently when the forgings are small and simple in 
 shape two or more may be forged at once. The dies 
 
 .'m 
 
 Ill 
 
II 
 
 CHAPTER IX 
 WELDING, SOLDERING AND BRAZING 
 
 General Classes of Welding. — Welding, as a branch 
 of blacksmithing, is a very old process — a general out- 
 line of smith welding was given in the chapter on 
 Forging. Of recent years new methods and ma- 
 chines have been developed which have enormously 
 increased the importance of welding and extended 
 its use. 
 
 Welding is the uniting of metals into one piece or 
 mass by hammering, pressing, or casting them 
 together while in a heated condition. Soldering is 
 the uniting of two pieces of metal with a third metal 
 applied in a molten state. Brazing, really a form of 
 soldering, is the uniting of two pieces of metal by a 
 thin film of soft brass. These processes run into each 
 other more or less. Two unlike metals such as iron 
 and platinum may be welded, while two pieces of steel 
 may be united by placing platinum foil between them, 
 pressing them together, and heating them. While 
 this is strictly welding, yet the platinum foil acts as a 
 solder. 
 
 There are two general classes of welding: First, 
 pressure welding — which includes both hand and 
 steam-hammer work on wrought iron and steel — and 
 electric resistance welding, known as the Thomson 
 
 118 
 
 WELDING, SOLDERING, BRAZING 119 
 
 process; and second, welding by casting, which in- 
 cludes electric-arc, gas-flame and thermit welding. 
 
 Welding under pressure is a mechanical process, 
 not a chemical one, and depends upon the plasticity 
 or flow of the metal as well as upon the wetting or 
 cohesion of the two surfaces at welding heat. The 
 latter can occur only when the two metallic surfaces 
 are m absolute contact. The interposition of any 
 foreign substance, such as a film of oxide which 
 cannot be pressed out by hammering or other means, 
 precludes welding. As pointed out on page 87 the 
 
 ::lZ/' 'ZV"" '^™ ^ «"^^ «lag by chemica 
 combination with the oxide which can be pressed out 
 
 and allow the two surfaces to come into actual con- 
 
 n.?"- T'^ P^'^P"'"' P'""^^"'"^ welding must 
 be done ma few second's time, and the previous 
 
 notT/tr , 'r""^ ""^^^ "•'* *^^^ ''^«- Were it 
 and^h.r . "' ^''' «^y-l»ydrogen, oxy-acetylene, 
 and thermit processes, commercial welding would be 
 confined to wrought iron, steel, nickel! and the 
 precious metals. 
 
 The term autogenous welding, as applied to the 
 eectnc arc and gas-flame methods is a misnomer 
 since It means self-welding. Fusion welding Tuld' 
 
 vlrZlVTT "°'^^^ '''' ^^^'•^-^'y hfgh tern 
 ftto ?„ " T ^"""^ "If ^ ^^' "^«*^1 I««^"y. causes 
 
 as w!fr' ^'^fi^.^y Hammering._What is known 
 a^^^w ding.heat varies with different compositions^ 
 
 grade, to dazzling white, about 1,500 degrees. As 
 
II 
 
 120 
 
 THE MECHANICAL EQUIPMENT 
 
 already pointed out (see page 87) the material mnst 
 be heated cleanly in a reducing fire, and the surfaces 
 must be shaped or prepared for the joint. As the 
 strength of a welded joint is less than that of the 
 stock itself, the joint is usually made on an angle. 
 Scarfing the joint at an angle strengthens the joint 
 by increasing the welding surface, and makes it 
 easier to apply the heavy pressures necessary to bring 
 the surfaces into contact. In general, large welds are 
 unreliable, as it is difficult to insure perfect contact 
 over all of the surface to be welded, and for this 
 reason steel castings are superseding built-up forg- 
 ings for large pieces such as ships' frames, rudder 
 posts, and locomotive side-frames. 
 
 Copper is weldable by pressure; it is not often 
 welded in this way, however, since soldering or 
 brazing is preferred. To weld copper the metal is 
 heated to redness, calcined flux containing borax and 
 a phosphate salt is sprinkled on the surface, and the 
 pieces are joined at a yellow heat and hammered 
 together, as in iron-welding. Copper may also be 
 welded by the electric process. Aluminum may be 
 pressure-welded, but it is not easy to keep the ends 
 free from oxidizing. The usual method of welding 
 is by the oxy-acetylene process, described later. 
 Platinum, gold, and silver may also be welded, but 
 need not be considered here. 
 
 Many manufactured products are based on the 
 process of welding. The oldest of these are welded 
 pipe and chains. Pipes are made from long, thin 
 strips of wrought iron or steel known as skelp. The 
 strips are curled up into tubes by drawing them 
 
 WELDING, SOLDERING, BRAZING 
 
 121 
 
 LAP WELD 
 
 CORRECT SCARFING 
 
 I 
 
 IMCORRECT SCARFING 
 
 BUTT WELD 
 
 ZJ 
 
 CZHK 
 
 JUMP WELD 
 
 CORRECT SCARFING 
 
 J nZMMHI] 
 
 INCORRECT SCARFING 
 
 CORRECT SCARFING 
 
 I 
 
 :^ 
 
 CLEFT WELD. USED FOR 
 STEEL 
 
 Z2 
 
 .SPLIT-WELD. USED FOR THIN 
 STOCK 
 
 FIG. 27. TYPES OP WELDS WITH CORRECT AND 
 INCORRECT SCARFING 
 
 through circular dies. The two edges are brought 
 ogether and welded, in the case of butt welds, 
 by being drawn through the annular opening between 
 a mandril and a circular die slightly smaller in size 
 than the outside of the pipe, which produces the 
 pressure necessary to make the weld. In the case of 
 lap or scarf welds a roll is also used to press the joint 
 down against a mandril or bar inside the pipe. Welded 
 pipes are made in commercial sizes of from %-inch 
 to 30-inch internal diameter. Beyond this size they 
 a e generally riveted. High carbon steels cannot he 
 
 r.r. r ^i^l' ^' ^^^^ '^"''^ '« P°"rly that the high 
 f hf tri ^^l^l^^^^'^l - «ff-t by the uncertainly 
 ot the weld. Chains are still welded largely by hand 
 a hou h 3^ ,1 ^^ ^^^ ^^^ ^^^^ automati c'alirfn 
 
 tTtCTr" ■"' *'' '''°™^°" *yP«- For small 
 
 ] eated^„ ^"" '"* ^'""^ ^P''-^"^ ^"""d bars, 
 
 Wlr! r ^ ^^' °^^''' ^"^^ '^^««<^ «!• scarfed by a 
 
 hydraulic press with a die of suitable shape The 
 
 ^ 1 
 
122 
 
 THE MECHANICAL EQUIPMENT 
 
 steel for chains must be pure, and low in carbon. 
 With chains, as with pipe, the strength depends 
 mainly on the perfection of the weld, and good prac- 
 tice limits the load to 50 per cent of the working 
 tensile strength of the material. For manufacturing 
 purposes electric resistance welding and the various 
 forms of fusion welding are generally more efficient 
 than smith welding. 
 
 Electric Resistance Welding. — There are two clearly 
 defined types of electric welding — resistance and arc 
 welding. Resistance welding was invented by Elihu 
 Thomson in 1877, and has been used commercially 
 since 1880. In this process a large volume of cur- 
 rent at low voltage is forced through the work and 
 across the joints to be welded. The heat developed 
 at the point of contact, which is the point of highest 
 electrical resistance, raises the temperature of the 
 material quickly to a welding heat. At the same time 
 the pieces are pressed together by heavy mechanical 
 pressure, which forces the softening surfaces together 
 so that complete contact is effected. The metal can 
 be raised to the temperature desired, and the heat 
 can be held for any length of time and increased or 
 decreased at will. 
 
 The elements of the apparatus are (1) a suppiy 
 of alternating current from a generator or power 
 service system; (2) a step-down transformer, usually 
 carried in the body of the machine, to lower the 
 voltage; (3) apparatus for regulating the current, 
 sometimes arranged to shut off the current automati- 
 cally as soon as welding heat is reached; (4) clamps 
 for holding the metal to be welded and transmitting 
 
 WELDING, SOLDERING, BRAZING 123 
 
 t?on« wl*" V\ "'""^ ''' ^^'•''^"^ tl^- t^o -c- 
 Hre bunffn '■ ■?''^'"'' '^'"'>«dy'"g these elements 
 tnfhrl ^ ^ J ' ^^"'*^ "*■ ^'^«« «"d types suited 
 to the kind and section of metal to be welded. One 
 or them is shown in Figure 28. 
 The following table shows the power and time re- 
 
 anrstelP ^^^^^ ""^ ^^"°"' ^^^^ '^^^^""' ^° i™° 
 
 Time and Poweb Reqmbed m e,.ectr,c Resistance Welbino. 
 
 Diameter 
 Inches 
 
 Area in I Kilowatts. 
 Square Inches Transformer 
 
 
 V4. 
 
 0.05 
 
 
 % 
 
 0.11 
 
 
 V2 
 
 0.20 
 
 
 % 
 
 0.31 
 
 
 % 
 
 0.44 
 
 
 % 
 
 0.60 
 
 
 1 
 
 0.79 
 
 
 11/8 
 
 0.99 
 
 
 W4 
 
 1.23 
 
 
 IV2 
 
 1.77 
 
 
 1% 
 
 2.41 
 
 
 2 
 
 3.14 
 
 Seconds To 
 Make Weld 
 
 Cost per 1000 
 Welds at One 
 Cent per Kilo- 
 watt Hour 
 
 The Thomson process has many advantages. The 
 operation, as seen from the table, is very rapid. Even 
 as many as twenty welds may be made in a minute. In 
 chain.we ding ten links a minute can be welded, of 
 
 ndef 7 r'- "^^^ ^^^""^ ^« --' local, knd 
 ;»der^perfect control. There is little danger of ex- 
 
 ♦ Machinery's Reference Book No, 127. p. 21. 
 
 M\ 
 
 i «? 
 
 I '• 
 
 ill 
 
 No 
 

 Trofta/brmer 
 
 f%ot-con!roi 
 
 
 FIG. 28. THOMSON BUTT-WELDING MACHINE 
 
 124 
 
 WELDING, SOLDERING, BRAZING 125 
 
 cessive heating, as there is with the arc and gas- 
 flame methods, consequently there is very little oxida- 
 tion or decarbonizing of the material. Practically all 
 the heat generated goes into the weld, and is so low 
 that the whole process can be watched with the naked 
 eye. Arc and gas-flame welding require glasses and 
 a hood to protect the operator's eyes from the blind- 
 ing light, and this hood necessarily is a hindrance 
 to the worker. 
 
 The clamps that are used for forcing the pieces 
 together may be machine-operated and accurately 
 alhgned, so that the locating of the parts during the 
 weld may be very close. There is a high power effi. 
 ciency amounting to 75 per cent and over. The 
 power IS used only as long as needed, and may be 
 
 moderate, fimshed or nearly finished work may be 
 ^.•elded with little or no damage. Finally, the ap. 
 paratus can be operated by even a moderately skilled 
 workman with little danger. 
 
 The method has been applied successfully to weld- 
 ng more lands of metals and combinations of metals 
 
 The Thomson process is better adapted to "repeti- 
 mes T'~;° ^7'°™'"^ '""^ same operation m'any 
 <tpparatus requires a more or less elaborate machine 
 
 general outside work as gas-flame welding It de 
 2^a large amount of power at irregular intervals, 
 
 Modern Shop Practice, Vol. 11, p. 239. 
 
 " i 
 
 . 
 
'Fhessurc honcf/e. 
 
 IBrec//rJir/7cA 
 
 'Trarta/hr/ner 
 
 f^ot- cotifrot 
 of- bre<if< srrifct 
 
 
 v^#' 
 
 FIG. 28. THOMSON 1JUTT-WKL1)1X(J MACHINE 
 
 324 
 
 WELDIXO, SOLDERTXO, BRAZING 125 
 
 cessivo liealinu- as tlioro is will, tlie arc and gas- 
 ilamc methods, ('oi,sc(iiieiitly there is verv littlo oxida- 
 tion or decarbonizing of tJie inaterial. Practically all 
 the heat g.^nerate<l goes into the wehl, and is so' low 
 that the whole process can he watched with the naked 
 eye. Arc and gas-flanu^ welding- require^ glasses and 
 a hood to protect th(^ operator^ eyes from the l,lin<i- 
 n.i;- light, and this hoo<l necessarily is a hindrance 
 to the worker. 
 
 Tlu. .-lamps (lu.f .-u-o usod for lo,-,.i„g. i|h. pieces 
 to«vllu.r nmy l„. ,na.-hin,.-operat.,l an.l accurately 
 aII.Kn..<l, so that the locating, of the parts .luring the 
 ^vehl may he very close. Th.-re is a high power effi- 
 '■'wicy amou.it.ng to n per .-..„t ami over. The 
 l">^^"'- IS u..,.,l only as long as n.....le,|, ami mav be 
 
 ■•'|"'l off n..stantly. Sin.v the h.-ating is b.-afaml 
 
 "'■''';■'' ^^"'' '""'■ "'• >"> 'l.-'.nag... Finallv, th.^ ap- 
 i""-'l"s .-an l„. „perat,.,l by evn a mo.leratelv skilled 
 workman with iitll.. danger. 
 
 . '•''"' "'"tll'Ml has b,.,.n applie,! su....essfullv to w.-ld- 
 ;".«■ .M.nv kin.ls or nu.lals an.l .•..n.bim.tion; of m.4ah 
 '.■'-' any oth..- proc.-.s.s, as „,ay I,., s.-e,. by the list on 
 (lie tollowing page.* 
 
 'I'l';' Th.,mson pr.,....ss is b,.tter a.lapt...! to "rep..ti- 
 - w..rk-t., p.Mfonning th,. san... ..peration nmnv 
 '""••^-than t.) .loiMg sp....ial or job work Th'.. 
 •;i'l'=""<i-s r...p,ir..s a mon- or l....s elab.>rate machine 
 """ -••'■;'l.v portabl.., an.l is (h,.r..for.. n<.t .so g.,od W 
 :-;al outsi.le w.,rk as gas-name w..hling: U !;:: 
 •'^mds_a large anu.unt of pow..r at irregular intervals 
 
 .M"(l,.|n .SI,,,,, [',-,„.(i(e. Vol. II, ,,. r^X ' 
 
126 
 
 THE MECHANICAL EQUIPMENT 
 
 Wrought Iron Lead 
 Cast Iron Tin 
 
 Copper Zinc 
 
 METALS 
 
 Antimony 
 
 Cobalt 
 
 Nickel 
 
 Bismuth 
 
 Aluminum 
 
 Silver 
 
 Platinum 
 Gold (pure) 
 Manganese 
 
 Brass 
 Solder 
 Stub Steel 
 Coin Silver 
 Gold Alloy 
 Cast Steel 
 
 KIckel Steel 
 Gun Metal 
 Fuse Metal 
 Type Metal 
 Chrome Steel 
 Mushet Steel 
 
 ALLOYS 
 
 Crescent Steel 
 Bessemer Steel 
 German Silver 
 Silicon Bronze 
 Aluminum Iron 
 Aluminum Brass 
 
 COMBINATIONS 
 
 Aluminum Bronze 
 Phosphor Bronze 
 Brass Composition 
 Various Tool Steels 
 Various Mild Steels 
 
 Copper to Brass 
 
 Copper to German Silver 
 
 Copper to Gold 
 
 Copper to Silver 
 
 Tin to Zinc 
 
 Tin to Brass 
 
 Tin to Lead 
 
 Brass to German Silver 
 
 Brass to Platinum 
 
 Brass to Tin 
 
 Brass to Mild Steel 
 
 Brass to Wrought Iron 
 
 Wrought Iron to Cast Steel 
 
 Wrought Iron to Mild Steel 
 
 Wrought Iron to Tool Steel 
 Wrought Iron to Mushet Steel 
 Wrought Iron to Stub Steel 
 AVrought Iron to Crescent Steel 
 AVrought Iron to Cast Brass 
 Wrought Iron to German Silver 
 Wrought Iron to Nickel 
 Mild Steel to Tool Steel 
 Nickel Steel to Machine Steel 
 Gold to German Silver 
 Gold to Silver 
 Gold to Platinum 
 Silver to Platinum 
 Steel to Platinum 
 
 and for tMs reason may give trouble on the electrical- 
 supply lines from which the current is drawn. These 
 disadvantages, however, are not serious, and for 
 manufacturing work this method of welding is one of 
 the most useful that has yet been developed. It has 
 been extensively used in the manufacture of bicycles, 
 automobiles, typewriters, chains, wire fences, rakes, 
 and railway cars, and in spot welding of all kinds. 
 It is particularly good for small butt welds. The 
 strength efficiency of the weld is very high, running 
 from 75 to 95 per cent, and even over 100 per cent 
 
 WELDING, SOLDERING, BRAZING 127 
 
 When the upset resulting from the weld is not cut off 
 which means, of course, that the material when 
 
 welST ?,? " l'^ °"^'"^' ^^^^"^ -d not at Z 
 weld. In welding chain, from 10 to 30 per cent of 
 
 the joint. This loss of current is expensive, and con- 
 titutes one of the reasons why hand welding Z 
 holds Its place in the trade. The loss of current is 
 less for large rings. Garden rakes, which used to be 
 eastings, are now made by jump-welding the teeth on 
 to the crossbar. Rail-welding was first done by tMs 
 process, and special machines have been deveUed 
 for this particular kind of work. 
 La Grange-Hoho Piocess.-The La Grange-Hoho 
 
 hea nTV;r '^"^-^ -^^ ^" ''^' -erely^'ele^S 
 
 nof as ve^forr'' T^'""*'** ^" ^^'S'™' «"d has 
 not as yet found much use in this country The 
 
 oiTe Joir'l '" '^^^^"^^ '' '"^^ -^-ti've pole 
 ot the circuit and immersed in an electrolyte bath 
 
 such as potassium carbonate solution. As the cur- 
 
 ent flows from the positive pole through the soL 
 
 taon and into the metal pieces, the solution begin^^^^^^ 
 
 decompose and deposits a thin film of hydrogen aboS 
 
 the pieces, protecting them as thev become hot As 
 
 soon as the welding heat is reached, the piecl; ate 
 
 vithdrawn from the solution and welded between tl e 
 
 hammer and the anvil i„ the usual manner The ad 
 
 vantage of the process is that the metals are cleansed 
 
 rom grease and dirt by the bath, and are pr tec ed 
 
 fi r il Tl ^""^ '''' ^^'^^'"^ »'y the hydrogen 
 him. The heat, however, is not very easily controlled 
 and the hot metal will oxidize in the air Vhen £ 
 
128 
 
 THE MECHANICAL EQUIPMENT 
 
 out just as quickly as if it had been heated in a 
 forge fire. 
 
 Electric-Arc Welding.— The three best known sys- 
 tems of electric-arc welding are the Zerener, the Ber- 
 nardos, and the Slavianoff. In the Zerener process 
 there are two carbon electrodes mounted in a frame 
 that holds them pointed towards each other and 
 toward the work. The electric arc between them is 
 deflected by a magnet and used in the same way as a 
 gas flame. Welding material is furnished in the 
 shape of a melt, bar. The apparatus is bulky, more 
 or less complicated, cannot be used with large 
 amounts of current, so that it is limited to use in 
 comparatively light work. The advantage claimed for 
 this system is that the arc may be controlled by the 
 magnet, and consequently fine work can be done. 
 
 The Bernardos system allows for the production of 
 an electric arc between a carbon negative electrode 
 and the material to be welded. Welding metal is 
 furnished by a melt bar. Direct current is used. 
 While any metal which does not volatilize or burn too 
 easily may be welded by the Bernardo process, it is 
 best adapted for use with cast iron, copper alloys, 
 and aluminum. When the graphite pencil is used, a 
 rotary motion is given to it which causes the arc to 
 play over the surface of the job, distributes the heat 
 evenly, and prevents burning. This motion also 
 drives the slag or impurities off to one side and away 
 from the weld. The adaptation of the Bernardos arc 
 to cutting is of recent date. When used for cutting, 
 the arc begins at the top and moves downward across 
 the face of the piece. It is not so efficient for this 
 
 WELDING, SOLDERING, BRAZING 129 
 
 purpose, however, as the gas flame, which makes a 
 cleaner and smaller cut and clears away the metal 
 as the flame advances. 
 
 In the Slavianoff process the welding heat is pro- 
 duced by an arc between the melt bar, or welding 
 metal— which forms the negative electrode—and the 
 metal to be welded. Continuous current at a low 
 voltage IS used. After the arc has been established 
 by touching the electrodes together and separating 
 then^ the welding pencil begins to melt and furnishes 
 the fil mg material. This system has been more sue 
 cessful with iron and steel than with other metals- 
 Its mam application has been in sheet-metal work,' 
 the metal electrode being deposited along the joint to 
 be made. The current required for this Slavianoff 
 process is much less than that for the Bernardos 
 process, but its action is much slower for operations 
 requiring the deposit of large amounts of metal, 
 l^robably, however, it is the most successful of the 
 arc welding processes. 
 
 All three of the arc welding methods are used on 
 large and varied kinds of work, such as jobbing work, 
 repairs, and so on. The temperatures in the arcs are 
 unknown, probably ranging from 5,000 to 7,000 de- 
 grees Fahrenheit, which is far above the melting 
 point of any metal. A skilful operator is required 
 and great care must be used to avoid over-oxidation 
 and burning away of the metal. As with the gas- 
 flame methods, the light produced is blinding to the 
 naked eye and the workmen must be protected by 
 noods or glasses, which more or less hamper manipu- 
 
130 
 
 THE MECHANICAL EQUIPMENT 
 
 Gas-Flame Welding.— These forms of welding 
 usually take their name from the gases used, as oxy- 
 acetylene, oxy-hydrogen, and so on. The oldest of 
 these uses an oxy-acetylene torch which is practically 
 a blowpipe that burns acetylene gas and oxygen. As 
 first applied, these gases were used under high pres- 
 sure; later, low pressure systems were developed and 
 now the danger that attended the process in its 
 earlier years has been largely eliminated. Figure 29 
 shows the connections of a typical torch with a section 
 of the nozzle. The utility of the torch comes from the 
 high temperature of the flame, which ranges from 
 6300 to 7000 degrees Fahrenheit, and which is able 
 to bring the part of the metal acted upon to a molten 
 condition before the heat can be radiated or con- 
 ducted away. This makes possible welding through 
 local recasting, and also cutting by burning a section 
 across the piece to be parted. In welding it is usu- 
 
 JOXVOEN 
 
 ^CCTYLBNB 
 
 &^^^m 
 
 H 
 
 FIG. 29. OXY-ACETYLENE WELDING TORCH AND TIPS 
 
 Davis-Bournanville Co. 
 
 H, H, Hose connections, with needle valves, for oxygen and acetylene. 
 T, Removable welding tip — five tips are furnished for varying pres- 
 sures and different thicknesses of metal. O, Oxygen inlet. A, Acety- 
 lene inlet, from both sides at right angles to oxygen inlet. M, mix- 
 ing chamber in tip. 
 
 WELDING, SOLDERING, BRAZING 131 
 
 ally necessary except in the case of very thin sheets, 
 to add meta to the joint. This is melted in from a 
 weldmg stick, or melt bar, of the same material as 
 the pieces to be welded. If the metals joined are 
 
 mlTi": " t'^ '' ""*^""' ^^^^^"^ the' same ele^ 
 Ted TV. T '°\'* ^ ^'^'' temperature should be 
 3;, 1 T^ '^""'"^ ^^ '^'•«« ^"«"gh to heat the 
 
 consumnfL T'''' ^T ''^ «™^ ""^^ ^ "-^^-naWe 
 consumption of gases. Ordinarily the flame is manip- 
 
 1 ated by hand, but recently various forms of apZ. 
 
 directed in a deS ^a^.'^^Tl^isTes^Tar:^^^^^ 
 ful in cutting and spot welding ^ 
 
 pressurTt/fir' f" l'"'*.""'' ^'' «^ "^^^^^ ™der 
 pressure is fed into the flame. The flame proper 
 
 raises the temperature of the metal far aborfhe 
 
 melting point; the excess oxygen furnished b^ tJe 
 
 burned, not melted, away. The cutting speed and 
 the penetration of these torches is remarkable ^r> 
 oxy-acetylene torch will cut steel 12 to iTinche 'thifk 
 and a hydrogen torch has cut metal 24 inches tW,' 
 
 tion are re™ r'^ °' ^" oxy-acetylene installa- 
 non are the apparatus generating or storing oxygen 
 
 ^a corpoVnH !r't""'- f ''*^'^"^ ^«« i« « "hemi- 
 
 the reactrbefw ? '"'* ^^^'•°^^"' ^^^^^ ^^om 
 
 eii™ carbTde ^Tr T '''^'^' ""*^ ^^t^^' ^al- 
 um carbide Itself IS not explosive when drv It 
 
 "as, however, a great affinity for moisture JZi fi 
 .as generated is explosive. I't is therete 'storedt 
 
132 
 
 THE MECHANICAL EQUIPMENT 
 
 air-tight cans. For large plants the oxygen may be 
 generated profitably, but for small plants and port- 
 able work it is purchased in steel tanks. The acety- 
 lene is generated in small quantities as used. The 
 generator is a steel receptacle for holding the gas, 
 with various attachments for controlling the action 
 of the water on the carbide. 
 
 The hydrogen used in oxy-hydrogen flames may be 
 obtained from the decomposition of water into oxy- 
 gen and hydrogen, both gases being collected and 
 used, or it may be formed by passing steam over 
 coke. It is, however, usually purchased in heavily 
 charged tanks. The oxygen used is produced com- 
 mercially by three methods: from the air, by liqui- 
 faction and distillation; from water, by electrolytic 
 action; and from potassium chlorate. The first of 
 these methods is the most important commercially. 
 Although the production of oxygen is not a compli- 
 cated process, the apparatus is rather expensive and 
 its use is justified only when the quantities used are 
 rather large. Oxygen is sold in tanks containing 5, 
 25, 50 and 100 cubic feet. 
 
 Two kinds of acetylene generators are used, known 
 as the water-to-carbide, or water feed, and the car- 
 bide-to-water, or carbide feed. The first is little used, 
 because the apparatus may get hot and be a source 
 of danger. When the second method is used, pow- 
 dered or granular carbide is dropped into the water; 
 the gas is washed as it is evolved, and the apparatus 
 is kept cool. Furthermore, water-feed generators give 
 off gas long after the water is stopped, but the car- 
 bide feed gives off gas only for a short time after- 
 
 WELDING, SOLDERING, BRAZING 133 
 
 ward. GeneraJIy about a gallon of water is used for 
 each pound of carbid^ne pound of lump carbide 
 will generate 41/2 cubic feet of gas 
 
 .rttlTT'-~'^^' advantages of gas-flame welding 
 are that the apparatus required may be either light 
 and easily portable, or may be installed permanenfly 
 For repair work, the gas flame shows low cost and 
 ^celent results. The improved methods of controll- 
 ing and guiding the flame have extended the use to 
 manufacturing work, in which it is compeLrac 
 
 hJatVtt t ^'^"""^ P™^^^^- ^-'^^ t' ^« higt 
 
 once ff 5 7' T^ ™'*^^ "^° ^' ™«"ed locally at 
 
 those of frf\ ■^'' disadvantages are similar to 
 
 e„, 12 *^!,t'*"' ^''' ^° *^^* « ^J^i'l^d operator is 
 
 teTh i:?f^'' "?* "'' " """"^ ^°^ sl--« to pro- 
 tect himself from the intense brightness of the in 
 
 meuT?- V- ^-t^^™-. as the weld is a' 
 o'xldaS " *'^ ''^" ""'' '' "^ ^"^^--^ *« -- or less 
 ^rZ^'l'^^^ gas flame is used for welding wrought 
 
 and steerl^r'r^^l'" "" ^^^' ^^ ''^^^^ on iron 
 
 b lot il/ • I '* ^^' ^'^° ^PPli^d successfully 
 in spot welding m the manufacture of metal goods It 
 
 has been widely used in cutting work of evfrTkln? 
 
 S In ki'nds '°^ ""* ''''^' '"^ ^'""^ ^^'^^S« ^ork 
 
 by^rTl^?**-^-"^"'"'"^* ^«'^^"g ^as invented 
 ^y 13r. Goldschmidt, of Essen, Germany. By this nro 
 
 tiie parts to be joined, and finely divided iron oxide 
 
 I 
 
 :«.!<' 
 ,,jjii. 
 
 4 
 
 '^1 
 
134 
 
 THE MECHANICAL EQUIPMENT 
 
 and powdered aluminum are poured into the mold and 
 burned. A chemical reaction follows which produces 
 pure iron and aluminum oxide. The temperature of 
 the reaction is about 5400 degrees Fahrenheit, or 
 nearly 2000 degrees above the melting point of iron 
 and steel. The iron formed by the reaction makes a 
 superheated bath around the joint. The ends of the 
 work which are to be joined are therefore melted, and 
 fuse with the molten metal in the mold, while the 
 aluminum oxide formed rises to the top of the molten 
 mass and is skimmed off. When the reaction is over, 
 the whole cools into a solid mass. 
 
 The thermit process is obviously applicable only to 
 iron and steel, as it involves a chemical reaction with 
 iron. Its advantages may be summed up as follows: 
 first, the apparatus is simple; second, high skill is 
 not needed to do the work; third, it is possible to re- 
 pair breaks difficult of access and to mend broken 
 parts where they are which otherwise would have to 
 be taken out; fourth, local heating is possible on a 
 larger scale than is possible with the gas flame. The 
 thermit process has been used successfully in welding 
 rail joints, and forms of molds have been developed 
 specially adapted to that work. The process is 
 adapted only to rough and large work, and is too 
 cumbersome for general use in manufacture where 
 the Thomson process and the gas flame have been 
 successful. For pieces below four square inches in 
 cross section, other processes are better. Some won- 
 derful repair work has been done with this process 
 in the welding of ship frames, rudder posts, and so 
 on. The breaking strength of a thermit weld runs 
 
 WELDING, SOLDERING, BRAZING 135 
 
 about 60,000 pounds a square inch. If the reinforce- 
 ment can be left on the weld, it will have a greater 
 strength than the original material; if it is ma^chined 
 
 sttngth'' '^'"' ^^^'' """* "^ ^^' ^^i^i^-1 
 
 for^tJT''^ ^^ Brazing.-Soldering and brazing dif- 
 
 tie sold Tl' '^' ''''''' ^^^ ^^^^^i^l ^^^^ 
 
 tor the solder must be such as will actually wet the 
 
 surfaces or amalgamate with the pieces to be joined 
 
 An alloy of lead and tin is generally used, althTgh 
 
 special solders are made without either of them. Sol-" 
 
 on'lf ir Z "'! "' ^'^'^^ ^' ^^^^^^ ^^ brazed 
 ones, because the strength is limited to that of the 
 
 t*"f hr\f '^' "f .' ^^ ''^''' ^'-^y^ ^-- than 
 
 iea LT 'S'' ""'^'^ ^^' P^^^^^« ^^^^i-^« less 
 heat than welding or brazing, is easily performed, 
 
 and requires almost no apparatus. An ordinary gas 
 
 flame or blow pipe may be used. For work of mS 
 
 erate size a gasolene or kerosene torch may be em- 
 
 nZttT 'T.'"^ r^ ''' frequently'used for 
 running m the solder. The common fluxes are sal 
 
 and borax. These are used to dissolve any grease 
 and to remove any oxide present, and they leave a 
 ^tTborttn .'" ^'^ '""''^^ '^ ^^*- Most Ll^rs^^^^^^^ 
 
 procei 'T i ^^'^' ^^^ ^'^''''' The soldering 
 
 process consists of scraping the surfaces clean, heat 
 
 m!2'l^^^^^ temperature by any s;itablL 
 
 soSer% rf/ ^.^' '"'^^''' *^ ^' ^'^^"^^^ melting the 
 solder into the joint, and finishing off the joint after 
 
 
 ■'!!, 
 
136 
 
 THE MECHANICAL EQUIPMENT 
 
 it has cooled. The most important requirements are 
 to watch the temperature and the flux. Too high heat 
 causes oxidation and makes the solder run too freely; 
 poor fluxing prevents the solder from amalgamating 
 with the pieces to be joined. Nearly all the metals 
 except aluminum are soldered commercially. The 
 process is used only for small work and on joints 
 which do not have to carry a heavy strain. 
 
 Bra^ng Process. — This process is similar to solder- 
 ing, the main difference being the use of a harder 
 filling material, which requires a higher melting tem- 
 perature. Iron, copper, and brass may be brazed. 
 Brazing alloys— or spelters, as they are called— are 
 mixtures of copper, zinc, and tin. The composition 
 varies with the nature of the work; the hard spelters 
 give a stronger joint, but require a higher tempera- 
 ture. The flux used is made of borax or boracic acid, 
 and the heating apparatus usually takes the form 
 of a gasolene or kerosene torch for small and moder- 
 ate-sized work. A blacksmith 's fire may be used, but 
 care must be taken to keep the parts from touching 
 the fuel, and a reducing flame is necessary since the 
 work is done at high temperature. Iron and steel 
 require a high heat, for which a blue Bunsen flame 
 is generally used. 
 
 In brazing, the surfaces must be cleaned by scrap- 
 ing, washing and brushing, then the flux is applied, 
 and the pieces are clamped in position ready for join- 
 ing. The heating should be gradual and well distrib- 
 uted. The spelter, which is melted in when the proper 
 temperature is reached, will flow into the space left 
 between the parts and make a tight joint. After the 
 
 WELDING, SOLDERING, BRAZING 137 
 
 operation is completed, the pieces should be allowed 
 to cool slowly. For large quantities of work, immer- 
 sion brazing is used, which consists in cleaning and 
 fluxmg the parts, clamping them together, and dip- 
 pmg them into a tank of molten spelter. Brazed 
 joints, when well made, may be as strong as the orig- 
 inal metal and while they are not so good as welds 
 they are cheaper and easier to make. When used in 
 manufacturing processes, special holding devices may 
 be employed, which greatly facilitate the work. Braz- 
 ing is used widely for small joints, and is a reliable 
 commercial process. ^^uaoie 
 
 
 Am 
 
 lit 
 
 I , . . I; 
 
 i. 
 

 . 
 
 CHAPTER X 
 HEAT TREATAIENTS 
 
 Variability of Steel Properties.— The physical prop- 
 erties of steel, such as hardness, strength, and tough- 
 ness, may be varied to suit particular needs to a de- 
 gree possible with no other material. We are so used 
 to the marvel of easily and accurately cutting a piece 
 of steel -with an edged tool made from the same bar 
 that we do not appreciate it. A railroad rail, the 
 rudder post of an ocean liner, a watch spring, and a 
 razor are composed, in the main, of the same material. 
 The difference in their properties is due to the pres- 
 ence of certain alloying constituents and to the heat 
 treatment to which they may have been subjected. 
 These two factors are closely inter-related. Heat 
 treatment consists of heating and cooling the metal 
 through certain temperature ranges and with certain 
 rates of temperature change. Of the various metallic 
 materials, steel offers the widest variation of physical 
 properties through heat treatment. The capacity so 
 to manipulate it depends upon both the kind and the 
 percentage of alloying constituents. Pure iron cannot 
 be hardened. 
 
 The principal alloying element in steel is carbon, 
 and steels which contain only carbon as a useful ele- 
 ment are called carbon steels. The percentage of car- 
 
 138 
 
 . . HEAT TREATMENTS 139 
 
 bon present forms the basis for commercial classifica- 
 tion. Below 0.15 per cent the material may be either 
 steel or wrought iron, according to whether it was, or 
 was not, molten in the early stage of its manufacture. 
 Steel which contains from 0.15 to 0.35 per cent of 
 carbon is known as machinery steel; from 0.35 to 60 
 per cent, as open-hearth steel; and from 0.60 per cent 
 up to a maximum of 2 per cent, as crucible or too) 
 steel. Other elements— such as sulphur, phosphorus, 
 and sihcon-may be present in small quantities, but 
 constitute undesirable impurities. Manganese is also 
 present, and up to a certain limited percentage is a 
 desirable element. Carbon steels are referred to as 
 twenty point or thirty point, according to the number 
 ot hundredths of one per cent of carbon present In 
 general the strength of steel rises with the increase 
 m the carbon. Ten-point steel is nearly 25 per cent 
 stronger than pure iron, and through a considerable 
 range the tensile strength rises about 214 per cent for 
 each point of carbon added. Of recent years there 
 has been rapid development of steels known as high- 
 speed steels, for cutting purposes, which derive their 
 properties from the addition of other elements, such 
 as chromium, tungsten, vanadium, molybdenum, man- 
 ganese, and nickel. Since, however, their composition 
 and treatment are too complex to be discussed here, 
 this discussion will be confined mainly to a consider- 
 ation of carbon steel. 
 
 Heat Treat Processes.-There are the following 
 tour well-known forms of heat treatment: 
 
 1- Hardening, which consists of heating the steel 
 
140 
 
 THE MECHANICAL EQUIPMENT 
 
 
 to a certain temperature and quenching it sud- 
 denly in some cooling medium. This process is 
 used to produce very hard wearing surfaces, 
 and the cutting edges of tools. 
 
 2. Annealing, which is similar to hardening, ex- 
 cept that the steel is cooled slowly instead of 
 suddenly. It is used to relieve internal stress 
 due to cooling or mechanical working, to pro- 
 duce soft steel suitable for machining, and to 
 restore fine grain to steel which has been coars- 
 ened by overheating. 
 
 3. Tempering, which consists in reheating hard- 
 ened steel to a certain temperature, much below 
 that used in hardening or annealing, for the 
 purpose of partially restoring its ductility and 
 softness. The rate of cooling is unimportant. 
 This process is used to produce a desired de- 
 gree of toughness and hardness, and to raise 
 the elastic limit to permit large deformations 
 without permanent set, as in springs. 
 
 These three processes act through temperature 
 changes merely to alter the molecular condition of 
 the steel without varying the total carbon content. 
 To these may be added a fourth closely allied process: 
 
 4. Case-Hardening, which consists of raising the 
 carbon content of the surface of low carbon 
 steel so that it can be hardened, annealed, or 
 tempered like a high carbon steel. 
 
 Bardeningf. — The hardening of carbon steel is due 
 to a change of internal structure which takes place 
 
 HEAT TREATMENTS 141 
 
 when it is heated properly to a definite temperature. 
 Ihis temperature varies with different steels. The 
 process is applicable only to those having more than 
 a20 per cent of carbon, and is usually confined to 
 those m the neighborhood of 1.0 per cent. To under- 
 stand the process it is necessary to glance at what 
 happens to the internal structure of steel when it is 
 heated and cooled. 
 
 In steel at normal temperatures the chief hardening 
 
 knor:f "1-?' Tr '' ^ p^^* '' - --titrnf 
 
 known as pearlite. If heated to a certain critical 
 empei^ture the pearlite takes another f m k^own 
 as a^steni e, which gives steel its hardening prop 
 erty. If a lowed to cool slowly from this temperature 
 the a^stenite changes back again to pearlite,Vd the 
 el becomes soft again. In Figure 30, the horizon! 
 
 SeflVrr""^' ?^^' '^^'''^ '^ a' specimen of 
 steel and the vertical scale the rise in temperature 
 
 The heat, when first applied, all goes into rafs^g the 
 
 temperature of the piece until about 1350 Te|ree 
 
 b^ act?allvTT''''t ^^"' ""'' ^"^^ ''^^'^ '^ ri«e, 
 out actually falls as heat is added. This critiea 
 
 e?S e^^^^^ '^^^^^^--^ point anTv! 
 
 ^es with each kind of steel. The heat expended goes, 
 not into raismg the temperature of the piece but into 
 
 ro "? 1> r '"^"^ ^^^ ^"*^™^ nioEa^^^^^^^^^^ 
 from pearhte to austenite. Since all the heat is goiS 
 
 u e TSh " TV"''' '' ^^^^ ^ ^^" - tempera 
 ture, which IS due to surface radiation. After the 
 
 change IS complete, any further heat added goes into 
 raising the temperature until the final point is'reaeS 
 
f 
 
 I 
 
 I 
 
 142 
 
 THE MECHANICAL EQUIPMENT 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1700 
 
 
 
 
 r 
 
 — 
 
 
 I 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1500 
 
 
 
 
 
 
 
 \ 
 
 ■ t?or'/yl ^K^^nr'O — 
 
 
 
 
 
 
 R- 
 
 1 
 
 
 
 \ 
 
 .' Point about IZIS"* 
 
 
 ^•1300 
 
 
 f — *-| 1 1 1 ^ 
 
 I becalescence 
 
 \ n ' J, L A i-rr/^0 
 
 \ 
 
 
 
 
 
 
 
 
 
 
 — r 
 
 v/fff. 
 
 aovi 
 
 41 /J 
 
 JV/ 
 
 \ 
 
 
 
 
 
 
 
 ^1100 
 
 • 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 III 
 
 < 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 5) 900 
 
 > 
 
 > 
 
 S 1 
 
 
 
 
 
 
 
 ... \o 
 
 
 
 
 
 
 
 ^1 
 
 K 1 
 t 1 
 
 
 
 
 
 
 
 
 
 
 
 
 < 700 
 a: 
 
 
 
 
 
 
 
 
 
 \ r 
 
 :» 
 
 
 
 
 
 0. 
 
 1" /N^N 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 uj 500 
 
 / 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 
 • 
 
 
 
 / 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 
 
 
 3 00 
 
 / 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 
 
 
 
 / 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 
 
 
 lOO 
 
 
 
 
 
 
 
 
 
 
 \ 
 
 \ 
 
 
 
 
 HEAT SCALE 
 
 FIG. 30. HEAT-TEMPERATURE CURVE 
 
 If at this point the piece should be cooled slowly, 
 heat is radiated away and the temperature falls 
 until another point of inflection, called the recal- 
 escenee point, is reached. In general, this will be 
 somewhat lower than the decalescence point. Here 
 the condition of the carbon is changed back to pearl- 
 ite, and the energy previously absorbed is converted 
 
 HEAT TREATMENTS 143 
 
 back into heat. After this second change is complete, 
 the cooling is resumed until the final temperature is 
 reached. The change at the recalescence point re- 
 quires a certain time. If, instead of being cooled 
 slowly, the steel is quenched suddenly by being 
 plunged into a cold bath, it passes through a compli- 
 cated structural rearrangement, but does not return 
 fully to pearlite, the soft form. Tlie piece, when com- 
 pletely cooled, will be very hard and brittle, and the 
 tensile strength and elastic limit will have been raised. 
 The hardness obtained will vary with the carbon 
 content and the suddenness of the cooling. The cor- 
 rect hardening temperature is the lowest possible one 
 above the decalescence point which will make sure 
 that the steel has been completely changed into aus- 
 tenite. If heated considerably beyond this point the 
 grain will be coarsened and the steel will be burned 
 or oxidized. The danger of this is greater the higher 
 the carbon content. The interesting fact that steel, 
 when heated beyond this critical temperature, be- 
 comes non-magnetic may be made use of in deter- 
 mining the decalescence point. The composition of 
 the quenching bath varies for different purposes, 
 brine, oil and water being most used, and the degree 
 ot hardness obtained by quenching from the same 
 temperature is greatest with brine, less with water, 
 still less with oil. This is probably due to the 
 rapidity with which the several liquids will absorb the 
 fteat. The above process of heating and quenching 
 suddenly ,s used for hardening all carbon steels, 
 ^elt-hardenmg or air-hardening steels, however, are 
 hardened by slow cooling. 
 
144 
 
 THE MECHANICAL EQUIPMENT 
 
 HEAT TREATMENTS 
 
 145 
 
 Heating.— Carbon steels should be heated slowly 
 and evenly to the right temperature, kept from con- 
 tact with air to avoid oxidation, and always quenched 
 from a rising, not a falling, heat. Care should be 
 used not to overheat any cutting edges and corners 
 before the body of the material is brought up to the 
 right heat. It is obvious that unevenness of tempera- 
 ture will cause a variation in hardness. 
 
 One of the common methods of heating is to use 
 a bath of molten lead, potassium cyanide, or barium 
 chloride. Care must be exercised in using these baths 
 to have the piece absolutely dry before immersing it. 
 The slightest moisture will cause the molten liquid to 
 fly in all directions and burn the operator. The safest 
 method is to heat the piece beforehand sufficiently to 
 insure its being perfectly dry. At temperatures above 
 1200 degrees Fahrenheit lead gives off a poisonous 
 vapor, and cyanide of potassium, as is well known, is 
 an active poison. The furnaces used for heating these 
 baths should be carefully guarded, and should be 
 equipped with hoods to carry away the fumes. Pow- 
 dered charcoal is often floated as a purifier on the top 
 of the molten liquid. 
 
 Of the various baths, the lead bath is most used. 
 It is especially adapted for heating small pieces that 
 are hardened in quantities. The lead used should be 
 pure, and free from sulphur. Various paints and 
 pastes are used to prevent the lead from sticking to 
 the work, or the piece may be heated and dipped into 
 salt water just before immersion in the bath. Steel 
 melting pots last much longer than those made of 
 cast iron when the lead bath is used. 
 
 The potassium cyanide bath is much used for 
 cutting tools, for dies, and in gun shops for color 
 effects. The barium chloride bath, which has a high 
 temperature, (about 2200 degrees Fahrenheit) is used 
 to some extent with high-speed steels. The pieces are 
 usually pre-heated in a gas furnace to a dull red in 
 order to save time in the bath. For the lower tem- 
 peratures required for carbon steels— about 1400 de- 
 grees— barium chloride and potassium chloride are 
 mixed in the proportion of three to two. Tempera- 
 tures below 1075 degrees are obtained by mixing 
 equal parts of potassium nitrate and sodium nitrate. 
 This mixture is used mainly as a tempering bath. 
 
 Modern heating furnaces are ordinarily oil or gas 
 fired. Many types are on the market especially 
 adapted for various sizes and kinds of products The 
 simplest type of gas furnace is a plain, circular pot 
 of refractory material, as shown in Figure 31. Gas in 
 general is a cleaner fuel than oil, but is more expen- 
 sive. Where oxidation is objectionable, muffles or 
 refractory retorts are used. Oil is the cheapest of all 
 the fuels for large work. It is pumped under pres- 
 sure to the furnaces from an underground tank, atom- 
 ized m a suitable burner, and mixed with a proper 
 proportion in air. Often a jet of steam is used which 
 impinges on the hot brickwork of the furnace and 
 IS broken up into hydrogen and oxygen-both gases 
 jelp m the combustion. Large heating furnaces are 
 
 eniL''^ .. ''^ ^""^ refractory linings, and are 
 equipped with pyrometers to aid in controlling the 
 temperatures. Coal and coke are inferior as fuels 
 as they are dirtier, the temperature control is more 
 
 is 
 
Il 
 
 146 
 
 THE MECHANICAL EQUIPMENT 
 
 HEAT TREATMENTS 
 
 147 
 
 ii 
 
 ! 
 
 PIG. 31. SIMPLEST TYPE OP CRUCIBLE GAS-FIRED 
 
 HEATING FURNACE 
 
 difficult, they require more labor in attendance, and 
 the sulphur and other impurities are more or less ab- 
 sorbed by the steel being heated. 
 
 Quenching.— The hardening obtained by quenching 
 will vary with the temperature, mass, and conductiv- 
 ity of the cooling medium. The degree of hardness 
 obtained with various baths in 0.90- to 1.0-point car- 
 bon steel ranges in the following order: mercury, 
 carbonate of lime, brine, pure water, soap water, milk, 
 oils, tallow, and wax. These different materials are 
 used for different purposes. Oil, having a lower vis- 
 cosity and heat-carrying capacity, cools the steel com- 
 paratively slowly. It is therefore used when the 
 piece is to be tough rather than very hard. Water, 
 being higher in heat-carrying capacity, cools the steel ' 
 more quickly, making it harder and brittle. Brine 
 makes it still harder. For excessively hard work, 
 quicksilver is sometimes used. Delicate and compli- 
 cated pieces cannot be cooled in brine without danger 
 of warping and cracking. 
 
 The temperature of the bath is important, as water, 
 for instance, at 60 degrees will give a greater hard- 
 ness than water at 150 degrees. A large body of 
 liquid is better than a small one, because the heat 
 given out by the steel will raise the temperature of 
 a small bath where it will have no appreciable effect 
 on a large one; and the capacity to carry away heat 
 IS increased if the liquid is in circulation. Clear 
 water is generally used for ordinary carbon steel, 
 sperm or lard oil for springs, and linseed oil for cut- 
 ters and other small tools. Certain portions of an 
 article may be hardened more than the rest of it by 
 
 n 
 
148 
 
 THE MECHANICAL EQUIPMENT 
 
 having cool jets of the quenching liquid impinge on 
 the surface at these points. This method is used for 
 hardening the face of forging dies, by immersing them 
 face downward into the quenching bath and causing 
 a jet to play into the impressions. In cooling, these 
 impressions will become harder than the rest of the 
 die. 
 
 Skill and care are required in successful quenching. 
 The pieces should not be thrown in carelessly, be- 
 cause unsymmetrical cooling will cause warping and 
 cracks and, even if these do not develop, will pro- 
 duce severe internal strains, which are all the more 
 dangerous because they may not show on the out- 
 side. Even with the best of care warping cannot 
 ' be wholly obviated, and for this reason very accurate 
 machined pieces must be ground after heat treatment. 
 
 There are a number of rules which apply generally. 
 The piece should be stirred in the bath to break up 
 the coating of vapor which tends to gather on its sur- 
 face and retard the rapidity of cooling. Stirring 
 also serves to bring the piece into cooler portions of 
 the bath. Long, thin pieces should be quenched in 
 the direction of the principal axis of symmetry, to 
 avoid warping. A gear wheel should be hardened 
 perpendicularly to its plane, and a shaft vertically. 
 Hollow pieces should have the ends plugged, since 
 otherwise they cannot be quenched vertically with- 
 out the formation of steam inside. When pieces have 
 thick and thin sections the thicker portions should 
 be immersed first. 
 
 Self-Hardening Steels. — These steels are obtained 
 by the addition of chromium and other elements, as 
 
 HEAT TREATMENTS 
 
 149 
 
 already mentioned. The proper form of treatment 
 varies with the composition, and the directions given 
 by the makers should be followed. Usually they 
 are heated to a red heat and cooled in an air blast, 
 or dipped in oil. It is not necessary to draw the 
 temper. Great care is required in heating them for 
 forging, since the forging heat has a very narrow range 
 of temperature and they may be very easily spoiled. 
 Some grades of self -hardening steel may be annealed 
 by heating to a bright heat in the centre of a good 
 forge fire and allowing the fire to die out, the fire and 
 the steel cooling off together. Steel so annealed may 
 be hardened again by heating to the hardening heat 
 and cooling in oil. 
 
 Taylor- White Steel.— This type of steel should be 
 heated slowly to red heat and then, as quickly as 
 possible, to a temperature just short of the melting 
 point, when it begins to show signs of softening. It 
 should then be cooled suddenly in oil to a low red 
 heat. From then on the cooling may be either fast or 
 slow, down to the temperature of the air. Taylor- 
 White, or high-speed steel, is no harder than hardened 
 carbon steel. It has, however, the remarkable qual- 
 ity of **red hardness;'' that is, the steel remains hard 
 even at a red heat, which corresponds to something 
 over 1000 degrees Fahrenheit, while ordinary carbon 
 steels begin to soften at about 390 degrees and lose 
 all of their hardness when heated to about 700 de- 
 grees. The larger part of the work done by a cutting 
 tool goes into heating the object cut, the chip and the 
 pomt of the tool. In continuous, heavy cutting at 
 high speed, that portion of the heat entering the too] 
 
 ill 
 
150 
 
 THE MECHANICAL EQUIPMENT 
 
 will raise the temperature high enough to draw the 
 temper of carbon steel. When this occurs the tool 
 begins to soften, the edge is lost, and the cutting 
 qualities are gone. In high-speed steel there is a 
 leeway of more than 600 degrees before this action 
 takes place, and consequently much higher cutting 
 speeds and heavier cuts are possible than with car- 
 bon steels.. 
 
 Annealing. — ^In making complex steel forgings it 
 is impossible to heat all parts alike. Some parts 
 therefore cool from a higher temperature than others. 
 A uniform fine grain may be given them by anneal- 
 ing. Steel castings are also annealed to relieve in- 
 ternal strains due to the unequal cooling after pour- 
 ing, and to refine the grain. The steel is heated to a 
 little above its critical temperature, as if for harden- 
 ing, but instead of being cooled suddenly, it is al- 
 lowed to cool from this temperature very slowly. 
 When this is done, the fine-grained austenite struc- 
 ture has time to readjust itself in passing the recal- 
 escence point, and thereby acquires its natural pearl- 
 ite structure. When it is completely cooled it will 
 be soft and tough. 
 
 The principal difference between the annealing and 
 the hardening process, therefore, is the substitution 
 of slow cooling for sudden quenching. Steel, to be 
 annealed, should be packed in boxes in powdered 
 charcoal or lime, sealed in order to prevent oxidation, 
 and heated slowly. Very low carbon steel should be 
 heated to about 1625 degrees Fahrenheit, and high 
 carbon steel to 1475 degrees. The heat should be 
 held there long enough to insure an even temperature 
 
 HEAT TREATMENTS 
 
 151 
 
 throughout the piece that is being annealed. As with 
 hardening, the piece should not be heated much be- 
 yond the critical temperature. If this is done the 
 gram is coarsened and the steel may be decarbonized 
 Slow cooling is the essential feature of the annealing 
 process. 
 
 Brass and copper are also annealed. When these 
 metals have been drawn or rolled to more than a cer- 
 tain percentage of reduction, they become hard and 
 brittle and will split on further working. The soft 
 structure may be restored by heating them to a dull 
 red heat and allowing the pieces to cool. Unlike 
 steel, these metals may be cooled suddenly as well as 
 slowlv. 
 
 Tempering.— Tempering is a secondary process, 
 coming after hardening, and the reheating is always 
 to a temperature much less than the critical or hard- 
 emng temperature. The main purpose of this process 
 IS to reduce the brittleness and increase the tough- 
 ness, but unfortunately it always undoes to some ex- 
 tent the work of hardening. If the piece is reheated 
 to only a low temperature, most of the hardness and 
 bnttleness will remain. The higher the temperature 
 to which It IS heated, the more of these qualities will 
 be taken out until, if it is heated to above the critical 
 temperature, they will entirely disappear and the 
 tempering process will have become annealing. Cut- 
 ting tools should always be left as hard as possible 
 and yet tough enough for the work intended 
 
 The Color Scale.-When hardened steel is heated 
 the color changes with the rising temperature from' 
 a pale yellow through a darker yellow into brown 
 
 
 ■J" 
 
I 
 
 152 THE MECHANICAL EQUIPMENT 
 
 brown-purple, purple, and finally to a dark blue. This 
 color scale has long been used as a gauge for temper- 
 atures in tempering. Its use requires great skill and 
 uniform conditions of lighting, and so on, if uniform 
 results are to be obtained, and for accurate work a 
 pyrometer should be used. The color scale, with the 
 corresponding temperatures and the class of tools for 
 which they are used, is given below. 
 
 CoLOB AND Temperature Scale for Tool Hardening* 
 
 Color 
 
 Very pale yellow 
 
 Light yellow 
 Pale straw yellow 
 Straw yellow 
 Deep straw yellow 
 Dark yellow 
 Yellow brown 
 Brown yellow 
 Spotted brown 
 Brown purple 
 Light purple 
 Full purple 
 Dark purple 
 Full blue 
 Dark blue 
 
 Degrees 
 
 Fahr. 
 
 430 
 
 440 
 450 
 460 
 470 
 480 
 490 
 500 
 510 
 520 
 530 
 540 
 550 
 560 
 570 
 
 Cent. 
 
 221 
 
 227 
 232 
 238 
 243 
 249 
 254 
 260 
 266 
 271 
 277 
 282 
 288 
 293 
 299 
 
 Class of Tools 
 
 Punches, Scraping Tools, Draw- 
 ing Dies 
 Milling Cutters, Reamers 
 Twist Drills 
 Counterbores 
 Edging Cutters 
 Pipe Cutters 
 
 Knurling Tools, Pen Knives 
 Threading Dies and Taps 
 Cold Chisels 
 Small Taps 
 
 Dies for threading to a shouUler 
 Springs 
 
 Molding Cutters 
 Wood Saws 
 
 Edged tools, such as chisels, are tempered by heat- 
 ing the cutting end to a cherry red and then quench- 
 ing the part to be hardened. When the tool is re- 
 moved from the quenching bath, the heat remaining 
 in the unquenched part of the tool will raise the tem- 
 
 *This table is compiled from Machinery's Mechanical Library, 
 Vol. VIII, pp. 70 and 76, and Rose's "Modern Machine Shop Practice. 
 
 HEAT TREATMENTS 153 
 
 perature of the cutting end to the desired color when 
 the entire tool is quenched. The modern method of 
 tempering in quantity is to heat the pieces in a bath 
 of molten lead, heated oil, or other liquid, the tem- 
 perature of which may be kept within very close 
 limits. Beds of heated sand and salt are also used. 
 The use of baths or sand beds is preferable to open 
 heating because there is a closer control of the tem- 
 perature which determines the degree to which the 
 tempering is carried. High-speed steel does not re- 
 quire tempering. It should be cooled in some thin oil, 
 such as lard or paraffine. If paraffine is used the 
 piece should be kept under the surface until cooled to 
 the temperature of the bath; otherwise the oil will 
 ignite. 
 
 Carbonizingr.— Carbonizing is a very valuable pro- 
 cess for a good many classes of articles in which the 
 contradictory qualities of toughness and hardness are 
 both wanted. Low-carbon steel is tough, but cannot 
 be hardened. High-carbon steel can be hardened, but 
 becomes brittle in the process. Case-hardening is 
 simply the partial carrying out of the old cementation 
 process of making steel, in which bars of wrought 
 iron were heated a long time in the presence of car- 
 bonaceous material, and the carbon given off was ab- 
 sorbed by the iron until its carbon content was raised 
 to the point desired and it became steel. 
 
 In case-hardening the process is carried on long 
 enough to drive the carbon in to the depth desired A 
 low-carbon steel, properly packed in carbonaceous ma- 
 terial and maintained at a temperature of 1650 de- 
 grees Fahrenheit for about two hours, will be changed 
 
 I 
 
 !!!, 
 
 :|i 
 
 >i 
 
 \i 
 
 I': I 
 
 it ' ' 
 
r 
 
 "I 
 
 154 
 
 THE MECHANICAL EQUIPMENT 
 
 I 
 
 to 80 point carbon steel to a depth of about 1/64 inch; 
 heating it for four hours will case-harden it to 1/32 
 inch, and the carbon will be 1.0. If it is heated for 
 six hours, the case-hardening will be 1/16 inch deep 
 and the carbon content 1.15. In case-hardening, the 
 material is packed in cast-iron boxes or pots with the 
 carbonizing material, such as charcoal, charred 
 leather scraps, or burnt bone. It is then covered and 
 sealed. A number of case-hardening compounds are 
 on the market and may be used instead of the ma- 
 terials mentioned, as some of them have become too 
 valuable for general case-hardening work. 
 
 If the piece is quenched after being case-hardened, 
 the surface, having been transformed into high-carbon 
 steel, will become hardened to the depth of the case- 
 hardening, and the soft low carbon interior, which 
 cannot be hardened, will remain tough. The article 
 will therefore have the double qualities desired. The 
 **Harveyizing" of armor plate is case-hardening ap- 
 plied on a large scale. Quenching from the same heat 
 is practiced when only color effects and a hard sur- 
 face are desired. For a better quality of temper the 
 piece is cooled slowly, and hardened after a subse- 
 quent heating, since the hardening temperature is not 
 so high as the case-hardening temperature and a sec- 
 ond heating gives better results. 
 
 CHAPTER XI 
 THE TOOL ROOM— FIXTURES AND GAUGES 
 
 The Tool Room a Modem Development.— As there 
 will be no frequent references in the chapters dealing 
 with machine tools to the tool room and to tool-room 
 methods, it is well to consider briefly the functions of 
 the tool room and the part they play in machine- 
 shop methods. The tool room is a modern develop- 
 ment and an embodiment of the principle of the sub- 
 division of labor. The typical figure in the old-time 
 machine shop, which built its products before manu- 
 facturing methods became general, was *'the general 
 all-round mechanic." He was a man of skill and ex- 
 perience. He ground his own tools to suit himself, 
 and sometimes even forged them. With the possible 
 help from time to time of an overdriven foreman, he 
 decided how the work was to be done, set the work 
 upon the lathe or planer, and measured it to deter- 
 mine the setting of the tools, generally using his own 
 scales and small tools in the process. Much of his 
 time went into work that could be done by a less 
 skilled man, and his measurements, however skillful, 
 were subject to more or less variation. 
 
 Relation of Tool Room to Shop.— The general me- 
 (•lianic has largely disappeared from the machine 
 'ooms of the modern shop that turns out interchange- 
 . > 155 . 
 
 "''ii 
 
 
156 THE MECHANICAL EQUIPMENT 
 
 able products. His work has been split up into that 
 of the skilled tool-maker and that of the handy man, 
 or machine tender, who does little more than set the 
 work into a fixture and tend the machine. The tool- 
 maker now plans the operations, makes the small-tool 
 equipment to carry them out, and maintains the ma- 
 chines in proper condition. The tool department also 
 sharpens the tools and takes care of them, issuing 
 them to the workmen as needed. The tool room car- 
 ries on such important work that it has well been 
 called '*the heart of the shop." It is here that the 
 quality of the output of a plant is set, and maintamed. 
 A good tool room usually implies a good shop, and 
 a good shop cannot exist if there is a poor tool room. 
 The quality of the work done throughout the plant 
 will run down and the cost of production go up un- 
 der the following conditions: 
 
 a. If the producing machines throughout the factory are not 
 properly equipped with the necessary fixtures and cut- 
 ting tools. . 
 
 b If the tool equipment is not maintained in good condition. 
 
 c If the gauges used to check the quality of the product are 
 not properly designed, well made, and kept in repair. 
 
 d. If the tools, fixtures, and gauges are not at all times ready 
 
 for use. 
 
 e. If they cannot be found promptly when wanted. 
 
 t If the producing machines themselves are not maintained 
 in good repair. Good tool equipment on a worn-out 
 machine will do bad work. 
 Functions of the Tool Room.— The foregoing con- 
 siderations determine the functions of the tool room, 
 which are three in number. 
 
 The first function is to build and maintain fixtures, 
 
 FIXTURES AND GAUGES 157 
 
 gauges, special machines used for manufacture, and 
 such small tools as are not purchased from outside, 
 ihis cares for items a, b, and c, and, as pointed out 
 m a previous chapter, involves close touch with both 
 the drafting room and the shop. This is particu- 
 larly important in the manufacture of interchange- 
 able products. Some shops have a tool-room commit- 
 tee, analogous to the design committee described in 
 Chapter II. Such a committee is composed of the 
 tool-room foreman, the principal machine-room fore- 
 man, and the drafting-room man who is in charge of 
 tool design. No new design of such an article as a 
 gun IS complete until a list of operations giving the 
 number and order of operations has been settled upon, 
 mcludmg all the working points, as they are called, 
 which are the points or surfaces used for locating the 
 work during the various cutting operations. 
 
 Another list giving the sequence of the gauffinff 
 operations and their relation to the manufacturing 
 operations should be settled upon at the same time. 
 Ihese are necessary before any work can be intelli- 
 gently started on the fixtures, special tools, and 
 gauges which are to be built. Before these lists are 
 determined upon, all those modifications of the design 
 ot the product which are desirable for economy in 
 manufacture, must have been made. Few things will 
 demoralize a tool room more completely than con- 
 tinued tinkering with the design of new output after 
 work has been started on the tools. 
 
 The second function of the tool room is to sharpen 
 and grind all tools and maintain them in proper work- 
 ing condition. There is a right and best way to grind 
 
158 THE MECHANICAL EQUIPMENT 
 
 each tool. If the decision of this question is left to 
 the whim or fancy of each machine hand, few tools 
 will be ground properly and there will be no stand- 
 ards of tool practice in the shop. Furthermore, spe- 
 cial tool-grinders have been developed which not only 
 turn out correctly ground work, but enable this work 
 to be done by labor much less skilled than the gen- 
 eral mechanic. 
 
 The third function of the tool room is to store 
 and to charge out the small-tool equipment and sup- 
 plies to the workmen as needed. This is done by a 
 tool storeroom, which may or may not be a part of 
 the main tool-room organization. 
 
 The Tool Storeroom. — The functions of the tool 
 storeroom are: 
 
 a. To protect tools against loss, theft, deterioration, and con- 
 
 fusion. 
 
 b. To provide a place for every tool, which place shall be re- 
 
 served for that tool and identified with it. ^ 
 c To provide means for locating where any tool is when it is 
 not in the storeroom. This is done through some form 
 of check system or its equivalent. 
 
 d. To show what tools any man has at any given time. 
 
 e. To maintain records covering breakage, wear, and so on, 
 
 which will furnish a basis for determination of tool 
 costs. 
 The storage facilities should be as simple as possible, 
 should conform to a well thought out plan, and should 
 be readily intelligible, economical of space, and capa- 
 ble of expansion. 
 
 In general, the tool-building for the entire plant 
 may be centralized in one room or department for 
 convenience in administration, but the tool-grinding 
 
 FIXTURES AND GAUGES 159 
 
 and tool-storage may sometimes be divided to ad- 
 vantage and carried on in small storerooms about the 
 plant, one in each department— the controlling con- 
 sideration would be, what arrangement, under the 
 given conditions, will entail the fewest steps and lea^t 
 loss of time! 
 
 Machine Equipment.— The machine equipment of 
 the tool room for a moderate-sized plant will consist 
 of one or more of the following machines: 
 
 High-class lathes, 8 to 24 inches, seldom for work awev 6 
 or 8 leet long. 
 
 Universd milling machines, with index head, etc. 
 
 Horizontal boring mills. 
 
 Die-sinking machines. 
 
 Planers, moderate size. 
 
 Shapers. 
 
 Drill presses. 
 
 Radial drills. 
 
 Precision grinders, for surface and circular work. 
 Rough grinders. 
 Power hack saw. 
 
 Full equipment of standard gauges adapted to the work in 
 hand, such as plug and ring, screw-thread and pipe 
 gauges, gauges for standard tapers, surface plates, 
 squares, etc. 
 
 These machines will be used in the general tool room. 
 To these may be added drill and milling cutter grind- 
 ers, lathe and planer tool-grinders, and so on, which 
 rnay be either in the main tool room, or the branch 
 tool rooms if there are any throughout the plant.* 
 
 ..m *^^^ ^^^ design of fixtures, gauges, and special tools, see 
 J^oois and Patterns," by A. A. Dowd, Factory Management Course. 
 
160 THE MECHANICAL EQUIPMENT 
 
 PoUcies.-Certain policies are desirable in tool-room 
 practice. Day wages prevail because of the variety and 
 accuracy of the work. In making tools precision ot 
 workmanship is more desirable than great economy 
 of production. The tool-room foreman should be the 
 best man obtainable. The best is not too good, tor 
 there are few men in the whole plant who have 
 greater influence on the quality of the work and the 
 cost of production. If the tool room is of fairly large 
 size, the principles of standardization can always 
 be profitably applied on such details as cutters, 
 shanks, bushings, tapers, and so on. Often the work 
 may be subdivided into skilled and less skilted func- 
 tions, and the workmen may be chosen accordingly. 
 New tools and fixtures should be estimated on, the 
 estimates covering the anticipated saving; and these 
 estimates should be checked with the cost of the 
 fixtures and the actual saving in output reahzed. 
 This offers one of the few checks possible on the work 
 
 of the tool room. 
 
 Fixtures and Jigs.— A fixture may be defined as a 
 device for locating and clamping work in proper po- 
 sition for a machining operation. A jig is a device 
 for guiding a cutting tool; usually it is combmed with 
 a fixture. These terms are used loosely and m most 
 shops interchangeably, but properly speaking a fix- 
 ture relies upon the machine to locate and guide a 
 cutting tool with reference to the work. While a 
 jig often locates and clamps the work, it combines 
 with this means for guiding the cutting tool during 
 its operation. A fixture is usually clamped firmly to 
 the table of the machine; a jig is usually free to move 
 
 FIXTURES AND GAUGES 161 
 
 and to find its own position, as in the case of a drill- 
 ing jig, which centers itself on the point of the drill. 
 1 shall not attempt here to go into the details of jig 
 and fixture design, but shall consider merely general 
 principles, partly economic and partly mechanical. 
 
 Economic Principles.-!. The jigs and fixtures 
 should be suited to the work. This is not so obvious 
 as It It seems, for there are many ways of doing most 
 operations and many instruments that can be used, 
 and the selection of the best ways and means is often 
 a matter of skill and experience. 
 
 2. They should not be idle most of the time. 
 Sometimes a fixture is built which will perform an 
 operation in one-half or one-third of the time required 
 without It, but the total money value represented by 
 the saving may not be large enough to justify the ex- 
 pense. A saving of 5 per cent on the cost of a much- 
 used operation may justify a greater tool expense than 
 a saving of 90 per cent on another operation which 
 goes through the shop only occasionally. 
 
 3. Fixtures should show an adequate return on the 
 investment through the saving in cost of operation, or 
 should materially improve the quality of the output. 
 Well-designed fixtures usually do both. When the 
 post of the fixtures is balanced against the saving in 
 operation cost, the wear and maintenance of the fix- 
 tures, which is usually considerable, must be taken 
 into account and charged against it. 
 
 4. Fixtures should be arranged, whenever possi- 
 ble, to perform simultaneous operations. This not 
 on y saves cost of handling, but usually increases the 
 accuracy of the output. 
 
 '11' 
 
 :;*■ 
 
162 THE MECHANICAL EQUIPMENT 
 
 Mechanical Principles.-!. Fixtures should be firm 
 enough to equal the stability of the machine and the 
 cutting tool, and should be heavy enough to preclude 
 
 all chattering. 
 
 2 The clamping devices should be rapid in action 
 and positive in locating the work. The clampmg is 
 usually done by screws and nuts, toggle joints, or 
 cams. In general, it is desirable, whatever the clamp- 
 ing device, to have a quick motion set the jaws up on 
 the work, and then a slow movement with increased 
 power to produce the clamping effect. 
 
 3 • All vises, and like equipment used for holding 
 work should have one fixed jaw, and the rotation of 
 the cutter and the thrust of the feed should be against 
 
 this jaw. , , « .. 1, 
 
 4 There should be adherence to the definite work- 
 ing' points laid out in the list of operations. If pos- 
 sible the working point should come against the fixed 
 
 jaw. . , 
 
 5 Parts which locate the work or clamp against 
 
 it, and in the case of jigs the legs also which bear 
 on the drill-press table, should be tool-steel hardened, 
 or machinerv steel case-hardened. 
 
 6 There should be clearance in the corners for 
 dirt and for burrs left from any previous operation, 
 as well as ample room for the chips to get away. 
 
 7 All wing nuts, handles, levers, and so on, 
 should be made large enough to operate with a mod- 
 erate pressure. If this is done, the fixture will work 
 faster be more accurate, and last longer than if these 
 parts 'were skimped. Wherever the workmen is ham- 
 mering these down with a mallet after setting them 
 
 FIXTURES AND GAUGES 163 
 
 np by hand, he is losing time and is in serious danger 
 of springing the work, or the fixture, or both. 
 
 8 In the oase of multiple fixtures, avoid stacking 
 the pie.'es against one another. Every piece should 
 be set agaiHift a solid stop. 
 
 9. In the designing of fixtures for formed milling 
 operations, the piece should be so positioned that the 
 Tarious sections of the milling cutter will be as nearly 
 the same- diameter as possible. 
 
 10 If possible, the locating points should be so 
 arranged that the piece cannot be placed in the fix- 
 ture in a wrong position. 
 
 11. in the case of drilling jigs it is desirable to 
 have four legs bearing on the drill table. If the table 
 IS out of true, or if one of the legs is resting upon a 
 chip, the rocking of the jig will show it. A three- 
 legged Jig, like a three-legged stool, will sit firmly 
 on an irregular surface, and consequently the oper- 
 ator will not detect an unevenness that will be shown 
 up by a four-legged one. 
 
 • T^T £''"o^^i"g additional points are brought out 
 m A Treatise on Milling and Milling Machines" by 
 the Cincinnati Milling Machine Company: 
 
 Doir.t'"' ntr^ ^^'"i'l- ^ immediately above the supporting 
 Hf ?1 J?r^^''*^,°*,*'"' ^^^^^ ^ springing of the work, or 
 into a fulcram. ^ '"^^*"^' P"'"* ^'""^ transformed 
 
 fnr J'""^* ^^'^ srapporting points should be the maximtnn 
 lor any rough surfaces. 
 
 Supporting points for finished surfaces should be as 
 Hmaii in area as is consistent with the pressure to be exerted 
 oy the clamps. 
 
 m 
 
164 THE MECHANICAL EQUIPMENT 
 
 All supporting points should be set as far apart as the 
 nature of the work will allow. 
 
 All side clamps should be arranged to press downward. 
 
 The fixed supporting points should always circumscribe 
 the center of gravity of the work. ..,*!.« 
 
 All supporting points over and above the original three 
 shoiild be sensitive in their adjustment. 
 
 All clamps and adjusting support should be operated 
 from the front of the fixture. 
 
 All clamps and support points that are operated or 
 locked by wrench should have the same size head. 
 
 Support points should be set so ... as to mmi- 
 mize the amount of cleaning required. 
 
 Support points should have provision for easy removing 
 and replacing in the event of breakage. 
 
 Fixed support points should have provision for adjust- 
 ments to take care of variations in castings from time to time. 
 
 Clamps should be arranged so that they can be easily 
 withdrawn from the work. This is to avoid lengthy un- 
 Tcrewlng of the nut in order to give ample clearance between 
 
 clamp and work. . . , 
 
 Snrinffs should be used to hold clamp up against clamping 
 nut This is to avoid the falling down of the clamp and the 
 c»ent loss of time attendant on holding it up while insert- 
 ing the work beneath. 
 
 Supporting points and clamps to be accessible to the 
 operator's hand and eye. , ^i.- 
 
 Adequate provision for taking up end thrust so that this 
 will not be dependent upon friction between work and clamp. 
 
 All of the above axioms are applicable to almost every 
 type of fixture. 
 
 Gauging.— Extensive and well-planned ganging is 
 necessary in any machine shop where interchange- 
 able work is being done. There is a constant ten- 
 dency toward degredation of quality from the wear 
 of tools, machines, and fixtures, and of the gauges 
 
 FIXTURES AND GAUGES 
 
 165 
 
 themselves. No work i« ever done exactly to size. 
 Precision workmanship simply means that the devia- 
 tions are known to be very minute. 
 
 Three terms are used in connection with these dev- 
 iations. The greatest and least dimensions above and 
 below the nominal size which will be permitted to 
 pass inspection are called ** limits.'' These limits 
 have been determined carefully as the extremes be- 
 tween which the piece is sure of being usable for the 
 purpose designed. If these are exceeded the work 
 must be rejected. The difference between the two 
 limits is called *' tolerance." Deviation from the nom- 
 inal size within the limits is unintentional, but per- 
 missible. *' Allowance'' is an intentional difference 
 in size of two parts which are to go together. If the 
 joint is to be a drive fit, the hole is purposely made 
 a certain amount smaller than the other member. If 
 a running fit is desired, it is purposely made a cer- 
 tain amount larger. It is evident that limits may be 
 set for the two dimensions called for by the allow- 
 ance. 
 
 Types of Gauges.— For the ordinary gauging of 
 surfaces and angles, it is customary to use surface 
 plates, squares, and protractors. For very accurate 
 work precision methods are used, which will not be 
 taken up here. 
 
 For linear distances the simplest form of gauge is 
 the graduated scale, which has the advantage of being 
 available for any length within its limit and of not 
 wearing out in use. It is the least accurate form 
 of gauge, but a skilled man with a caliper will take 
 off dimensions from it to within .002-.003 inch. The 
 
I'tll 
 
 166 THE MECHANICAL EQUIPMENT 
 
 graduated scale constitutes what is known as a line 
 measure, where the eyesight is relied on in determin- 
 ing the size, and because of its convenience, it will 
 always have a place where great, precision is not re- 
 quired. Figure 32 shows several of the more com- 
 monly used gauges. End measures, as they are called, 
 comprise bars of standard length, plug and ring 
 gauges, and '*snap'' gauges. When these are used, 
 the work is gauged by thfe sense of touch and not 
 sight. They are far more accurate than the ordinary 
 line gauges, but in generar they are good for only 
 one size and are subject to wear. Differences of a 
 few ten-thousandths of an inch may be easily detected. 
 The vernier and micrometer types of calipers com- 
 bine the advantages of both line and end measure 
 svstems, and have at the same time the accuracy of 
 touch of an end measure and the wide range of sizes 
 within their limits characteristic of the linear scale. 
 The vernier and micrometer calipers were both intro- 
 duced by the Brown & Sharpe Manufacturing Com- 
 pany, the vernier in 1851 and the micrometer in 1867. 
 The influence of these two types of gauges, especially 
 that of the latter, upon the standards of accuracy 
 in commercial work has been very great, for they 
 placed in the hands of the workman convenient and 
 practical tools capable of measuring differences previ- 
 ously unrecognized in practical shop work. It is a 
 well-defined principle that the limit of precision in 
 production is what you can measure. 
 
 The linear scale, the vernier, and the micrometer 
 are used mainly in the tool room. For general 
 production work, plug and ring gauges, and snap 
 
 FIXTURES AND GAUGES 
 
 167 
 
 PLUG AND RING GAUGES 
 
 END MEASURES 
 
 LIMIT SNAP GAUGE 
 
 LIMIT PLUG GAUGE 
 
 DIAL TEST INDICATOR 
 
 VERNIER CALIPER 
 
 MICROMETER CALIPER 
 
 yiG, 32, TYPES OP GAUGES 
 
 
 'Ml 
 
168 THE MECHANICAL EQUIPMENT 
 
 gauges, Figure 32, are more used. Any of these may 
 combine two sizes and become a limit gauge. These 
 relieve the workman in the shop of the necessity of 
 exercising judgment in determining sizes and machme 
 fits. The working gauge supplied him embodies two 
 dimensions representing the limits allowed, the differ- 
 ence between them being the tolerance. All the work- 
 man has to do is to make sure that the work will 
 pass **A," and will not pass **B.'' The limit gauges 
 shown are of the very simplest form. For special 
 work, they are varied to suit the special case. 
 
 Gauges of another class— such as difference gauges, 
 dial gauges, and indicators— are used by tool makers, 
 not so much to determine absolute distances as to as- 
 certain differences from some standard. For instance, 
 the diameter of a shaft would be measured by a mi- 
 crometer or snap gauge, but its variation in alignment 
 would be measured by an indicator or dial gauge in 
 thousandths of an inch without reference to the size. 
 The correctness of special profiles or contours given 
 to any piece of work is determined by a *' receiver'' 
 gauge, such as that shown in Figure 33. The piece 
 is located by a pin. A, which fits into the hole, B. 
 It must slide on to the pin. A, and fit accurately 
 into the receiving space, C, which has the contour 
 desired. The receiver gauge shown is also provided 
 with a snap gauge, D, on the edge, which is used to 
 gauge the thickness, E, of the piece. The one shown 
 is very simple in character. When the surfaces are 
 irregular, and intricate in their relationship the gauge 
 may become a delicate and complicated affair. 
 Another class of gauges is used for locating the po- 
 
 FIXTURES AND GAUGES 
 
 169 
 
 FIG. 33. CONTOUR GAUGE 
 
 sition of pins, holes, and surfaces. Profile or receiver 
 gauges may include this feature, as in the gauge 
 shown in Figure 33, which locates the hole, B, with 
 reference to the contours of the piece. The pin. A, 
 is in effect a plug gauge for the hole, B. The more 
 intricate gauges may be used for all three forms of 
 gauging— for size, contours, and location. 
 
 General Considerations.— In shops where accurate 
 work is done in great quantities there will be three 
 sets of similar gauges: wofking gauges, used by the 
 workman during production; inspector's gauges,. used 
 by the shop inspectors, and master gauges, used to 
 check the other gauges. 
 
 The working and inspector's gauges are used con- 
 tinually and are therefore subject to wear. The mas- 
 ter gauges remain in the tool room and are used for 
 reference only; they therefore retain their size a long 
 time. 
 
 Gauging is done at various stages during the prog- 
 ress of the work: 
 
 a. 
 
 First piece inspection— gauging by the tool-setter or in- 
 
 11 
 
 M 7 
 [ ■ I , 
 
 I' > 
 
 /(:• 
 
 
 I- 
 
 1 
 
 I 
 
170 THE MECHANICAL EQUIPMENT 
 
 spector, to insure the correct setting of the cutting 
 tools and fixtures before proceeding with the work. 
 
 b Working inspection-gauging by the workman during the 
 progress of the run, to discover wear of cutting tools, 
 etc., or changes in setting. 
 
 c. Operation inspection-all the pieces put through may be 
 gauged by an inspector before proceeding with the next 
 operation. This is done to detect bad woi:k in the early 
 stages of manufacture, and thereby to save doing 
 further work on a piece already spoiled. 
 
 a. Piece inspection— by the inspectors, of the finished part 
 before it is sent to the assembling room. 
 
 e. Selective inspection— This is often practiced when the 
 pieces are simple and made in very great quantities, 
 such as hardened balls for ball bearings. To gauge 
 each one would add greatly to the cost of production. 
 Only one out of a certain lot or number is gauged; 
 if this passes inspection, the rest are assumed to be 
 correct ; if not, others are gauged and if a certain num- 
 ber are found incorrect the whole lot i^ rejected. 
 
 1 Unit-assembling inspection— usually done in the assem- 
 bling room, to make sure that parts of certain dehnite 
 units, as, for instance, a typewriter carriage or a lathe 
 head, are in proper relation to one another. This 
 may involve very refined types of position gauges. 
 g. Performance inspection— by the inspectors, of the per- 
 * f ormance of the machine as a whole. 
 
 I have taken up the work of the tool room in the 
 foregoing consideration only in a most general way, 
 for the purpose of making clearer what follows. For 
 detailed consideration of tool-room practice and the 
 design of fixtures, gauges, and special tools, the 
 reader is referred to Dowd's ** Tools and Patterns," 
 Factory Management Course. 
 
 II : 
 
 CHAPTER XII 
 CUTTING TOOLS 
 
 MateriaI.~Since the purpose of all the machine 
 tools IS to drive some form of cutting tool, before 
 taking up the machines I shall take up the various 
 forms of cutting tools used. Cutting tools are made 
 from tool steel or from some form of abrasive. The 
 latter material forms the basis of grinding wheels; 
 while their action is that of pure cutting, they con- 
 stitute a distinct type of tool and will be taken up in 
 another chapter. 
 
 Carbon Steel.— Formerly, tool steels for cutting pur- 
 poses were composed of iron, carbon, and minor 
 elements which were either neutral or which acted as 
 impurities. These steels, known as carbon steels, 
 have been in use for many generations. The carbon 
 content, which varies from 0.80 to 1.50 per cent, gives 
 the steel the hardening and tempering qualities al- 
 ready considered. Good carbon steel properly heat- 
 treated is as hard as any of the later kinds of steel, 
 and in fact will take a keener cutting edge. Its limi- 
 tation, as compared with high-speed steel, comes from 
 the fact that it begins to lose its hardness when 
 heated above 400 degrees Fahrenheit and conse- 
 quently cannot be used for such heavy cuts or high- 
 cutting speeds. For finishing work and for light, ac- 
 
 171 
 
 I 
 
172 THE MECHANICAL EQUIPMENT 
 
 curate cuts, however, carbon steel is as good as any 
 
 ''^wishet, or Self-Hardening Steel.-This kind of steel 
 y^BiS developed between 1860 and 1870 by Robert 
 Mushet, an Englishman, who introduced about 5.5 
 per cent of tungsten and 1.6 per cent of manganese 
 into the steel, which caused it to be almost as hard 
 when cooled slowly in the air from a forging heat as 
 carbon steel when quenched in water; hence the name 
 air-hardening, or self-hardening, steel. This stee 
 would cut faster and stand more abuse than any steel 
 
 then known. . , -.tt m 
 
 High-Speed Steels.— About 1900, Frederick W. Tay- 
 lor and Maunsell White patented a steel that had the 
 quality of "red hardness," so called because it would 
 remain hard and retain a cutting edge even after the 
 ed<'e was red hot. A cutting tool made of this steel 
 could be operated on cuts so heavy and fast as not 
 only to turn a steel chip dark blue, but even to rnake 
 it red hot. In the later steels described by Mr. Tay- 
 lor in his "On the Art of Cutting Metals," the tung- 
 sten is given at 18.9 per cent, chromium 5.47 per cent, 
 carbon 0.67 per cent, and manganese 0.11 per cent. He 
 gives the following cutting speeds for these various 
 steels when cutting machinery steel: 
 
 CUTTING TOOLS 
 
 Jessop carbon steel, 16 feet per minute 
 
 Mushet steel, 26 ^^ 
 
 Original Taylor- White steel, 58 
 
 Taylor- White steel, 1906, 99 
 
 (< 
 
 Many brands of high-speed steel are noW on the 
 market. Compared with carbon steel it is very expen- 
 
 17J? 
 
 fiive, and various forms of tool-holders have be^n de- 
 vised to economize in its use. Its advantage over 
 carbon steel is most marked in the making of heavy, 
 rough cuts, work in which the purpose is to remove 
 as much material as possible in a short time. 
 
 Mr. Taylor's paper, *^0n the Art of Cutting 
 Metals,'' read before the American Society of Me- 
 chanical Engineers in 1906, is one of the greatest con- 
 tributions ever made to machine-shop practice. In 
 this discussion he points out that the three funda- 
 mental questions which must be answered every day, 
 in every machine shop, in connection with metal- 
 cutting machines such as the lathe, the planer, the 
 drill press, the milling machine, and their like, are: 
 
 1. What tool shall I use? 
 
 2. What cutting speed shall I use! 
 
 3. What feed shall I use? 
 
 He then describes experiments which covered 26 vears, 
 employed the best energies of a number of experts, 
 and had a profound effect not only upon cutting steels 
 but upon the whole design of machine tools. He 
 shows how many variables were involved in answer- 
 ing the three questions above, and the principles of 
 successful experimentation in working out a prob- 
 lem of that nature. He reviews the history of the 
 investigation with the successive improvements devel- 
 oped, and lays down standard shapes for cutting tools 
 and methods and formulas for determining cutting 
 speeds. He also gives a full description of the com- 
 position and the method of heat-treating high-speed 
 tool steel. While the paper deals mainly with heavy 
 
 I 
 
 I:,, 
 
 i;.k 
 
 h \ 
 
 if 
 
 f' 
 
 ! i 
 
 I* 
 
 
174 THE MECHANICAL EQUIPMENT 
 
 roughing operations, it is a mine of general informa- 
 tion and should be read by every one interested in 
 the art of cutting metals. 
 
 A wide variety of cutting tools is used for the vari- 
 ous types of operations throughout the shop. The 
 principal types will be considered briefly. 
 
 The Lathe-Planer.— This type of tool has been used 
 for a hundred years or more and is the typical cut- 
 ting tool used on lathes, boring mills, planers, shapers, 
 and so on. It has a single cutting edge, shaped to 
 suit the particular type of cut; a few of the stand- 
 ard forms of cutting edge are shown in Figure 34. 
 The principal ones are the ** round nose," A, and 
 diamond point tool, B, the most common of the lathe 
 tools. These remove chips easily, and are used for 
 both roughing and finishing cuts. Certain angles 
 have generally recognized names. The angle, a, is 
 called the top rake; b, the side rake; c, the clearance 
 angle, and d, the angle between the cutting edges. 
 C and D are right- and left-hand side tools; E, is a 
 parting, or cutting-off, tool; F, is a bull-nose tool; 
 G, a finishing tool. There are some minor differences 
 between the tools used on lathes and on planers re- 
 spectively, but the general type is much the same in 
 both cases. Lathe tools should be set so that the 
 cutting edge is slightly above the center. If they are 
 set so that it is below the center, the material is 
 scraped off instead of cut off and the cutting edge 
 is soon lost. If the cutting edge is too far above 
 the center, the pressure comes on the front of the 
 tool, and not on the cutting edge. On many planer 
 tools the end is goose-necked, as shown in H, Figure 
 
 CUTTING TOOLS 
 
 FIG. M. TYPES OF LATHE AND PLANER TOOLS 
 
 34. If the cutting edge is forward of the supporting 
 surface on the tool head, it will tend to dig into the 
 material when taking a heavy cut or upon striking 
 a hard spot in the material. If the cutting edge is 
 even with, or back of, the supporting face, this ten- 
 dency is done away with. 
 
 The advantages of the lathe-planer type of tool 
 are that it is easily sharpened, and can be used for 
 a wide variety of operations. Its disadvantage lies 
 
 
 '" .' 
 
 V 
 
 ;1 
 
176 THE MECHANICAL EQUIPMENT 
 
 in the fact that since the work is concentrated on a 
 single small cutting edge, the wear is rapid and the 
 tool must be frequently re-ground. With carbon 
 steels the shank and nose of the tool are usually a 
 single forging; when the cutting edge has worn down 
 beyond a certain point, the tool is re-dressed by the 
 blacksmith and used over again. This process may 
 be repeated until the shank has become too short 
 to be used in the tool-holder. High-speed steels are 
 too expensive to be used in this way. Figure 34 
 shows two forms of tool-holders in which the shank, 
 or body, is a machinery-steel forging carrying at 
 its end a clamping device for holding a small bar 
 of high-speed steel which can be moved up toward 
 the cutting point with each successive grinding and 
 nearly all of which can be used. 
 
 What the best form of tool will be, depends on 
 the kind and hardness of metal to be cut, the charac- 
 ter of the cut— whether roughing or finishing— and 
 the manner of presenting the tool to the work. Since 
 a tool cuts by wedging action, the sharper the cut- 
 ting angle the less power it takes to drive it. The 
 cutting angle, d, should therefore be as small as is 
 consistent with strength. In general the angle may 
 be more acute for the soft metals than for the harder 
 ones such as chilled cast iron or tool steel. 
 
 The surface of most metals, especially that of cast- 
 ings, is harder than the interior, and is liable to con- 
 tain some sand or scale. For this reason a first, or 
 roughing, cut should be deep enough to go beneath 
 this hard surface; otherwise the tool will be quickly 
 dulled. For roughing cuts, metal can be removed 
 
 CUTTING TOOLS 177 
 
 most rapidly by taking heavy cuts at low speed; for 
 finishing cuts, it is better to use a fine feed and faster 
 speed. The principal limitations of feed and speed 
 lie within the tool itself, in the strength of the tool, 
 the wear of the cutting edge, and the heating of the 
 tool with a consequent loss of hardness. In addition 
 to these limitations there may be others, from lack 
 of stability in the work, which may be too weak to 
 stand up against a heavy cut and spring away from 
 the tool; or the lack of stability may lie in the ma- 
 chine tool itself. One of the most far-reaching ef- 
 fects of Dr. Taylor's work was a general re-design of 
 machine tools to furnish the power and stiffness re- 
 quired for the new high-speed steel tools. If spring- 
 ing is bad in the work and the machine, it is, of 
 course, equally bad in the tool itself, and the sup- 
 porting point of the tool should be as near the cutting 
 edge as possible. Cutting speeds vary so much that 
 only a general idea of them can be given here. For 
 good grades of carbon steel, such as Jessop's, the 
 approximate cutting speeds are as follows: 
 
 Fn^f * ''p!!''- 30- 40 feet per minute 
 
 i^or wrought iron 25— 30 " 
 
 For steel [[' i5__ ^q «< 
 
 ^or brass 60—100 
 
 The cutting speed is of course affected by the 
 amount of feed— a higher cutting speed is possible 
 with a light feed than with a heavy one. 
 
 For high-speed steel the approximate speeds are as 
 tollows:* 
 
 i|: (« 
 
 Modern Shop Practice," Vol. I, pp. 93-94. 
 
178 
 
 THE MECHANICAL EQUIPMENT 
 
 CUTTING TOOLS 
 
 179 
 
 Soft cast iron 50— 60 feet per minute 
 
 Hard cast iron 20— 40 
 
 Hard cast steel 30— 40 
 
 Soft machine-steel 60— 90 
 
 Hard machine-steel 20 — 30 
 
 Wrought iron 35 — 45 
 
 Tool steel annealed 50 — 80 
 
 Tool steel not annealed 15 — 20 
 
 Soft brass 110—130 
 
 Hard brass 90—110 
 
 Bronze 60 — 80 
 
 Gun metal 40— 60 
 
 A general idea of the feeds possible can be gained 
 from the following table. 
 
 5 per inch 
 5—8 " 
 
 Roughing cuts on cast iron 
 
 Roughing cuts on machine steel 
 
 Sizing cuts on cast iron 12 — 16 
 
 Sizing cuts on machinery steel 16 — 20 
 
 Finishing cuts on soft cast iron with a narrow- 
 point tool 15 — ^25 
 
 Finishing cuts on machinery steel with a nar- 
 row-point tool 20 — 40 
 
 Finishing cuts on cast iron with wide-faced 
 tool 1—4 
 
 Finishing cuts on machinery steel with wide- 
 faced tool 4—8 
 
 Finishing cuts for brass, according to kind of 
 cut and shape of tool 10 — 40 
 
 The above speeds and feeds are for tools of the 
 lathe-planer type. 
 
 Multiple Tool-Holders. — Tool-holders may be ar- 
 ranged to carry two or more tools of the lathe-planer 
 type, arranged one behind the other with reference 
 
 << 
 
 i€ 
 
 €t 
 
 i« 
 
 (C 
 
 «« 
 
 it 
 
 to the direction of feed. The first one takes a rough- 
 ing cut, the second one takes up the cut where the 
 first one leaves off, and so on to the last one, which 
 acts as a finishing tool. This is done for heavy work, 
 and is found more frequently on heavy lathes and 
 planers than elsewhere. 
 
 Single-Edged Forming Tools.— When the finished 
 surface is to have some curve or other definite shape, 
 this shape may be incorporated in the cutting edge 
 of the tool. Such tools are known as forming tools. 
 They may be either flat as shown at A, Figure 35, or 
 formed bars, as at B, or circular as at C. In forms 
 A and B the required shape is given to the front 
 edge, and the grinding is done on the top. In form 
 C the cutter is in the form of a surface of revolution. 
 Part of the tool is cut away, leaving a cutting edge 
 
 ^Shape of 
 surface to be 
 formed 
 
 TYPE- B 
 
 Shape of 
 Surface 
 to be formed 
 
 VARIOUS FORMED CUTTING^ARS FOR 
 TYPE . B 
 
 It'. ♦ 
 
 if.i r 
 
 B:i 
 
 FIG. 35. TYPES OP SINGLE-EDGED FORMING TOOLS 
 
180 
 
 THE MECHANICAL EQUIPMENT 
 
 It 
 
 as shown. When the edge becomes dull the flat face, 
 c, is ground away as much as may be necessary. 
 This process may be carried on until the whole cir- 
 cumference of the tool has been used. 
 
 Milling Cutters.— Figures 36 and 37 show various 
 forms of milling cutters— used on milling machines- 
 profilers, die-sinkers, and so on. In these a number 
 of cutting edges are arranged around the circumfer- 
 ence of a rotating tool, which is cylindrical, or some 
 surface of revolution. The cutting speed comes from 
 the revolution of the cutter, and the feed is usually 
 given by moving the work against the cutter, al- 
 though this is not necessarily so. Although they are 
 generally considered as more modern, milling cutters 
 are as old as the lathe type of tool. A milling cut- 
 ter made in 1780 by Jacques Vaucanson, a French me- 
 chanic, is now in the possession of The Brown & 
 Sharpe Manufacturing Company. This cutter, like 
 most of the early milling cutters, has very fine teeth. 
 Modern experiments, however, have shown that mill- 
 ing cutters with few teeth are much more efficient. 
 
 The milling cutter has a wide and increasing use. 
 The wear is not concentrated at one place, as in a 
 lathe tool, and the milling cutter will therefore hold 
 its shape longer. The cutting edge of the lathe tool 
 is in the work during the entire time of the cut; 
 with the milling cutter, any single cutting edge is in 
 the work only a small proportion of its revolution. 
 Consequently with a good stream lubrication it has 
 time to cool, which means that the cutting speed can 
 be higher. While the cutting done by any given edge 
 is intermittent, the cutting is continuous so far as 
 
 Wosher 
 
 a- PLAIN MILLING CUTTER 
 
 e- END MILL WITH STRAIGHT TEETH 
 
 f- END MILL WITH SPIRAL TEETH 
 
 d- INTERLOCKED SIDE 
 MILLING CUTTER 
 
 g - T SLOT CUTTER 
 
 b- SIDE MILLING CUTTER 
 
 C- SHELL END MILL WITM 
 SPIRAL TEETH 
 
 h- ANGULAR CUTTERS 
 
 f •Jf 
 
 ■ •ITlr 
 
 SHARPENED WITHOUT CHANGING 
 CONTOUR 
 
 MILLING CUTTER TYPE OF TEETH 
 
 FIG. 36. STANDARD TYPES OF MILLING CUTTERS 
 
 I 
 
 111 
 
 !■!■ 
 
 ♦ I 
 
 ii 11 
 
 m 
 
 Ha 37. MILUNG CUTTERS WITH OPPOSED SPIRALS 
 
 38X 
 
182 
 
 THE MECHANICAL EQUIPMENT 
 
 the work is concerned. There is therefore a saving 
 in time over a planer which has the idle return stroke. 
 
 Milling cutters are made in an infinite variety of 
 forms. The plain milling cutter, a, Figure 36, has 
 teeth on the circumference only, and they are parallel 
 to the axis. When the teeth are parallel, as in this 
 type, the entire cutting edge strikes the work at once, 
 giving a tendency to produce chatter, which increases 
 with the width of the cutter. When milling cutters 
 are long, the teeth are arranged spirally, to avoid 
 end-thrust. Two cutters, one with a right-hand spiral 
 and one with a left-hand spiral, may be placed side 
 by side, as shown in Figure 37. The side-thrusts 
 then will neutralize each other. Frequently the teeth 
 are nicked, as shown, to break up the chips. These 
 nicks do not appear on the work, since they are stag- 
 gered in each successive tooth, so that a high spot 
 left by any nick is cleared away by the tooth follow- 
 ing. Cutters made in this manner can be run at 
 coarser feeds than those with plain teeth. 
 
 The side milling cutter, b, Figure 36, is similar 
 to the plain one, except for the addition of teeth on 
 one or both sides. When it is necessary to maintain 
 accurately the distance between the two faces, two 
 such cutters are placed side by side with their teeth 
 ** interlocked "—that is, with the alternate teeth on 
 each mill reaching over into the zone of the other 
 cutter (see d. Figure 36). This is done to avoid a fin 
 or burr on the work, which might be left by the crack 
 between the two cutters. The width between the side 
 faces is maintained by packing thin washers between 
 the cutters each time the teeth are ground. 
 
 CUTTING TOOLS 133 
 
 A face milling cutter has teeth on the periphery 
 and on one face. It is carried on the end of the 
 niachme spindle, the teeth on the flat face being in 
 full contact with the work, while only a small length 
 ot the teeth on the periphery acts on the piece. The 
 shel end mill is similar to the face mill, but is used 
 for light operations. It may be solid, with a taper 
 shank, or separate, as shown at ^c." End mills with 
 right-hand teeth usually have a left-hand spiral and 
 vice versa. This tends to force the shank of the mill 
 solidly into the spindle of the machine. The T-slot 
 cutter, g, has teeth on its periphery and alternating 
 teeth on the side. It is used for milling T-slots in 
 fixtures and machine tables. Angular cutters, h, have 
 their teeth cut at some oblique angle. They are em- 
 ployed for finishing dove-tails and on a wide variety 
 of work calhng for surfaces machined to some re- 
 quired angle. 
 
 Formed cutters (i and j) are an important class 
 There are two kinds in general use. In the first' 
 the teeth are of the same character as those of plain 
 milling cutters and are sharpened by grinding on the 
 top As ordinarily done, this changes the contour of 
 he teeth and of the outline produced by them, which 
 « a serious objection when it is necessary to maintain 
 the original form. Special machines have recently 
 
 and .f r ^^ !"" ''^''''^^^ this type of cutter, 
 and at the same time preserving the original contour 
 ihe other style of cutter has teeth that are -relieved - 
 f>nt the contour is retained so that thev may be sharn 
 -ned repeatedly without changing the original form 
 '^0 long as the teeth are ground radially on their faces 
 
 }>'••■! 
 
184 THE MECHANICAL EQUIPMENT 
 
 With this style of cutter interchangeable work of a 
 regular outline may be produced more cheaply than 
 by any other method, and this type is widely used 
 for cutting gear teeth, the contour of the cutter 
 being the same shape as the space between the gear 
 
 teeth. 
 
 The fly cutter is the simplest form of milling cut- 
 ter. A tool similar to the lathe type which may have 
 any desired form of cutting edge is inserted in a 
 holder and acts in the same way as one of the cut- 
 ting edges in an ordinary mill. It has, of course, 
 only one cutting edge, but it can be made at little 
 expense and is used for short operations on special 
 
 work. 
 
 When milling cutters are large, the cost of making 
 them entirely of tool steel would be very high. This 
 cost may be reduced by making the body of the mill 
 of machine steel and inserting cutters of tool steel. 
 In Figure 38, **A'* and ''B'' show cutters of this 
 type, and ''C" shows one of the methods of insert- 
 ing the teeth. The upper screw pulls down a wedge 
 which forces the cutter against a shoulder integral 
 with the body of the mill. Both the hole in the 
 wedge and the hole in the body of the mill are threaded. 
 The holding-down screw engages the threads in the 
 body of the mill, but does not engage with those in 
 the wedge. Its action is therefore to draw the wedge 
 downward. When it is necessary to remove the 
 wedge, the holding-down screw is taken out and a 
 second screw, shown below, is inserted. The action 
 of this screw, as clearly shown by the figure, is such 
 as to withdraw the wedge. 
 
 CUTTING TOOLS 
 
 185 
 
 B 
 
 C - DETAIL OF METHOD OF SECURIMG 
 CUTTERS IN A AND B 
 
 TWO TVP.S or .«c. coTrc.Ps..yow,Ne sr>H.,Ro „,™oo op 
 
 FIG. 38. TYPES OP INSERTED-TOOTH MILUNG CUTTERS 
 
 Gang Mills.— These receive their name from the 
 tact that two or more cutters are placed together on 
 tlie same arbor and are used at the same time. (See 
 Figure 39.) "Sometimes plain milling cutters are so 
 combined in order to cover a wider space; and again, 
 termed cutters may be used either with or without 
 plain or side milling cutters. The use of formed cut- 
 ters and plain milling cutters together should be 
 avoided on account of the difficulty of maintaining 
 the relative diameters in sharpening. . . . Gang 
 milling reduces the cost of production and insures 
 
186 
 
 THE MEl HANICAL EQl II\MENT 
 
 FIG. 39. HEAVY GANG MILLING CUTTER 
 
 accuracy of work, as several operations can be per- 
 formed simultaneously and at one setting."* 
 
 In milling of this kind the cutters of the largest 
 diameter, which of course have the heaviest work to 
 do, should if possible be nearest the spindle, and it 
 is often desirable to have some of the cutters right- 
 hand and some left-hand spirals in order to equalize 
 the end-thrust. Sometimes, when the cutters vary 
 considerably in diameter, the inequality of the peri- 
 pheral speeds may be cared for by having the large 
 cutters made of high-speed steel and the smaller ones 
 of carbon steel. 
 
 ♦ "Treatise on Milling Machines," Brown & Shnrpe Mfg. Co. 
 
 CUTTINO TOOLS 137 
 
 Speeds and Feeds.- -The speeds and feeds in mill- 
 
 itToTirr; ''\''^r^^' - the power an^ nS- 
 
 andln h f T' T^^"''' ^^^^ ^^ ^^terial, width 
 and depth of cut, and quality of finish required No 
 dehmte rules are established. Delicate work requir 
 mg accurate finish calls for light cuts and fine feed 
 In general, the speed should be as fast as the cutter 
 wi 1 stand, and the feed as coarse a^ is crnsSent 
 with good work. The following surface speed 13 
 voeated by Brown & Sharpe in their treatise on^'Mnt 
 
 „.„ SPEED IN FEET 
 
 CARBON STEEL CUTTERS prr miNUTE 
 
 Z,^^^ SOtolOO 
 
 J;"«V 40to 60 
 
 Machinery Steel goto 40 
 
 Annealed Tool Steel 20 to 30 
 
 SPEED IN FEET 
 HIGH-SPEED STEEL CUTTERS PER MINUTE 
 
 ^^f; • 150to200 
 
 5^'*>» SOtolOO 
 
 Machmery Steel gotoioo 
 
 Annealed Tool Steel. 60 to 80 
 
 Drills._DriIls are used for originating holes in 
 
 ht elf • 1 ^ f'i" ™*^*^^' ^"^ -« P--<ie5 -""-t 
 
 ZeforTf '"^ "' "' P"'"*- ^* ^^ distinguished, 
 therefore froni a reamer, which has cutting edges 
 
 fat dri,r r- """"f ''' '' *"« ^^"^'•«' classel The 
 «a dnil, shown at "A," Figure 40, is the oldest type 
 
 but IS comparatively little used today. ^^' 
 
 ihe prevailing type of drill is the twist drill, shown 
 
isi; 
 
 TllK .MKCIIANICAL Ki^ll PM KNT 
 
 FIG. 39. HEAVY <1AN(1 MILLIN(J CTTTER 
 
 aeeuraey of work, as several operations caii U^ per 
 formed simultaneously and at one setting-."* 
 
 In niillino- of this kind the cutters of the largest 
 diameter, which of course have the heaviest work to 
 do, should if possihle be nearest the spindle, and il 
 is often desirable to have some of the cutters right 
 hand and some left-hand spirals in order to equalize 
 the end-thrust. Sometimes, when the cutters varv 
 considerably in diameter, the inequality of the pen 
 pheral speeds may be cared for by having the laigv 
 cutters made of high-speed steel and the smaller on'^^ 
 of carbon steel. 
 
 * "Tmitise on Millinjr Ma<'hiiu>s." Rn.wn i^ Sluiip*' Mfj:. Co. 
 
 CllTVlsa TOOLS 187 
 
 Speeds and Feeds.- -The sp.eds and feeds in mill- 
 ^ jerations ar. dependent or, the power and rigid- 
 't> the diNerent machines, kind of material, width 
 -;' ^i;Pth of cut, and quality of finish required lo 
 :'^*<^'^^te rules are established. Delicate work requh-! 
 n.g accurate finish calls ior light cuts and fine ?^ed 
 in genera , the speed should be as fast as the cutter 
 w. stand, and the feed as coarse as is conJ^n 
 ^Mtli good work. The following surface speed 'd 
 ->-^ted ,y Brown & 8harpe in their treatise oi'\li" 
 ing Machines,'^ will oiye som^ ;.^. / 
 practice: " ^"'' ^^'^^ "^ prevailing 
 
 SPEED rx FEET 
 f-ARBON -,TKKI, CfTTKRS PFR MINUTE 
 
 f:'''\ HOtolOO 
 
 ^fV"" -*0to 60 
 
 Miicliiiipiy Stool 3Q^^ ^Q 
 
 Aniioalcd Tool Steel :>o to .'50 
 
 SPKED IN FEET 
 
 ri„;H.RPrF:n stkri, c-ttkrs pkr minute 
 !:'"":'% 150 to 200 
 
 [r{ SOtolOO 
 
 .Mm-hniory Steel gOtolOO 
 
 Aniioiileil Tool Steel eo to 80 
 
 -Ko;:;:^'"\"', T T^ <■"'• originating, holo. h 
 
 I s oek A dnll rotate.., and is provided with ent- 
 
 'I'lff edges located at its noinf Tf ;. r ♦• , , 
 
 Iherefnr... t '^ " '• <'''*t]ngiiislio( . 
 
 ' efore froni a reamer, which has cutting edges 
 
 to sides. Dnils are of two general classed. The 
 
 'nil, shown at "A," Figure 40, is the oldest tvpe 
 '•''IS comparatively little „sed today. ' ^ ' 
 
 iUe prevailing type of drill is the twist drill, shown 
 
i 
 
 188 
 
 THE MECHANICAL EQUIPMENT 
 
 a- FLAT DRILL 
 
 b- TAPER SHANK STRAIGHT FLUTED DRILLi 
 
 C - STRA16HT SHANK Sr«AI6HT FLUTED DRILL 
 
 d- 5TRAI6HT SHANK TWrST DRILL 
 
 e-TAPEH SHANK TWIST DRILL 
 
 ■il2%/i': 
 
 f- STANDARD ANOLES ON A TWIST DRILL 
 
 q- END OF A SINGLE 
 LIPPED DEEP HOLE 
 DRILL 
 
 WG. 40. TYPES OF DRILLS 
 
 CUTTING TOOLS 139 
 
 at /'D'' and "E," Figure 40. This usually has two 
 spiral flutes, which are sharpened on the end, and are 
 ground down as the tool wears. Twist drills are 
 made m all sizes, for the smallest hole up to about 
 tour inches in diameter, although they are not common 
 much above two inches diameter. They may have 
 straight shanks, or tapered shanks made to one of the 
 well-known standards prevailing, such as the Morse 
 taper, which is % inch to the foot. This type of 
 drill was developed about 1860, and has marked a 
 very important advance in mechanical history There 
 are many refinements in the design and manufacture 
 of these drills which cannot be taken up here. The 
 point of the drill, F, Figure 40, is ground off at 
 an angle of 59 degrees with the axis. The ends are 
 not truly conical but are slightly spiral to give re- 
 . ,i /""'°^ ^^^^' *^^ ^"^'« »f clearance being 
 
 Z / .». '^f -n • ^* ^' ""^"^ ^^«^"«al tJiat the two 
 ips of the drill should be absolutely symmetrical, 
 that IS, the cutting edges at equal angles and of 
 equal length; otherwise the pressure will be heavier 
 on one side than on the other, and the drill will run 
 
 itself" ^ ^°'^ ^^"^^'' '° *^^^™^te^ tlian the drill 
 
 The speeds of drills must be varied to suit the 
 
 mended by the manufacturers of twist drills for soe- 
 cial cases The following recommendations are made 
 by the Cleveland Twist Drill Company: 
 
 ^u'bon sttl Ss with r n/"^ '■ '' ^ ^'^ ™'« t° «tart 
 Bieei urilis with a peripheral speed of 30 feet per 
 
 If I 
 
i 
 
 
 190 
 
 THE MECHANICAL EQUIPMENT 
 
 minute for soft tool steel and machinery steel ; 35 feet for cast 
 iron, and 60 feet for brass ; and a feed of from .004 to .007 
 inch per revolution for drills one-half inch and smaller, and 
 from .005 to .015 inch per revolution for drills larger than 
 one-half inch. At these speeds and feeds a good cutting 
 compound is recommended. In case of high-speed drills the 
 above feeds should remain unchanged, but the speeds should 
 be increased to from 2 to 21/2 times. 
 
 The cutting compound referred to is mainly for the 
 purpose of cooling the tool. The following com- 
 pounds are recommended in the order named: 
 
 For hard, refractory steel — ^turpentine, kerosene, or soda 
 
 water. 
 For soft steel and wrought iron — ^lard oil or soda water. 
 For malleable iron — soda water. 
 For brass — a flood of paraffine oil, if any. 
 For aluminum and soft alloys — ^kerosene or soda water. 
 Cast iron should be worked dry or with a jet of compressed 
 
 air. 
 
 Special forms of drills are used for many purposes. 
 For drilling soft metal, such as brass, especially when 
 the drill passes entirely through the piece, straight 
 fluted drills of the type shown at C, Figure 40, are 
 used. For deep-hole drilling, such as rifle barrels 
 in hard stock, a special form shown at 6, Figure 
 40, which has a single cutting edge, a, and a passage, 
 b, for the cutting lubricant, which is fed under pres- 
 sure, has been developed. 
 
 In general, the drill is not a very accurate tool. 
 There is a heavy pressure on the conical point, which 
 tends to press the tool off to one side if the con- 
 ditions at the point are not exactly right. The sur- 
 prise is not so much that they are inaccurate as that 
 
 CUTTING TOOLS igj 
 
 they do their work as well as they do. When verv 
 
 str!ShTcu^^^^ r''"'^^ ^^^^^^ i« ^ '^ol with long, 
 iS^Fi^^^^^^ with its axif: 
 
 is ua«i vh™ L >»»Je«M to the greatest wear. Oil 
 
 <« set.i„ ... .,. i;:i ^it^j-'t, Tr 
 ....» iLr: r„rti,nat;/'s '° '° -: 
 
 accuracy of work ' ^^ ^creased 
 
 ^'■i. .... J thX't z ttr„r tS'e te"r„ 
 
 
I 
 
 I 
 
 STANDARD HA.ND REAMER 
 
 EXPANSION REAMER 
 
 STANDARD SHELL REAMER 
 
 ROUGHING AND FINISHING 
 
 MORSE TAPER REAMER 
 
 WITH SQUARE SHANKS 
 
 STANDARD ROSE SHELL REAMER 
 
 SOLID ADJUSTABLE BLADE SHELL REAMER SECTION SHOWING CONSTRUCTION 
 WITH CARBON OR HIGHSPEED OF ADJUSTABLE BLADE REAMERS 
 
 STEEL BLADES 
 
 FIG. 41. TYPES OP REAMERS 
 
 192 
 
 CUTTING TOOLS 
 
 193 
 
 FIG. 42. TAPS 
 
 Mo.f nV.1. ^P'ndle, so that the tap is free to fall 
 
 
 11 V 
 
 m 
 
194 
 
 THE MECHANICAL EQUIPMENT 
 
 but there are other well-established forms that are 
 used for special purposes. The desirability of uni- 
 formity in screw threads is so great that the stand- 
 ard should not be departed from except for very 
 good reasons. The detailed consideration of the vari- 
 ous standard forms of threads, and their uses, will 
 be given in the chapter on Thread Cutting. 
 
 There is a wide variety of taps for special pur- 
 poses. The first one shown. A, Figure 42, is known 
 as the tapered tap. It will be noted that the whole 
 of the thread is cut away on the front end, the 
 amount gradually lessening until full threads are left 
 in the upper part of the tap. This distributes the 
 work of cutting along the length of the tap, and con- 
 sequently relieves the wear on the threads. The 
 final threads have little to do except to bring the 
 work to exact size. This type of tap is used in holes 
 that go clear through the work. The second, or plug, 
 tap, B, is used for threading holes that do not go 
 through, but where a few imperfect threads at the 
 bottom of the hole are not objectionable. The bot- 
 toming tap, C, is used when it is necessary to cut 
 the threads quite to the bottom of the whole. This 
 form is not used except when absolutely necessary. 
 As will be seen, the plug tap is a compromise be- 
 tween A and C. 
 
 Taps are also made with long shanks when threads 
 are required at the bottom of a long hole. As the 
 size of the tap increases, a point is reached where 
 inserted tooth cutters become profitable, as in the 
 case of milling cutters and reamers. This also al- 
 lows for adjustability in connection with regrind- 
 
 CUTTING TOOLS 195 
 
 Wk J^^.1' ^'^\^^^^^ cutting tools, must have relief 
 back of the cutting edge, and in most of the solid 
 taps now used, when they are reground on the face 
 there is a sLght change in size. When the taps are 
 arge enough, this may be compensated for hjlZ. 
 ting the tap and spreading the sections apart w h 
 a threaded taper plug which acts along the aLil of 
 the tap, as shown in D, Figure 42. 
 
 Dies.--Taps are used for cutting internal threads- 
 externa threads are cut in dies. Figure Shor^^^^^ 
 simplest form of solid threading die Dies as well as 
 taps must have a relief back of the cutting edge as 
 they also will lose their size on regrinding^ ^^^^^^ 
 may be compensated for by slitting the die and 
 springing It together with an adjusting screw in the 
 
 PoSs anT'".".?^' ^^ *^ «P^^* *^' ^- -toM': 
 portions and make these adjustable in the die-holder 
 
 toward each other. For large work and for accumte 
 
 Puichei %^''T^'^ ^^t^r "«der Screw-Threading 
 Funches.-Punches are used for originating holes 
 
 SOLID 
 THRCAOING Dies 
 
 ^ ADJUSTABLE 
 THREADING DIES 
 
 WG. 43. THREADING DIES 
 
 ' ' 
 
 ht'fl'; 
 
 
 IIG. 44 PUNCH 
 
r> 
 
 196 THE MECHANICAL EQUIPMENT 
 
 in thin stock when accuracy is not required. They 
 are usually round, but there is no reason why an 
 odd-shaped hole may not be punched as well. The 
 simplest form of punch is a short, cylindrical tool with 
 a flat end which goes through a corresponding ring 
 known as the die. The material is placed between 
 the two, and the punch forces a plug, or wad, the 
 size of its own diameter through the hole in the die. 
 The die is always fixed to the bed of the machine, 
 and the punch is carried on a movable power-driven 
 head. The work of punching with a punch that has a 
 flat end is very severe, since all of the circumference 
 begins to cut at once. A punch with a curved edge of 
 the type shown in Figure 44, relieves the suddenness 
 of this shock. In this type the conical point in the 
 middle enters the plate first, and holds it securely. 
 The lower portion of the curved edge enters the work 
 first, and the highest portion is last. This distributes 
 the work of cutting through a vertical zone repre- 
 sented by the difference in height of the lowest and 
 highest portions of the edge. A punch does not have 
 to cut its way entirely through the plate, as the plug, 
 or wad, is sheared completely from the surrounding 
 material after the punch has gone part way through, 
 and from then on the punch has merely to push the 
 plug out. The percentage of the work actually per- 
 formed to the apparent work of cutting the entire 
 thickness of plate is lowest for thick plates, varying 
 from about 25 per cent on a one-inch plate, and 37 
 per cent for a half-inch plate, to about 75 per cent 
 for a plate 1/16 inch thick. For very thin plates, it 
 approaches 100 per cent. In large machines, a num- 
 
 CUTTING TOOLS 197 
 
 \Z If fr"!!"' ""^^ ^' ^P"'^*"^ "^ ^^gangs.- Punch- 
 i in \ ?^f S^'^^ ^^'* '^^'^ ^^y ^f producing 
 S ro'.fr' ''^^'- I' ''^ ^^— ^ - --curat? 
 TI .^ ''''^''' ^""^ ^h^n accurate work is re- 
 quired the holes should be drilled 
 
 fnr .T*""?'^"'' ^' ^^''' ^^^^ ™Plies, are used 
 to suit the material. For cutting plates straight 
 
 tfnfedt"t^'^^'" '-' "^^^^^- ^'-' wfhrt 
 
 t ng edge set at an angle to distribute the work of 
 eutxng and to relieve the machine from the shock 
 
 TonTe ""'' '' ''' ''''''' ^^^^ -^-^^ the work 
 
 sto!r*Th?r t' ^^'' T^ ^'' ^^*«^^ ^P rough 
 Ted for .H^^^^' ^""^-'^^ ^^' it« counterpart, 
 
 with 1\'S',^"' f '"^' '''''' ^'^^^ '^ '^'^ -ide' 
 ^itn a hole in each end. This is mounted in thp 
 
 frame of an automatic machine which giv^the^^^^^^^^^ 
 
 or metll flT"" ''"t. ^""^^^^ «^"« ^^^ -^ used 
 lor metal-they generally consist of a soft steel di^k 
 
 S 'ZTiT'^' "TT' •-"■■ ■f-- St 
 
 acK saws, do their work by pure cultins action 
 l»m disk of soft stee] which runs at very m-eal ™ri 
 
 ot work to be cut is concentrated at the point 
 
f' ! 
 
 198 THE MECHANICAL EQUIPMENT 
 
 of contact; on the saw it is distributed around the 
 entire circumference, and the cooling stream is suf- 
 ficient to preclude heating. The disk therefore liter- 
 ally melts its way through the work with a rapidity 
 incredible to those who have not seen it work. This 
 type of saw may be used to cut hardened tool steel. 
 In this case the temper will be drawn for a slight 
 distance possibly 1/64 or 1/32 inch back from the 
 surface. This may be ground off on an emery wheel 
 down to the hard metal and the piece, if it is a cut- 
 ting tool such as a threading die, will be again ready 
 
 for ^^^' . XI I.- u 
 
 There are many special forms of cutting tools which 
 do not fall under any of the classes described. Some 
 of these, such as broaches, hobs and forming tools 
 for stampings, will be taken up in connection with 
 the machine tools with which they are used. 
 
 Cutting Lubricants.— A list of the cutting lubri- 
 cants suggested by one of the well-known firms was 
 given in connection with twist drills. In most of 
 the machining operations some form of lubricant is 
 used, the conspicuous exceptions being the cutting of 
 cast iron and brass, which is done dry. In general, 
 lard oil is an excellent lubricant when turning or 
 threading steel or wrought iron, and it is largely used 
 on automatic screw machines, especially on small 
 work. For high cutting speeds, soda water is more 
 satisfactory, as oil is more sluggish and does not 
 reach the cutting point with sufficient rapidity. ' Many 
 cutting compounds are on the market which consist 
 usuallv of a mixture of carbonate of soda and water, 
 with iard oil or soft soap to thicken it, and which 
 
 CUTTING TOOLS 
 
 199 
 
 act as a lubricant. The different kinds of lubricants 
 for the various types of cuts on the various metals 
 are so many that they cannot be taken up here. Fred- 
 erick W. Taylor was the first to point out the great 
 saving in stream lubrication for a cutting tool. One 
 of the principal limitations to the cutting speed is 
 the rise in temperature of the tool, with the conse- 
 quent drawing of the temper and loss of cutting edge. 
 He discovered that a heavy stream of water-— not the 
 little dribble previously used, but a heavy stream 
 poured directly on the chip at the point where it 
 was being removed by the tool— would permit an in- 
 crease in cutting speed amounting in some cases to 
 30 or 40 per cent. The stream is used, not for lubri- 
 cation, but for the purpose of carrying away the heat 
 generated at the point of the tool. This practice has 
 become very general for heavy roughing cuts of the 
 kind described by Dr. Taylor. 
 
 
CHAPTER XIII 
 
 LATHES 
 
 LATHES 
 
 201 
 
 Development of the Lathe. — The lathe is the oldest 
 of the machine tools. In its rudimentary form — as, 
 for instance, the potter's wheel — it comes down from 
 the earliest dawn of civilization. In the old whip 
 lathe the work was mounted on two centers. A cord 
 was run from a long wooden spring, secured to the 
 ceiling, down to the work, around it for one or two 
 turns, and then on down to a foot treadle on the 
 floor. By the working of the foot treadle the piece 
 to be cut was oscillated backward and forward, and 
 a hand tool, resting on a guide in front of the work, 
 was used to do the cutting. The cut was taken with 
 every alternate movement as the work rotated for- 
 ward. Later, the continuous revolution was substi- 
 tuted for oscillating motion, but the driving cord was 
 still carried around the piece itself. In the next step 
 in the development, the work was mounted on cen- 
 ters as before, but was connected by suitable means 
 to a live spindle which had a permanent pulley driven 
 by the belt. With all of these types only hand cut 
 ting tools were used. It is rather surprising, as we 
 look back, to see what good turning was done in this 
 way at such an early period of mechanical develop- 
 ment. 
 
 200 
 
 Henry Maudslay and Modem Tools. — Modern tools 
 really had their beginning with the application of the 
 ** slide rest" principle to turning lathes by Henry 
 Maudslay, a principle which has been extended to 
 nearly every form of machine tool. It was first de- 
 veloped by Maudslay between 1790 and 1800 in the 
 shop of Joseph Bramah, in London. Instead of being 
 manipulated by hand, the cutting tool was clamped 
 solidly in a tool post carried on a slide rest movable 
 along accurately finished guides on the bed of the 
 machine. For many years the slide rest was known 
 in English as ** Maudslay 's Go-Cart.'' 
 
 In its first and simplest form the motion was con- 
 trolled by hand-operated screws. In a short time, 
 provison was made for connecting the operating 
 screws by gearing to the driving spindle, giving the 
 tool a power feed. This invention enormously in- 
 creased the accuracy of the machine as well as the 
 size of the cuts which could be taken. The old hand 
 tools had to be skillfully used, for occasionally they 
 **dug in" and lifted the workman over the lathe. 
 
 The lead screw, for which, also, Maudslay is respon- 
 sible, followed within a very few years, and was a 
 natural development from the slide rest. In its first 
 form, Figure 45, a lead screw with the same number 
 of threads per inch as it was desired to cut, was 
 attached to a slide rest and driven at the same speed 
 as the work. This caused the cutting tool in the 
 slide rest to move forward over the work and generate 
 the screw thread required. It, of course, necessitated 
 a separate lead screw for every pitch to be cut. 
 Within a year or so Maudslay developed the idea 
 
 SJ.'!; 
 
 y] 
 
 I 
 
 ■"i 
 
I 
 
 202 
 
 THE MECHANICAL EQUIPMENT 
 
 FIG. 45. maudslay's first screw-cutting lathe, 
 
 ABOUT 1797 
 
 of a single lead screw, much more accurately formed, 
 which could be made to cut any pitch of thread by 
 changing its turning velocity, relatively to the work, 
 through a gear reduction. The various gears used 
 to change the speed of the lead screw are still known 
 as ** change gears." 
 
 These essential features of the screw-cutting lathe, 
 although varied in proportions and greatly improved 
 in workmanship, remain unchanged in principle to 
 this day. Maudslay lived until 1830; shortly before 
 his death he built a lathe capable of turning work 12 
 feet in diameter and boring steam cylinders up to ten 
 feet in diameter, which shows the remarkable devel- 
 opment in this machine during the lifetime of one 
 man. So important were Maudslay 's contributions 
 that he may well be termed the father of modern 
 machine tools. The back gears used to increase the 
 power of the drive were invented by Richard Roberts 
 about 1817. From 1830 onward there was little dv- 
 
 LATHES 
 
 203 
 
 FIG. 46. SPEED LATHE 
 Oliver Machinery Co. 
 
 velopnient in the essential design of the turning lathe 
 until, about 25 years later, the turret lathe was de- 
 veloped, and later still the automatic turret lathe. 
 Both of these are American in their origin. 
 
 The Speed Lathe.— The simplest form of lathe used 
 today is the speed lathe, Figure 46, which consists 
 of a bed having guides or ways on its top, and at 
 one end— invariably the left-hand end as the workmen 
 faces the machine— a headstock, or casting, contain- 
 ing two bearings. In these bearings is the live spin- 
 
 h 
 
202 
 
 THE MKCHAMCAL KQril\\IKi\1 
 
 FIG. 45. maudslay's first screw-cutting lathe, 
 
 ABorT 171)7 
 
 of a siniilc lead screw, niiich more accurately roinicd, 
 
 which coiihl ho made to cut any pitcli of tlircad by 
 
 c]ian<»ini^ its turnin^;- vok)city, ridativcly to the work, 
 
 tlirougli a n'ear reduction. Tlie various iACjirs used 
 
 to chaui^e the speed of the h^ad screw are still known 
 
 as *' change gears." 
 
 Tliese essential features of the screw-cutting lathe, 
 
 althougli varied in proportions and greatly improved 
 
 in workmanship, remain unchanged in piinciple to 
 
 this ilay. ^laudslav lived until 18o(); shortly het'ore 
 
 his death he huilt a lathe ca})ahle of turning work ll' 
 
 feet in diameter and horing steam cylinders up to ten 
 
 feet in diameter, which shows the remarkahle devel- 
 
 oi)ment in this nuichine during the lifetinu* of one 
 
 man. 8o important were Alaudslay's contributions 
 
 that he may well be termed the lather of modern 
 
 machine tools. The back gears used to inci*ease the 
 
 power of the drive were inventcnl by Ivichard liobert- 
 
 about 1817. From 18.*)() onward there was little <1< 
 
 LATJIKS 
 
 2( !:'. 
 
 via. 4(). spi:i:i) lathe 
 
 olivtT Macl.iucry (N>. 
 
 velopment in the essential design of the turning lathe 
 iinlil, about 2:) yc^-irs later, the turret lathe was de- 
 veloped, and later still the automatic turret lathe. 
 I'oth of these are American in their origin. 
 
 The Speed Lathe.— The sinrph^st form of lathe used 
 
 ''May is the speed lathe, Figure 46, which consists 
 
 'I a bed having guides or ways on its top, and at 
 
 nc end— invariably the left-hand end as the workmen 
 
 '<M's the machine— a headstock, or casting, contain- 
 
 i; two bearings. In these bearings is the live spin- 
 
f 
 
 2ai 
 
 THE MECHANICAL EQUIPMENT 
 
 die, and between the bearings is a pulley, called the 
 cone pulley from its step-like form, which is used to 
 drive the work. At the right-hand end is the tail- 
 stock, which contains the dead center, on« of the 
 conical points on which the work turns. The front 
 of the driving spindle contains the other center, 
 which is known as the live center, because it rotates 
 with the live spindle. It is highly important that this 
 should run true, or it will cause the work to revolve 
 in an eccentric path. 
 
 On the end of the live spindle just back of the 
 center is a flat plate, called the face plate, which, for 
 metal turning, is notched. The work is mounted on 
 these two centers, and a projection, usually the horn 
 of a lathe dog secured to the work, engages with 
 this notch. The turning force is transmitted through 
 the live spindle, the notch in the face plate and the 
 dog, to the work, which rotates freely about the axis 
 of the two centers. An adjustable slide carries a 
 light, straight rest, which is set parallel with the 
 work, and a hand tool resting on this support close 
 to the piece turned, is manipulated by the operator 
 to make the desired cuts. This form of lathe is so 
 simple that its construction will be understood from 
 the illustration without further explanation. Speed 
 lathes are little use now for metal turning; they are 
 mainly confined to pattern shops and wood-working 
 plants, where they will always have a place, as the 
 Avork of cutting is not heavy and a hand tool may be 
 used freely and safely. 
 
 The Engine Lathe. — The rather archaic name of 
 *' engine" lathe still clings to the standard type of 
 
 LATHES 
 
 200 
 
 i) 
 
 metal-cutting lathe which is power driven and 
 equipped with a slide rest and screw-cutting attach- 
 ment. The principal elements of the engine lathe, 
 Figure 47, are the bed, headstock, spindle, back gears, 
 tail stock, slide rest or carriage, apron, a lead screw, 
 change gears, and feed rod. Auxiliary attach- 
 ments that go with the lathe are the chuck, steady 
 rest and follower, dogs, taper attachment, and boring 
 bar. The lathe bed is the main frame that carries 
 the working parts. For small and moderate-sized 
 lathes this is carried on legs at, or near, each end. 
 Frequently one of these legs, usually the left-hand 
 one, IS expanded into a box or chest. 
 
 It is desirable to have the center line at a level 
 convenient for operation. Consequently, as the size 
 of lathes increases, the bed becomes lower, the legs 
 shorter, and finally, in the largest sizes, the legs dis- 
 appear altogether and the bed rests directly on the 
 foundation. (See Figure 53.) Generally the cross- 
 section of the bed consists of two parallel girders ap- 
 proximately of an I-section, braced across at 'fre- 
 quent intervals. On the tops of these girders are the 
 ways, which in America are inverted V-shaped 
 guides. The European tool-makers prefer flat, square 
 shdes, but the universal practice in the United States 
 IS to make the ways of inverted V-section. There are 
 two sets of these ways, one on each side; the outer 
 pair carry the slide rest, and the inner pair the head- 
 and tail-stocks. In some Iatlie.=5 a single V is used for 
 one side of the slide rest; the other side resting on a 
 flat surface. In small and, medium sizes, it is quite 
 common to have an oil pan for catching oil and chips 
 
I 
 
 I 
 
 206 
 
 » 
 
 W 
 H 
 
 o 
 
 G 
 
 d 
 
 LATHES 
 
 207 
 
 running the entire length of the lathe, which may 
 or may not be a part of the main casting. The bed 
 should be not only strong enough to carry the bending 
 and twisting strain due to the cutting action, but 
 stiff enough to have no appreciable springing even 
 under the heaviest load. The ways must be straight 
 and truly parallel, and the head- and tail-stocks 
 parallel and in line. 
 
 Head-Stock.— The head-stock at the left-hand end 
 of the lathe is either cast or otherwise permanently 
 secured to the bed. It carries the live spindle and 
 the driving mechanism. A cross-section of a head- 
 stock is shown in Figure 48. It has two adjustable, 
 accurately made bearings in which the live spindle 
 runs. This is driven by a large gear. A, which is 
 keyed to it. The stepped driving pullev, P, runs 
 freely on this spindle; when the lathe is used for 
 light fast cuts a locking pin, B, secures the cone pul- 
 ley to the gear. A, and drives the spindle direct. For 
 heavy cuts, when slow speed and great power are 
 needed, the back gears are used. These are shown 
 in Figures 47 and 48. They are usually on the same 
 level as the spindle and directlv behind it, as in 
 Figure 47. In Figure 48, they are drawn in a false 
 . position above, in order to bring them into the plane 
 with the picture. The bearings, c, for the back gear 
 shaft are part of the head-stock, and the shaft, which 
 is an eccentric, carries the two gears, b and c. 
 
 Speeds.— When the spindle is driven directly by 
 the pulley, as described above, the eccentric shaft is 
 turned back, and the back gears are thrown out of 
 mesh with the gears, d and A; otherwise the mechan- 
 
 .'11 
 
 \\i\. 
 
208 
 
 THE MECHANICAL EQUIPMENT 
 
 ^ 
 
 0-. 
 
 .-b 
 
 .■ Eccentric 
 
 C-. ..a 
 
 -JL. 
 
 ^^ 
 
 FIG. 48. CROSS-SECTION OF HEAD STOCK 
 Pratt & Whitney Co. 
 
 ism would lock and be inoperative. When the slow 
 speeds are required, the locking pin, B, is withdrawn 
 so that the cone is no longer connected with the 
 driving gear, A, aad is free to rotate on the spindle. 
 The eccentric back-gear shaft is then turned forward 
 to the position shown in Figure 48, throwing the 
 larger of the back gears into mesh with the gear, d, 
 carried on, and rotating with, the cone pulley, and 
 throwing the smaller one, c, into mesh with the main 
 driving gear. A, on the spindle. The power is then 
 transmitted around through the back gears and back 
 on to the spindle. If there are four steps on the cone 
 
 LATHES 
 
 209 
 
 pulley, as shown in Figure 48, four speeds are pos- 
 sible on the direct drive, and if the lathe is thrown 
 *4nto back gear" four more are possible. The speed:; 
 are usually so arranged as to be in geometrical 
 progression. With very large and heavy lathes there 
 i::ay be two back-gear shafts— such lathes are said to 
 be tripled-geared. Between the cone-pulley gear and 
 the left-hand bearing is a small gear, e, keyed to the 
 driving spindle from which the feed mechanism is 
 taken. 
 
 Spindle and Tail Stock.— The main driving spindle 
 is usually hollow. This permits cutting operations on 
 bar stock which is slipped in through the left-hand 
 end of the spindle and is grasped by the hollow tube 
 shown. This tube has on its right-hand end spring 
 jaws, f, which are drawn together, clamping the bar 
 close to the cutting point when the hand wheel at the 
 extreme left is turned. Instead of this spring collet, 
 as it is called, a solid plug may be used, and the sur- 
 rounding collar, g, engaging it may be split. The 
 hand wheel may then be used to spread the collar so 
 that it can be used as an expanding chuck to hold 
 and center work that has a hole in it, the piece being 
 slipped over the collar and the collar expanding until 
 the work is firmly held. The tail-stock is shown on 
 the right in Figure 47. This is adjustable, as a whole, 
 lengthwise on the ways of the bed to accommodate 
 different lengths of stock. A finer adjustment of the 
 dead center is operated by the hand wheel, h, at the 
 extreme right. After the work is set, the handle, i, 
 on the top of the tail-stock locks the center in posi- 
 tion. 
 
 1, 
 
 i', 
 
210 
 
 THE MECHANICAL EQUIPMENT 
 
 Slide Rest.— The slide rest, or carriage, shown be- 
 tween the head- and the tail-stock, carries the tool 
 post which holds the cutting tool. The rest has a 
 motion lengthwise of the bed and may be operated 
 by the hand wheel, j, or by a clutch mechanism, which 
 engages the feed rod, k, and throws in the power 
 feed. The rate of the power feed may be controlled 
 by changing the gears at the left-hand end of the ma- 
 chine. For screw-cutting, a screw, 1, is provided 
 known as the lead screw, which gives the required 
 traverse to the carriage. The same screw might be 
 used for the feed and for thread-cutting, but as 
 thread-cutting is an accurate operation, this function 
 is dissociated from ordinary feeding and performed 
 by a separated lead screw. The proper rotation 
 necessary to give the cutting tool the required feed is 
 obtained through change gears. 
 
 Change-Gear Box.— In the standard type of engine 
 lathe used for many years the change gears were 
 exposed at the left-hand end of the lathe, as in Figure 
 47. In the more modern lathes these gears are col- 
 lected in a *' change-gear box" at the side and in 
 front of the headstock, and the handle, a, shown in 
 Figure 49, which projects forward, enables the opera- 
 tor to make a rapid selection of the proper combina- 
 tion of gears required to give the lead desired. The 
 two handles to the right of the gear box operate the 
 change gear for the feed. The apron is the flat plate 
 mounted on the slide rest which drops down over the 
 front of the bed and carries the various feed attach- 
 ments that connect the feed rod and lead screw with 
 the carriage. A proper combination of the change 
 
 ^%/j\ 
 
 U'r''. 
 
 !;;- 
 
 \ 
 
 FIGS. 49 AND 50. HIGH-DUTY LATHE 
 
 ^inti^^^n ^^^^ Shows a 24-inch lathe with 8-speed geared lead for 
 
 single pulley belt drive. Below is shown details of carriage, tool 
 
 post, and follow rest of a Pratt & Whitney Lathe. 
 
 211 
 
210 
 
 TJIK MHCHANirAL EQriPMKNT 
 
 Slide Rest.— The slido i-est, or carriage, shown l)e- 
 tweon tlu' head- and Ww tail-stock, carrios the tool 
 post wliich holds tlu' cutting- tool. The rest has a 
 motion iengtiiw isc ol* the hed and may he operated 
 by the hand wheel, j, or l)y a clutch mechanism, which 
 en.iia.«;es the I'vrd rod, k, and throws in the power 
 feed. The rate of the \n)\\vv teed may he controlled 
 hy chanuiiii;- the gears at the left-hand end ot* the ma- 
 chitie. For scn^w-cutting, a screw, 1, is ])r()vide(l 
 known as the lead screw, which gives the reciuired 
 traverse to the carriage. The same screw might he 
 ii^i^d for the feed an<l for thread-cutting, hut as 
 threatl-cutting is an accurate operation, this function 
 is dissociated from ordinary feiuling and i)erronne(l 
 hy a sei)ai-ated lead screw. The proper rotation 
 necessary to give the cutting tool the reciuired feed is 
 ohtained through change gears. 
 
 Change-Gear Box.— In the standard type of engine 
 lathe used for many years the change geai's were 
 exi)ose(l at the left-hand end of the lathe, as in Kigun^ 
 47. In the more modern lathes these gears are col- 
 lected in a ''ehange-g(^ar box'' at the side and in 
 Front of tlie headstock, and the handle, a, shown in 
 Figure V.\ which ])r(>jects forward, enables the ojiera- 
 tor to mak<' a rapid selection of the i)roper combina- 
 tion of gears recjuired to giv(^ the lea<l desired. The 
 two handles to the right of the gear box operate the 
 change gear for the feed. The ai)ron is the flat plate 
 mounted on the slide rest which droi)s down over the 
 front of the l)«'d and cari-ies the various feed attach- 
 ments that connect the W^i^d rod and lead screw with 
 the can-iage. A ])roper conibimitiou of the change 
 
 FKJS. 49 AND ;")(). HKJJI-DITV LATUK 
 •yipiH'i- vitnv shows a L'4-iiicli lathe with S-siKvd ^-caivd lead foi 
 ^it i.ullev hell drive. IJelow is sh(.\vn (h'tnils of carria.ue, too 
 
 ])ost. and t\.llo\v ivsr of a I'l-ait iV: Whiinc.v l.alhe. 
 
 I'll 
 
212 
 
 THE MECHANICAL EQUIPMENT 
 
 gears will permit the cutting of either right- or left- 
 hand screw threads. The cone pulley is driven from 
 a countershaft which is usually hung from the ceil- 
 ing over the lathe and carries a similar cone with 
 the ends reversed from the one on the lathe spindle. 
 Single Driving Pulley.— One of the recent develop- 
 ments in tool construction is the use of a single 
 driving pulley running at a constant speed. The 
 speed variations of the lathe spindle are obtained by 
 additional gearing in the head-stock casing operated 
 by the levers, b, shown on the front of the casing 
 above the change gear box in Figure 49. Lathes 
 equipped with this type of drive do not need a cone 
 pulley countershaft, and they are especially adapted 
 to individual motor drives with a constant-speed 
 
 motor. 
 
 Mounting the Work.— The work is ordinarily 
 mounted on the centers carried in the head- and tail- 
 stocks. The piece is driven through a lathe dog, m, 
 Figure 47, which is clamped on the piece and has an 
 arm that is bent to the left and engages a slot, n, in 
 the faceplate, shown in Figures 47 and 50. For short 
 pieces the tail-stock is frequently not used. In this 
 case the face plate on the end of the live spindle is 
 replaced with some form of chuck similar to that 
 shown in Figure 51. In such chucks, a long bar of 
 stock is put through the hole in the spindle and 
 grasped by the three jaws, or short pieces, which 
 have a hole through them, may be carried on the 
 stepped faces shown on the jaws. The steps, a, a', 
 are used to decrease the amount of motion that it is 
 necessary to give the jaws, these being arranged to 
 
 LATHES 
 
 213 
 
 FIG. 51. LATHE CHUCK 
 
 have a motion little more than the distance between 
 steps. If the work is slightly smaller than the capac- 
 ity of the outermost step, a, the jaws are run out and 
 the second set of steps, a', is used— and so on to the 
 smallest set, a". 
 
 In the simplest form of chucks, each jaw is oper- 
 ated by an independent screw on the periphery of the 
 chuck. This entails care and time on the part of the 
 workmen in centering work. In the more refined 
 forms of chucks, all of the jaws are operated from 
 any one of the adjustling screws, b, there being one 
 opposite each jaw, so that they may be moved in and 
 out simultaneously from whichever adjusting screw 
 liappens to be in the front of the chuck. In many 
 chucks, the jaws are reversible in the head so that 
 
 ,1..' 
 
 '<! 
 
 
 
 4 
 
 I' ■■ i 
 
214 
 
 THE MECHANICAL EQUIPMENT 
 
 they may be used for exterior as well as interior 
 work. 
 
 Tool Post. — The construction of the tool post, o, is 
 clearly indicated in Figures 47 and 50. The slide rest 
 that carries it has a feed lengthwise of the bed as a 
 part of the general movement of the carriage, and a 
 crosswise feed operated by the handle, p, shown in 
 front. Compound slides are arranged to swivel at an 
 angle horizontally, and have an independent power 
 feed for the tool post at this angle. This gives a 
 convenient means of turning conical surfaces. Long 
 cones or tapers are cut much more accurately by 
 what is known as the taper attachment. This con- 
 sists of a straight edge, carried usually at the back 
 of the bed. The cross slide carrying the tool post is 
 attached to a block sliding on this straight edge. If 
 the straight edge is set at the desired angle, the tool 
 post will move in and out uniformly as the carriage 
 is fed lengthwise, thus generating very accurately the 
 taper desired. 
 
 In long, slender work it is desirable to guide the 
 piece between the centers, to prevent its springing 
 tinder the pressure of the cutting tool. For this pur- 
 pose a steady rest is provided, similar to the one 
 shown at c in Figure 49, which consists of a circular 
 frame with three sliding pieces that can be adjusted 
 in and out from the center to bear on the work and 
 hold it in position. It is often better to have the 
 guide close to the tool, and to follow it as it makes 
 the cut. In this case, it is called a follow rest and is 
 mounted on the carriage directly behind the cutting 
 tool, as shown in a modified form in Figure 50. 
 
 LATHES 
 
 215 
 
 Special Lathes.^There are many forms of lathes 
 designed for special purposes, the proportions of 
 which differ materially from those shown. A gap 
 lathe is one with a gap or sag in the bed in the zone 
 of the face plate which gives a combination lathe 
 capable of turning long work of small diameter, or 
 short work of large diameter. Another type of lathe 
 has two sets of centers at different heights from the 
 bed. For work of small diameters the lower set of 
 centers is used, and for an occasioal job of large 
 diameter the upper set of centers is employed. Such 
 a tool is essentially a jobbing machine, and is not to 
 be recommended for ordinary work. 
 
 Figure 52 shows a car-wheel lathe, for turning loco- 
 motive driving wheels. In this lathe the tail-stock 
 has been replaced with another head-stock and there 
 are two tool posts so that the wheels, mounted on the 
 axles, are swung on centers and driven from both 
 sides, and cuts are taken on each wheel simul- 
 taneously. This view shows the type of face plate 
 used on large lathes, with T-slots in the face, which 
 are used to secure the work. Figure 53 shows a lathe 
 of the very largest type used for boring and turning 
 a 100-inch gun. This machine is over 185 feet long, 
 each carriage weighs 125 tons, and the complete ma- 
 chine weighs 800,000 pounds. 
 
 Lathe Operation.— Care should be used in drilling 
 the center-holes that are to carry the work. These 
 should be concentric, and the conical surfaces that 
 bear on the lathe centers should be cut at the same 
 angle as the centers. It is often necessary to do turn- 
 ing operations that shall be concentric with a hole 
 
FIGS. 52 AND 53. ABOVE: CAR WHEEL LATHE. BELOW: 
 
 LARGE GUN LATHE 
 216 Niles-Bement-Pond Co. 
 
 LATHES 
 
 217 
 
 already formed in the piece. Work of this character 
 is often done on an arbor, which is a bar carried 
 on the lathe centers and driven from the face plate. 
 The piece is mounted directly on this arbor, which 
 may be made expanding, to grasp the work in a man- 
 ner similar to that described in connection with the 
 chuck. If they are properly mounted, the subsequent 
 operations will have a correct relationship to the 
 bored hole. Pieces too large for a chuck which are 
 comparatively short and large in diameter, are 
 clamped directly to the face plate by means of the 
 T-slots already referred to. 
 
 Boring may be done on the turning lathe by mount- 
 ing the work on the face plate and reaching in from 
 the end with a boring tool carried in the tool post. 
 This can be done, however, only for holes that are 
 readily accessible from one end. When the hole is 
 long, the work may be mounted on the carriage and 
 a cutting tool may be mounted on a bar carried be- 
 tween the two centers and driven from the face plate. 
 If the carriage is moved along the bed, the work 
 may be fed past the tool, and the hole may be bored. 
 Large lathes may be fitted with a special boring bar 
 provided with means of feeding the cutting tool along 
 Its length. In this case, the work is clamped to the 
 athe bed and the tool is fed past it. In general, 
 however, work of this character is performed on 
 bormg machines, which are more conveniently 
 adapted to this type of operations. 
 
 Eccentric work, such as crankshaft pins, may be 
 turned on a lathe. The ordinary lathe can turn only 
 round work that is concentric with the live spindle 
 
>'"^^Sc. 
 
 lit 
 
 .»2 AM) 
 
 ■ )■). 
 
 .lUJ 
 
 \lU)Vi:: CAR WUKF.L LNTIII 
 
 LAK<;i: iivs lathi: 
 
 Nih's-HcMiUMil-I'ni:*) ( 'o. 
 
 HKi.inv 
 
 LATHES 
 
 217 
 
 already formed in the piece. Work of tins diameter 
 
 IS often done on an arl 
 
 )or, wliicli is a bar cirried 
 
 on tlie lathe ecntcrs and d 
 
 riven from the face j)late 
 
 The piece is mounted diivetly on this arbor, which 
 may he made expandinjL--, to <;ras]) the work 
 
 111 a man- 
 
 in ('oniH'ction with tiie 
 
 ner similar to tliat (h'scrihed 
 
 chuck, if tliey are properly inoiinted, the snhsiwjueiit 
 
 operations will have a correct ivlationship to the 
 
 hored hole. Pieces too 1 
 
 comparatively short and lar 
 
 clamped directly to the face ])late hv means of the 
 
 ur^e for a chuck which are 
 U(^ in diameter, ai'e 
 
 T-slots alreadv referred to 
 
 I 
 
 Torino- may he done on the turninu- lathe I 
 
 )v mount- 
 
 mi;- the work on the f 
 
 :ice plate and reachiiii; in I'l 
 
 om 
 
 tli<* ^nu\ with a horino- tool carried in the tool post 
 This can be done, however, only for holes Hint are 
 ivadily accessible from one end. When the hole is 
 Ion.!*-, the work may be mounted on the carria.nc and 
 a cuttino- tool may be mounted on a bar carried be- 
 
 ind driven from the face ])late. 
 
 le work 
 e mav be bored. 
 
 tween the two center 
 
 ir tl 
 
 le carria<'e is moved alono- tin* bed, tl 
 
 may be \\h\ past the tool, and the hoi 
 
 f 
 
 irii'e 
 
 latli 
 
 es may be fitted with a special borino | 
 JHovided with means of feeding- the cuttiim- tool al 
 
 »ar 
 
 'ts leiii»-th. In tlii 
 
 on 
 
 (V 
 
 s cas(s tli(^ work is clamiM^l to the 
 
 I'lthe bed and the tool is Uh\ past it. 1 
 
 Ik 
 
 •wever, work of this charact 
 
 '»'ini»- machine 
 
 which 
 
 Japted to this tvne of 
 
 n i^cneral, 
 er is iJerfoj-iiied on 
 are more conveniently 
 
 pe ot operations. 
 
 I^>centi*ic work, such a 
 'ned on a lathe. The ord 
 
 nid work that is r 
 
 crankshaft pins, may be 
 inary lathe can turn only 
 
 ive si)iFMlh'. 
 
 oncentric with the | 
 
218 
 
 THE MECHANICAL EQUIPMENT 
 
 To turn a crankshaft pin, therefore, the main body 
 of the crank is set **off center'' by an amount equal 
 to the crank throw, and firmly clamped in that posi- 
 tion. This puts the portion to be turned in line with 
 the lathe centers. 
 
 Spherical work may be done on a lathe if the work 
 is revolved as usual and the tool is given a circular 
 motion in a plane about a point lying in the axis of 
 the lathe. In heavy work, frequently several tools are 
 mounted on the tool post, one behind the other, the 
 successive tools being set to take up the cut where 
 the previous one left it — the last is the finishing tool. 
 In this way heavy reductions can be made in one pass 
 of the carriage. 
 
 Knurling is properly a rolling process, not a cut- 
 ting one. This is performed by pressing two 
 hardened steel rollers, mounted in the tool post, 
 against the revolving work and rolling the impression 
 of grooves on the face of the rolls into the surface of 
 the work. The operation is a very common one in 
 tool rooms where the handles of gauges are roughened 
 in order that they may be grasped the more easily. 
 The small diamond-shaped knurling which is so com- 
 mon is done })y two rollers with spiral grooves, one 
 right-hand and one left-hand. The impressions of 
 these rollers crossing each other form the diamond- 
 shaped projections. 
 
 Thread-cutting, one of the most important opera- 
 tions performed on the lathe, will be taken up in the 
 chapter devoted to that subject. 
 
 CHAPTER XIV 
 TUEEET AND AUTOMATIC LATHES 
 
 The Turret Principle.— While the engine lathe is 
 one of the best machines ever designed for general or 
 jobbing work, its use requires a skilled operator, and 
 the time required in changing and setting tools and in 
 measuring length and depth of cuts is usually largely 
 in excess of that required to make the cuts them- 
 selves. Both the skill and the time required to do 
 lathe work may be reduced, with a consequent saving 
 in the cost of production, by the use of the turret 
 principle. In the turret lathe a slide is substituted 
 for the tail-stock, and mounted on this is a re- 
 volving member, or turret, which has certain stops 
 or positions, usually from four to six. The cutting 
 tools are mounted on this turret, and are accurately 
 set with reference to the work. The work— which 
 may be either castings or forgings held in some form 
 of chuck, or barstock, which is fed through the hole 
 m the live spindle— is carried entirely from the head- 
 stock end. 
 
 The sliding carriage is fed forward, either by hand 
 or automatically, to a definite stop which limits the 
 length of the cut; the carriage is then withdrawn and 
 brought forward again. This action indexes the tur- 
 ret to the second position, and brings into action a 
 
 219 
 
 i 
 
 Mil Ml 
 
220 
 
 THE MECHANICAL EQUIPMENT 
 
 second tool which has been definitely set for the 
 operation it performs. The second motion also comes 
 to a definite stop, set to correspond to the second cut 
 and independent of the one previously made. Suc- 
 cessive movements of the carriage bring the other 
 tools mounted on the turret into action in a similar 
 way; each motion has a definite stop arranged for 
 that cut. In most turret lathes auxiliary side tools 
 are carried to definite stops on a cross slide mounted 
 on the bed between the head-stock and the turret, 
 which may also be either hand-operated or automatic. 
 
 Turret Lathe vs. Engine Lathe. — The use of this 
 turret principle greatly reduces the time necessary 
 to set the tools and so on. With an engine lathe the 
 operator will place the tool in the tool post, after the 
 work has been properly mounted on the face plate, 
 will make a trial cut, caliper the piece, adjust the 
 tool, and repeat the process until the correct size is 
 reached. He will then start the cut. As he ap- 
 proaches the end of the cut, he will stop the machine 
 and measure the work to see whether the cut is long 
 enough or deep enough, repeating the process until 
 the correct length of cut has been made. Whenever 
 it is necessary to change the tool to perform some 
 other type of operation, the whole process must be 
 repeated. This round must be gone through for 
 every piece made, and it is this work which is 
 eliminated by the turret lathe. 
 
 In the latter type of lathe the various cutting tools 
 are placed in position by the tool-setter, who is a 
 skilled man. This work is done with care, and one or 
 two trial pieces are run through. When the machine 
 
 TURRET AND AUTOMATIC LATHES 221 
 
 has been -set up,- it is turned over to the machine 
 operator who has only to clamp the successive pieces 
 m the chuck and feed the turret and tools forward to 
 make^ the cuts. In the case of automatic lathes for 
 bar stock, he does not even have to do the latter. His 
 work becomes merely that of keeping the bars sup- 
 plied to a number of machines, each of which will 
 automatically feed forward the required amount of 
 bar stock, clamp it, perform the successive opera- 
 ions, cut off the finished piece, and feed forward 
 stock for the next piece. The work of setting the 
 tools and measuring the length of feed is conse- 
 quently done but once-by the tool-setter-and the 
 cost of doing It, instead of being carried by each 
 piece as in the case of the engine lathe, is distributed 
 over the entire run. 
 
 Hand and Automatic Turret Lathes.-The turret 
 rm ^V^' *"■'* '^^'"^' improvement on the 
 Roberts, and others. There were probably a number 
 
 mnl'l T'f'"^^ "*" *^* ^"'■'•^t P""«'Pi« prior to 
 
 nwln . J'* °°' ""^'"^ ^^« "-^S^l^riy built and 
 
 placed upon the market was brought out by Jones 
 & Lamson then of Windsor, Vermont, about 1855. 
 ihe principle was applied to the manufacture of guns 
 
 FoTThnTf 1 : ^"** '^^'' interchangeable articles.' 
 i"or about twenty years turret lathes were hand 
 
 teZJZ ^}'''''P^'' ^- Spencer, of Hartford, de- 
 veloped the Idea of automatic operation, in which the 
 
 «huek, operating the turret and cross sUde, and cut- 
 
 
! 
 
 I'l 
 
 222 
 
 THE MECHANICAL EQUIPMENT 
 
 ting off, were all controlled by a single camshaft 
 mounted in the body of the lathe parallel to its axis 
 and making one revolution for the complete cycle of 
 operations. This invention greatly increased the 
 capacity of the lathe and enabled an operator to tend 
 a number of machines. 
 
 Multi-Spindle Automatics. — The next increase in 
 the capacity of the lathe came about twenty years 
 later, when Mr. Henn and Mr. Hakewessel developed 
 the first multi-spindle automatics. In both the hand 
 and the automatic single-spindle lathe the work re- 
 volved, but remained in the same position, and the 
 tools were brought to bear upon it in succession. 
 The time required to finish a piece was, therefore, 
 that required for the sum of the various operations. 
 In the multi-spindle automatic, the axis of the index- 
 ing member is horizontal, and parallel to the axis of 
 the lathe; and there are several live spindles corre- 
 sponding in number to the number of tool positions. 
 Each of these spindles carries a bar of stock which 
 is being operated upon, and all the tools are cutting 
 simultaneously. "When the longest cut is finished, 
 either the tools or the spindles are rotated to the 
 next position and the operation is repeated. A bar 
 is fed forward for the first operation, and then in- 
 dexed progressively through the successive positions 
 until the piece is completed. Either the tools or the 
 spindles may be indexed. With this type of lathe, 
 the time required to finish the piece is reduced from 
 the total time of all the operations to the time 
 required for the longest individual operation on the 
 piece. 
 
 TURRET AND AUTOMATIC LATHES 
 
 223 
 
 Hand-Operated Turret Lathes.— Of the various 
 types of turret lathes, the simplest is the plain hand- 
 operated machine, shown in Figure 54. This is used 
 for small and light work. In the one illustrated, the 
 oil pan and bed are in one casting. As stiffness and 
 perfect alignment are essential in all turret work, 
 the head is also frequently cast solid with the bed, 
 although the one shown is a separate casting. To 
 increase the stiffness, the small end of the cone pulley 
 is pointed toward the right, which permits a firmer 
 support for the main bearing of the spindle. The 
 spindle bearings are babbitted. Two-speed counter- 
 
 FIG. 54. HAND-OPERATED TURRET LATHE 
 Pratt & Whitney Co. 
 
222 
 
 THE MECHANICAL EQUIPMENT 
 
 ting off, were all controlled by a sinp'le eamsliaft 
 mounted in the body of the lathe parallel to its axis 
 and making one revolution for the complete cycle of 
 operations. This invention greatly increased the 
 capacity of the lathe and enabled an operator to tend 
 a numl)er of machines. 
 
 Multi-Spindle Automatics. — The next increase in 
 the capacity of the latlie came al)out twenty years 
 later, when ^Ir. Henn and Mr. TTakewessel developed 
 the iirst multi-spindle automatics. In both the hand 
 and the automatic single-spindle lathe the work re- 
 volved, but remained in the same position, and the 
 tools were brought to bear upon it in succession. 
 The time required to finish a piece was, therefore, 
 that reciuired for the sum of the various operations. 
 Tn the multi-spindle autonuitic, the axis of the index- 
 ing member is horizontal, and parallel to the axis of 
 the lathe; and there are several live spindles corn^- 
 sponding in number to the number of tool i)()sition>. 
 Each of these spindles carries a bar of stock which 
 is being operated upon, and all the tools are cuttini; 
 simultaneously. "When the longest cut is finishiMl, 
 either the tools or the spindles arc rotated to tlic 
 next position and the operation is repeated. A bar 
 is fed forward for the first operation, and then in- 
 dexed progressively through the successive position-^ 
 until the piece is completed. Either the tools or tii^' 
 spindles may be indexed. With this type of latins 
 the time required to finish the piece is reduced tVoni 
 the total time of all the operations to the ti;!!^' 
 required for the longest individual operation on ii<' 
 piece. 
 
 rrUKET AM) ACTOMATlC LATHES 
 
 22'] 
 
 Hand-Operated Turret Lathes.— Of th(' various 
 types of turret lathes, the simplest is the plain hand- 
 operated niacliiii(% shown in Figure^ r)4. This is used 
 for small and light work. Jn the one illustrated, the 
 oil pan and bed are in one casting. As stiffness and 
 perfect alignment are essential in all turret work, 
 the head is also frequently cast solid with the bed, 
 although the one shown is a separate casting. To 
 increase the stiffness, the small end of the cone pulley 
 is pointed toward the right, which permits a firmer 
 support for the main ])earing of the spindle. The 
 spindle bearings are babbitted. Two-speed counter- 
 
 HAXn-OPKKATKl) TrWRKT i.ATin; 
 Prat I & wiiiiiu'.v (\». 
 
224 
 
 THE MECHANICAL EQUIPMENT 
 
 shafts are used either for forward and reverse or for 
 two speeds forward when opening dies are used. 
 
 The turret slide, 1, is mounted in a block, 2, which 
 is adjustable longitudinally along the bed to accom- 
 modate different lengths of work. The turret re- 
 volves on a conical central stud, or pin, fixed on the 
 turret slide. The bolt which locks the turret in its 
 various positions is located horizontally in the slide, 
 and is hardened and ground; it is supported for its 
 entire length, and engages the turret directly under 
 the cutting tool. The index ring on the turret, which 
 the locking bolt engages, is also hardened and ground 
 and is securely doweled and bolted to the under side 
 of the turret. The stop mechanism which limits the 
 feed for the various positions of turret, is clearly 
 shown. The stops, 6, are short steel bars located on 
 a radius in a steel bracket, 3, which is on the front of 
 the block, 2. An oscillating lever, 4, on the shaft, 5, 
 engages one or other of the adjustable stops, 6, ac- 
 cording to the position of the turret. The position of 
 the arm, or lever, 4, is controlled by a cam, 7, on the 
 lower periphery of the turret. As the turret re- 
 volves from one position to another, this cam, acting 
 through the shaft, 5, brings the arm, 4, into position 
 for contact with the proper stop. The arm, 4, is re- 
 lieved of any strain by being backed up by the pro- 
 jection, 8, which is a part of the turret slide, 1. 
 
 In small machines of this character the turret slide 
 is operated by a single hand-lever as shown, and the 
 indexing of the turret is done by the movement of 
 the slide. A cross slide, 9, carries the forming and 
 cutting-off tools, one in front of the work and the 
 
 TURRET AND AUTOMATIC LATHES 225 
 
 other behind it. The slide is adjustable lengthwise 
 on the bed between the head-stock and turret slide, 
 and can be clamped to the ways in the position de- 
 sired. The feed of the slide is by hand lever through 
 a rack and pinion, and is accurately governed in both 
 directions by means of adjustable stops. The bar 
 stock, which is not shown in Figure 54, is fed 
 forward by means of the hand lever on the left 
 
 FIG. 55. MULTIPLE BOX TOOL 
 
 Pushing this handle to the left unclamps the chuck 
 and moves the feeding mechanism back along the bar 
 the distance required for the next piece. The return 
 movement of the handle brings the bar forward this 
 
 TTr! . I* *^' '^^ ^^ *^^ ^^*i<^« the accurately 
 Jnished and hardened chuck jaws clamp the work 
 concentrically with the spindle 
 
 The cutting tools are carried in the holes, 10, shown 
 m the turret. Two of these tools are shown in Figure 
 
 u LTi't "^'^' ^' " ^"^ '' ^^^ characteristic tS 
 used m turret work. As there is no tail-stock on the 
 
226 
 
 THE MECHANICAL EQUIPMENT 
 
 turret lathe, a heavy side cut on a long bar would 
 tend to spring it out of position. To prevent this, an 
 adjustable stop, a, is provided which is carried on 
 the tool body immediately opposite the cutting tool, 
 b. Tools of this character are used in a wide variety 
 of forms. 
 
 Gisholt Lathe.— A turret lathe of a much more com- 
 plex type is the Gisholt lathe, shown in Figure 5b\ 
 This machine was a pioneer in applying the turret 
 principle to large and heavy work, and is built in 
 sizes having a swing as large as 41 inches. The 
 spindle is bored to enable the use of barstock, but 
 the machine is more commonly used on castings and 
 forgings held in a chuck. This lathe was the first to 
 employ the pilot bar principle in heavy turret work. 
 The pilot bar is very useful in relieving the machine 
 of much of the strain due to heavy cuts. 
 
 The first operation on the piece is to establish 
 an accurately bored hole in the piece to be machined. 
 Pilot bars, shown at a in Figure 56 and at a' in Figure 
 57, used with the succeeding operations, enter this 
 hole and center the cutting tool, b and b'. The side 
 strains between the cutting tool, b', and the pilot bar, 
 a', due to the cut — which w^ould otherwise extend 
 dowm through the turret, along the bed, up through 
 the head, and out upon the w^ork — are carried by the 
 fixture itself. The machine is therefore relieved of 
 these strains, and the resulting work is more accurate. 
 The axis of the hexagonal turret is inclined backward 
 instead of standing vertical, as in other machines. 
 This is done to enable the long pilot bars and other 
 tools to swiKg clear of the operator in front. The 
 
 Vv 
 
 ■^1 
 
 FIGS. 56 AND 57. ABOVE: TOP VIEW OF A GISHOLT LATHE. 
 
 BELOW; WARNER & SWASEY LATHE 227 
 
22(i 
 
 TlIK MECllANK AL K^^ll PMl^NT 
 
 furrof. lallic, a lu^nvy side cut on a loni;' l>ar would 
 tcMid to spi'iii,!; it out of |)ositioii. To prevent tliis, an 
 adjustable sto]), a, is ])ro\ided wliicli is carrie*! on 
 the tool l)ody innuediately opposite the cuttini;- tool, 
 b. Tools of this charaeter are used in a wide variety 
 of forms. 
 
 Gisholt Lathe.— A turret lathe of a nnieh more com- 
 plex tyi)e is the Oisholt lathe, shown in Figure r)(). 
 This machine was a pioneer in applyini;- the turret 
 principle to large and heavy work, and is built in 
 sizes liaving a swing as lai'ge as 41 inches. The 
 spindle is l)ored to en.able the use of barstock, but 
 the macliine is more connnonly used on castings and 
 forging? held in a chuck. This lathe was the (irst to 
 employ the pilot bar ])rinciple in heavy turret work. 
 The pilot bar is very useful in relieving the machiTve 
 of much of the strain due to heavy cuts. 
 
 The first operation on the ])iece is to establish 
 an accnrately bored liole in the piece to be machined. 
 Pilot bars, shown at a in Figui-e ')6 an<l at a' in Figun^ 
 57, used with the sncceeding operations, enter this 
 hole and center the cutting tool, b and b'. The side 
 strains between the cutting tool, b', and the pilot bar, 
 a', due to the cnt — which would otherwise^ extend 
 down through the turret, ah)ng the bed, up through 
 the head, and ont upon the work — are carried by th<' 
 fixture itself. The machine is therefoi-e relieved of 
 these strains, and the resulting work is more accurate. 
 The axis of the hexagonal tui*i-et is inclined bacl:war<l 
 instead of standing vei'tical, as in otliei* machine-. 
 This is done to enable the long pilot bars and oth< ;' 
 tools to swii/^g cleai- of the o})eiator iu front. Tiie 
 
 FIGS. 56 AND 57. ABOVE : TOP VIEW OF A GISIIOLT LATHE. 
 
 BELOW: WARXEK & SWASEY LATHE 227 
 
I 
 
 ,' 1 
 
 : I 
 
 i 
 
 
 228 
 
 THE MECHANICAL EQUIPMENT 
 
 machine is equipped with a cone pulley and a back 
 gear, and the head-stock is cast solid with the bed. A 
 sliding carriage between the head-stock and the tur- 
 ret has a revolving tool post, designed to hold four 
 cutting tools, which is in effect an auxiliary turret. 
 
 Any one of these tools may be brought into cutting 
 position by revolving the tool post, and each is in- 
 dependently adjustable for height and is provided 
 with an automatic stop. The tool post has an inde- 
 pendent power cross feed, and the carriage is also 
 fitted with an attachment for turning tapers, and w^ith 
 a support for rigidly holding boring bars, drills, and 
 so on, in line with the spindle. This is so designed 
 that when not in use it may be swung back out of 
 position to clear the chuck. Both the tool-post car- 
 riage and the turret slide are screw-cutting, and the 
 power feed may be varied without changing the 
 gears. The carriage and slide are also provided with 
 clamping devices to bind them rigidly to the ways 
 at any desired location. This machine has been in 
 successful use for many years and has had a wide 
 influence on machine shop practice, extending the use 
 of the turret principle to the machining of such 
 pieces as pistons, cylinder heads, flanges, couplings, 
 and pulleys. The Gisholt Company has also de- 
 veloped a lathe in which the operations when once 
 the piece has been chucked in place are entirely 
 automatic. This last machine is of the single-pulley, 
 one-speed type. 
 
 Warner and Swasey Lathe.— Figure 57 shows 
 another large turret lathe, built by the Warner & 
 Swasey Company. The turret, or revolving member, 
 
 TURRET AND AUTOMATIC LATHES 
 
 229 
 
 in this machine is a large, hollow hexagon mounted 
 on a saddle, or slide. This form permits the attachment 
 of much heavier tools than allowed by the holes shown 
 in Figure 54. Several of the tools shown are pro- 
 vided with pilot bars just described in connection 
 with the Gisholt lathe. This lathe, like the Gisholt, 
 may be used either for bar-stock work or for cast- 
 ings and forgings; simultaneous operations may be 
 performed by the turret and by a carriage with a 
 square tool post which can be indexed to four posi- 
 tions. 
 
 The saddle, or main slide, is mounted directly on 
 the bed, and both the saddle and the carriage have 
 power feeds or may be operated by hand wheels; the 
 various motions are controlled by independent auto- 
 matic stops. The head and the bed are cast in one 
 piece. There is a constant-speed, single-pulley drive, 
 the various changes of spindle speed being obtained 
 by a gearing enclosed in the head and running in oil. 
 The machine can be belted directly to a line shaft, 
 or can be driven by a constant-speed motor. The 
 changes of feed for the carriage and the main turret 
 saddle are controlled by a feed box at the head end. 
 This lathe will handle round bar stock 31/0 inches in 
 diameter, or a maximum of swing for face-plate work 
 of 2IY2 inches. The maximum length turned is 44 
 inches, and the maximum horsepower required is 10. 
 
 Hartness Flat-Turret Lathe.— Another type of tur- 
 ret lathe is the Hartness flat-turret lathe, which was 
 invented about 1891 (see Figure 58). The character- 
 istic feature of this machine from its earliest appear- 
 mice has been the flat circular plate mounted on the 
 
 i, ■/■'(' 
 
 »■ 
 
 •1 1 
 
 h 
 
'r. 
 . ,i 
 
 <i' 
 
 
 230 
 
 THE MECHANICAL EQUIPMENT 
 
 saddle, which carries the various tools and tool- 
 holders on its upper surface, thus replacing the usual 
 barrel turret mounted on a stud and carrying the 
 tools around the periphery. The advantage of this 
 construction is that the tools do not overhang their 
 support, and th-e whole construction is very rigid as 
 the flat turret plate is secured to the saddle by an an- 
 nular clamp which holds it rigidly at all points. The 
 turret is automatic in action, turning as the tools 
 clear the work, and it may be set so as to skip one or 
 more of the indexing positions when desired. 
 
 As in other types of turrets, the locking bolt is on 
 the outer edge, directly under the cutting tool. In 
 the earlier forms of this lathe, the crosscuts were ob- 
 tained from a saddle between the head-stock and the 
 turret. In the later types the carriage is done away 
 with, and the head is provided with a cross motion. 
 As in the machine just described, there is a single- 
 speed driving pulley, and the changes of speed are 
 derived from change gears, which run in oil inside the 
 head casing. The flat turret, which gives this lathe 
 its advantage, limits it to work of moderate diameter; 
 its natural field is for threading and turning large 
 studs, bolts and arbors. The size of work done 
 ranges up to 3 inches in diameter and 36 inches in 
 length. 
 
 Instead of one working spindle and a circular tur- 
 ret with six positions, this type of lathe is also made 
 with two working spindles and a turret which is 
 square. Each face of the square turret carries two 
 sets of tools, and two similar cuts may be carried 
 on simultaneously. If the turret is indexed four sets 
 
 I 
 
 H 
 
 03 
 
 
 (M 
 
 I 
 
 I 
 
230 
 
 THE MECllAMl'AL EQl'IPMENT 
 
 saddle, wliicli can-'u's tlie vai'ious tools and tool- 
 lioldei's on its nppei- snrfaeo, tluis roplacin.i;' the usual 
 barrel turret mounted on a stud and earrvini;- the 
 tools around the j)eriphery. TIk* advantage of this 
 construction is that the tools do not overhang their 
 suppoi't, and the whole construction is very rigid as 
 the llat turret f)late is secured to the sachlle by an an- 
 nular clamp which liolds it rigidly at all points. The 
 turret is autonuitic in action, turning as the tools 
 chnir the work, and it may be set so as to ski}) one or 
 moi-e of the indexing positions wh(»n desired. 
 
 As in other tyj)es of turrets, the locking bolt is on 
 the outer iH\<i;i\ dii'eetly under tlie cutting tool. In 
 the earlier forms of this lathe, the crosscuts w(M"e ob- 
 tained from a saddle between the head-stock an<l the 
 turret. Jn the later types the carriage is do]w away 
 with, and the head is provided with a cross motion. 
 As in the machine just (h\scribed, there is a single- 
 speed driving pulley, and the (*hanges of speed are 
 derived from change gears, which run in oil inside tln' 
 lu^ad casing. The Hat turi'et, which gives this lathe 
 its advantage, limits it to woi-k of moderate diann^ter: 
 its natural field is foi* threa<ling and tui'uing lai'ge 
 studs, bolts and arboi-s. The siz<* of wo!*k done 
 ranges up to 3 inches in diameter and 'Mi inches in 
 h'ngth. 
 
 Instead of one woi'king spindle and a circular tui 
 ret with six positions, this type of lathe is also mad<' 
 with two working spindles and a turret which i- 
 square. Each face of the square turret carries tw ' 
 sets of tools, and two similar cuts mav be carrie ! 
 on simultaneouslv. If the tnr?-(M is in<l(»xed four ><• 
 
232 
 
 THE MECHANICAL EQUIPMENT 
 
 
 1 
 
 of tools may be used. Figure 59 shows a typical set- 
 up for this type of machine. 
 
 An automatic chucking and turning lathe which 
 has been very successful, is the Potter & Johnson 
 machine, shown in Figure 60. In this machine, 
 rigidity for the turret tools is sought in another way. 
 A vertical turret is used, but the stud or pin upon 
 which it revolves is braced on the top by a heavy 
 overhead support which extends back to the rear of 
 the turret slide. The machine has a geared head 
 with a single-pulley drive, cross slide with double, 
 independent, adjustable tool blocks, and an auto- 
 matic back facer bar operated through the spindle. 
 The chuck is 16 inches in diameter and the hole 
 through the spindle is 3i/2 inches in diameter. 
 
 Principle of Automatic Lathes. — The first automatic 
 lathe, as mentioned in the beginning of the chapter, 
 was developed by Spencer for the Hartford Machine 
 Screw Company. A later form of this lathe is illus- 
 trated in Figure 61 which shows very clearly the gen- 
 eral principle underlying the construction of nearly 
 all of the full automatic lathes. The driving spindle, 
 cross slide, and turret are present, as in the simple 
 type of turret lathe in Figure 54. The control that 
 makes them automatic is derived from the long cam 
 shaft running through the frame, parallel to and be- 
 low the main center. This shaft revolves slowly, 
 making one revolution for each complete cycle of 
 operations. The large drum to the left controls the 
 operation of the mechanism that feeds the bar stock 
 forward each time a piece is completed. This feeding 
 is done by means of the strips bolted on the face. 
 
 i 
 
 ; i^', 
 
 <'l 
 
 
 PIGS. 59 AND 60. ABOVE: HARTNESS DOUBLE-SPINDLE LATHE. 
 BELOW: POTTER & JOHNSON LATHE 
 
 233 
 

 THE MECHANICAL EQUIPMENT 
 
 of tool? may l)o used. Figure 59 shows a typical .set- 
 up for this type of machine. 
 
 An automatic chucking and turning lathe which 
 has heen very successful, is the Potter & Johnson 
 nuichine, shown in Figure (iO. In this machine, 
 rigidity for the turret tools is sought in another way. 
 A vertical turret is used, hut the stud or pin upon 
 which it i-evolvcs is hraced on the top hy a heavy 
 overhead support which extends hack to the rear of 
 the turret slide. The machine has a geared head 
 with a single-pulley drive, cross slide with douhle, 
 independent, adjustahle tool hlocks, and an auto- 
 matic hack facer har operated through the spindle. 
 The chuck is 16 inches in diameter and the hole 
 through the spindle is 3V2 inches in diameter. 
 
 Principle of Automatic Lathes. — The first automatic 
 hdhe, as mentioned in the heginning of the chapter, 
 was (U'V('h)ped hy Spencer for the Hartford ^lachine 
 Screw Company. A later form of this lathe is illus- 
 trated in Figure (il which shows very clearly the gen- 
 eral principle underlying the construction of nearly 
 all of the full automatic lathes. The driving spindle, 
 cross sli(h', and turret are present, as in the simple 
 type of turret lathe in Figure 54. The control that 
 makes them autonuitic is derived from the long cam 
 shaft running through the frame, parallel to and he- 
 low the main center. This shaft revolves slowly, 
 making one revolution for each complete cycle oT 
 operations. The large drum to the left controls the 
 operation of the mechanism that feeds the har stock 
 forward each time a piece is completed. This feeding, 
 is done hy nutans of tlie strips holted on the face. 
 
 I'lus. 59 AND GO. ABovi:: iiartnkss double-spixule lathe. 
 
 BELOW: I'OTTEK & .lOHXSON LATHE 
 
 233 
 

 TURRET AND Al TOMATIC LATHES 
 
 233 
 
 FIGS. 61 AND 62. AUTOMATIC SCREW MACHINES 
 
 Upper: Hartford Machine Screw Co. Lower: Brown & Sharpe 
 234 Mfg. Co. 
 
 wliicli oiigago a pin in the nieebanism above. The 
 plate under the driving pulleys operates the belt- 
 shifting mechanism by means of the dogs shown on 
 the edge. The timing of the belt-shifting is accom- 
 plished by sliding these dogs to the required position 
 around the edge of the plate. The next cam controls 
 th<? motions of the cutting-off tool located in the slide 
 immediately above it. The large cam to the right 
 controls the motions of the turret carriage. The 
 worm wheel drives the cam shaft, and the plate at the 
 extreme right controls the fast and slow speeds of 
 the cam shaft. 
 
 In this machine, as in those previously described, 
 the axis of the turret is vertical. A second position 
 is possible — that is, the axis of the turret may be 
 horizontal, and at right angles to the line of the 
 driving spindle, the rotation being in a vertical plane. 
 This position is utilized in the Brown & Sharpe 
 automatic screw machine, shown in Figure 62. This 
 machine is fitted with a motor in the base, driven by 
 a short belt through the constant-speed pulley shown 
 at the left of the head-stock. A spring-actuated 
 idler pulley near the motor shaft (not shown) main- 
 tains the proper belt tension. In this machine the 
 cam shaft, controlling the motions, is in front of the 
 bed, and the turret is at the forward end of the 
 turret slide. The various tools, threading dies, and 
 so on, are arranged around the face of the turret in 
 the six positions, and are held in place by bolts which 
 appear on the front face of the turret. 
 
 In the third position of the turret the axis is also 
 horizontal, but is parallel with the axis of the driving 
 
 |i 
 
 ' .. t 
 
 Mi 
 ■I » ' 
 
 III 
 
m 
 
 s 
 
 
 \a\ 
 
 ^ 
 
 
 %t'« *. ' 
 
 ^i'i ' 
 
 ^^n 
 
 y 
 
 
 
 Hj^N 
 
 SI 
 
 ^9 
 
 
 - f 
 
 -ii 
 
 
 i 
 
 M 
 
 
 ^-^ 
 
 r HH 
 
 %A 
 
 ^B^ - 
 
 ^^ 
 
 
 ^Ipms"*^ 
 
 
 jBjfc^ 
 
 HPQ^^Kf ' ^ 
 
 H»r . - 
 
 ,i.t..jB6t" ,-,%.V - 
 
 
 ■'■^^^fff 
 
 ^Pj^ail^^^^-a^.-,^ 
 
 
 
 
 
 
 r ;' _.^ 
 
 H^ 
 
 FKIS. ()1 AND f)2. AUTOMATIC SCREW MACIIINIIS 
 
 Upikt: llnrtfortl Mathine Screw Co. Lower: IJrowh ..V Sluiri"' 
 234 Mt> Co. 
 
 Tl UU'KT AM) AlTo.MATh' LATIIKS 
 
 :!:;:> 
 
 \v1iicli (Mii;;i.i;(' a pin in tlic nicclianisin al)()v<'. Tho 
 plate under llic drivini; pulleys ()|)erates tlie l)elt- 
 Nliirtini; in<'clianisin hy means oi' the (loii,'s shown on 
 llie edo-e. The tiniin.^' ol* the helt-shii'lin.i;- is aceoni- 
 |)lishe(l by slidin*;' thes(» dogs to the ie(piired position 
 around tlu* edge of the plat(^ The next earn controls 
 til* motions oi* the cuttiiig-olT tool located in the sTuh' 
 immc<liatelv ahove it. The lai'i;'e cam to the riiiht 
 controls the motions ot* the turret cai'riage. Tin* 
 woivm wheel drives the cam shaft, and the plate at the 
 (wtreme i"iij;ht controls the last and slow speeds ol* 
 the cam shaft. 
 
 In this machine, as in those* previously <l(^scribed, 
 the axis of the turret is veilical. A second })osition 
 is possible — that is, the axis of the turret may he 
 horizontal, and at i'it;ht angles to the line ol* the 
 dri\'iiii;- spindle, the i-otation heing in a vei'tical plane, 
 '^riiis position is utilized in the Brown «S: Sharpe 
 automatic screw machine, shown in Figure ()2. This 
 machine is litt(Nl with a motoi' in the base, driven by 
 a short belt through tlu* constant-speed pulley shown 
 at the h4't of the head-stock. A spring-actuat(Nl 
 idler pull(\v near the motoi- shaft (not shown) main- 
 tains th(^ pi'op(M" belt tension. In this machine the 
 '•am shaft, controlling the motions, is in front of the 
 bed, and the turret is at the foi'wai'd end of the 
 'iirret slide. The vai'ious tools, threa<ling dii\s, and 
 o (jn, are ananged around the face of the turret in 
 'lie six [jositions, and ar(» held in place by bolts which 
 '|>pear on the fi'ont face of the turret. 
 Ill the third position of the turret the axis is also 
 >rizontal. but is parallel with the axis of the (h'i\in<» 
 
236 THE MECHANICAL EQUIPMENT 
 
 spindle instead of at right angles to it, as in the 
 Brown & Sharpe machine. An example of this is 
 given in Figure 63, which shows a plan view of the 
 Cleveland automatic lathe, in which the turret takes 
 the form of a drum, with five tool positions that 
 rotate in a plane at right angles to the axis of the 
 machine. The cam shaft in this lathe is located m 
 
 'Chuck'closikA riNacus 
 
 FIG. 63. TOP VIEW OF A CLEVELAND AUTOMATIC LATHE 
 
 Cleveland Automatic Machine Co. 
 
 the rear. The various drums are clearly shown. 
 The large wheel at the right is called the regulating 
 wheel and carries ten segments, two for each hole m 
 the turret, which can be adjusted while the machine 
 is in motion to suit the feed requirements of each of 
 the five cutting tools. 
 
 Gridley* Automatic Lathe.— The Gridley automatic 
 lathe, shown in Figure 64, another horizontal ma- 
 chine, represents a more radical departure from the 
 old standard lathe design. The long bed characteris- 
 tic of all the previous machines is shortened into a 
 more or less box-like frame, and the turret, instead of 
 
 riNarn holder 
 
 STOCK VUSHCa TUBE. 
 
 FEED SHAFT 
 FTEO nELEASiNO LATC 
 
 TUBNlW 
 
 U SLIOC 
 
 Fi.ExiaLC Oil Tuae 
 
 ORAW BAR 
 
 STOCK FEED CA 
 
 FEED CAM 
 RETURN CAM ■ 
 
 FEEO CAvt DRU 
 CmuCK OOERATINO CAM^ 
 
 HISH SBEED LEVER 
 
 ■ ELT ShirreRs' 
 
 TURRET HtvOLV'^G DOG 
 'ORE'RATiNG CA^4 DRUM 
 BELT SHIPPER CAMS 
 
 D CUTTING OFF. CAM. DISC 
 
 ORMING SLIDE CAK 
 (CUTTING OFF CAM ON 
 OTHER SIDE OF OlSC; 
 
 II 
 
 FIG. 64. GRIDLEY AUTOMATIC LATHE — TURRET WITH 
 
 HORIZONTAL AXIS 
 Above: Location of parts. Below: Sectional view through the tur- 
 ret, showing turret supports and tool slides. The National Acme Co. 
 
 tmOt 
 
 n 
 
O! 
 
 230 
 
 TUK MKrilANHAl. K(^ril*Mi:NT 
 
 siMiullo instcail ol' nt ri-lit angles to it, as Jii tlio 
 Brown & Sliai'pe machine. An example of this is 
 oiv(^ii in Fiuure (KJ, which shows a phm view ol' tlie 
 Clevehmd automat ie hithe, in which the tunvl takes 
 the form of a drum, with five tool positions that 
 rotate in a. plane at right angles to the axis of the 
 machine. The cam shaft in this lathe is located in 
 
 FIG. 63. TOP VIEW or A CLKVKLANl) AITOMATIC LATHE 
 ClevelaiKl Automatic Mucliine Co. 
 
 tlie rear. The various drums are clearly sliown. 
 Tlu» large wheel at the right is called the regulating 
 ^vll('cl and carries ten segments, two for each hole in 
 the turret, which can he adjusted while the machine 
 is in motion to suit the feed requirements of each of 
 the five cutting tools. 
 
 Gridley Automatic Lathe— The Gridley automatic 
 lathe, shown in Figure 64, another horizontal ma- 
 chine, represents a more radical departure from thi 
 old standard lathe design. The long bed characteris 
 tic of all the previous machines is shortened into : 
 more or less box-like frame, and the turret, instead (- 
 
 T* ,^^i Qf f ^..-.i i;,, 
 
 u - - ■ _ 
 
 FlC,. ()4. (iKlDLKV AUTOMATIC LATIIE — TURRET WITH 
 
 HORIZONTAL AXIS 
 \Im»v»': Location of i)arts. Below: Sectional view Hinnmli the nir- 
 n'l, sliowiiit;- lurrct siippoiMs ami ♦ool slides. Tlie National Acme To. 
 
 
238 
 
 THE MECHANICAL EQUIPMENT 
 
 being- on a carriage on top of the bed, overhangs at 
 the end. The various tools are carried on the faces of 
 the turret, and the feed is parallel to its axis. The 
 cam shaft controlling the operations, which makes the 
 machine automatic, is clearly shown in the frame 
 below; the large drum at the left controls the turret 
 feeds through a long draw-bar and a pin which en- 
 gages the cam at the left. The cam in the middle 
 revolves the turret and operates the belt-shifting 
 mechanism. The cam at the right operates the cross 
 slide and cutting-off tools. 
 
 Multi-Spindle Automatics.— The longitudinal posi- 
 tion of the turret axis is the only one that permits of 
 the use of multiple spindles. This fact is made use 
 of in the Acme, Gridley, New Britain, and other 
 machines. Figure 65 shows a multi-spindle lathe of 
 this type. In this machine an indexing head, which 
 corresponds to a turret, carries six spindles, eacb of 
 which may contain a bar stock to be cut. The tool 
 carriage carries an equal number of cutting tools in 
 alignment witb each of these revolving shafts. Each 
 of the cutting operations has an independent feed, 
 controlled by the operating cams, and all the cutting 
 tools work simultaneously. The cutting tools include 
 the cross-cut tools as well as those carried in the main 
 head. When the longest cut is finished, the tools are 
 withdrawn, and the head with all six spindles is in- 
 dexed around to the next position. Then the process 
 
 is repeated. 
 
 The feeding of the stock is done at one of the posi- 
 tions only, at each indexing of the turret. This 
 spindle performs the first operation, the other opera- 
 
 
 
 FIGS. 65 AND 66. 
 
 Above: Multi-spindle Automatic Lathe for Bar Stock. Below: Mul- 
 ti-spindle Automatic Chucking Lathe. New Britain Machine Co. 
 
 239 
 

 Till-: MKciiANicAL K(,)ri i\\ii:nt 
 
 iM'iii- oil n cai-ria.uc on lop of Ihc Ixnl, oviMliangs at 
 tlic end. I'lic various tools aiv carruHl on the faces of 
 the turret, aiul tiu' feed is i)arallel to its axis. The 
 cam shaft eontroUiui;- the operations, vrhieh makes tlu^ 
 uuu'hine automatic, is clearly shown in the frame 
 Ih'Iow; tli(^ large drum at the left controls the turret 
 feeds through u long draw-har and a ])in which en- 
 gages the cam at the left. The cam in the middle 
 revolves the turret and o])erates the helt-shiftirig 
 mechanism. The cam at the right operates the cross 
 slide and cutting-off tools. 
 
 Multi-Spindle Automatics.— The longitudinal po^ i- 
 tion of the turret axis is the only one that permits of 
 tlie nse of multiple spindles. This fact is made use 
 of in the Acme, Gridley, New Britain, and other 
 nuicliines. Figure 05 shows a multi-spindle lathe of 
 tliis type. In this machine an indexing head, Avliicli 
 corresponds to a turret, carries six spindles, each of 
 which nuiy contain a har stock to he cut. The tool 
 earriage carries an equal numher of cutting tools in 
 alignment with each of these revolving shafts. Each 
 of the cutting operations lias an independent feisl, 
 controlled hy the operating cams, and all the cuttin,';' 
 tools work simultaneously. The cutting tools includ.^ 
 tlie cross-cut tools as well as those cari'ied in the main 
 head. AVhen the longest cut is finished, the tools ar<' 
 withdrawn, and the head with all six spindles is in 
 (U'xed around to the next position. Then the proces 
 is re])eated. 
 
 The feeding of the stock is done at one of the post 
 tions only, at each indexing of the turret. Thi 
 spindle performs the tirst operation, the other oper;>- 
 
 FIGS. (io AND 66. 
 
 AIk)V(»: ^IiiI11-si»iiHile Autonintic l.utlie for Bar Stock. Below: Mill 
 ti-spiiulle AiitoiiijiJic ( Miuckini: Ljitlu'. New Britain Msicliiiir- Co. 
 
240 
 
 THE MECHANICAL EQUIPMENT 
 
 
 1 1 
 
 III 
 
 tioiis are performed in the successive positions, and 
 the piece is completed at the last. A piece is there- 
 fore finished on the last spindle at each indexing. 
 As many operations may be performed as there are 
 driving spindles. If there are fewer operations than 
 there are spindles the longest operation may be sub- 
 divided, half of it being done on one spindle and the 
 remaining half on the next one. In this way, the 
 time for finishing the piece may be materially cut 
 down. This type of machine is intended for bar- 
 stock work. 
 
 The machine illustrated in Figure 66 shows a type 
 designed for chucking f orgings and castings, in which 
 the horizontal turret principle is used. Here the 
 turret is carried in the middle on a long shaft that 
 has bearings along the top of the machine and rotates 
 only. There are two spindle heads, one on each side, 
 each with three working spindles, and four positions 
 in the turret. There are four chucks, which corre- 
 spond to these four positions. While the front one is 
 being filled, work is going on on each side of the 
 other three positions. In this way simultaneous 
 machining operations may be performed on two sides 
 of such pieces as sprinkler heads, globe valves, and so 
 on. This not only saves time, but saves a double 
 chucking of the piece — consequently there is a more 
 accurate alignment of the two cuts. 
 
 Fay Automatic Lathe. — In all of the automatic 
 lathes described, the turret principle has been em- 
 ployed in some form. The Fay automatic lathe, 
 shown in Figure 67, applies the automatic principle 
 and cam control to the engine type of lathe. This 
 
 
 li I 
 
 m 
 
 FIGS. 67 AND 68. ABOVE: FAY AUTOMATIC LATHE 
 
 BELOW: LO-SWING LATHE 
 
 241 
 
--*'<■" 
 
 240 
 
 THE .AIEnTANICAL EQUIPMENT 
 
 lions arc pcrroniicd in tlir sncccssivc |)()siiions, and 
 llic piece is coniplcU'd at the last. A piece is there- 
 I'ore linished on the last spindle at each indexing. 
 As many oi)erations may he perrormod as there are 
 driving spincUes. It* there are fewer operations than 
 there are spindk's the longest operation may be sub- 
 divided, half of it being done on one spindle and the 
 i-emaining half on the next one. In this way, the 
 time for finishing the piece may be materially cut 
 down. This type of machine is intended for bar- 
 stock work. 
 
 The machine illustrated in Figure 66 shows a type 
 designed for chucking forgings and castings, in which 
 the horizontal turret principle is used. Here the 
 turret is carried in the middle on a long shaft that 
 has bearings along the top of the machine and rotates 
 only. There are two spindle heads, one on each side, 
 eacii with three working spindles, and four positions 
 in the turret. There are four chucks, which corre- 
 spond to these four positions. AVhile the front one is 
 being filled, work is going on on each side of the 
 otliei- thi'ce positions. In this way simultaneous 
 machining operations may be performed on two sides 
 of such pieces as sprinkler heads, globe valves, and so 
 on. This not only saves time, but saves a double 
 cliucking of the piece— consequently there is a more 
 a:'curate alignment of the two cuts. 
 
 Fay Automatic Lathe. — In all of the automatic 
 lathes described, the turret principle has been em- 
 ployed in some form. The Fay automatic latlus 
 sliown in Figure 67, applies the automatic princi])!*' 
 and cam control to the engine type of lathe. This 
 
 ri<JS. ()7 AM) (IS. AMOVi:: FAV AlTO.MAriC I.ATIIE 
 
 ni:u)\v : ia)-s\vl\<; i.athi: 
 
 LMl 
 

 242 
 
 THE ME( HANICAL EQUIPMENT 
 
 lathe has a head-stock, a tail-stock, and a carriage, 
 but they are modified to adapt them to automatic 
 operation. It is intended for turning work which is 
 held on centers, and especially for that class that is 
 done on arbors, where the cuts are to be concentric 
 with a previously finished hole. It is adapted to do 
 straight, taper, and formed turning, straight and 
 bevelled facing, and recessing, either singly or in 
 combination with roughing or finishing cuts. It will 
 not, however, do threading work, for which it is not 
 intended. 
 
 The spindle of this lathe is a large, stiff, iron cast- 
 ing running in iron-to-iron bearings, and is worm- 
 driven. This locates the machine drive at right 
 angles with the center line of the machine, a rather 
 unusual arrangement. The carriage, instead of 
 sliding on V-ways on the bed, is carried on a heavy 
 steel bar seated in the head- and tail-stock castings, 
 which ties the tool-supporting and work-supporting 
 members directly together. The feeding motion in 
 this direction is governed by a former bar secured to 
 the front of the bed. As the carriage feeds over this 
 former it is swung up or down, and the tools are 
 correspondingly swung toward, or away from, the 
 work, thus controlling the contour turned. The bar 
 is so arranged that the carriage tools are swung away 
 from the work in returning them to their initial 
 position after having finished a cut. 
 
 A back arm is provided for facing cuts, which may 
 be made while turning cuts are in progress with the 
 carriage tools. This back arm is pivoted on another 
 bar, which is also supported in the head- and tail- 
 
 TURRET AND AUTOMATIC LATHES 
 
 243 
 
 stocks. It is swung inward by a heart cam, which is 
 geared with the main cam drum. This arm also 
 carries a multiple tool block of the same construction 
 as that used on the carriage. It is normally used for 
 square facing, but may be employed for recessing, 
 bevel facing, and for taper or form turning. All the 
 movements of the machine are controlled by cams. 
 
 Lo-Swing Lathe. — Figure 68 shows a special-pur- 
 pose lathe, for heavy production, which is another 
 modification of the standard engine lathe. This lathe 
 is intended to turn work of comparatively small 
 diameter and of considerable length, which must be 
 carried on centers. The face plate and the chuck of 
 the ordinary lathe are discarded. The swing is thus 
 greatly reduced, and at the same time the chances for 
 springing in the tool carriage, the tail-stock, and so 
 on, are lessened. There are two tool carriages, each 
 capable of holding several tools, so arranged as to 
 pass by the tail-stock for starting cuts and for short 
 work. The cross-section of the bed is radically dif- 
 ferent from that of an ordinary engine lathe, and the 
 carriage, instead of sliding on V-ways at the front and 
 back, is carried on a strong, narrow guide at the top 
 and front of the bed. The tool-holder is a low, solid 
 block, resting directly on the carriage, which pro- 
 vides an exceptionally rigid support for the cutting 
 tools ; there is only one joint between the cutting edge 
 and 'the bed. A taper attachment controlled by a tem- 
 plate furnishes means for cutting two tapers while 
 other cuts are in progress. One or both of the car- 
 riages may be used and each carriage may have 
 multiple-cutting tools. While the Lo-swing lathe has 
 
 '.'Ml 
 
 
244 
 
 THE MECHANICAL EQUIPMENT 
 
 no turret, there are present the essential features of 
 the turret, namely, the use of several tools and the' 
 preservation of the adjustment of the tools. The lathe 
 is especially adapted for the production of axles, 
 spindles, and other pieces that have diameters up to 
 314 inches and a length of 9 feet or under. 
 
 Blanchard Lathe. — Another very interesting type of 
 automatic lathe is known as the Blanchard lathe. It 
 is named after its inventor, an ingenious old New 
 England mechanic, who developed the lathe for the 
 Springfield Armory in 1818, to be used in turning gun 
 stocks. In this type the work is rotated at a moder- 
 ate speed, and the cutting tool has an independent 
 rotation of its own like that of a milling cutter or a 
 saw. This cutting tool is moved in and out from the 
 center of the work under the influence of a former, 
 which rotates at the same speed as that of the work. 
 As the cutting tool travels lengthwise, it can be made 
 to reproduce accurately very irregular shapes. Two 
 pieces of work on different centers may be made to 
 rotate in opposite directions, the cutters used on them 
 being operated by the same former. This will cause 
 the former to reproduce two shapes, which will be 
 ** right and left." This device is used in making shoe 
 lasts. The principle involved, in addition to its 
 original purpose of turning gun stocks, has been ap- 
 plied in an endless variety of uses, from manufactur- 
 ing wheel spokes to making hobby-horse heads: A 
 modern form of this lathe, is shown in Figure 170. 
 
 CHAPTER XV 
 BOEING 
 
 Wilkinson's Boring Machine.— The boring machine 
 is closely allied to the lathe. Historically, it is the 
 oldest of the modern machine tools. The boring 
 machine invented by John Wilkinson, of Bersham, 
 England, in 1775, made Watt's steam engine possible, 
 Watt invented his engine, with the separate con- 
 denser, in 1765. A model that he made in a few days 
 clearly demonstrated the correctness of its principle, 
 but he was unable for ten years to build a full-sized 
 engine that could be a commercial success. His 
 trouble— the inability to make the piston steam- 
 tight— was due to the impossibility, at that time, of 
 boring a cylinder round. And it was not until Wil- 
 kinson built a boring machine with a boring bar 
 supported on each side of the work, that cylinders 
 could be obtained sufficiently true to make the 
 engine a practical possibility. 
 
 From that time on, it was a success. Wilkinson's 
 machine, at the first trial, bored a cylinder for Watt 
 57 inches in diameter which did not deviate from 
 truth by more than **the thickness of an old shilling," 
 possibly a little more than 1/32 of an inch. This was 
 not bad work, certainly not for those days, and Wil- 
 kinson's machine may be considered as the first of 
 
 245 
 
 \n 
 
 '■ .( H 
 
 K 
 

 246 
 
 THE MECHANICAL EQUIPMENT 
 
 the modern maxjhine tools for anything like large 
 work. Maudslay's slide rest and improvements in 
 the lathe did not come until nearly twenty-five years 
 later. In Wilkinson's machine the cylinder was 
 strapped to heavy oak timbers. A large cast-iron 
 boring bar was put through the hole and carried on 
 trunions which were mounted on the timbers at 
 either end of the cylinder. This boring bar was 
 rotated by power, and carried a cutting tool which 
 was fed lengthwise as the work progressed. His ma- 
 chine, therefore, contained the essential elements of 
 the modern horizontal boring machine. 
 
 The vertical boring mill seems to have been first 
 suggested by John George Bodmer, a Swiss engineer 
 who lived for many years in England. He described 
 it in his remarkable patent about 1840, and called it a 
 ** rotary planer." The vertical boring mill apparently 
 made very little impression upon English mechanics 
 at that time, and it was left to American .tool builders 
 to develop this type of machine and to show its pos- 
 sibilities. For this reason, it has generally been con- 
 sidered of. American origin, although there is little 
 doubt that Bodmer 's machine antedates the use of 
 boring mills in this country. 
 
 Boring Mills Classified. — The term, boring mill, is 
 often used for both the horizontal and the vertical 
 type. This usage, however, is not followed by tool 
 builders, who confine the term '* boring mill" to the 
 type (usually vertical) in which the work revolves 
 and the tool is stationary except for the feed. The 
 horizontal type, in which the cutting tool revolves, is 
 termed a horizontal boring '* machine," the essential 
 
 BORING 
 
 247 
 
 idea being that the term **miU" is confined to the 
 cases where the work rotates. 
 
 Machines for boring range in size from those that 
 handle work 12 or 14 inches in diameter, to those 
 capable of turning work 30 and even 40 feet in diame- 
 ter; the latter are among the very largest machine 
 tools built. This wide variety of machines may be 
 roughly classified under three general heads: Vertical 
 boring mills, horizontal boring machines which are 
 self-contained, and portable boring machines which 
 are used in floor-plate work, and are picked up by a 
 crane and moved from place to place, as they are 
 needed, around the work. 
 
 Vertical Boring Mill versus Lathe.— The vertical 
 boring mill is adapted to boring, turning, and facing 
 cuts that are concentric with, or related to, a single 
 axis. Reference to Figure 69, and also to Figure 71, 
 will show that it is, in effect, a lathe which has been 
 stood up on its headstock end, and that its principal 
 elements are adaptations of lathe parts, the tailstock 
 being omitted. The bed of the machine, a, support- 
 ing the table and resting upon the floor, corresponds 
 to the headstock; the rotating table, b, to the lathe 
 faceplace; the uprights, c, c, to the lathe bed; the 
 cross rail, d, to the lathe carriage. The tool-carrying 
 head, e, is an elaborate development of the simple 
 tool post of the engine lathe. The machine shown in 
 Figure 69 is very properly termed a vertical turret 
 lathe, since the turret head corresponds closely to 
 the turret and turret slide of the lathes shown in 
 Figures 56 and 57, and the side tools correspond to 
 the cross-cutting slide shown in the same figures. It 
 
248 
 
 THE MECHANICAL EQUIPMENT 
 
 FIG. 69. VERTICAL TURRET LATHE 
 Bullard Machine Tool Co, 
 
 BORING 
 
 249 
 
 contains substantially all the elements of these ma- 
 chines, modified, of course, to suit their position and 
 the different conditions of operation. 
 
 The vertical position characteristic of the boring 
 mill gives it many advantages over a lathe for hand- 
 ling short, heavy work of comparatively large diame- 
 ter, such as pulleys, gears, flywheels, pistons and 
 cylinder heads, car wheels, turbine disks and casings, 
 and so on. In the first place, it occupies very much 
 less floor space than a lathe of corresponding size. It 
 would be difficult to secure to the vertical face of a 
 lathe faceplate the large castings handled in a machine 
 of this type. It would be difficult, also, to balance such 
 pieces, since they are frequently unsymmetrical; and 
 the overhanging weight would produce a heavy 
 bending strain upon a lathe spindle. Pieces of this 
 kind, however, may be set by a crane onto the table 
 of a boring mill with little difficulty, and may be 
 easily centered. In other words, *^it is easier to lay a 
 heavy piece down than to hang it up." Any eccen- 
 tricity of weight has little effect, as the center of 
 gravity is almost certain to fall well within the circle 
 of support. The very weight of the piece is a help 
 in holding it to a boring-mill table, instead of being 
 a hindrance, as it would be in the case of a lathe 
 faceplate. 
 
 Vertical Boring MiU versus Planer.— Plain facing 
 work may be done on a vertical boring mill or on a 
 planer. Eound or nearly round work may be faced 
 to greater advantage on a boring mill. A planer cuts 
 only in one direction, and has an idle return stroke. 
 It therefore works at a disadvantage on cuts, on 
 
 I 
 
248 
 
 THE ME( HANK^XL EQUIPMENT 
 
 FIG. 69. VERTICAL TURRET LATHE 
 Bullard Mudiiue Tool Co, 
 
 BORING 
 
 249 
 
 contains substantially all the elements of these ma- 
 chines, modified, of course, to suit their position and 
 the different conditions of operation. 
 
 The vertical position characteristic of the boring 
 mill gives it many advantages over a lathe for hand- 
 ling short, heavy work of comparatively large diame- 
 ter, such as pulleys, gears, flywheels, pistons and 
 cylinder heads, car wheels, turbine disks and casings, 
 and so on. In the first place, it occupies very much 
 less floor space than a lathe of corresponding size. It 
 would be difficult to s(U'ure to the vertical face of a 
 lathe faceplate the large castings handled in a machine 
 of this type. It would be difficult, also, to balance such 
 pieces, since they are frequently unsymmetrical; and 
 the overhanging weight would produce a heavy 
 bending strain upon a lathe spindle. Pieces of this 
 kind, however, may be set by a crane onto the table 
 of a boring mill with little difficulty, and mav be 
 easily centered. In other words, ^'it is easier to lay a 
 lieavy piece down than to hang it up." Any eccen- 
 tricity of weight has little effect, as the center of 
 gravity is almost certain to Fall well within the circle 
 of support. The very wcMglit of the i)iece is a help 
 in holding it to a boring-mill table, instead of beini;- 
 .1 hindrance, as it would be in the case of a lathe 
 I'accplate. 
 
 Vertical Boring Mill versus Planer.— Plain facing 
 work may be done on a vertical boring mill or on a 
 I>laner. Round oi- nearly round work may be faced 
 t<) greater advantage on a boring mill. A planer cuts 
 only in one direction, and has an idle return stroke. 
 Tt therefore works at a disadvantage on cuts, on 
 
250 
 
 THE MECHANICAL EQUIPMENT 
 
 BORING 
 
 251 
 
 I 
 
 y MM 
 
 ir 
 
 which a boring tool could be working continuously, 
 or nearly so. On long, narrow faces the advantage 
 is reversed, as by far the larger part of the time a 
 boring mill tool would be making its slow motion 
 through the air, and much more time would be lost 
 than would be the case with the quick return stroke 
 of the planer. The reader will understand this more 
 clearly if he will refer to Figure 70. 
 
 A flat annular surface, such as the flanged end of 
 a valve, might be faced on a planer which has a 
 stroke equal to the outside diameter and a side feed 
 of the same amount. The cutting tool, in covering 
 the square indicated at A, would machine the sur- 
 
 Cross Feed of Planet' Tool 
 
 \Sfrolos of 
 FlaneK Tool 
 
 p'iS&^'ffe 
 
 FIG. 70. EFFECTIVE CUTTING AREAS ON THE PLANER AND 
 
 BORING MILL 
 
 Pace, but it would do useful work only on the shaded 
 portion, a. The motion of the tool over the unshaded 
 portions, b, b, inside and out, represents lost time. If 
 the job were done on a boring mill, the tool would be 
 set at the outer edge, would be given an inward 
 radial feed, represented by the width of the flange, 
 and the work would be rotated under the tool, as in- 
 dicated at B. In this case, the cutting tool would be 
 in contact with the work all the time, instead of only 
 part of the time, and the length of feed would be but 
 a small fraction of that required in the first case. 
 The advantage is therefore clearly with the boring 
 mill. 
 
 If, however, the face to be machined is long and 
 narrow, as at C, the boring mill must take in a radius 
 equal to the distance, c, across the corners, and 
 the tool must be started at this radius and fed in 
 to the center. Not until it has reached the radius, 
 d, is the tool in the work during the entire rotation, 
 and much time is therefore lost. If, on the other 
 hand, the work is nearly square, as shown below at 
 D, the proportion of time lost between the radii, c' 
 and d', is much smaller, and the gain from having the 
 tool in the work continuously inside the radius, d', 
 may render it desirable to do the work on a boring 
 mill. 
 
 Construction of Vertical Boring Mill.— The tools in 
 vertical boring mills are generally carried on a head 
 which, in turn, is carried on a cross rail. This cross 
 rail, in small mills, is mounted on a single vertical 
 support, as in Figure 69, of box-like cross section, 
 adapted to stand the combined bending and torsional 
 
 It"" 
 
 PI 
 
252 
 
 THE MECHANICAL EQUIPMENT 
 
 i( 
 
 strains produced by the cut. In all except the smaller 
 sizes there are two supports, as show in Figures 71 
 and 72. The single support, or upright, is used on 
 machines that table up to about 42 inches in diame- 
 ter. For medium-sized machines, ranging from this 
 size up to 15 to 20 feet in diameter, there are two 
 uprights rigidly bolted to the bed of the machine. 
 For large mills, the two uprights are sometimes so 
 arranged that they may be slid backward, as shown 
 at f, Figure 71, away from the table, so that the 
 diameter of work which may be machined is thus in- 
 creased. Two, or even three, tool posts may be 
 carried on the cross rail; and in small sizes, the tool 
 head may be equipped with a turret and used in 
 every way as the turret might be on a heavy turret 
 chucking-lathe. Such a turret is shown at g in 
 Figure 69. The heads, e, in all cases swivel about a 
 center, may be adjusted to any angle, and have a 
 power feed at the angle so set. 
 
 For straight boring or turning, the head remains 
 stationary, and the tool post or turret, as the case 
 may be, is fed vertically downward. For machining 
 a taper surface, the head is set at the required angle 
 and the tool post is fed in that direction. In this 
 case, as in the previous one, the head would be 
 clamped to the rail. When it is desired to machine a 
 flange or flat face at right angles to the axis, the 
 tool post is held in a constant position in the head, 
 and the whole head is given a horizontal side feed 
 along the rail. In certain types of the smaller boring 
 mills, the upright is equipped with an auxiliary side 
 head, h, shown in Figure 69, which has a vertical 
 
 1 .(in 
 
 I 
 
 i 
 
 ; M 
 
 Aia^ ^^^* ^^ ^^^ ^^' VERTICAL BORING MILLS 
 
 16-foot mUl -^t^^^^^^^^^^^^ above; a 34-foot mil,, below, 
 
 uotn built by Niles-Bement-Pond Co. 
 
 253 
 
252 
 
 THE MEtllAiNKAl. Hi^lll^MEiNT 
 
 strains produced by the cut. Jn all except tlie smaller 
 sizes there are two supports, as show in Figures 71 
 and 72. The single suppoi't, or upright, is used on 
 machines that table up to about 42 inches in diame- 
 ter. For medium-sized machines, ranging from this 
 size up to IT) to 2i) feet in diameter, there are two 
 uprights rigidly bolted to the bed of the machine. 
 For large mills, the two uprights are sometimes so 
 arranged that thev mav be slid backward, as shown 
 at f, Figure 71, away from the table, so that the 
 diameter of work which may l)e machined is thus in- 
 creased. Two, or even three, tool posts may i)e 
 carried on the cross rail; and in small sizes, the tool 
 head may be equipped with a turret and used in 
 every way as the tui-ret inight be on a heavy turrc^t 
 chucking-lathe. Such a turret is shown at g in 
 Figure 69. The heads, e, in all cases swivel about n 
 center, may be adjusted to any angle, and have a 
 power feed at the angle so set. 
 
 For straight boring or turning, the head remains 
 stationary, and the tool post or turret, as the case 
 mav be, is fed verticallv downward. For machinin.u 
 a taper surface, tlu^ head is st^t at the required angle 
 and the tool post is fed in that direction. In this 
 case, as in the previous one, the head would 1h' 
 clamped to the rail. When it is desired to machine n 
 flange or flat face at right angles to the axis, Hk' 
 tool post is held in a eonstant position in the head 
 and the whole hea<[ is given a hoi-i/onlal side Tefl 
 along the rail. In certain lyjies ol* the smaller borii ,: 
 mills, the upright is ('([uipped with an auxiliary si-i-' 
 head, h, shown in Figure (J!), wliieh has a vertierJ 
 
 ^^^^' ^^ ^^^ '^-- ^'^'RTICAL BORING MILLS 
 ISotli built by Nilos-lJeiiieni-INMul ( \> 
 
 LM3 
 
254 
 
 THE MECHANICAL EQUIPMENT 
 
 feed np and down the face of the work and a hori- 
 zontal feed toward the center. This head, also, may 
 carry a turret tool holder, h', and the tools may work 
 simultaneously with those in the head carried on the 
 cross rail. In this respect, again, the boring mill 
 corresponds closely to the turret lathes referred to in 
 Figures 56 and 57. 
 
 When two heads are carried on the cross rail, they 
 are provided with independent feeds in all direc- 
 tions, in order that they may work simultaneously, 
 and independently of each other. As the weight of 
 the cross rail and heads is considerable, they are 
 counterbalanced by weights, shown in Figure 71. In 
 boring mills with the adjustable uprights, the latter 
 are set well back, and the usual type of tool head, 
 shown to the right in Figure 71, would not reach in 
 close enough to the center to work on small diame- 
 ters. This difficulty is met by mounting one of the 
 tool heads on an extension, i, which reaches forward 
 toward the center, enabling that head to machine the 
 small diameters. The feeds of the cross rail on the 
 uprights, the tool heads on the cross rail, the slides 
 in the tool heads, as well as the feeds in the side head, 
 if there are any, are all power-driven. 
 
 In the early history of the boring mill, al- 
 though its great capacity for removing metal was 
 clearly recognized, it was considered only as a 
 roughing tool and accurate work was performed upon 
 a large engine lathe. Of late years, however, the de- 
 sign and construction of the boring mill have been 
 so refined and developed that it has almost com- 
 pletely taken over work of this character. This is 
 
 BORING 
 
 255 
 
 especially true in the case of the vertical turret 
 machines, which have come into very wide use for 
 such work in connection with car wheels, gears, and 
 so on. 
 
 Table, Drive and Tools.— The revolving table in a 
 boring mill is the important factor upon which ac- 
 curacy and quality of the work depends. It should 
 be very rigid, and capable of revolving smoothly at 
 high speeds under heavy cuts. The spindle under- 
 neath, which corresponds to the spindle of the lathe, 
 is a sufficient support for the smaller sizes. In all 
 medium and larger sizes the spindle is relied on to 
 do the centering only, and the weight and the vertical 
 tool thrust are carried on a circular bearing of larger 
 diameter, which usually is slightly conical so that it 
 will be self-centering as it wears. The table is driven 
 from a point near the rim, located as nearly under the 
 cutting tool as possible to eliminate torsion on the 
 spindle. 
 
 The bevel gear form of drive is most used, but it 
 has some disadvantages, since it has a slight tendency 
 to lift the table. To obviate this, worm gearing is 
 used in some cases, as its action is smoother and 
 more continuous than that of either spur or bevel 
 gearing. For heavy work the worm gear is not 
 available, on account of its low efficiency and heavy 
 end pressure. Large boring mills are therefore driven 
 by spur or bevel gearing; spur gearing is used on 
 the largest types of machines, as shown at i in Fig- 
 ure 71. ^ 
 
 The cutting tools used in these machines may be 
 (^ither of the type used on a heavy planer or of the 
 
256 
 
 THE MECHANICAL EQUIPMENT 
 
 kind used in a large turret chucking lathe. The 
 pilot bar principle, described in the last chapter, is 
 made use of on the boring mill as well. The vertical 
 boring mill, in its larger sizes, is used for work of a 
 varied nature, ranging from general jobbing work to 
 the machining of large castings incident to building 
 heavy machinery of all kinds. The smaller sizes, 
 with special tool equipment, are used for accurate 
 repetition work on a strictly manufacturing basis. 
 They are well adapted for this, since, because they 
 require little floor space, the work may be set in 
 position easily and quickly, and the machine will take 
 heavy and simultaneous cuts with all the accuracy 
 required in this type of work. 
 
 Bullard Mult-au-matic Vertical Lathe. — Figure 73 
 shows the Bullard Mult-au-matic vertical lathe, a de- 
 velopment from the small boring mill shown in 
 Figure 69. It is, in effect, five automatic chucking 
 lathes arranged vertically around one bed, in a space 
 6 feet in diameter and 12 feet 3 inches high, including 
 the motor. There are 5 tool heads, which will face, 
 bore, and turn at any angle independently of one 
 another; and 6 independently rotating chucks or 
 tables, 14 inches in diameter, are carried on an in- 
 dexing, circular base. Five of the chucks revolve 
 under the tool heads — the sixth is at the loading posi- 
 tion or station at rest. While a new piece is being set 
 in this chuck, all of the others are working. When a 
 new piece is in place, the circular base is indexed one 
 station and each piece comes under the next tool head; 
 the last comes to the loading station, finished and ready 
 to be taken out. The next piece is then sent on its 
 
 no. 73. 
 
 ** MULT-AU-MATIC*' VERTICAL LATHE 
 Bullard Machine Tool C!o. 
 257 
 
 tw 
 
25G 
 
 'p 
 
 THE MECHAXICAL EQl IPMENT 
 
 kind used in a largo turret chucking latlie. The 
 pilot bar principle, described in the last chapter, is 
 made use of on the boring mill as well. The vertical 
 boring mill, in its larger sizes, is used for work of a 
 varied nature, ranging from gcMiei-al jobbing work to 
 the machining of large castings incident to building 
 heavy machinery of all kinds. The smaller sizes, 
 with special tool equipment, are used for accurate 
 repetition work on a strictly manufacturing basis. 
 They are well adapted for this, since, because they 
 require little floor space, the work may be set in 
 position easily and quickly, and the machine will take 
 heavy and simultaneous cuts with all the accuracy 
 required in this type of work. 
 
 BuUard Mult-au-matic Vertical Lathe.— Figure 73 
 shows the Bullard Mult-au-matic vertical lathe, a de- 
 velopment from the small boring mill shown in 
 Figure 69. It is, in effect, five automatic chucking 
 lathes arranged vertically around one bed, in a space 
 6 feet in diameter and 12 feet 3 inches high, including 
 the motor. There are T) tool heads, which will t'ac(\ 
 bore, and turn at any angle independently of on<' 
 another; and 6 independently rotating chucks or 
 tables, 14 inches in diameter, are carried on an in- 
 dexing, circular base. Five of the chucks revolve- 
 under the tool heads — the sixth is at the loading posi- 
 tion or station at rest. While a new piece is being set 
 in this chuck, all of the others are working. When u 
 new piece is in place, the circular base is indexed one 
 station and each piece comes under the next tool head: 
 the last comes to the loading station, linished and read; 
 to be taken out. The next piece is then sent on i*^ 
 
 V. 
 
 FIG. 73. **MILT-Al-MATIC" VERTICAL LATHE 
 Bullanl Mnoliine Tool Co. 
 
 257 
 
258 
 
 THE MECHANICAL EQUIPMENT 
 
 way around. This method is an application of the 
 ** station'' principle used in the multi-spindle lathes 
 described in Chapter XIV. The indexing, fast and 
 slow feeds of all the tool heads, both forward and 
 return, are entirely automatic. This machine reduced 
 the time of finishing a fly wheel on the Ford motor 
 from thirty-two minutes to fifty seconds. 
 
 Horizontal Boring Machine.— As there is an 
 analogy between the vertical boring mill and the lathe 
 with the work bolted to the faceplate, so the horizon- 
 tal boring machine may be likened to a lathe with 
 the work bolted to the carriage. There is, however, 
 a fundamental difference between these arrange- 
 ments, since in one case the work revolves against 
 the tool, and in the other the tool moves against the 
 work. It will be found that there is a similar dif- 
 ference between the planer and the shaper. Which of 
 these methods is the better, depends upon the size 
 and shape of the piece, and of the cut in relation to the 
 piece. The feasibility of revolving the work in an 
 operation like that of turning a carwheel, is evident. 
 It is equally clear that it would be disadvantageous 
 to revolve a large engine bed around the center line 
 of the main shaft bearing, merely to bore out that 
 bearing. The swing required would be enormous and 
 would call for a boring mill utterly disproportionate 
 to the size of the cut to be made. With such a piece 
 as this, it is obviously better to clamp the casting 
 firmly on a base, place a boring bar on the center 
 line of the shaft, and bore the bearing by revolving 
 a tool carried by the bar. 
 
 Unlike the vertical boring mill, the horizontal 
 
 BORING 
 
 259 
 
 boring machine offers a means of machining con- 
 veniently and accurately surfaces which are related 
 to several axes; these axes may be either parallel, at 
 right angles, or even at an odd angle. A case in 
 point is the machining of the main cylinder bore and 
 the holes for the steam and exhaust valve in a Corliss 
 engine cylinder. The latter holes — four in number — 
 are parallel to one another, and at right angles to 
 the main cylinder bore. The casting may be mounted 
 on the table of a horizontal boring machine — like 
 those in Figures 74 to 77 — the cylinder hole bored, 
 and the end flanges faced. The table, with the 
 cylinder still clamped to it, may then be indexed 
 through 90 degrees. 
 
 By operating the traverses of the table and the 
 head spindle, the spindle may be brought opposite 
 one of the valve holes, and that may be bored and its 
 end flanges may be faced. The spindle center may 
 then be shifted to coincide with each of the other 
 three valve hole centers, and these may be finished 
 successively as the first one was. All these opera- 
 tions may be finished, within the limits of accuracy 
 of the adjustments of the machine, with a single 
 clamping of the work upon the table. Thus it is 
 possible to avoid the loss of time and the chances of 
 error involved in shifting the work and making a 
 series of set-ups. The horizontal type of machine is 
 better for boring holes which are long in proportion 
 to their diameter. This advantage comes from the 
 use of the outboard bearing or tail-block which sup- 
 ports the boring bar at the farther end, as shown in 
 Figure 75. 
 

 
 260 
 
 THE MECHANICAL EQUIPMENT 
 
 Similarity to the Lathe.— The horizontal type of 
 machine is more closely similar, in general design, to 
 the lathe than is the vertical boring mill. This is 
 especially true of the machines which have stationary 
 spindles and elevating tables, as in the Niles-Bement- 
 Pond machine, Figure 74. The boring head is similar 
 in position and general design to the headstock of the 
 engine lathe, the essential difference being a pro- 
 vision for the horizontal feed of the spindle. This 
 provision is usually made by having a hollow rotat- 
 ing spindle, b, without lateral motion, and an inner 
 spindle, c, sliding longitudinally through this outer 
 one, which is provided with an independent traverse 
 feed. In machines of this type the table and platen, 
 a, are carried on elevating screws, d, which afford a 
 vertical adjustment for the adaptation of the table to 
 various types of work. The outboard bearing, e, is 
 carried in a stationary yoke, f, which corresponds to 
 the tailstock of the engine lathe. This outboard 
 bearing is used in boring long holes, or wherever 
 support for the spindle is needed, and the yoke serves 
 as a support to which the table may be clamped when 
 it has been brought to the desired position. 
 
 An Adaptable Type.— Another widely used type is 
 shown in Figure 75. In this machine, built by the 
 Lucas Machine Tool Co., variation in height between 
 spindle and table is obtained by adjusting the height 
 of the boring head, a, instead of that of the table. The 
 bed of the machine is of rectangular box section, and 
 the boring head is carried on a heavy column at the 
 left end of the machine; the head is adjustable verti- 
 cally on suitable gibbed slideways, b. A stiff back 
 
 ' ,' 
 
 
 1. 1 
 
 FIGS. 74 AND 75. HORIZONTAL BORING MACHINES 2eX 
 
260 
 
 THE MECHANICAL i:(^CJPMi:\T 
 
 Similarity to the Lathe.— The horizontal typo of 
 machine is more closely similar, in general design, to 
 the lathe than is the vertical horini;' mill. This is 
 especially true of the machines which have stationarv 
 
 « 
 
 spindles and elevating tables, as in the Xiles-P>ement- 
 Pond machine, Figure 74. The boring head is similar 
 in position and general design to the headstock of the 
 engine lathe, the essential dilTerence being a pro- 
 vision for the horizontal feed of the spindle. This 
 provision is usually made by having a h'jllow rotat- 
 ing spindle, b, without lateral motion, and an inner 
 spindle, e, sliding longitudinally through this outer 
 one, which is provided with an independent traverse 
 feed. In machines of this type the table and platen, 
 a, are carried on elevating screws, d, which afford a 
 vertical adjustment for the adaptation of the table to 
 various types of work. The outl)oard bearing, e, is 
 carried in a stationary yoke, f, vMch corresi)onds to 
 the tailstock of the engine lathe. This outboard 
 bearing is used in boring long holes, or wluM-ever 
 support for the s])indle is needed, and tlie yoke serves 
 as a support to which the table may be cbimi)ed when 
 it has been brought to the desired position. 
 
 An Adaptable Type.— Another widely used type is 
 shown in Figure 7.'). In this machine, built bv the 
 Lucas Machine Tool Co., variation in height between 
 spindle and table is obtained by adjusting the height 
 of the boring head, a, instead of that of the table. The 
 bed of the machine is of rectangulai* box section, and 
 the boring head is carried on a heavy column at tlir 
 left end of the machine; the head is adjustable verti 
 eally on suitable gibbed slide ways, b. A stiff back 
 
 •^■'^■jf'- 
 
 FKiS. 74 AND 75. IIOKIZOXTAL BORING MACHINES 
 
 201 
 
262 
 
 THE MECHANICAL EQUIPMENT 
 
 BORING 
 
 263 
 
 i 
 
 rest, c, at the right end of the machine has slide- 
 ways for a tail-block, d, which is fed up and down in 
 conjunction with the main boring head; the proper 
 alignment with the spindle is maintained by feed 
 screws operated through bevel gears from a common 
 shaft. After the tail-block is in position, it may be 
 locked in place, when it becomes practically of one 
 piece with the back rest. The back rest, c, is ad- 
 justable forward and backward, so that it will accom- 
 modate work of various lengths, or it may be removed 
 from the bed without disturbing any of the other 
 mechanism. The main spindle is driven through back 
 gears in the head, which are engaged and disengaged 
 by convenient interlocking levers. The platen, e, is 
 furnished with T-slots and with a circular swiveling 
 table, not shown. It slides transversely on the 
 saddle, f, which in turn slides lengthwise of the 
 machine. 
 
 Power feeds are provided for the spindlo in and 
 out, the spindle and tail-block up and down, the saddle 
 along the bed, and the platen across the saddle. 
 Reverse feeds, rapid traverse, and hand adjustments 
 are provided for all feeds. The machine has a con- 
 stant-speed drive, which may be operated by either 
 belt or motor, the variations in spindle speed being 
 made through change gears operated by the levers 
 at the front of the bed. This type of machine is 
 useful for many kinds of boring, drilling, and milling 
 operations. For drilling, the tool is mounted directly 
 in the head spindle, g, and the platen is brought close 
 to the spindle head. This position may also be used 
 for milling operations; the milling cutter is mounted 
 
 on the end of the spindle or carried on an arbor 
 between the head, a, and tail-block, d. For boring 
 long holes, the tail-block and the back rest are used, 
 the spindle is extended to run through the tail-block, 
 and the cutting tool is mounted on the spindle, which 
 is rotated and fed forward at the same time. For 
 vertical milling work, an attachment is provided, 
 which IS shown in Figure 76. This consists of a 
 heavy cast iron yoke, h, which spans the opening 
 between the spindle head, a, and the tailblock, d, and 
 is firmly bolted to each. On this yoke is mounted 
 a traveling head, i, carrying a vertical spindle driven 
 from the main spindle through bevel gears. A face 
 milling cutter, j, may be mounted on the lower end 
 of this spindle, and the machine may be used to do 
 vertical milling operations. In the latest type of 
 Bement boring machine, all the operating levers are 
 arranged in pairs, one on each side of the machine, so 
 that it may be controlled from whichever side happens 
 to be most convenient. Figure 77 shows a much larger 
 machine of the same general type. 
 
 Portable Boring Machines. — In very heavy ma- 
 chinery — as, for instance, rolling mill engines — some 
 of the parts to be machined are of very great size and 
 weight. In machining such pieces, it would be ex- 
 pensive and inconvenient to shift their positions to 
 make the various cuts required. It is simpler and 
 easier to move the machines around the castings. 
 Shops equipped for work of this magnitude are pro- 
 vided with slotted floor plates, which are located in 
 the main bay of a building of the type shown in 
 Figure 1, under the large traveling crane. 
 
 •1 
 

 BORING 
 
 265 
 
 FIGS. 76 AND 77. HORIZONTAL BORING MACHINES 
 The Tipper, Fig. 76, is shown with vertical milling attachment and 
 is built by Lucas Machine Tool Co. The lower machine is built 
 
 by Niles-Bement-Pond Co. 
 264 
 
 These plates are built up of sections, and may cover 
 a considerable portion of the floor. Their upper sur- 
 face is machined and is provided with T-slots. They 
 are firmly bedded in a heavy concrete foundation 
 and, when finished, correspond, except for their much 
 greater size, to the base plate, a, shown in Figure 77. 
 The large casting to be machined is brought in from 
 the foundry, leveled, and clamped in place upon this 
 floor plate; it is not moved until all the machine work 
 is done. When boring operations are necessary, a 
 portable boring mill— corresponding to the vertical 
 portion of the mill shown in Figure 77— is placed in 
 position on the floor plate beside the casting, is 
 clamped into place, and the operations called for at 
 that location are performed. 
 
 When it is necessary to move the machine to some 
 other part of the casting, the crane hook is slipped 
 into a heavy loop, or bail, at the top of the machine, 
 and it is lifted bodily, turned around, and transported 
 as may be necessary. It is set in its new location, 
 and the slots in the floor plate are used to orient the 
 machine in proper position. The same thing is done 
 with other types of machines, such as large draw-cut 
 shapers, and so on. Whether it is desirable to move 
 the machine around the work or the work around the 
 machine, is largely a question of the relative size of 
 the two; when the work is of very great size, the 
 former method is the cheaper. Portable boring ma- 
 chines of this type are invariably motor-driven, the 
 motor being mounted on the machine itself and trans- 
 ported with it. 
 
 !', tl 
 
 0j 
 
FIGS. 7() AND 77. HORIZONTAL BOKIXO MACHINES 
 
 The upper, Fi.?. 7G, is sliown with vertical niilllng attaclimont an' 
 IS biiiU by Lucas :Ma('hine Tool To. The lower machine is buii 
 
 l>.v NiIes-P,«»nuMit-ron(i Co, 
 204 
 
 BORING 
 
 265 
 
 Those platos are huUi up of sections, and may cover 
 a consi(l(M-al)le portion of the th)or. Their ii{)per sur- 
 face is macliined and is jn-ovided witli T-sh)ts. They 
 ai-e firmly hedchnl in a heavy concrete foun(hition 
 and, \vh(^n finislied, correspond, except for their much 
 greater size, to the ])ase pkite, a, shown in Figure 77. 
 The hirge casting to be macliined is brought in from 
 the foundry, leveled, and clamped in i)lace upon this 
 floor plate; it is not moved until all the machine work 
 is done. AVlien boring operations are necessary, a 
 portable boring mill — corresponding to the vertical 
 ])ortion of the mill shown in P'igure 77— is ])laced in 
 position on the lloor plate ])eside the casting, is 
 clamijcd into place, and the operations called for at 
 that location are performed. 
 
 When it is necessary to move the machine to some 
 other part of the casting, the crane hook is slipped 
 into a heavy loop, or bail, at the top of the machine, 
 and it is lifted l)odily, turned around, and transported 
 as may be necessary. It is set in its new location, 
 and the slots in the floor plate are used to orient the 
 machine in proper position. The same thing is done 
 with other types of machines, such as large draw-cut 
 shapers, and so on. Whether it is desirable to move 
 the machine around the work or the work around the 
 machine, is largely a question of the relative size of 
 the two; when the work is of very great size, the 
 iormer method is the cheaper. Portable boring ma- 
 fliines of this type are invariably motor-driven, the 
 motor being mounted on the machine itself and trans- 
 ported with it. 
 
Ii 
 
 CHAPTER XVI 
 DEILLING MACHINEKY 
 
 The Sensitive Drill. — Drilling machines, in some 
 form, are found in every shop. They are used for 
 drilling round holes in all kinds of castings and 
 forgings; for tapping or threading the holes; for 
 countersinking or making a tapered enlargement of the 
 upper end of a hole; for counterboring or making an 
 annular enlargement of the upper end of a hole; for 
 reaming, which is passing a reamer through the hole 
 to increase the accuracy of form ; and for spot facing, 
 which is making a shallow counterbore deep enough 
 to form a smooth face for the head or nut of a bolt. 
 
 The smallest and simplest form is a sensitive drill, 
 Figure 78. It consists of an upright standard, a 
 smooth horizontal table on which to rest the work, 
 a vertical spindle capable of holding and rotating the 
 drill, and means for feeding either the work or the 
 drill, usually the latter. The variations in speed are 
 generally obtained by means of friction disks which 
 form part of the driving mechanism. One of these 
 disks, a, revolves in the vertical plane parallel with 
 the axis. A horizontal driving wheel, b, on the 
 spindle has a narrow leather band, c, which bears 
 against this. The leather-faced wheel is adjustable 
 vertically and, when set to bear upon the vertical 
 
 266 
 
 S3 
 
 > 
 
 02 
 
 00 
 Em 
 
 CO 
 
CHAPTER XVI 
 DEILLIXG :\lACniXEEY 
 
 The Sensitive Drill. — Drilling macliincs, in some 
 form, are found in every shop. They are used for 
 drilling round holes in all kinds of castings and 
 forgings; for tapping or threading the hok's; for 
 countersinking or making a tapered enlargement of the 
 upper end of a hole; for counterhoring or making an 
 annular enlargement of the upper end of a hole; for 
 reaming, which is passing a reamer through the hole 
 to increase the accuracy of form; and for spot facing, 
 which is making a shallow countei'hore d(H'p enough 
 to form a smooth face for the head or nut of a ])olt. 
 
 The smallest and simplest form is a sensitive drill, 
 Figure 78. It consists of an upright standard, a 
 smooth horizontal table on which to rest the work, 
 a vertical spindle capal)le of holding and rotating the 
 drill, and means for feeding eitlier the work or tlie 
 drill, usually the latter. The variations in speed are 
 orenerallv obtained bv means of friction disks whicli 
 form part of the driving mechanism. One of these 
 disks, a, revolves in the vertical plane parallel with 
 the axis. A horizontal driving wheel, )>, on tin* 
 spindle has a narrow leather band, c, which bear> 
 against this. The leather-faced wheel is adjustahl« 
 vertically and, when set to bear upon the v(Mtic;if 
 
 266 
 
 I 
 
■: i 
 
 268 
 
 THE MECHANICAL EQUIPMENT 
 
 
 
 disk near its rim, will drive the spindle at the great- 
 est speed. By lowering it toward the center of the 
 vertical wheel, the speed may be reduced to zero. By 
 lowering it still further, the direction of rotation may 
 be reversed. The wheel, b, drives the spindle by 
 means of a sliding key, or spline, and is retained in 
 its proper position by the finger, d, while the spindle 
 is fed downward by means of the light hand-lever 
 shown at the right. In some types, the friction disks 
 are arranged at the base of the upright, and in others 
 the variations in speed are obtained by means of 
 cone pulleys. The drill is often tised as a bench 
 machine, and only for light rapid work of the simplest 
 nature. 
 
 Upright Drills. — The commonest type of drill is 
 the standard upright drill press, shown in Figure 79. 
 The essential elements are the main upright or 
 column, the table, the spindle, and the driving and 
 feed mechanism. The drill, or tool, is carried in a 
 smooth tapered socket at the lower end of the main 
 spindle, into which it will seat itself firmly enough to 
 transmit the power required to make the cut. To re- 
 move it, a taper key or drift is inserted through the 
 slot, a, and driven across the end of the shank of the 
 drill, which forces it out of the hole. 
 
 In most upright drills the lower portion of the 
 column is cylindrical, as shown, and the table is 
 carried on a swinging arm, which is capable of being 
 raised or lowered by means of an elevating screw, b, 
 shown at the right, and clamped to accommodate dif- 
 ferent types of work. The circular table is carried at 
 the end of this arm on a short vertical spindk, the 
 
 DRILLING MACHINERY 
 
 269 
 
 center of which is at the same distance from the 
 frame as the drill spindle. This arrangement of 
 swinging arm and rotatable table is very convenient 
 in the drilling of bolt holes in flanges. A flange may 
 be clamped concentrically to the table, and the center 
 of the table set off to one side a distance equal to the 
 radius of the bolt circle. The table may then be 
 rotated about its center and the successive holes 
 drilled in turn. In most upright drills the column 
 branches out at the top, one branch curving forward 
 to carry the upper bearing of the spindle and its 
 driving mechanism, the other branch curving back- 
 ward to carry the bearing behind the upper driving 
 pulley. 
 
 Details of the Drive. — The chief strain to which 
 the column is subjected is the upward axial pressure 
 against the drill, which produces a bending move- 
 ment. In many drills this is cared for by the addi- 
 tion of a secondary column in the rear, which helps 
 to carry this strain. The lower end of the driving 
 spindle is carried in the sliding head, c, which is 
 gibbed to a vertical slide, on the front and upper 
 portion of the column. The spindle, like that of the 
 horizontal boring machine, has two motions — one of 
 rotation, and the other of longitudinal traverse. It 
 consists of a vertical steel shaft passing through two 
 sleeves. The upper one, driven by the bevel gear, e, 
 imparts the rotary motion to the spindle through a 
 sliding key; the lower sleeve slides vertically without 
 rotation, carrying the spindle up and down, and is 
 actuated by a rack-and-pinion feeding mechanism 
 located in the head. The upward thrust in most 
 

 I 
 
 lei 
 
 270 
 
 THE MECHANICAL EQUIPMENT 
 
 modern drills is cared for by ball or roller thrust 
 bearings, which are clearly seen in the heavier ma- 
 chines, shown in Figures 80 and 81. 
 
 In many machines the lower head, c, Figure 79, is 
 cast solid with the column; this arrangement gives a 
 stiffer construction. The sliding head, however, with 
 its adjustment up and down, is more convenient for 
 varying heights of work, gives a longer vertical move- 
 ment to the spindle, and supports it close to the drill 
 at all times. In some machines the sliding head itself 
 moves up and down with the feed; in others the head 
 is clamped and the spindle is fed downward through 
 it. The latter form is a little more rigid, while the 
 former does away with the rack and pinion on the 
 sleeve, and permits of a longer traverse. In addition 
 to the adjustable swinging table, most upright drilk 
 are provided with a forward extension of the base 
 which is planed and slotted to hold large work. 
 
 The driving mechanism consists of a countershaft 
 with a tight and a loose pulley, and a cone pulley 
 usually located at the base of the machine, as shown., 
 The upper shaft carries the secondary cone and the 
 necessary gearing for the speed changes. The front 
 end of the shaft carries the bevel pinion which drives 
 the bevel gear, e, and through it the main spindle. 
 All except small drills are provided with power feed, 
 and most of them are, or may be, equipped with tap- 
 ping attachments used for threading holes. The 
 various adjustments may be operated by hand as well 
 as by power. 
 
 Heavy Duty Drill-Presses.— While the circular col- 
 UMui is very convenient in many ways, it is obviously 
 
 271 
 
 i,'f 
 
270 
 
 THE iMECHANICAL EQUIPMENT 
 
 modern drills is cared for hv ball or roller thrust 
 bearings, which are clearly seen in the heavier ma- 
 chines, shown in Figures Hi) and 81. 
 
 In many machines the lower head, c, Figure 79, is 
 cast solid with the column; this arrangement gives a 
 stiffer construction. The sliding head, however, with 
 its adjustment up and down, is more convenient for 
 varying heights of work, gives a longer vertical move- 
 ment to the spindle, and supports it close to the drill 
 at all times. In some machines the sliding head itself 
 moves up and down with the feed; in others the head 
 is clamped and the spindle is fed downward through 
 it. The latter form is a little more rigid, while the 
 former does away with the rack and pinion on the 
 sleeve, and permits of a longer traverse. In addition 
 to the adjustable swinging table, most upright drills 
 are provided with a forward extension of the base 
 which is planed and slotted to hold large work. 
 
 The driving mechanism consists of a countershaft 
 with a tight and a loose pulley, and a cone pulley 
 usually located at the base of the machine, as shown 
 The upper shaft carries the secondary cone and tlie 
 necessary gearing for the speed changes. The front 
 end of tlie shaft carries the bevel pinion which drives 
 the bevel gear, e, and through it the main spindle 
 All except small drills are provided with power feed. 
 and most of them are, or may be, equipped with ta}i 
 ping attachments used for threading holes. Tli< 
 various adjustments may be operated by hand as well 
 as by ()()wer. 
 
 Heavy Duty Drill-Presses.— While the eireular ce! 
 uniii is very eonvenient in many ways, it is obviousl^ 
 
 IN 
 
 J71 
 
272 
 
 THE MECHANICAL EQUIPMENT 
 
 DRILLING MACHINERY 
 
 273 
 
 I 
 
 limited in strength. Heavy-dnty drill presses for 
 large work and for use with high-speed steel may 
 take the form shown in Figures 80 and 81; the frame 
 is a heavy box section designed for severe service, and 
 the tipper and lower spindle bearings are both solid 
 with it. 
 
 The machine shown in Figure 80 has a single- 
 speed belt drive; the main driving pulley, being on 
 the other side of the machine, is not shown. The 
 axis of the driving pulley is parallel to the front of 
 the machine, an arrangement which allows the ma- 
 chine to be set as one of a row down the shop. The 
 speed changes are provided through change gears. 
 The feed mechanism is very powerful, and is pro- 
 vided with a safety device to protect the driving 
 mechanism in case of overload. This device takes 
 the form of a ** shearing pin" proportioned to let go 
 when an overload is reached. The swinging table is 
 done away with, and an adjustable table mounted 
 on heavy guides is substituted, as in Figure 80. For 
 the still heavier machines, shown in Figure 81, the 
 work is carried on the slotted floor plate. The plane 
 surfaces at the front of the uprights on the latter 
 machines are employed, not to carry work, but to 
 support guides (not shown), which may be used to 
 steady the spindle when desired. 
 
 This type of machine is similar in many ways to a 
 horizontal boring machine, except for its vertical posi- 
 tion, and is used for many kinds of boring operations. 
 Figure 80 shows a set of tools in place for doing a 
 typical boring operation— the turning of the conical 
 face of bevel-gear blanks. This is a case of what is 
 
 known as **second operation" work. The blanks in 
 the smaller pile at the left show that a hole has 
 already been drilled and one side has been faced. 
 The tool head is equipped with a pilot bar, a, which 
 enters this hole and centers the spindles during the 
 heavy cutting operations, which here include facing 
 the top, turning the hub, and facing the conical sur- 
 face. The machines shown in Figure 81 are heavy 
 enough to do much of the work that used to be done 
 on a boring mill, for the spindle is 10 inches in 
 diameter at the end. The one in the foreground is 
 fitted with heavy facing tool and pilot bar. While 
 technically known as drilling machines, these have 
 really passed into the boring-machine class. 
 
 Radial Drills. — As the work grows larger, it is 
 easier to move the tool about the work than to shift 
 the work under the tool. A class of drilling ma- 
 chines, known as radial drills, have been developed 
 for this service. These are known as plain, half- 
 universal, or full-universal drills according to the 
 character of the motion that may be given to the 
 drilling head. In the plain radial, shown in Figure 82, 
 the drilling head, a, has a motion in and out from 
 the column, and may be swung radially about the 
 column, its axis at all times remaining vertical. In 
 the half-universal, the head swivels in a vertical plane 
 parallel to the face of the arm, so that the spindle 
 may be set at any angle in that plane. In the full- 
 universal, the radial arm itself has a swiveling motion 
 in addition. Such a machine is shown in Figure 84. 
 It is remarkably flexible, and will drill a hole at any 
 angle. 
 
274 
 
 THE MECHANICAL EQUIPMENT 
 
 'J 
 
 The plain radial is simpler, easier to operate and, 
 because it has fewer joints, is more accurate, but it 
 is of course more limited with respect to the work 
 that it will do. The base of the radial drill has a 
 heavy floor plate under the arm for carrying the 
 work. These are often fitted with a removable 
 slotted table, or block, as shown, to accommodate 
 lighter work; if the squared surfaces are used, holes 
 may be drilled at right angles. Some radials are 
 fitted with blocks which may be tilted on bearings, 
 and which carry a round swiveling plate. This at- 
 tachment gives to the plain radial the flexibility of a 
 full-universal, but such a holding device will not 
 handle as large work as a full-universal drill. 
 
 The Column and Drivings Mechanism. — Of the sev- 
 eral types of columns the favorite is the double cir- 
 cular — a section is shown in Figure 83. The inner 
 column, a, is part of the fixed frame of the ma- 
 chine. It has a circular ball bearing, b, at the top, 
 and a large sliding bearing, c, at the bottom, which 
 carry the outer sleeve, d. The downward thrust of 
 the weight is carried on the ball bearing, e. The 
 large bearing, c, at the lower end of the outer sleeve, 
 d, is split, and is provided with a clamp operated by 
 the handle, b (Figures 82 and 84), which binds the 
 surfaces together, and clamps the outer sleeve and 
 arm in any position desired. 
 
 The radial arm slides on the smooth cylindrical 
 surface of the exterior column, or sleeve, and is pro- 
 vided with an elevating screw, c, shown in Figure 
 82, to raise and lower it. When the desired height 
 is reached, the operating screw is thrown out of gear 
 
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274 
 
 Tllb: MKCIIANK AL EQllPMEiNT 
 
 The plain radial is simpler, easier to operate and, 
 because it has fewer joints, is more aecurate, but it 
 is of course more limited with respect to the work 
 that it will do. The base of the radial drill has a 
 heavy floor plate under the arm for carrying the 
 work. Thrse are often fitted with a removable 
 slotted table, or block, as shown, to acconunodate 
 lighter work; if the scjuared surfaces are used, holes 
 may be drilled at right angles. Some radials are 
 titled with blocks which may be tilted on bearings, 
 and which vnvvy a round swiveling plate. This at- 
 tachment gives to the plain radial the flexibility of a 
 full-universal, but sucli a holding device will not 
 handle as larue work as a lull-universal drill. 
 
 The Column and Driving Mechanism. — Of the sev- 
 eral types of colunms the favorite is the double cir- 
 cular — a section is shown in Figure S.']. The inner 
 column, a, is part of the fixed frame of the ma- 
 chine. It has a circular ball bearing, b, at the top, 
 and a large sliding ])earing, c, at tlie bottom, w^liich 
 carrv the outer sleev(% d. The downwai'd thrust of 
 the weight is cariied o]i the ball bearing, e. The 
 large bearing, c, at tlie lower end of the outer sleeve, 
 d, is split, and is provided with a clamp operated by 
 the handle, b (Figures 82 and 84), wliich binds the 
 surfaces together, and clamps the outer sleeve and 
 arm in any position desired. 
 
 The radial arm slides on the smooth cylindrical 
 surface of the exterior column, or sleeve, aud is pro- 
 vided witli an elevating screw, c, shown in Figure 
 82, to raise and lower it. When the desired heiglit 
 is reached, the operating screw is thrown out of ge.')^' 
 
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276 
 
 THE MECHANICAL EQUIPMENT 
 
 and the arm is clamped to the sleeve by means of the 
 handles shown at the left. When the arm is thus 
 clamped to the sleeve, it becomes practically solid 
 with it. All the rotary motion takes place in the 
 bearings, b and c (Figure 83), at the top and bot- 
 tom of the column, while the vertical motion is cared 
 for solely by the joint, d (Figures 82 and 84), be- 
 tween the outer sleeve and arm. The radial arm is 
 designed to carry the heavy vertical thrust of the 
 tool. 
 
 On the side are slideways, e, which carry the drill 
 head. This head contains the mechanisms for re- 
 volving the spindle at the proper speed for the power 
 feed of the drill, for stopping them, and for the quick 
 return. The spindle, as in other drills, has a rotary 
 and a vertical motion. The spindle is graduated at 
 f, so that the depth of the hole may be known, and 
 some machines are arranged with a device that may 
 be set to disengage the feed at any depth desired. 
 
 The machine is driven by a single-speed pulley 
 through a change gear box at the base of the column, 
 thence through a pair of beveled gears upward 
 through a shaft, g, concentric with the column, to 
 gears located on the top. From these the power is 
 transmitted downward, outside, to the radial arm, 
 and outward to the mechanism located in the head. 
 All of the power feeds are also equipped with hand 
 control mechanisms. In some drills there is a floor 
 plate on each side of the column, so that the work 
 may be set up on one side while drilling operations 
 are going on at the other side, and often the table is 
 at the side, as at h in Figure 84. In the full-univer- 
 
 :N. 
 
27G 
 
 THE MECllAiMCAL EiiLir.ME.NT 
 
 us 
 
 ami tlie arm is ('lanii)ed to liic slccvo l>y means of tl 
 liaiulles siiown at the left. When tlie arm is tli 
 clamped to the sleeve, it heeomes practically solid 
 Avith it. All the rotary jiiotion takes place in tlie 
 hearings, h and c (Figure 8:j), at the top and bot- 
 
 tom of the colunm, while tl 
 
 le vertical motion is cared 
 
 for solely by the joint, d (Figures 8l> and 84), be- 
 tween the outer sleeve and arm. The radial arm is 
 designed to carry the heavy vertical thrust of the 
 tool. 
 
 On the side are slideways, e, which carry the drill 
 head. This head contains the mechanisms for re- 
 volving tlie spindle at the proper speed foi' the power 
 feed of the drill, for stopping tluvm, and for the quick 
 return. The spindle, as in other drills, has a rotary 
 and a vertical motion. The spindle is graduated at 
 f, so that tlie depth of the hoh^ may be known, and 
 some machines are arranged with a device that 
 
 be set to disengage the feed at 
 
 may 
 
 any depth desired. 
 
 The machine is driven by a single-spe(»d pulley 
 through a change gear box at {ho base of the cohnnn, 
 thence through a pair of beveled gi^ars u])wai'd 
 through a shaft, g, conc(Mitric Avith the column, to 
 gears located on tlie top. From these i]w power is 
 transmitted downward, outside, to tlie j'adial arm, 
 and outward to the mechanism located in the liead. 
 All of the power feeds are also erpiipped with ban.! 
 control mechanisms. In some di'ills tluM-e is a iloo] 
 plate on each side of the column, so that the wor' 
 may be set np on one side while drilling operation 
 are going on at the other side, and ot'tem the table i 
 at the side, as at h in Figure 84. In the full-unive' 
 
278 
 
 THE MECHANICAL EQUIPMENT 
 
 DRILLING MACHINERY 
 
 279 
 
 
 I 
 
 
 sal the driving motion is carried from the motor to 
 the drill through shafts located in the axis of the 
 swiveling joints, where the arm turns on its sup- 
 porting piece and the spindle head turns on the. 
 saddle. One of these, i, is clearly shown in Figure 
 84, coming out centrally along the arm. The spindle 
 at the center of the head, a, which the shaft, i, 
 drives, is hidden in the head. 
 
 Multiple-Spindle Drill.— Many classes of work call 
 for the drilling of a number of parallel holes, as, for 
 instance, the bolt holes in a flange. The multiple- 
 spindle drill has been developed to drill such holes 
 simultaneously. In this type, one of which is shown 
 in Figure 85, the frame is a box-like column with an 
 adjustable sliding table. Instead of the single spindle 
 with its drill socket there are a number of drill 
 sockets, a,a, carried in adjustable brackets, b,b, 
 mounted on the basket-like head at the top of the 
 machine. Each of these short spindles, with its 
 socket, is adjustable in and out and sidewise, and is 
 driven by a double-universal joint, c, from a corre- 
 sponding fixed upper shaft, c'; the lower ends of some 
 of these may be seen through the opening in the 
 head. 
 
 These upper shafts are fixed in position and ar- 
 ranged in a circle around a common driving pinion 
 operated from the large horizontal pulley on the top 
 of the machine. This pulley is driven by the half- 
 turn belt, which extends back, horizontally, over the 
 guide pulleys and down to the main driving pulley 
 below. When this pulley is rotated, it drives all of 
 the spindles at the same speed. Any number of the 
 
 spindles, from one to the full number, may be em- 
 ployed as desired; those not used are pushed off to 
 one side out of the way. 
 
 When, for instance, it is desired to drill an eight- 
 holed flange, eight of the spindles are arranged in a 
 circle at the desired radius, the drills are inserted, 
 and all the holes are drilled at the same time. In 
 the machine shown, the work is lifted against the 
 drills, as this arrangenient somewhat simplifies the 
 problem of driving. To permit this, the front of the 
 machine carries a saddle, d, which is adjusted to the 
 height desired. This saddle, d, in turn carries a slide, 
 e, which is operated by a rack and pinion through the 
 hand lever, f. The table, g, is bolted to the slide, e, 
 and moves up with the work as the lever is pushed 
 down; stops are provided to limit the motion when 
 desired. Other makers keep the table still, and bring 
 the head with all the drill spindles down toward the 
 work. 
 
 For certain classes of work, such as the drilling of 
 the holes in the flanges of cast-iron pipe, the ma- 
 chine is arranged in a horizontal position on a long 
 bed, somewhat like a lathe bed, and two drilling 
 heads, similar to the one shown, are arranged one 
 at each end. Each of these heads carries a set of 
 drilling spindles, and may be fed inward toward the 
 center, drilling all of the holes in both ends at the 
 same time. 
 
 Drilling Jigs. — ^Drilling is not a very accurate 
 operation, as there is a heavy reaction against the 
 end of the drill which tends always to force it out of 
 line, if conditions are not absolutely right. Further- 
 
 ^- TT 
 
280 
 
 THE MECHANICAL EQUIPMENT 
 
 DRILLING MACHINERY 
 
 281 
 
 1 1 
 
 more, the spindle frequently projei^ts some distance 
 from the bearings and the drill projects from the 
 end of the spindle, conditions increasing the tendency 
 to spring, or **run.'' In manufacturing practice, this 
 tendency is reduced and the accuracy of the drilling 
 process is greatly increased by the use of drilling 
 jigs. These may vary from a simple template, with 
 bushings in it, to complicated and ingenious devices.* 
 The function of the jig is to clamp the work firmly 
 in position, and to hold in the correct location a hard- 
 ened steel bushing the size of the hole to be drilled. 
 
 This bushing is usually located in a leaf, which is 
 turned down into position after the work is in place. 
 The hole in the bushing is rounded at the upper end 
 in order that the end of the drill may find its way 
 easily into the hole; the bushing should be set as 
 close as possible to the surface to be drilled. As the 
 bushing is hardened, the drill makes no impression 
 upon it, and the former acts as a guide to hold the 
 drill in the exact location desired. More than one 
 hole may be drilled in the jig, and these holes do not 
 necessarily have to be of the same size. Practically 
 all repetition work is drilled with the use of jigs, and 
 these may often be very elaborate. The Ford motor 
 cylinder base is drilled, in one of the operations, in a 
 jig in a special machine that has forty-five drills 
 operating simultaneously from four sides. 
 
 When a single hole is to be drilled in an ordinary 
 drill press, a prick punch mark is made on the center 
 of the hole, and a circle is scribed around it the size 
 
 *For a detailed description of drilling ji^s see "Tools and P.ii- 
 terns." by Albert A. Dowd. Factory Manaj^ement Course. 
 
 of the hole. The hole is just started with the conical 
 nose of the twist drill, and the drill is then with- 
 drawn. If it is found that the hole has started eccen- 
 trically, part of the material is chipped away on the 
 side toward the center and the drill is brought down 
 to the work again. As there the material is then less 
 on the side toward the center, it tends to run over 
 toward that side and to correct the eccentricity. This 
 process is repeated until the hole is started true. 
 This is skilled work and takes time — ^it is evident 
 why the use of drilling jigs, which obviate this diffi- 
 culty, is so general. 
 
 Work Commonly Done on Drill Press.— For very 
 accurate deep-hole drilling the relative rotation of the 
 work and the drill is reversed; the drill is held 
 stationary and the work is revolved. This arrange- 
 ment is less convenient, but gives a more accurate 
 result, and is the method used in drilling the long 
 accurate holes required in gun manufacture. At the 
 beginning of this chapter a number of operations were 
 mentioned, which are done on a drilling press in 
 addition to ordinary drilling. Countersinking and 
 counterboring are second operations which would 
 naturally be done on a drill at the same time the hole 
 is originally made. In these operations usually a 
 pilot bar is employed which enters the hole and 
 centers the cutting tool that does the enlarging. 
 Reaming is another second operation which naturally 
 is done on a drill press. For accurate work, the 
 reaming tool is connected loosely with the driving 
 spindle, so that the spindle merely rotates it, and in 
 no way controls its position. Thus the reamer is 
 
 
 
 ■: iiU 
 
 .1 
 
282 
 
 THE MECHANICAL EQUIPMENT 
 
 allowed to find its own center and do true work. 
 Tapping is one of the commonest operations per- 
 formed on the drill press, and most drills are provided 
 with attachments for this work. In most cases the 
 connection between the tap and the driving spindle 
 IS made through some form of friction drive which 
 transmits enough power to make the normal cut. If, 
 through carelessness or otherwise, the tap bottoms in 
 the hole, the friction drive slips and prevents the 
 breaking of the tap. 
 
 Heavy-duty drills are used for many operations thaf 
 mght be classed as boring work. By the use of pilot 
 bars and self-contained guiding devices in fixtures es- 
 pecially designed for the purpose, accurate work may 
 be done on drill presses to great advantage, and they 
 are increasingly used for this class of work. 
 
 CHAPTER XVII 
 PLANERS, SHAPERS, AND SLOTTERS 
 
 Definition of Field. — Flat surfaces may be finished 
 with a reciprocating cutting tool in a planer, shaper, 
 or slotting machine. While the fields of these ma- 
 chines overlap somewhat they are, in the main, 
 fairly well defined. The planer is used for long and 
 narrow faces, and for machining a number of pieces 
 that may be set up one behind the other, making, in 
 effect, one long surface. It is also used for surfaces that 
 are straight in one direction, but not necessarily flat. 
 One good example is the top of a lathe bed. Figure 
 47, in which the flat faces and V-ways may be finished 
 at one setting. The inside surface of the upright 
 guides in a drop hammer, shown in Figure 22, is 
 another example. Generally speaking, the planer is 
 used for large cuts on heavy pieces. The feeding 
 motion is given to the tool, and the cutting stroke 
 is made by moving the work past the tool. 
 
 The shaper is very convenient for special cuts on 
 small work, and is therefore especially suited to the 
 class of work done in the tool room. In the standard 
 type of shaper, the cutting motion is given to the table 
 and nearly all of the feeds are given to the table 
 carrying the work; the only feed given to the tool is a 
 hand feed downward. The slotting machine is used 
 
 283 
 
 ) 
 
 4 
 
 ( H 
 
284 
 
 THE MECHANICAL EQUIPMENT 
 
 i 
 
 ,r|. 
 
 
 on medium- and large-sized work, for edging cuts, 
 inside faces, and keyways that are to be at right 
 angles to some face which, usually, has been ma- 
 chined in a previous operation. In the slotter, as in 
 the shaper, the working motion is given to the cut- 
 ting tool, and the feed is taken by the table carrying 
 the work. The stroke of the cutting tool in the 
 shaper is horizontal, and in the slotting machine it is 
 vertical. 
 
 Early Types of Planers.^The first planer of any- 
 thing like modern design, of which we have record, 
 was built by Eichard Eoberts in England in 1817. 
 The machine is now in the South Kensington Museum 
 in London. Chisel and file marks on the bed and 
 ways indicate that it was itself made without the 
 use of a planer. The machine was small— it took in 
 work less than a foot wide; the table was operated 
 by hand by means of a chain drive. Within twenty 
 years, Joseph Clement built a planer that would 
 take in w^ork six feet square; it was for many years 
 known as *^The Great Planer." Work was brought 
 to it from all the districts about London, and it is 
 said to have earned for its owner $100 a day for many 
 years. This, by the way, was also a hand-operated 
 machine. 
 
 The Modem Planer.— Today the planer is found in 
 all shops that do medium- and large-sized work. It 
 uses the standard type of single-edged cutting tool, 
 and the tool equipment, unlike that of the milling 
 machine, is inexpensive and may be used for a great 
 many purposes. A disadvantage of the planer, as 
 well as of other machines with a reciprocating action, 
 
 PLANERS, SHAPERS, SLOTTERS 
 
 285 
 
 is that it has an idle return stroke. In the early 
 forms of planer the motion was derived from an 
 ordinary crank, and the return stroke was made at 
 the same speed as that of the working stroke. The 
 slow return stroke has long since been eliminated by 
 the use of some form of driving mechanism that 
 quickens the return, and so cuts down the idle time. 
 It would seem comparatively easy to make a planer 
 that would cut both ways — many have been tried. 
 For a number of very practical reasons, however, they 
 have never been successful. 
 
 The flexibility of the planer, and its adaptability to 
 various uses,- require a skilled mechanic to run it. 
 This principle is general throughout the whole field of 
 machine tools. Adaptability in a machine tool re- 
 quires a number of feeds and adjustments that call 
 for skill in setting. When a tool becomes a single- 
 purpose machine, the adjustments may be simplified 
 and reduced in number so that a comparatively un- 
 skilled attendant may operate it. 
 
 Standard Type of Planer. — The standard type of 
 planer is shown in Figure 86. It consists of a deep, 
 heavv bed which has accurately machined slidewavs 
 along the entire length of the top. A heavy platen, 
 which carries the "work to be machined, slides on 
 these ways. The bed is hollow and rectangular in 
 cross-section, is heavily ribbed, and carries the bear- 
 ings, and so on, for the mechanism that operates the 
 traverse of the bed. The platen must be long enough 
 to carry the longest piece that the planer will have 
 to handle, and the bed must be long enough to carry 
 the platen and to permit it a travel equal to the 
 
 I 
 
 1 
 
 f-m'} 
 
286 
 
 THE MECHANICAL EQUIPMENT 
 
 longest cut to be made. The length of the bed is, 
 therefore, a little less than the length of the platen, 
 plus that of the longest cut. Accordingly there are 
 about 20 inches of length of bed for each foot in the 
 length of the platen. 
 
 ^ The slideways on both bed and platen must be true, 
 since upon their correctness depends the accuracy of 
 the work. They should be liberal in area, and should 
 provide means for the take-up of wear. In Ameri- 
 can practice, this is usually done by making at least 
 one of the ways of V-section. In the smaller ma- 
 machines, both of the ways, a,a, may be of this section, 
 as in Figure 86 and 87. But when the platen has 
 considerable width, one of them is a plain flat surface, 
 and its only function is to give a vertical support to 
 the platen; the other is relied on to guide the platen 
 in a horizontal plane. The heavy planer shown in 
 Figure 90 has three ways— a V-way in the middle, and 
 a flat one on each side. The top of the platen is pro- 
 vided with T-slots and holes, which aid in clamping 
 down the work. On the under side of the platen is a 
 rack, which is driven either by a gear wheel or by an 
 endless screw. The platen has no motion other than 
 that of reciprocation along the ways on the bed. All 
 the feeding motions are given to tlie cutting tool. 
 
 Rack-and-Pinion Drive.— With the rack-and-pinion 
 drive, the power is usually transmitted to the table 
 through a train of gears housed in the bed from tight 
 and loose pulleys at the side of the machine, which 
 are clearly shown at b. Figure 86. Open and crossed 
 belts are used on these pulleys, one for the forward 
 cutting motion and the other for the quick return 
 
 FIGS. 86 AND 87. STANDARD PLANERS 
 The 20 X 17-inch type, above, is made by Whitcomb-BlalsdeU Ma- 
 chine Tool Co. The lower view shows a 42-inch Niles-Bement-Pond 
 
 planer. 287 
 
286 
 
 THE MECHANICAL EQUIPMENT 
 
 longest cut to be made. The lengtli of the bed is, 
 therefore, a little less than the length of the platen, 
 phis that of the longest cut. Accordingly there are 
 about 20 inches of length of bed for each foot in the 
 length of the platen. 
 
 ^ The slideways on both bed and platen must be true, 
 since upon their correctness depends tlip accuracy of 
 the \york. They should be liberal in area, and should 
 provide means for the take-up of wear. In Ameri- 
 can practice, this is usually done by making at least 
 one of the ways of V-section. In the smaller ma- 
 machines, both of the ways, a,a, may be of this section, 
 as in Figure 8() and 87. But when the platen has 
 considerable width, one of them is a plain flat surface, 
 and its only function is to give a vertical support to 
 the platen; the other is relied on to guide the platen 
 in a horizontal plane. The heavy planer shown in 
 Figure 90 has three ways— a V-way in the middle, and 
 a Hat one on each side. The top of the platen is pro- 
 vided with T-slots and holes, which aid in clampin.ii 
 down the work. On the under side ol* the platen is a 
 rack, which is driven either by a geai- wheel oi- by an 
 endless screw. The platen has no motion other than 
 that of reciprocation along the ways on the bed. All 
 the feeding motions are given to tlie cutting tool. 
 
 Rack-and-Pinion Drive.— With the rack-and-pinion 
 drive, the power is usually transmitted to the tabh 
 through a train of gears housed in the bed from tiglii 
 and loose pulleys at the side of the machine, whicli 
 are clearly shown at b, Figure 86. Open and crossed 
 belts are used on these pulleys, one for the forwiU'd 
 cutting motion and the other for the quick retui' 
 
 I 
 
 VUiS. 8() AND 87. STANDARD PLANF.KS 
 llu' 20x 17-iiK-li lypo. above, is niado by Wbitonnb-Iilaisdt'll Ma- 
 ' iiiiu' Tdul Cit. 'riic lower view sbows a 42-iiu-b Nnt'.s-lJeiaeiit-Pon<i 
 
 planer. 2S7 
 
(I 
 
 it 
 
 I. 
 
 w 
 
 III 
 
 II 
 
 288 
 
 THE MECHANICAL EQUIPMENT 
 
 motion. They are driven from a countershaft above, 
 and are shifted backward and forward from the tight 
 pulleys to the loose pulley. Various forms of shift- 
 ing mechanism have been developed by the different 
 tool-builders for this purpose. The motion required 
 is not so simple as it might seem, for two belts can not 
 be on the loose pulley at the same time; hence, one 
 must be shifted somewhat ahead of the other. 
 
 The shifting of the belts, with the resulting re- 
 versal of the motion of the platen, or table, is con- 
 trolled from a tripping device located at the side of 
 the bed. This usually takes the form of a lever, c, 
 which may be thrown by hand when desired, but 
 which, in the ordinary operation of the machine, is 
 thrown by two adjustable stops, d,d', located on the 
 side of the platen. These may be moved along the 
 side and clamped in any position required. The stop, 
 d, at the front end of the platen, strikes the lever, c, 
 at the end of the cutting stroke, throws out the main 
 forward drive, and throws in the quick return. 
 When the plate has traveled forward to the point 
 desired, the stop, d', reverses the drive and throws out 
 the return motion, and the next cutting stroke be- 
 gins. With the stops in the position shown, the 
 platen will make a comparatively short stroke near 
 the middle of its possible travel. If the stops were 
 both well forward to the left, the bed would make a 
 short stroke with the front end of the table under the 
 tool; with the stop, d, at the front end, and d' well to 
 the rear, the platen would make a full stroke and the 
 tool would make a cut for the entire length of the 
 capacity of the machine. 
 
 PLANERS, SHAPERS, BLOTTERS 
 
 289 
 
 The Uprights. — Either cast solid or bolted firmly 
 to the sides of the bed, are the two uprights that 
 carry the cross rail and the tool heads. These up- 
 rights are usually two in number, one on each side, 
 and the tables passes between them. The bracing 
 of the uprights is usually parabolic in form — as in 
 Figures 86 to 88 — the correct design for maximum 
 strength to withstand the main thrust of the tool as 
 the work comes forward on the cutting stroke. The 
 brace across the top helps the uprights to withstand 
 the side pressure, which is also present, and which 
 may be very considerable. 
 
 On the front of the uprights are machined slide- 
 
 PIG. 88. 24 BY 24 BY 24-INCH CRANK PLANER 
 Cincinnati Shaper Co. 
 
 
288 
 
 TIIH MKCJIAXICAL KQClPAfEXT 
 
 PLANERS. SI!AIM:RS, SLOTTERS 
 
 28!) 
 
 motion. Tliey ai'o driven from a eonntci'sliaft above, 
 and avo sliil'tcd backward and forward from tlie tight 
 pulleys to the loose pulley. \'ai*ious forms of shift- 
 ing meehanism have been developed by the different 
 tool-l)uilders for this ])urpose. The motion required 
 is not so simple as it might sec^n, for two belts ean not 
 be on th(» loose pulley at the same time; hence, one 
 nuist be shifted sonu*what ahead of the other. 
 
 The shifting of the belts, with the resulting re- 
 versal of the motion of the platen, or table, is eon- 
 trolled from a tripping device located at the side of 
 the bed. This usually takes the form of a lever, c, 
 which may be thrown bv hand when desired, but 
 which, in the ordinai'y operation of the machine, is 
 thrown by two adjustable stops, (U\\ located on the 
 side of the platen. These mav be moved alonii- the 
 side and clamped in any position re({uired. The sto|), 
 d, at the front end of the platen, strikes the lever, c, 
 at the end of the cutting stroke, throws out the nuiiii 
 forward drive, and throws in the (piick return. 
 When the plate has traveled forward to the point 
 desired, the stof), d', I'everses the drivi* and throws out 
 the retui'u motion, and the next cutting stroke be 
 gins. With the stops in the position shown, the 
 platen will nudvc a comparatively short stroke near 
 the middle of its possible travel. If the stops were 
 both well forward to the left, the bed would nud;e ;• 
 short stroke with the fi'ont end of the table undcM* the 
 tool; with the stoj), d, at the front end, and d' well to 
 the rear, the platen would make a full stroke and tho 
 tool would make a cut for the entire length of tin 
 capacity of the machine. 
 
 The Uprignts. — Either cast solid or l)olted iirmly 
 to tli(^ sides of the bed, are the two u[)rights that 
 cari'y the cross rail and the tool heads. Tli(\<e up- 
 rights are usually two in number, one on each side, 
 and the tables passes belween them. The l)i*acing 
 of the uprights is usually j)arabolic in form — as iu 
 Figures 8(j to 88 — the cori'ect design for maxinmm 
 strength to withstand the nuiin thrust of the tool as 
 the work comes forward on the cutting stroke. The 
 brace across the to}) helps the u})rights to withstand 
 llie side pressure, which is also present, and ^vhich 
 mav be vei'v considerable. 
 
 On the front of the upi-ights ai"e machined slide- 
 
 FiG. 88. 24 BV 24 BY 24-iNrH crank planer 
 CiiK'imuni Sluipcr (V>. 
 
ii» 
 
 290 
 
 THE MECHANICAL EQUIPMENT 
 
 PLANERS, SHAPERS, SLOTTERS 
 
 291 
 
 Dl 
 
 i 
 
 il 
 
 ll^ 
 
 ways, to which the cross rail is gibbed; elevating 
 feed screws in the slideways operate the two ends 
 of the cross rail up and down. The elevating screws 
 are connected across by a common operating shaft, e, 
 to operate in unison and insure parallelism in the 
 motion of the two ends of the rail. On the rail are 
 mounted one or more saddles, which carry the tool 
 heads. 
 
 In small planers there will be one of these heads, 
 as shown in Figures 86 and 88, but on all medium- 
 and large-sized planers there are two heads. When 
 there are two heads, the cross rail is made long 
 enough to allow the full motion across the platen of 
 either head. The tool head, in all cases, has a sliding 
 member, f, which has a cross feed, and which carries 
 a tool-holder. This head, with its feeding screw, 
 may be indexed at any angle, and the cutting tool 
 may be fed downward on that angle when desired. 
 The cutting tool is carried by a clamp, g, shown on a 
 leaf, or clapper, h, which is pivoted at its upper end. 
 The purpose of the pivot is to allow the tool to lift 
 clear of the work and to ride upon it during the re- 
 turn stroke. When the work has run past the tool on 
 the return stroke, the leaf with the cutting tool drops 
 back into place and is ready for the next cut. 
 
 Feed Motions. — On all planers of any considerable 
 size, the various feed motions are power-driven as 
 well as hand-operated. These motions are as follows: 
 First, a downward feed of the cutting tool in the 
 head, which as said before, may be set to operate at 
 an odd angle; second, each of the heads has an inde- 
 pendent traverse feed along the cross rail; and, third. 
 
 the cross rail as a whole has a feed up and down on the 
 uprights. The various power feeds are arranged to 
 take place at the beginning of the return stroke, and 
 the tool is stationary during the working stroke. The 
 mechanism controlling these feeds is operated from 
 the vertical rack, i, on the outside of the right-hand 
 upright. 
 
 Since the axes of most of the shafts in the main 
 drive are at right angles to the motion of the table, 
 the driving pulleys are generally arranged at right 
 angles to the machine, as shown in Figure 86. This 
 plan usually necessitates setting the length of the 
 planer across the shop, in order to place the driving 
 pulleys parallel to the line shafting, a position which 
 may be inconvenient and obstruct the floor. To avoid 
 this the axis of the driving pulleys may be set parallel 
 to the machine, as shown in Figure 87, an arrangement 
 which permits long planer beds to be placed length- 
 wise of the shop. 
 
 The spiral-gear drive, introduced by William Sel- 
 lers, of Philadelphia, does away with most of the 
 reducing gears necessary in a spur-gear drive. The 
 rack underneath the platen is operated by a worm, 
 or ** endless screw," carried on the end of a shaft; 
 this shaft extends outward at an angle to the side 
 of the main bed, where it is driven by bevel gears 
 from pulleys, which may stand either at right angles 
 or parallel to the bed. It is used on the larger sizes 
 of planers, and has the advantage of great strength, 
 simplicity, and smoothness of action. 
 
 In recent years, belts have been done away with 
 entirely on many planers and the machine is driven 
 
 * I 
 
!(; 
 
 I" 1. 
 
 
 292 
 
 THE MECHANICAL EQUIPMENT 
 
 by a reversing electric motor directly coupled to the 
 driving shaft in the bed of the planer, as in Figure 
 89. The reciprocation of the table is accomplished 
 by a reversal of the current in the motor, controlled 
 by stops on the side of the bed similar to those de- 
 scribed in connection with Figure 86. 
 
 Special Types of Planers.— Small planers may be 
 operated by a Whitworth quick-return motion similar 
 to that shown in Figure 96. These are known as crank 
 planers. The stroke is rapid and smooth in action, and 
 may be varied in length and position as in the case of 
 the belt-driven planer. This type of planer is always 
 of comparatively short stroke. The one shown in Fig- 
 ure 88 has a stroke of 24 inches. 
 
 Figure 89 shows a modification of the standard type 
 of planer, known as the open-side planer. One of 
 the housings is eliminated and the cross-rail is 
 carried on a heavy extension arm or knee that 
 reaches across the table from a heavy upright. The 
 upright has a box section capable of withstanding the 
 torsion produced by the pressure on the tool. The 
 ordinary type of planer is limited to work that can 
 pass between the uprights. In this type, work may 
 be clamped on the table, which extends over to one 
 side, and the machine is therefore capable of planing 
 work that is wider than the table. Large planers, of 
 both the standard and the open-side type, may' be 
 equipped with tool heads on the uprights as well as 
 on the cross rails, for machining the sides of a cast- 
 ing while the rail heads are working on the top. 
 One of these side heads is shown in Figure 89. Open- 
 side planers are sometimes provided with an auxiliary 
 
 PLANERS, SHAPERS, BLOTTERS 
 
 293 
 
 FIG. 89. OPEN SIDE PLANER 
 Cleveland Planer Works. 
 
 upright, which may be bolted on the other side of the 
 frame to support a fourth tool head. 
 
 Figure 90 shows one of the largest planers ever built. 
 This huge machine is 60 feet long and weighs 845,000 
 pounds. The table is 32 feet long, 14 feet wide, slides 
 on three ways— the center, a, is a V-way and the two 
 outside ones, b,b, are flat— and is driven with two steel 
 **buir' wheels running in racks, c,c, 15 inches wide. 
 The main drive is operated by a 100-horsepower motor, 
 and the various feeds and other motions are operated 
 
 i i 
 
 **t"l;l|> 
 
XiO 
 
 
 TIIK Mi:( HANK AL Kl^UIPMKNT 
 
 PLAMvRS. SlIAPEHS. SLOTTHRS 
 
 
 by a reversing cloclric iriolor directly coupUhI to tlie 
 driving slial't in tlh' hod of the planer, as in figure 
 89. The reciprocation of llie table is accomplished 
 hy a reversal of the* current in the motor, controlled 
 ij stops on the side of the hed similar to those de- 
 schl)ed in connection with Figure SG. 
 
 Special Types of Planers.— Small planers mixy he 
 operated hy a Whitworth <piick-return motion similar 
 to that shown in Figure !)(i. Th(\^e are known as crank 
 planers. Tiie stroke is rapid and smooth in action, and 
 nuiy he varied in length an<l position as in the case of 
 the helt-driven planer. 1'his type of i)laner is always 
 of comparatively short stroke. The one shown in Fig- 
 ure 8S has a stroke of 24 inches. 
 
 Figure 89 shows a modilication of tlie stanchird type 
 of planer, known as the ojjen-side planer. One of 
 the housings is eliminated and the cross-rail is 
 carried on a heavy extension aim or knee that 
 reaches across the table from a heavy U})right. The 
 upright has a box section capable of withstanding the 
 torsion produced by the pressure on the tool. The 
 ordinary type of planer is limited to work that can 
 pass between the uprights. In this type, work may 
 be clamped on the table, which extends over to one 
 side, and the machine is therefoi'e capable of planing 
 work that is wider than the tabl(\ T^arge planers, ol 
 both the standard and the open-side type, may be 
 equipped with tool heads on tlu^ uprights as well a^ 
 on the cross rails, for machining the sides of a cast 
 ing wliile the rail heads are working on the to). 
 One of these side heads is shown in Figure 89. Opei, 
 side planers are sometimes piovided with an auxiliai v 
 
 FIG. SO. OPEN Sn^E PLANER 
 Clevolaml IMnnor AVorks. 
 
 upright, Avliicli may be bolted on tlie otluu' side of the 
 frame to support a fourth tool head. 
 
 Figure 90 shows one of the largest planers ever built. 
 Tlus"huge machine is (iO feet long and weighs 84r),0()() 
 l.ounds.^ The table is :V1 U^'i long, U f(H^t wide, slides 
 nu three ways— the center, a, is a V-way and the two 
 outside ones", b,b, are (lat— and is driven with two steel 
 •'buir' wheels running in racks, c,c, IT) inches wide. 
 The main drive is oju'rated ])y a lOO-horsei.ower motor, 
 ;md the various feeds and otlier motions are operated 
 
.11 
 
 I PI 
 
 294 
 
 THE MECHANICAL EQUIPMENT 
 
 • 
 
 by independent motors, so that the total motor capacity 
 is 2071/2 horsepower. The stroke of the table is 30 
 feet, the width between uprights 14 feet 4 inches, and 
 the maximum height from the top of the table to the 
 under side of the cross rail is 12 feet 3 inches. In 
 the main, the machine is of the usual planer type, but 
 it has, in addition, several unusual features. Slotter 
 bars, d, with an 8-foot stroke, are incorporated in the 
 rail heads, and one of these heads is provided with a 
 power cross-motion for transverse planing. The ma- 
 chine is therefore capable of planing in three direc- 
 tions with one setting of the work upon the table. 
 
 A special type of large planer, shown in Figure 91, 
 is used in the Midvale Steel Works for planing armor 
 plates. Such work is so heavy that it is easier to 
 move the machine with the cutting tool over the work 
 than to move the work under the tool. The plate is 
 set on the slotted bed between the horizontal rails, 
 and the cutting tool, with the head and two uprights, 
 is moved across the work. The motion of the two 
 uprights is derived from heavy screws, which are ar- 
 ranged to operate in unison to insure parellelism of 
 motion. In this case, the motions of the cutting 
 stroke and of the various feeds are given to the 
 cutting tool, and the work remains stationary. 
 
 Another screw-driven planer, shown in Figure 92, 
 consists of a large vertical head, a, which has a hori- 
 zontal motion along the lower bed. This head has 
 vertical guideways and a heavy saddle, b, which 
 carries the cutting tool. This saddle has a screw- 
 operated vertical motion, which may be used for ver- 
 tical cuts, the main head or upright, a, being clamped 
 
 PIG. 90. 12 BY 14 BY 30-FOOT PLANER 
 
 FIG. 91. ARMOR PLATE PLANER 
 
 JJIles-Bement-Pond Co, 
 
 295 
 
 
294: 
 
 THE MECHANICAL EQUIPMENT 
 
 by indepi^ndont motors, so tluit the total motor capacity 
 is 207 y^ horsepower. The stroke of the table is 30 
 feet, the width between uprights 14 feet 4 inches, and 
 the maxiimnn height from the top of the table to the 
 under side of the cross rail is 12 feet 3 inches. In 
 the main, the machine is of the usual planer type, but 
 it has, in addition, several unusual features. Slotter 
 bars, d, with an 8-foot stroke, are incorporated in the 
 rail heads, and one of these heads is provided with a 
 pow(M' cross-motion for transverse planing. The nia- 
 ciiine is therefore capable of planing in three direc- 
 tions with one setting of the work upon the table. 
 
 A special type of large planer, shown in Figure 91, 
 is used in the Midvale Steel Works for planing armor 
 plates. Such work is so heavy that it is easier to 
 move the machine with the cutting tool over the work 
 than to move the work under the tool. The plate i> 
 set on the slotted bed between the horizontal rails, 
 and the cutting tool, with the head and two uprights, 
 is moved across the work. The motion of the two 
 uprights is derived from heavy screws, which are ar- 
 ranged to operate in unison to insure parellelism of 
 motion. In this case, the motions of the cutting 
 stroke and of the various feeds are given to the 
 cutting tool, and the work remains stationary. 
 
 Another screw-driv(^n planer, shown in Figure 92, 
 consists of a large vertical head, a, which has a hori- 
 zontal motion along the lower bed. This head ha> 
 vertical guideways and a heavy saddle, b, wliicli 
 carries the cutting tool. This saddle has a screw 
 operated vertical motion, which nuiy be used for ver 
 tical cuts, the main head or upright, a, Ix^ng clamp< - 
 
 FIG. 90. 12 13Y 14 BY oO-FOOT PLANER 
 
 FIG. 91. ARMOR PLATE PLANER 
 
 Niles-noTnfnt-ron<l Co. 
 
 29.1 
 
'' fill 
 
 i 
 
 II 
 
 f 
 
 296 
 
 THE MECHANICAL EQUIPMENT 
 
 FIG. 92. SCREW-DRIVEN PLANER FOR WORK IN TWO DIRECTIONS 
 
 Niles-Bement-Pond Co. 
 
 to the bed; or, the saddle may be clamped to the up- 
 right and the head, a, moved sidewise to plane hori- 
 zontal cuts. With this type of machine it is possible to 
 make cuts at right angles to each other on the end 
 of a heavy piece at a single setting. The machine is 
 driven by a reversing motor. 
 
 Skill and judgment are required in clamping work 
 to a planer table, for the work must not slip, must 
 not spring in any direction under any of the cuts, 
 and yet, however tight the clamping, it must not 
 distort the piece in any way. Long-pitch, helical 
 grooves may be cut on a planer by mounting the 
 
 PLANERS, SHAPERS, SLOTTERS 
 
 297 
 
 piece on centers carried on the table, and giving to 
 the work a rotary feed that is directly proportional 
 to the longitudinal travel. Occasionally long, curved 
 surfaces are planed by mounting on the table beside 
 the work a ** former," which causes the cutting tool 
 to rise and fall as the table passes under it. The 
 combination of the two motions generates an irregular 
 cut which follows the curve of the *' former." Fre- 
 quently a number of cutting tools are set one behind 
 the other in the tool-holder, to make successive cuts 
 at the same pass from the rough to the finished sur- 
 face. Other points in regard to the setting of planer 
 tools have been mentioned in the chapter on ^'Cutting 
 Tools." 
 
 The Shaper and Its Work.— The shaper was in- 
 vented by James Nasmyth, and was for many years 
 known among the English mechanics as *' Nasmyth 's 
 Steel Arm," It was improved by Whitworth, who 
 introduced the quick-return motion, and gradually 
 took the form that is known today. Figure 93 shows 
 a modern shaper. It consists essentially of a stiff, 
 box-like frame carrying a vise or jaw mounted in 
 front on a slotted table, or support, and capable of 
 vertical and transverse motion under hand or power 
 feed. The top of the frame is gibbed to receive a 
 reciprocating ram, a, carrying on the front end a 
 tool head which may be set at any angle and which 
 has an independent hand-operated cross feed, b. 
 
 On the slide of this tool head is a tool post, and 
 clapper box, c, similar to those used on the planer. 
 The work is clamped in the jaws below, and the tool 
 is reciprocated across the work. Except for the hand 
 
 Mi 
 
 i \ 
 
 n 
 
29(> 
 
 THE MECIIAMCAL KQUIPMENT 
 
 PLANERS, SllAPKKS, SEOTTKRS 
 
 lil)* 
 
 FIG. 92. SCRE\V-DKI\ i:X PLANER FOR WORK IN TWO DIRECTIONS 
 
 Niles-lienient-Poinl ( 'o. 
 
 to tlic I)(m1; or, {\w saddle may hu clainjx'd to the up- 
 riglit and the li<'ad, a, moved siilcwisc to j)laiie hori- 
 zontal cuts. Witli this type of iiiaelniic it is possihh' to 
 make cuts at right ani»Ies to eacli othei- on the end 
 of a lieavy piece at a .single setting. The maehine is 
 drixcn hy a I'eversing motor. 
 
 Skill and Jndgment are required in elamping work 
 to a phiner table, for the work nmst not slip, must 
 not spring in any direction under anv of the cuts, 
 and yet, however tight the elamping, it must nol 
 distort the piece in any way. Long-pitch, helical 
 grooves may he cut on a ph-iner hy mounliim- thr 
 
 piece on centers carticd on tlie ta]>K', and giving to 
 the work a rotary I'eed that is directly pi'oporlional 
 to the longitudinal travel. Occasionally long, curved 
 surfaces are planed hy mounting on the table beside 
 the work a '^former," which causes the cutting tool 
 to rise and fall as the table passes under it. The 
 combiiuition of the two motions generates an irregular 
 cut which follows the curve of the 'former." Fre- 
 quently a number of cutting tools are set one Ijehind 
 the other in the tool-holder, to make successive cuts 
 at the same pass from the rough to the finished sur- 
 face. Other i)oints in regard to the setting of planer 
 tools have been mentioned in the chapter on "'Cutting 
 Tools.'' 
 
 The Shaper and Its Work.— The shaper was in- 
 vented bv dames Xasmvth, and was for many years 
 known among the English mechanics as ^^Xasmyth's 
 Steel Arm.'' It was impi'oved by Whitworth, who 
 introduced the quick-return motion, and gradually 
 took the form that is known today. Figure 93 shows 
 a modern shaper. It consists essentially of a stiff, 
 box-like frame carrying a vise or jaw mounted in 
 front on a slotted table, oi- su])port, and capal)le of 
 vei-tical and transverse motion under hand or power 
 IVed. The top of the frami' is gibbed to receive a 
 reciprocating ram, a, carrying on the front end a 
 tool head which mav be set at anv angle and which 
 has an itidependent hand-operated cross feed, b. 
 
 (hi the slide of this tool head is a tool post, and 
 clapper box, c, similar to those used on the planer. 
 The work is clampcnl in the jaws below, and the tool 
 is I'ecipi'ocated across the work. Exce])t for tlu' hand 
 
 V( 
 
 \n 
 
 \ .1 
 
298 
 
 THE MECHANICAL EQUIPMENT 
 
 FIG. 93. STANDARD SHAPER 
 Gould & Eberhardt. 
 
 feed on the head, all the feeds are given to the work- 
 holder. In the larger sizes of shaper, provision is 
 made for an adjustable support, d, which extends 
 from the table to the base, to preclude springing on 
 heavy cuts. There are various types of shaper drives, 
 all of them arranged to give a slow, powerful motion 
 on the forward stroke and a quick return. The stroke 
 may be varied from zero up to the full capacity of 
 the machine, and the ram may be set forward or 
 
 PLANERS, SHAPERS, SLOTTERS 
 
 299 
 
 backward with reference to the frame, so that short 
 cuts may be made on different parts of a piece. The 
 machine shown has the standard equipment, but spe- 
 cial attachments are used, such as tilting and swiveling 
 tables, which permit the shaping of a curved surface, 
 and index centers, somewhat similar to those that will 
 be described in connection with universal milling ma- 
 chines, which permit the cutting of long spirals. The 
 shaper is a good tool-room machine, and is much 
 better for small work than the planer. The type of 
 drive used gives a more accurate control of the 
 length of stroke than can be given by the shifting 
 belts used on a planer. For accurate special work, 
 such as die-sinking, it is an advantage to have the 
 work stationary, in order that the action of the 
 cutting tool, when machining to a line, may be 
 closely watched. 
 
 Construction and Operation of the Shaper. — ^In 
 most shapers, the tool cuts on the stroke toward the 
 operator. In some types, however, this is reversed 
 and the cutting is done on the inward stroke. The 
 latter types are known as draw-cut shapers. An ad- 
 vantage that is claimed for them is the fact that the 
 table and its connections are under compression 
 rather than under tension. This is somewhat offset 
 by the fact that the reverse is true of the joints in 
 the tool head. Ordinarily the ram is operated by a 
 Whitworth quick-return motion, as shown in Figure 
 95 and 96, or by a ** pillar drive," as illustrated in 
 P^igure 94. The latter method is the more" widely used 
 today. 
 
 A vertical lever, or pillar, a, Figure 94, is pivoted 
 
298 
 
 THK MHciJAMCAI. KQIIPMKXT 
 
 FIG. 98. STAXDAKI) .SIIAPKR 
 (f<nil<l & Khorhardt. 
 
 feed on the head, all the feeds are given to the work- 
 holder. In the larger sizes of shaper, provision is 
 made for an adjustable support, d, which extends 
 from the table to the base, to preclude springing oti 
 heavy cuts. There are various types of shaper di'ives, 
 all of them arranged to give a slow, powerful motion 
 on the forward stroke and a quick return. The stroke 
 may be varied from zero up to the full capacity of 
 tlie machine, and the ram may be set forward or 
 
 PLANHKs. siiajm^:hs, SL()TTP:RS 
 
 299 
 
 backwai'd with reference to the frame, so that short 
 cuts may l)e made on different parts of a piece. The 
 machine shown has the standard equipment, l)ut spe- 
 cial attachments are used, such as tilting and swivelling 
 tables, which pei'uiit the shaping of a curved surface, 
 and index centei's, somewhat similar to those that will 
 be described in connection with universal milling ma- 
 chines, which permit the cutting of long spirals. The 
 shaper is a good tool-room machine, and is much 
 better for small work than the planer. The type of 
 drive used gives a more accurate control of the 
 length of stroke than can be given by the shifting 
 belts used on a planer. For accurate special work, 
 such as die-sinking, it is an advantage to have the 
 work stationarv, in order that the action of the 
 cutting tool, when machining to a line, may be 
 closelv watched. 
 
 « 
 
 Construction and Operation of the Shaper. — In 
 
 most shapers, the tool cuts on the stroke toward the 
 operator. In some types, however, this is reversed 
 and the cutting is done on the inward stroke. The 
 latter types are known as draw-cut shapers. x\n ad- 
 vantage that is claimed for them is the fact that the 
 tal)le and its connections are under compression 
 inther than under tension. This is somewhat offset 
 l)y the fact that the reverse is ti'ue of the joints in 
 the tool head. Ordinarily the i-am is operated by a 
 Whitworth quick-return motion, as shown in Figure 
 !).") and !)(), or by a "pillar drive,'' as illustrated in 
 FiiAure 94. The iattei* method is the more widelv used 
 todav. 
 
 A vertical lever, or pillar, a. Figure 94, is piloted 
 

 J 
 
 W) 
 
 i 
 
 PLANERS, SHAPERS, SLOTTERS 
 
 301 
 
 at its lower end, b, to the frame near the floor. The 
 upper end is connected with the ram. This lever os- 
 cillates backward and forward about its lower end 
 under the influence of a crank pin, c, and sliding 
 block, d, which rotate about the shaft, e. When the 
 crank pin and the block are turning forward on the 
 upper part of their rotation, they are close to the ram, 
 where they give the slowest movement and exert the 
 greatest power. On the return stroke, they are in the 
 lower half of the rotation and closest to the fulcrum, 
 b, of the pillar, and consequently give a quick return 
 to the ram above. The stroke length is varied by 
 turning the shaft, f, which screws the block, d, and 
 the crank pin, c, in toward the center, thus reducing 
 the crank throw. The position of the ram is changed 
 by loosening the clamp, g, and turning the screw, h, 
 by means of the hand-wheel, i, which moves the ram 
 forward or backward with reference to the lever, a. 
 
 The length of the ram is usually a little more than 
 double the nominal size of the machine; the length of 
 the guides on the top of the column in which it slides, 
 is about 1% times the length of the stroke of the ma- 
 chine. Theoretically, for the most even wear these 
 should be of the same length, but practically this con- 
 dition is not necessary, since short-stroke work is 
 kept back on the table as near the column as pos- 
 sible. The cross-section of the ram is substantially 
 that of an inverted letter U, as shown at j. Figure 
 94, with the sliding surfaces along the outer edge of 
 the bottom. The cross rail slides directly on the 
 front face of the upright; the table slides horizontally 
 on the cross rail, and is provided with a transverse 
 
» 
 
 I 
 
 
 302 
 
 THE MECHANICAL EQUIPMENT 
 
 power- and hand-operated feed. The rod that oper- 
 ates the power feeds is seen at e, Figure 93, on the 
 side of the frame. 
 
 The Traversing Shaper.— Figure 95 shows a trav- 
 ersing shaper, a type of machine useful in finishing 
 small spots on large, long, and unwieldy pieces. These 
 may be clamped to the face along the front of the 
 main frame in place of the tables shown in the illus- 
 tration. The rams, a, of which there are several, 
 are carried in sliding heads, b, which move along the 
 guide on top of the frame; each ram is driven by a 
 Whitworth quick-return motion, shown in Figure 96. 
 The large gears, c, c. Figures 95 and 96, carrying the 
 crank, are driven from small pinions, d, d, on a hori- 
 zontal shaft just behind the upper corner of the 
 frame. These pinions traverse sidewise with the slid- 
 ing head, or carriage, and are eyed to this shaft with a 
 sliding key. The shaft is therefore able to drive the 
 mechanism of the carriage at any position along the 
 top. 
 
 Figure 96 shows a detail of the driving mechanism. 
 The large gear, c, which rotates uniformly, turns in 
 the head, b, on the center, e. The slotted crank, f, 
 which drives the ram through the pin, g, turns about 
 the center, h, which is also fixed with respect to the 
 head, b. The crank, f, is driven by a pin, i, fixed in 
 the gear, c. Since this pin, i, turns about e, its path 
 is circular, but it is eccentric to the center, h, of the 
 crank. That portion of the motion of the pin, i, 
 which is above the horizontal line through h, causes 
 the return motion, indicated in Figure 96 as the **arc 
 of return." The motion below this horizontal line, 
 
 ^ 
 
 »i 
 
 » 
 
 I 
 
 li 
 
302 
 
 THE MECHANICAL EQUIPMENT 
 
 power- and hand-operated feed. The rod that oper- 
 ates tlie power feeds is seen at e, Figure 93, on thv 
 side of the frame. 
 
 The Traversing Shaper.— Figure 9r) sliows a trav- 
 ersing shaper, a type of machine useful in iinishing 
 small spots on large, long, and unwieldy pieces. These 
 may be clamped to the face along the front of the 
 main frame in place of the tables shown in the illus- 
 tration. The rams, a, of which there are several, 
 are carried in sliding heads, 1), which move along the 
 guide on top of the frame; each ram is driven by a 
 AVhitworth quick-return motion, shown in Figure 9(). 
 The large gears, c, c, Figures 95 and 9(i, carrving th(^ 
 crank, are driven from small pinions, d, d, on a hori- 
 zontal shaft just behind the upper corner of the 
 frame. These pinions traverse sidewise with the slid- 
 ing head, or carriage, and are eyed to this shaft with a 
 sliding key. The shaft is therefore able to drive the 
 mechanism of the carriage at any position along the 
 top. 
 
 P'igure 96 sIioavs a detail of the driving mechanism. 
 The large gear, c, which rotates uniformly, turns in 
 the head, b, on the center, e. The slotted crank, f, 
 which drives the ram through the pin, g, turns about 
 the center, h, which is also fixed with respect to the 
 head, b. The crank, f, is driven ])y a i)in, i, iixed in 
 the gear, c. Since this pin, i, turns about e, its path 
 is circular, but it is eccentric to the center, h, of tlir 
 crank. That portion of the motion of the pin, i, 
 which is above the horizontal line through h, cause.< 
 the return motion, indicated in Figure 9() as the *'ar'' 
 of return." The motion below this horizontal line. 
 
 D5 
 
 m 
 
 
 gi 
 
 
 CO 
 
 © 
 
 00 
 
304 
 
 THE MECHANICAL EQUIPMENT 
 
 PLANERS, SHAPERS, BLOTTERS 
 
 305 
 
 ^ 
 
 FIG. 96. WHITWORTH QUICK-RETURN MOTION 
 
 indicated as **arc of cut,'' causes the forward mo- 
 tion. Since the pin is moving at a constant rate, and 
 the arc of return is much shorter than the arc of cut, 
 the return motion is made in much less time than the 
 forward motion. If the pin, g, is out at the end of 
 the crank-slot, as at g' in Figure 95, the ram is tak- 
 ing a full stroke. If it is in close to the center, the ram 
 is taking a short one. 
 
 The base in Figure 95 is shown equipped with 
 tables; these convert the machine into two standard 
 shapers, which may be used for small work. On the 
 floor is an index center which may be set on the table 
 for planing circular work along a line parallel to its 
 axis. The table to the right carries on its upper face 
 a swiveling vise, which may be set at any angle in the 
 
 plane of the face to which it is clamped. Since the 
 tables may be swiveled in a vertical plane, the com- 
 bination of the. two circular motions enables the shaper 
 to plane at any angle. 
 
 The Vertical Shaper, or Blotter. — The slotter, or 
 vertical shaper. Figure 97, is, as the latter name im- 
 plies, a shaper in which the motion of the ram is 
 vertical, instead of horizontal. On these machines the 
 work is carried on a slotted, circular table, a, which 
 is provided with a rotary feed operated by hand or 
 machine power. The table, and its base, b, have a 
 transverse hand or power feed on a saddle, c, which, 
 in turn, has a feed in and out on the main base of the 
 machine. This combination of feeds permits the 
 shaper to cut faces at right angles in two directions, 
 and also to plane circular faces. The last is particu- 
 larly useful in machining curved surfaces that have 
 a projection which precludes their being turned on 
 a lathe. 
 
 The ram in this machine can be tilted outward for 
 any angle from zero to 5 degrees, an advantage that 
 is of particular value in the cutting of tapered key- 
 ways. Like the shaper, the ram is driven by some 
 form of quick-return motion. Any part may be 
 clamped rigidly to its neighbor, and, by a combina- 
 tion of two of the motions, oblique or irregular out- 
 lines may be cut. It is therefore often used for finish- 
 ing the profiles of irregular pieces. 
 
 Figure 98 shows a machine especially adapted for 
 key-seating work. The slotter is often used for this 
 purpose. The key seater is a single-purpose machine, 
 used for cutting the keyways on pulleys, gears, and 
 
 
 
il 
 
 PLANERS, SHAPERS, SLOTTERS 
 
 307 
 
 PIG. 97. VERTICAL SLOTTING MACHINE 
 
 Pratt & Whitney Co. 
 
 306 
 
 FIG. 98. KEY-SEATING MACHINE 
 Baker Bros^ 
 
 SO on, which have already been bored and faced. The 
 illustration shows a large propeller set in place. The 
 cutter, a, in this machine is carried in the round bar, 
 
 b, which extends up through the hub. It is operated 
 by a rack-and-pinion driving mechanism located in 
 the frame below and does its work in a draw cut on 
 the downward stroke. The cutter has a guide carried 
 by the arm which extends forward from the upright, 
 
 c, at the back of the machine. 
 
 
 I 
 
PLANKRS. SllArKKS. SLoTTKKS 
 
 :>(>: 
 
 FIG. 97. VKRTICAL Sr.OTTIX(; MACHINK 
 I'nilf .V: WliiliM'V i\K 
 
 FIG. 98. KEY-SEATING MACHINE 
 r.ak<'r r.ros. 
 
 SO on, which have already been bored and faced. The 
 illustration shows a large propeller set in place. The 
 cutter, a, in this machine is carried in the round bar, 
 
 b, which extends up through the hub. It is operated 
 by a rack-and-pinion driving mechanism located in 
 the frame below and does its work in a draw cut on 
 the downward stroke. The cutter has a guide carried 
 bv the arm which ext(Mids forward from the upright, 
 
 c, at the back of the machine. 
 
MILLING MACHINES 
 
 309 
 
 CHAPTER XVIII 
 MILLING MACHINES 
 
 Some Advantages of the Milling Process.— The mill- 
 ing cutters, in Chapter XII, has grown steadily in 
 importance for the past fifty or sixty years. Profes- 
 sor C. H. Benjamin* has stated some of its ad- 
 vantages as follows: 
 
 Twenty-five years ago the milling machine was regarded 
 as a special tool, and the bulk of straight work was done on 
 the planer and the shaping; machine. Today the milling ma- 
 chine is in the lead, and is preferred by most manufacturers 
 for all work within its range. The reason for this is the 
 simple fact that this machine will do more work, or will do 
 the same work with a greater degree of accuracy. The mill- 
 ing cutter is a multiple tool having many cutting edges, and 
 it has no return motion, but cuts all the time. Furthermore, 
 the possibility of shaping regular outlines by one operation, 
 and of repeating that operation and thus duplicating the pat- 
 tern indefinitely, gives the milling machine a great advantage 
 over machines using a single point tool. Even in the simple 
 operation of facing plane surfaces, the milling cutter with 
 inserted teeth has made records which no reciprocating ma- 
 chine can hope to equal. The fact that both types of ma- 
 chines are today working side by side in the best shops, shows 
 that each is finding its own proper field and succeeding in 
 that field. 
 
 The Work of the Milling Machine.— The milling 
 machine, with the automatic lathe, is relied on to do 
 the bulk of the work in plants that are manufactur- 
 ing on an interchangeable basis. When first used it 
 
 ♦Modern American Machine Tools; C. H. Benjamin, p. 198. 
 
 308 
 
 was confined to light work, but of recent years has 
 been applied more and more to larger and heavier 
 operations. It is used for the simplest kind of repeti- 
 tion automatic work and, in the form of the universal 
 milling machine, for the most delicate and skilful 
 operations. The universal milling machine is the 
 most characteristic machine in the tool room. For 
 manufacturing purposes, the milling process is used 
 mainly for producing large quantities, as the tools are 
 comparatively expensive, require skill in setting, and 
 are more restricted in their use than lathe tools. On 
 the other hand, accurate milling operations can be 
 performed by comparatively cheap labor, the wear 
 on the cutters is slow, and a great many kinds of cuts 
 may be taken which would be difficult to produce 
 commercially in any other way. Some idea of the 
 variety of cuts that it is possible to make may be 
 gathered from the collection of milling cutters shown 
 in Figure 99. 
 
 Origin and Development of Milling Machine.— Prob- 
 ably the first milling machine ever built — certainly 
 the oldest now in existence — is at present in the 
 museum of the Sheffield Scientific School of Yale Uni- 
 versity. It was built by Eli Whitney some time before 
 1818, and was used for the manufacture of gun parts 
 for the United States Government. This machine is a 
 very simple affair and could never have been used for 
 anything but light, straight cuts. The '* lineal descend- 
 ant" of this machine embodying the same general ar- 
 rangement but greatly refined in design, of course, is 
 the hand milling machine shown in Figure 100. It 
 has a box-shaped body, and a head somewhat sim- 
 
 ,f 
 
 t 
 
 ii 
 
 ^ 
 
MILLING MACHINES 
 
 311 
 
 ' ■' ** - • - ■ - ■ * ■*J I L m.M ll1iW.ll ■ 1..JI, , 9 
 
 ilar to a lathe headstock, which is cast integral with 
 it. This head carries a spindle, which is driven hy 
 a stepped cone pulley. The small end of the pulley is 
 toward the front bearing, as this position permits a 
 firmer bracing for the front bearing, which takes the 
 end thrust. The front of the column is provided 
 with vertical ways, and carries the knee, a. The up- 
 and-down motion of the knee is operated by the 
 handle, b, and a rack and pinion, which does not 
 show. 
 
 Adjustable stops are provided on the side of the 
 guide, as shown, which limit the motion as may be 
 desired. On the top of the knee is a saddle, c, which 
 may be moved in and out from the frame of the 
 machine by the adjustable screw, d, and clamped in 
 any position. On the saddle is the table, e, which 
 has a transverse movement under the milling cutter, 
 operated through the hand lever, f, and the pinion 
 and rack, as clearly shown. The table is slotted to 
 carry a standard milling-machine vise or special fix- 
 ture to hold the work. 
 
 In operating the machine, the attendant sets the 
 work in the jaws, raises the knee and the table by 
 the handle, b, to a point determined by the side stop, 
 and then feeds the work horizontally with the other 
 handle, f , to a definite point set by the stop, g, at the 
 front of the table. The weight of the knee and the 
 table is counterbalanced by a weight within the 
 column, so that the operator does not have to lift 
 them at each operation. These machines are adapted 
 to milling the small parts of guns, sewing machines, 
 typewriters, and the like. 
 
 
 •■1 
 
 , ,■•11 , 
 
 4 i I 
 
MILLING MACHINES 
 
 :]U 
 
 ilar to a lathe lieadstock, Avliieh is east integral with 
 it. This head carries a spindle, which is driven by 
 a stepped cone pulley. The small end of the pulley is 
 toward the front bearing, as this position permits a 
 firmer bracing for the front bearing, which takes the 
 end thrust. The front of the column is provided 
 with vertical ways, and carries the knee, a. The up- 
 and-down motion of the knee is operated by the 
 liandle, b, and a rack and pinion, which does not 
 show. 
 
 Adjustable stops are provided on the side of the 
 guide, as shown, which limit the motion as may be 
 desired. On the top of the knee is a saddle, c, which 
 may be moved in and out from the frame of the 
 machine by the adjustable screw, d, and clamped in 
 any position. On the saddle is the table, e, which 
 has a transverse movement under the milling cutter, 
 operated through the hand lever, f, and the pinion 
 and rack, as clearly shown. The table is slotted to 
 carry a standard milling-machine vise or special fix- 
 ture to hold the work. 
 
 In operating the machine, the attendant sets the 
 work in the jaws, raises the knee and the table by 
 the handle, b, to a point determined by the side stop, 
 and then feeds the work horizontally with the other 
 handle, f, to a definite point set by the stop, g, at the 
 front of the table. The weight of the knee and the 
 table is counterbalanced by a weight within the 
 column, so that the operator does not have to lift 
 them at each operation. These machines are adapted 
 to milling the small parts of guns, sewing nincliiiies, 
 typewriters, and the like. 
 
i 
 
 MILLING MACHINES 
 
 313 
 
 The Lincoln Type.— About 1850, F. W. Howe and 
 R. S. Lawrence, of Robbins and Lawrence, Windsor, 
 Vermont, designed a miller which was the forerunner 
 of the Lincoln milling machine, shown in Figure lOL 
 They brought this to Hartford, and fifty machines of 
 the same general design were ordered from the Lin- 
 coln Iron Works of that city for the Colt Armory, 
 which was erected in 1855. The machines were built 
 under the direction of F. A. Pratt and Amos Whitney, 
 who later formed the firm of Pratt and Whitney. Mr. 
 Pratt added certain improvements — such as the screw 
 drive for the main table feed — and various details. 
 Many thousand machines of this design have been 
 built since that time; they are known, even in Europe, 
 as the Lincoln type of miller, from the name of the 
 builders of the early machines. 
 
 The Lincoln miller consists of a short, stiff bed, 
 with a headstock, a, either cast or bolted to it, which 
 carries a live spindle, b, and its driving mechanism. 
 At the other end of the machine is an upright, c, 
 which carries an adjustable block, d, supporting the 
 outboard end of the arbor that carries the milling 
 cutters. The spindle and the block are adjustable 
 vertically, and accommodate work of different 
 heights. The work is held in a jaw, e, or special 
 milling fixture, which is clamped to the movable table 
 between the headstock and the outboard guide. The 
 upright, c, and the saddle, f, carrying the table are 
 adjustable lengthwise ^p w?i^'^ at the top of the bed. 
 The saddle has no Tr . iiis direction but is 
 
 clamped to the bed when set in the desired position. 
 
 The table has a cross feed operated by hand or 
 
 
 I; 
 
 '/mi 
 
f 
 
 MTlJ.lXf! ArA( IIIXES 
 
 313 
 
 The Lincoln Type.- About 18:)(), K. \V. Jlowc mid 
 R. S. LawiTiieo, of Hobbins and Ijuwronco, Windsor, 
 Vermont, dosi<»'iUMl a inillcM* whicb was tlic forerunner 
 of the Lincoln milling machine, shown in Figure 101. 
 They ])rought tliis to Hartford, and iifty machines of 
 the same general design were ordered from the Lin- 
 coln li'on AVorks of that eitv for the Colt Armory, 
 which was erected in 185."). The machines were built 
 imder the direction of F. A. Pratt and Amos Whitney, 
 wlio later foi-med the firm of Pratt and AVhitney. Mr. 
 Pratt added certain improvements — snch as the scre\v 
 drive for the main tal)le feed — and various details. 
 Many thousand machines of this design have been 
 built since that time; they are known, even in Europe, 
 as the Lincoln type of miller, from the name of the 
 builders of the early machines. 
 
 TIk' Lincoln miller consists of a short, stiff bed, 
 with a headstock, a, either cast oi* bolted to it, which 
 carries a live spindle, b, and its driving mechanism. 
 At the other end of the machine is an upright, c, 
 which carries an adjustable block, d, supporting the 
 outboard end of the arbor that carries the milling 
 cutters. The spindle and the block are adjustable 
 vertically, and acconnnodatc work of different 
 heights. The work is held in a jaw% e, or special 
 milling fixture, which is clamped to the movable table 
 between the headstock and the outl)oard guide. The 
 upright, c, and the saddle, f, carrying the table are 
 adjustable lengthwise -»> - 'f the top of the be<l. 
 
 The saddle has no . dii\M'tion but is 
 
 ^'lamped to the bed when set in the desired position. 
 The table has a cross h^ed o])ei-at(Hl by hand or 
 
 r\^\ 
 
314 
 
 THE MECHANICAL EQUIPMENT 
 
 ^li 
 
 S- 
 
 power, which moves the work under the milling 
 cutter. In the very early machines, this was operated 
 by a pinion and a toothed rack on the under side of 
 the table. This arrangement caused the feed to chat- 
 ter badly under heavy cuts. One of the chief im- 
 provements made by Mr. Pratt was the substitution 
 of a screw feed, g, which operates through a nut se- 
 cured to the saddle. While seemingly a minor im- 
 provement, it really made the success of the machine. 
 This type of miller is used for straight milling cuts 
 on repetition work. It resembles in many respects 
 the horizontal boring machine shown in Figure 75 — in 
 fact, in many instances the same operations may be 
 performed on either machine. The spindle, b, on the 
 Lincoln miller, however, has no traverse motion, and 
 the only feed of the table is across the machine. Its 
 use is therefore confined to operations that can be 
 performed by a single pass of the work under the 
 cutting tool — ^but it is remarkable how much can be 
 done in this way. The simplicity of the machine is 
 an element of accuracy and permits of its operation 
 by unskilled attendants. 
 
 The Brings' Type. — Figure 102 shows a machine 
 for the same kind of work as the above, in which the 
 vertical adjustment is in the table instead of in the 
 spindle. In this machine the frame consists of two 
 uprights cast together at top and bottom. Between 
 these, carried by the guideways, a, is a saddle, b, 
 which may be adjusted vertically by the screw, c, 
 underneath. This in turn carries a slotted table 
 which moves in and out under hand or power feed, as 
 in the Lincoln miller. The cutter arbor, d, is fixed 
 
 
,^ 
 
 V 
 
 
 314 
 
 THE MECHANICAL EQUIPMENT 
 
 power, which moves llio work under the milling 
 cutter. In the very early machines, this was operated 
 by a pinion and a toothed rack on the under side of 
 the table. This arrangement caused the feed to chat- 
 ter badly under heavy cuts. One of the chief im- 
 provements made by Mr. Pratt was the substitution 
 of a screw feed, g, which operates through a nut se- 
 cured to the saddle. AVhile seemingly a minor im- 
 provement, it really made the success of the machine. 
 This type of miller is used for straight milling cuts 
 on repetition work. It resembles in many respects 
 the horizontal boring machine shown in Figure 75 — in 
 fact, in many instances the same operations may be 
 performed on either machine. The spindle, b, on the 
 Lincoln miller, however, has no traverse motion, and 
 the only feed of the table is across the machine. Its 
 use is therefore confined to operations that can be 
 performed by a single pass of the work under the 
 cutting tool — but it is remarkal)le how much can be 
 done in this way. The simplicity of the machine is 
 an element of accuracy and permits of its operation 
 by unskilled attendants. 
 
 The Brig^g^s' Type.— Figure 102 shows a machine 
 for the same kind of work as the above, in which the 
 vertical adjustment is in the table instead of in the 
 spindle. In this machine the frame consists of two 
 uprights cast together at top and bottom. Between 
 these, carried by the guideways, a, is a saddle, h, 
 which may be adjusted vertically by the screw, c, 
 underneath. This in turn carries a slotted table 
 which moves in and out under hand or power feed, .' 
 in the Lincoln miller. The cutter arbor, d, is fixe-i 
 
 
 '■.^ 
 
 |B ^^L— __^''^ ^^i^^H 
 
 m W 
 
 
 II 
 
 11 ^ 
 
 1 * *- 1 
 
 
 B^^^^^^^^^^yw^^^^BI 
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^p ' 
 
 
 ••P4 
 < 
 
 ^^ mm 
 
 
 
 ^ 
 
 ^ 
 
316 
 
 THE MECHANICAL EQUIPMENT 
 
 MILLING MACHINES 
 
 317 
 
 in position; the support for the outer end is a bronze 
 sleeve in the removable bushing, e, which is held in 
 the frame by an expanding belt, f . The space in the 
 base below is used as a tank for cutting lubricant. 
 
 Modem Development of Lincoln Miller. — Figure 103 
 shows a modern development of the Lincoln Miller. 
 It is an automatic machine of heavy construction 
 throughout. The uprights carrying the spindle and 
 the arbor support are parabolic in outline, and some- 
 what resemble the uprights of a planer; the strain 
 to which they are subject, in both machines, is very 
 similar in nature. The various motions on the ma- 
 chine may be operated by the hand levers in front; 
 in regular operation, however, they are automatic, 
 and are controlled by the circular plate shown at the 
 front of the machine. Adjustable dogs, a, may be set 
 in position around the edge of this plate, to throw in 
 and out the levers that control the reverse and feed 
 mechanism. The work starts from a position well to 
 the front — where the fixture may be loaded without 
 danger of injuring the hands of the operator — and 
 approaches the cutter with a rapid forward traverse. 
 Just before the work engages the cutter, the slow 
 feed is automatically thrown in. 
 
 After the milling operation has been completed, the 
 table is automatically returned quickly to its original 
 position, stops at the end of the motion, and waits 
 for the operator to load the fixture and start the for- 
 ward feed. As the table starts on the return traverse, 
 it is dropped somewhat to permit the work to clear 
 the cutter as the table goes back; this precaution 
 prevents any marring of the finished surface. Then, 
 
 as the table approaches the end of the return travel, 
 it is automatically elevated to its cutting position and 
 remains at this height during the cutting traverse. 
 Because the control of these motions is entirely auto- 
 matic, one operator can attend to several machines. 
 The cutting feeds, by means of change gears, may be 
 varied to suit the requirements, and the table feeds 
 are entirely independent of the spindle speeds. 
 
 Column-and-Knee Type.— The plain miller of the 
 column-and-knee type. Figure 104, is a refinement 
 of the hand miller, and is usually much larger and 
 equipped with power feeds in all directions. It is 
 more flexible than the Lincoln miller, as the table 
 has not only a transverse feed, but a vertical and an 
 in-and-out motion. Some of these machines have 
 both hand and power feeds for all three of these 
 movements; some, for the longitudinal and transverse 
 movements only; the vertical motion is operated by 
 hand; in still others, only the longitudinal feed is 
 power-driven. Figure 105 shows a vertical section of 
 another machine of the same type. Clamps are pro- 
 vided for locking the knee, a, to the main frame, the 
 saddle, b, to the knee, and the table, c, to the saddle, 
 when motion at any of these points is not required. 
 A heavy bar, d, at the top of the machine can be 
 adjusted in and out, according to the demands of the 
 work. This bar carries an outboard support for the 
 milling arbor, and is itself stiffened by braces, e, ex- 
 tending from the outer end down to the end of the 
 
 knee. 
 
 Modern machines of this type are driven by a 
 single-speed pulley, and the speed variations are ob- 
 
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 02 ^ 
 
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 o 
 
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 MILLING MACHINES 
 
 319 
 
 tained by means of change gears. All the feed move- 
 ments are power-operated, and are provided with 
 stops to limit the motion. The sectional view shows 
 the method of lubrication by which the bearing 
 lubricant stored in the reservoir, A, is pumped to the 
 top of the machine, where it is distributed through 
 a perforated pipe, f. The cutting lubricant is stored 
 in the reservoir, C, is pumped to the top of the ma- 
 chine, and from there is distributed over the cutters 
 and the work through adjustable nozzles, g. Then it 
 is returned to the reservoir, B. The latter acts as a 
 settling tank for the chips, which sink to the bottom; 
 the lubricant runs over the top of the partition into 
 the reservoir, C. 
 
 Vertical Miller.— The vertical type of plain miller 
 is in many ways similar to the column-and-knee type, 
 so far as the arrangements of the table are con- 
 cerned. The spindle, however, stands in a vertical 
 position, instead of being horizontal. It may be 
 carried in a head, adjustable with respect to the main 
 body of the machine, as shown in Figure 106, or the 
 head may be cast solid with the frame. The vertical 
 type of machine clearly embodies the principles of 
 the drilling machine. The spindle and the table 
 are similarly located, and the cutter is mounted on 
 the lower end of the spindle. The table, however, 
 has a series of movements not found on the drilling 
 machine. 
 
 For such work as face milling, die-sinking and 
 the cutting of profiles, the vertical-spindle machine 
 has many advantages as compared with the horizontal 
 type. In many cases a piece mav be fastened directlv 
 
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 MILLING MACHINES 
 
 319 
 
 o 
 
 o 
 
 
 tained by means of change gears. All the feed move- 
 ments are power-operated, and are provided with 
 stops to limit the motion. The sectional view shows 
 the method of lubrication by which the bearing 
 lubricant stored in the reservoir, A, is pumped to the 
 top of the machine, where it is distributed through 
 a perforated pipe, f. The cutting lubricant is stored 
 in the reservoir, C, is pumped to the top of the ma- 
 cliine, and from there is distributed over the cutters 
 and the work through adjustable nozzles, g. Then it 
 is returned to the reservoir, B. The latter acts as a 
 settling tank for the chips, which sink to the bottom; 
 the lubricant runs over the top of the partition into 
 the reservoir, C. 
 
 Vertical Miller.— The vertical type of plain miller 
 is in many ways similar to the column-and-knee type, 
 so far as the arrangements of the table are con- 
 cerned. The spindle, however, stands in a vertical 
 position, instead of being horizontal. Tt may be 
 carried in a head, adjustable with respect to the main 
 l)ody of the machine, as shown in Figure lOG, or the 
 head may be cast solid with the frame. The vertical 
 type of machine clearly embodies the principles of 
 the drilling machine. The spindle and the table 
 are similarly located, and the cutter is mounted on 
 the lower end of the spindle. The table, however, 
 has a series of movements not found on the drilling 
 machine. 
 
 For such work as face milling, die-sinking and 
 iiie cutting of profiles, the vertical-spindle machine 
 fias many advantages as compai-ed with the horizontal 
 type. In many cases a pieee may be fastened directly 
 

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 CJ OJ 
 
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 MILLING MACHINES 
 
 321 
 
 to the top of the table, whereas fixtures would be 
 necessary if the work were done on a horizontal ma- 
 chine. Also, the operator can see his work at all 
 times, and can follow any irregularities of outline 
 much more readily than when he uses the horizontal 
 type. 
 
 The die-sinker, Figure 107, is a type of vertical 
 milling machine especially adapted to the purpose 
 indicated by its name. The dies are clamped in the 
 jaws on the table, and a small end mill, formed or 
 plain as the case may be, is carried in the lower end 
 of the spindle. Longitudinal, transverse and vertical 
 movements, as well as horizontal rotation, may be 
 given to the work. Frequently a swiveling vise is 
 used, which permits of angular adjustments in a 
 vertical plane as well. These feeds are operated only 
 by hand, as this type of machine is used by skilled 
 tool makers who follow the outline laid out on the sur- 
 face of the die, and scarcely any two jobs are the 
 same. Power feeds would therefore be almost use- 
 less. As the cuts used in die-sinking are almost in- 
 variably light, the spindle is driven directly, with 
 gearing, by a half-turn belt from the cone pulley be- 
 low. 
 
 The heavier type of machine, shown in Figure 106, 
 is used for manufacturing purposes; it is provided 
 with a powerful drive that has the necessary speed 
 changes, and so on. Frequently machines of this 
 type are provided with a circular table that has a 
 rotary power feed. Figure 106 shows such a set-up — 
 the heavy face-milling cutter is machining the bot- 
 toms of flatirons, which are arranged around the top 
 
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mjllim; machinks 
 
 321 
 
 
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 1() llic lop of tli(* 1a])l(% wliorcas fixtures would l)o 
 iHH't'ssarv if I he work whm'c done on a liori/onlal nia- 
 eliino. Also, tlio operator can see liis work at all 
 times, and cau follow any irregularities of outline 
 much more readilv than when he uses the horizontal 
 
 The die-sinker, Figure 107, is a type of vertical 
 milling machine especially adapted to the purpose 
 indicatiMl by its name. Tln^ dies are clamped in the 
 jaws on the table, and a small end mill, formed or 
 plain as the case may he, is carried in the lower end 
 of the spindle. Longitudinal, transverse and vertical 
 movements, as well as horizontal rotation, may he 
 given to the work. Frequently a swiveling vise is 
 used, which permits of angular adjustments in a 
 vertical plane as well. These feeds are operated only 
 hy hand, as this type of machine is used by skilled 
 tool makers who follow the outline laid out on the sur- 
 face of the die, and scarciOv anv two iobs are the 
 same. Power feeds would therefore be almost use- 
 less. As the cuts nsed in die-sinking are almost in- 
 variably light, the spindle is driven directly, with 
 gearing, l)y a half-turn belt from the cone pulley be- 
 low. 
 
 The heavier type of machine, shown in Figure 106, 
 is used for mamifacturing purposes; it is provided 
 with a powerful drive that has the necessary speed 
 changes, and so on. Frequently machines of this 
 type are provided with a circular table that has a 
 rotary power W'od. Figure lOfi shows su(*h a set-up — 
 the heavy face-milling cutter is machining the ])ot- 
 toms of flatirons, which are arranged around the to]) 
 
322 
 
 THE MECHANICAL EQUIPMENT 
 
 of a fixture and given a continuous feed. As the feed- 
 ing motion is comparatively slow, the finished work 
 may be taken out and new pieces may be substituted 
 while the cutting is going on. The work of the ma- 
 chine is therefore continuous. 
 
 Profile Milling Machine.— By giving the* milling 
 cutter some desired contour, and moving the work 
 past it in the necessary irregular path, very irregular 
 surfaces may be cut. When such surfaces are to be 
 produced on a manufacturing basis, the profile mill- 
 ing machine, shown in Figure 108, is used. In this 
 machine the cutting tool is inserted in the end of 
 the spindle, at a, and a hardened steel guide pin is 
 clamped into the head at b or b'. As a part of the 
 fixture— holding the work, and at one side of it— is 
 a former plate, which has a shape similar to that of 
 the piece to be milled. By operating the handle, c, 
 which moves the table in and out, and the handle, d, 
 which moves the head sidewise, the operator causes 
 the pin, b, to follow the curved edge of this 
 **former." The work, accordingly, moves past the 
 cutter in the irregular path required. 
 
 Figure 109 shows the frame of an automatic pistol 
 that contains several cuts of this nature. A formed 
 milling cutter is used which has a concave outline of 
 the same curve as the edge. The work is fed so that 
 the cutter moves along the piece from a, around the 
 outside of the finger loop, and down the handle to b. 
 It may then be guided around to the back of the 
 handle, along it, and off the work at c. The former 
 plate which guides this cut will have a shape similar 
 to the path of the milling cutter around the stock. 
 
 MILLING MACHINES 
 
 323 
 
 FIG. 109. AN EXAMPLE OF PROFILING WORK 
 
 A second and smaller cut, of a similar nature, is 
 shown on the side of the frame from d to e; there is, 
 of course, a corresponding one on the opposite side. 
 A third profiling cut will be made around the inside 
 of the finger loop, which is still rough on the piece 
 shown. 
 
 Almost any contour can be given to the milling cut- 
 ter, and it can be made to travel in almost any path 
 — the only condition is that the radius of the curved 
 surface in corners, such as f and f , must be less than 
 the radius of the milling cutter. For internal cuts, 
 such as the one inside of the finger loop, provision is 
 made for lifting the guide pin and cutter, by means 
 of the lever, e, above the plane of the work and the 
 **former", and dropping them down again to the 
 zone in which the cut is to be made. 
 
 Frequently profiling machines are made in which 
 the upper rail is longer and carries an additional 
 head and spindle with its own guide pin. One of the 
 
 " »i 
 
 )( 
 
 
322 
 
 THE xMECHAiMCAL EQUIPMEJST 
 
 of a fixture and given a continuous feed. As tlie feed- 
 ing motion is comparatively slow, the finished work 
 may be taken out and new pieces may be substituted 
 while the cutting is going on. The work of the ma- 
 chine is therefore continuous. 
 
 Profile Milling: Machine.— By giving the milling 
 cutter some desired contour, and moving the work 
 past it in the necessary irregular path, very irregular 
 surfaces may be cut. When such surfaces are to be 
 produced on a manufacturing basis, the profile mill- 
 ing machine, shown in V'lgure 108, is used. In this 
 machine the cutting tool is inserted in the end of 
 the spindle, at a, and a hardened steel guide pin is 
 clamped into the head at b or b'. As a part of the 
 fixture— holding the work, and at one side of it— is 
 a former plate, which has a shape similar to tliat of 
 the piece to be milled. By operating the handle, c, 
 which moves the table in and out, and the handle, d, 
 which moves the head sidewise, the operator causes 
 the pin, b, to follow the curved edge of this 
 **former." The work, accordingly, moves past the 
 cutter in the irregular path required. 
 
 Figure 109 shows the frame of an automatic pistol 
 that contains several cuts of this nature. A formed 
 milling cutter is used which has a concave outline of 
 the same curve as the edge. The work is fed so that 
 the cutter moves along the piece from a, around the 
 outside of the finger loop, and down the handle to b. 
 It may then be guided around to the back of the 
 handle, along it, and off the work at c. The former 
 plate which guides this cut will have a shape similar 
 to the path of the milling cutter around the stock. 
 
 M1LIJX(; AFACIIINKS 
 
 .».).» 
 •>-•> 
 
 FIG. 109. AX EXAMl'Li: OF PROFILING WORK 
 
 A second and smaller cut, of a similar nature, is 
 shown on the side of the frame from d to e; there is, 
 of course, a corresponding one on the opposite side. 
 A third profiling cut will be made around the inside 
 of the finger loop, which is still rough on the piece 
 shown. 
 
 Almost any contour can be given to the milling cut- 
 ter, and it can be made to travel in almost any path 
 — the only condition is that the radius of the curved 
 sui-face in corners, such as f and f , must be less than 
 the radius of the milling cutter. P^'or internal cuts, 
 such as the one inside of the finger loop, provision is 
 made for lifting the guide pin and cutter, by means 
 of the lever, e, above the plane of the work and the 
 ** former", and dropping them down again to the 
 zone in which the cut is to be made. 
 
 Frequently profiling machines are made in which 
 the upper rail is longer and carries an additional 
 head and spindle with its own guide pin. One of the 
 
[Ill 
 
 324 THE MECHANICAL EQUIPMENT 
 
 heads is used for a roughing cut, and the other for a 
 finishing cut. Both are made in one setting of 
 the piece, finishing it ajccurately to dimensions; thus 
 hand fitting is done away with. It is obvious that 
 this type of machine can produce interchangeably 
 and on a manufacturing basis, some very irregular 
 shapes. 
 
 Universal Milling Machine.— The aristocrat among 
 nulling machines, and in fact in the whole field of 
 machine tools, is the universal milling machine, one 
 of which is shown in Figure 110. There is scarcely 
 a type of cut known in the machine shop which can- 
 not be made on this machine. It was first developed 
 by Brown & Sharpe in 1861, for milling the flutes 
 of a twist drill. The machine has the column, knee, 
 and saddle of the type shown in Figure 104. The 
 ' table, a, however, is arranged to swivel horizontally 
 through a very considerable angle, and is provided 
 with an accurately graduated measuring circle, b. 
 
 On the table is a so-called universal head, H, shown 
 in Figures 110, 111, and 112. This head corresponds 
 in some ways to the head-stock of the lathe, although 
 it is wholly different in design. The adjustable 
 bracket, c, which supports the outboard end of the 
 work, corresponds in function to the lathe tail-stock, 
 and the table of the machine to the lathe bed. In a 
 lathe the work revolves under the tool, and the tool is 
 fed past the work. In this case the milling cutter 
 revolves, and the work, carried on the two centers, d 
 and e, may be set at an angle with reference to the 
 cutter and fed past it or rotated— or these two mo- 
 tions may be used simultaneously. 
 
 FIG. 110. UNIVERSAL MILLING MACHINE 
 
 325 
 
 I 
 
 .V 
 
 M 
 
 If* 
 
324 
 
 THE MECHAXICAL KQUIPMExNT 
 
 heads is used lor a lougliino cut, and tlir oHut for a 
 finisJiiiig- cut. Both aiv made in one scttin- of 
 the piece, iinishing it aiceiirately to dimensioiis; "thus 
 liand fitting- is done away witli. It is obvious that 
 this type of machine can produce interchangeably 
 and on a manufacturing basis, some very irreonhiV 
 shapes. 
 
 Universal Milling Machine.— The ai-istociat amon- 
 mdhng macliines, and in fact in the whok^ field of 
 machine tools, is the universal milling machine, one 
 of which is shown in Figure 110. There is scarcely 
 a type of cut known in the machine shop which can- 
 not be made on this machine. It was first developed 
 by Brown & Sharpc in ISlil, for milling the flutes 
 of a twist drill. The machine has the colunm, knee, 
 and saddle of the type shown in Figure 104. The 
 table, a, however, is arranged to swivel horizontally 
 through a very considerable angle, and is provided 
 with an accurately graduated measuring circle, b. 
 
 On the table is a so-called universal head, H, shown 
 in Figures 110, 111, and 112. This head corresponds 
 in some ways to the head-stock of the lathe, although 
 it is wholly different in design. The adjustable 
 bracket, c, wdiich supports the outboard end of the 
 work, corresponds in function to the lathe tail-stock, 
 and the table of the machine to the lathe bed. In a 
 lathe the work revolves under the tool, and the tool is 
 fed past the w^ork. In this case the milling cutter 
 revolves, and the work, carried on the two centers, d 
 and e, may be set at an angle with reference to the 
 cutter and fed past it or rotated— or these two mo- 
 tions may be used simultaneously. 
 
 1 
 
 
 I 
 
 
 
 ' 'v- 
 
 N 
 
 
 
 
 b 
 
 FIG. 110. UNIVERSAL MILLING MACHINE 
 
 325 
 
( I 
 
 MILLING MACHINES 
 
 327 
 
 FIGS. Ill AND 112. INDEXING HEADS 
 
 The lower view shows a head arranged for six spindles. 
 
 Sharpe Mfg. Co. 
 
 326 
 
 Brown & 
 
 Milling Teeth of Spur Gear.— If the centers are set 
 at right angles to the axis of the spindle, and the 
 table is fed sidewise, the cutter will mill a straight 
 slot parallel to the axis of the piece. The table may 
 then be returned, the work may be indexed through 
 a desired angle by means of the mechanism in the 
 head, and the cut may be repeated. Such, for in- 
 stance, would be the '* set-up" for milling the teeth of 
 a small spur gear. Or the table may be clamped in 
 a definite position under the cutter, and the work 
 given a continuous rotary feed on its centers without 
 lateral change of position. By this method a circular 
 slot would be milled around the work. 
 
 Milling Long Spirals.— For milling long spirals- 
 such as the flutes of a twist drill, for which the ma- 
 chine was originally designed — the table is turned 
 horizontally to the pitch angle of the groove, and the 
 swiveling joint clamped in that position. The drill, 
 carried between the centers, d and e, is fed longi- 
 tudinally with the table at the angle so set, and at 
 the same time given a rotary power feed by means of 
 the head, H. The combination of these two move- 
 ments generates the helical cut required. The work 
 may then be run back to its starting position, the 
 spindle, d, and the drill being cut may be indexed 180 
 degrees, the feeds thrown in again and the second 
 
 groove cut. 
 
 Control of Rotary Motion.— The rotary motion of 
 the spindle in the dividing head is under the influ- 
 ence of two controls, one of which performs the func- 
 tion of indexing between the several cuts, the other 
 of imparting uniform rotation during the cut. The 
 
 i 
 
MILLING MACHINES 
 
 327 
 
 FIGS. Ill AND 112. INDEXING HEADS 
 The lower view shows .1 IiphM nrnuiL'ed for six spindles. 
 
 Shjirpe Mfjr. <'o. 
 
 Brown A 
 
 Milling: Teeth of Spur Gear.— If the centers are set 
 at right angles to the axis of the spindle, and the 
 table is fed sidewise, the cutter will mill a straight 
 slot parallel to the axis of the piece. The table may 
 then be returned, the work may be indexed through 
 a desired angle by means of the mechanism in the 
 head, and the cut may be repeated. Such, for in- 
 stance, would be the *\set-up" for milling the teeth of 
 a small spur gear. Or the table may be clamped in 
 a definite position under the cutter, and the work 
 given a continuous rotary feed on its centers without 
 hiteral ehange of position. By this method a circuhir 
 slot wouhl l)e miUed around the work. 
 
 Milling Long Spirals.— For milling long spirals- 
 such as the (lutes of a twist drill, for which the ma- 
 chine was originally designed — the table is turned 
 horizontally to the pitch angle of the groove, and the 
 swiveling joint clam])ed in that position. The drill, 
 carried between the centers, d and e, is fed longi- 
 tudinally with the table at the angle so set, and at 
 the same time given a rotary power feed by nutans of 
 the head, 11. The combination of these two move- 
 ments generates the helical cut required. The work 
 mav then be run back to its starting position, th(> 
 spindle, d, and the drill being cut may be indexed ISO 
 degrees, the feeds thrown in again and the second 
 
 groove cut. 
 
 Control of Rotary Motion.— The rotary motion of 
 the spindle in the dividing head is under the influ- 
 ence of two controls, oik* of whieh performs the func- 
 tion of indexing between the several cuts, the other 
 of imparting uniform lot.Mtion during the cut. The 
 
328 
 
 THE MECHANICAL EQUIPMENT 
 
 MILLING MACHINES 
 
 329 
 
 III 
 
 spindle that holds the center, d, carries, inside of the 
 head, a worm wheel and is operated by a hardened 
 steel worm located on the shaft, f, to which the in- 
 dex crank and handle, g, are fastened. When the 
 worm IS turned by means of the index crank, the in- 
 dexing IS accomplished. The index plate outside is 
 drilled with six rows of small holes. The crank is 
 turned a certain number of holes, and a spring pin in 
 the handle engages the hole that gives the angle de- 
 sired Two adjustable arms, h, h', may be set to take 
 just the number of holes required and minimize the 
 chance of making a mistake by turning the handle of 
 the indexing crank to the wrong hole. This operation 
 IS performed before the cut is begun, to turn the work 
 through the angle necessary to locate the cut. 
 
 Continuous Rotary Feeding.-For the continuous 
 rotary feeding during the cut, the index plate and 
 the worm are driven together from the table feed- 
 screw through the train of change gearing shown at 
 the end of the table. This may be done while the 
 index pin is in any hole of the plate. Through the 
 interposition of change gears shown, the rate of ro- 
 tary feed m relation to longitudinal traverse may be 
 varied to control the angle of the spiral generated. 
 For rapid indexing, in cutting taps, reamers, and so 
 on, the worm inside may be disengaged and the 
 spindle may be turned by hand. The principal divi- 
 sions most commonly used are determined directly by 
 the single row of holes in the index plate, i, which 
 are engaged by a pin operated by the handle, k. 
 
 It IS possible to tip the head in a vertical plane 
 so that the spmdle, d, can be set at any desired 
 
 angle from 10 degrees below the horizontal to 5 
 degrees beyond the perpendicular, without affecting 
 the operation of the mechanism. This tipping of the 
 head renders it possible to make cuts on conical sur- 
 faces. With special fixtures, the dividing head may 
 be used to index more than one piece of work at one 
 time. Figure 112 shows a head coupled to a special 
 fixture so as to index six pieces at once for milling 
 the spiral slots in push screw-drivers. 
 
 Various forms of heads are made for different pur- 
 poses. Some for spiral milling are without the verti- 
 cal swiveling, and the center of the spindle, d, remains 
 at all times horizontal; in others, the indexing heads 
 are made without either automatic driving mechan- 
 ism or vertical swiveling and are used for straight 
 work, such as the cutting of spur gears. The hori- 
 zontal swiveling of the main table may be omitted, 
 and the tool driving head may be swiveled instead. 
 With such a head, the work which otherwise would 
 require a universal machine can be done on one of 
 the plain column-and-knee types, as shown in Figure 
 111, where the work is at right angles to the main 
 axis of the machine, and the cutter axis, instead of 
 the table, is set at the pitch angle. 
 
 The universal miller is distinctly a tool-room ma- 
 chine. The adaptability which enables it to perform 
 almost every type of machining operation necessarily 
 involves refinements of design and delicate adjust- 
 ments that require skilful handling. 
 
 Planer Type of Milling Machine.— Nearly all the 
 machines described are for small or moderate-sized 
 work. The milling principle, however, has been ap- 
 
 * ft.. 
 
330 
 
 
 THE MECHANICAL EQUIPMENT 
 
 plied also to large work and heavy production. Figure 
 113 shows a machine of the so-called planer type. The 
 reason for the name is obvious, as the general appear- 
 ance of the machine is closely similar to that of the 
 planer. There are the main bed, the traversing table, 
 the uprights, the cross rail, and the tool heads of the 
 standard planer. Its action however is materially dif- 
 ferent. The tool heads of a planer contain single- 
 edged cutting tools which have no motion other than 
 the feed. The cutting heads of this machine carry re- 
 volvmg spindles and milling cutters usually, but not 
 always, of the face-milling type. 
 
 In the planer the table and the work move back 
 and forth under the cross rail many times while a 
 cut is being made. In this machine the action is like 
 that of a Lincoln miller. Figure 101. The work 
 moves forward slowly at the speed of the feed, and 
 passes under the cutting tool but once. The cutting 
 action in this case is continuous, instead of intermit- 
 tent as in the case of the planer. Machines of this 
 type are made in sizes from 20 inches square by 8 
 feet traverse, to 10 feet square by 30 feet traverse. 
 For special manufacturing operations, they are often 
 made with heavy fixed cross rails cast solid with the 
 uprights. 
 
 In the machine shown, the cross rail, a, is adjust- 
 able, and one of the vertical spindles, b, is equipped 
 with a vertical or boring feed. The other head, c, 
 is a straight milling head. The cross rail may carry 
 one milling head, or two, according to the size of the 
 machine, and frequently milling heads, as at d, are 
 provided on one or both of the uprights. These ma- 
 
 FIGS. 113 AND 114. PLANERS 
 The upper, Fig. 113, is a milling macliine of the planer type, built by 
 the Ingersoll Milling Machine Co. The lower, Fig. 114, is a rotary 
 planer made by Niles-Bement-Pond Co. o6i 
 
 •?1 1 
 
 1^1 
 
 
 ; i \ 
 
 1! 
 
 ' 
 
 ^11 
 

 THK MECHAMCAL K(^l'IPME\T 
 
 p led also lo large work and Ikvivv produclio.i. Fiou,v 
 113 shows a machino of the so-ealled planer tyi)(>. The 
 reason for the name is obvious, as the general appear- 
 ance of the machine is closely similar to that of th(' 
 planer. There are the main hod, the traversing table, 
 the uprights, the cross rail, and the tool heads of the 
 standard planer. Jts action however is materiallv dif- 
 ierent. The tool heads of a planer contain si'n<>l(>- 
 edged cutting tools which have no motion other than 
 the feed. The cutting heads of this machine carrv re- 
 volving spindles and milling cutters usuallv, but not 
 always, of the face-milling type. 
 
 In the planer the table and the work move back 
 and forth under tlie cross i-ail manv tinu^s while a 
 cut IS being made. In this macliine the action is like 
 that of a Lincoln miller, Figure 101. The work 
 moves forward slowly at the speed of the feed and 
 passes under tlie cutting tool but once. The cu'tting 
 action in this case is continuous, instead of iidermit'^ 
 tent as in the case of the planer. .Alachines of this 
 type are made in sizes from 20 inches squai-e by S 
 feet traverse, to 10 feet square by 30 feet traverse. 
 For special manufacturing operations, thev are often 
 made with heavy fixed cross rails cast solid with the 
 uprights. 
 
 In the machine shown, the cross rail, a, is adjust- 
 a])le, and one of the vertical spindles, b, is equipped 
 with a vertical or boring feed. The other liead, c, 
 IS a straight milling head. The cross rail may carrv 
 one milling head, or two, according to the size of tli'c 
 machines and frecjuently milling heads, as at d, an- 
 p.-'»vided on ()n<' or both of the uprights. These m;i 
 
 FIGS. 113 AND 114. PLANERS 
 The upper Fi^'. 113, is a millinj: machine of the planer type, built by 
 the Inpersoll Millinj; Machine Co. The lower, Fig. 114, is a rotary 
 phuier made by Niles-Bemeut-Pond Co. '^i- 
 
332 
 
 THE MECHANICAL EQUIPMENT 
 
 chines can do nearly all the work that could be done 
 by a planer of corresponding size, and will do it 
 much more rapidly, finishing it from the rough piece 
 in a single pass. They are, however, distinctly a 
 manufacturing type of machine, and are not so well 
 adapted for special jobbing work as the planer. 
 
 A machine of the proportions shown is by no 
 means confined to operation on long narrow work. 
 Special fixtures are often provided to mount a 
 series of castings— as automobile cylinders, for in- 
 tance— in a long row one behind another. When the 
 fixtures have been filled, the table is started past the 
 cutters on the forward feed. As each piece passes 
 the cutting heads, it is finished. Owing to the slow 
 feed of the table, the pieces that have been passed 
 under the rail may be removed while the cut is in 
 progress and new work may be substituted. When 
 the last piece in the row is finished, the quick re- 
 verse traverse may be thrown in, the table returned, 
 and a new cut started on the fresh pieces that have 
 been put in at the front end of the table. While 
 these are being cut, the last pieces may be replaced, 
 at the other end of the machine, so that, although the 
 feed is reciprocating, the cutting action may be al- 
 most as continuous, as in the rotary feed shown in 
 Figure 106. 
 
 Rotary Planer.— Another machine, known as the 
 rotary planer, shown in Figure 114, is in reality a 
 face-milling machine for machining large flat faces. 
 The work is clamped to the fixed table in the front 
 of the machine, and a large revolving head, mounted 
 on the travelling carriage, passes along the table. 
 
 MILLING MACHINES 
 
 333 
 
 The head carries a series of single-edged tools of the 
 planer type, which are inserted in the holes, a,a, in 
 the face, and are secured by means of screws oper- 
 ated from corresponding holes, b,b, in the rim. 
 
 The carriage, with its revolving head, is slowly fed 
 horizontally along the ways — the cut begins at one 
 side of the piece and passes progressively across the 
 face. It will be noted that the cutting tools drop 
 slightly below the level of the bed on which the 
 work is clamped, to insure that the bottom is finished, 
 and the width of the face of the work must not be 
 greater than the diameter of the circle of the cutting 
 tools. Machines of this type will finish flat faces on 
 large castings with astonishing rapidity. 
 

 Ill 
 
 CHAPTER XIX 
 GEAK-CUTTING 
 
 Two Systems of Tooth Forms.— The cutting of gear 
 teeth is one of the important operations in the ma- 
 chine shop, and a wide variety of machines have been 
 developed for this purpose. The kinds of gears are 
 so varied and the mechanical motions required to cut 
 some of them are so intricate, that in the design of 
 no other type of machine tool have more skill and 
 ingenuity been displayed. Before treating of the ma- 
 chinery, it is necessary to consider some points in re- 
 gard to tooth forms and types of gears. 
 
 Two systems of tooth forms have had wide use; 
 they are known, from the curves that govern their 
 shapes, as the cycloidal and the involute. Teeth with 
 sides formed of these curves will transmit motion 
 from one gear to another, quietly and smoothly, at a 
 constant velocity ratio. In both systems, the teeth 
 are designed with reference to a circle called the 
 pitch circle (see Figure 115), and the action of 
 the teeth is designed to duplicate exactly the mo- 
 tion that would be derived from the rolling of two 
 pitch circles together. While tooth forms are laid 
 out as lines related to a pitch circle, the gear always 
 has a finite thickness, and the sides of the teeth are 
 actually surfaces related to a pitch cylinder, or cone, 
 
 334 
 
 GEAR CUTTING 
 
 335 
 
 80S9 fine of Rack • 
 
 I *| V-Pitch line of Rack 
 
 Pitch C'irch 
 
 Pitch Circle-. 
 Base Circle 
 
 Base Circle 
 
 Imaginaiy -- 
 spring being 
 / unnraffed 
 
 ., Describing Point 
 
 \\c Circular Pitch 
 I ! 'o 
 
 FIG. 115. PAIR OF SPUR GEARS- SHOWING TOOTH 
 SURFACES FORMED FROM INVOLUTE CURVES 
 
 y////y/////////////////////////. 
 
 FIG. 118. THE DESCRIBING-GENERATING 
 PRINCIPLE OF FORMING GEAR TEETH 
 
 Pitch Circle 
 
 <5b*0 
 
 i^^ 
 
 FIG. 1 19. THE FORM-GENERATING PRINQPLE 
 OF FORMING GEAR TEETH 
 
 FIO. 116. CUTTING A BEVEL GEAR BLANK WITH 
 A FORMED MILUNG CUTTER 
 
 A 
 Gear-- 
 being 
 filmed 
 
 Forminqy 
 Rack 
 
 FIG. 117. THE TEMPLATE PRINCIPLE OF 
 FORMING GEAR TEETH 
 
 FIG. 120. FOUR WAYS OF USING THE FORM- 
 GENERATING PRINCIPLE 
 
 FIGS. 115-120. CUTTING GEAR TEETH 
 
 ill 
 
 t 
 
 k \ 
 
336 
 
 THE MECHANICAL EQUIPMENT 
 
 GEAR-CUTTING 
 
 337 
 
 of which the pitch circle is a cross section. The 
 theory of these systems is somewhat intricate, and 
 need not be given here.* The cycloidal system is the 
 older; it was developed about 1830, but it is now 
 falling into disuse, because teeth formed on the in- 
 volute system are simpler to generate and stronger. 
 Although formed milling cutters may be obtained for 
 both kinds of teeth, practically all machine-cut gear- 
 ing is now based on the involute system; only that 
 system, therefore, will be considered. 
 
 Spur Gears.— The gears in general use belong to 
 one of the following four types: spur gears, helical 
 gears, bevel gears, and worm gears. Spur gears 
 transmit motion between parallel shafts, and their 
 action in every way duplicates that of two pitch cyl- 
 inders when rolling upon each other (see Figure 115). 
 Spur gears may have as few as twelve teeth. Theoret- 
 ically, they may have still fewer, but practically this 
 is the limit, since the tooth form grows weak and 
 other troubles are encountered when fewer teeth are 
 used. Small spur gears are called pinions when they 
 mesh with a larger gear, which is ordinarily termed 
 the spur. As the size of the wheel grows larger, the 
 sides of the teeth, a, become flatter until the limit is 
 reached in a rack or straight bar, in which the sides 
 have become a plane surface, at b. Usually two 
 gears run on the outside of each other, as in 
 Figure 115, or a and b. Figure 126. Occasion- 
 
 * Those who wish to follow up this subject are referred to some 
 standard book on mechanism, such as "Elements of Mechanism." 
 Schwamb and Merrill; "Mechanism." Keown ; "Treatise on Gear 
 Wheels," Geo. D. Crrant, or some of the standard works on machine 
 design. 
 
 ally, however, a small pinion will engage with the in- 
 ner surface of the rim of a large gear, as c and 
 d in Figure 126, in which case the large one is 
 called an internal gear. Figure 126 also shows a 
 rack engaging a pinion, f. In spur gearing the 
 teeth are straight, parallel to the axis of the gear and 
 to each other, and of uniform size and shape through- 
 out the whole length. 
 
 Helical Gears. — These gears are similar to spurs, as 
 regards both use and general design, except that the 
 teeth, instead of being straight, are wrapped around 
 the pitch surface, each as a uniform helix. Although 
 not parallel to the axis, they are parallel to each 
 other and of uniform size and shape, as in spur gear- 
 ing. Helical gears are smoother in action than the 
 ordinary gear, and, as a result of the improved 
 methods of manufacturing them, they are coming 
 into increasing use. 
 
 Bevel Gears. — These gears are used for transmitting 
 motion between axes which are in the same plane but 
 not parallel. The teeth, theoretically, are formed on 
 pitch surfaces that are rolling cones, instead of roll- 
 ing cylinders as in spur gears, the apexes of the cones 
 coinciding with the intersection of the two axes of 
 the gears. The cross-section of a spur-tooth gear is 
 the same in any plane at right angles to the axis. 
 The cross-section of a bevel gear grows smaller and 
 smaller as it approaches the apex of the pitch cone, 
 since all the elements of each tooth center in toward 
 it (see Figure 117). 
 
 Worm Gears. — A worm gear is a toothed wheel 
 operated by a screw that meshes with it; the screw 
 
 iri! 
 
338 
 
 THE MECHANICAL EQUIPMENT 
 
 GEAR-CUTTING 
 
 339 
 
 t^ 
 
 lies tangential to the face, with its axis at right 
 angles to the axis of the wheel. A worm and worm 
 wheel are shown at g and h in Figure 126— in cross- 
 section in the main view, and in plan in small view 
 above. In the upper view the teeth on the worm 
 wheel, though not shown so, in reality extend entirely 
 around it. This type of gear is very useful for rapid 
 reductions of speed, and for fine dividing and index- 
 ing when it is necessary to control the angular mo- 
 tion with great accuracy. 
 
 There are various other forms of gear wheels, such 
 as skew gears and hyperbolic gears, but since they 
 are not extensively used they need not be considered 
 here. 
 
 Formed-Tooth Principle.— A gear-cutting machine 
 operates on one of the four following principles: the 
 formed-tooth principle, the template principle, the 
 describing-generating principle, and the form-gener- 
 ating principle. 
 
 Of these the oldest, simplest, and most widely used 
 is the formed-tooth principle. A *' blank,'' which 
 consists of the gear wheel bored, faced, turned, and 
 ready to be cut, is mounted on a suitable arbor, and 
 the space between two teeth is removed by a cutting 
 tool that has been accurately formed to the shape of 
 the open space between the teeth. The work may be 
 done on a shaper, in which case the cutting tool is 
 reciprocated across the face of the blank, parallel to 
 its axis, and is fed in gradually toward the center 
 until the required depth has been reached. The tool 
 is then raised to its original position, the gear blank 
 is indexed, and the action is repeated until all the 
 
 spaces have been cut out, leaving teeth of the re- 
 quired form between them. It is far more common, 
 however, to embody this principle in a milling oper- 
 ation (see Figures 121 and 123). In this case, a 
 formed milling cutter of the required shape, like that 
 shown in Figure 122, is used. The gear blank is 
 mounted on an arbor, as already described, and the 
 cutter is fed once across the face, parallel to the axis, 
 leaving a finished surface behind it. The cutter is 
 then returned to its original position, the blank is in- 
 dexed, and the cut is repeated until the gear is done. 
 The milling cuttor, shown in Figures 116 and 122, is 
 of the relieved type; that is, the sides of the cutting 
 teeth retain the correct form as they fall away from 
 the cutting edge. A cutter so relieved may be ground 
 on the face and will still cut the correct shape. The 
 deviation from correct work depends partly upon the 
 accuracy of the ** set-up," and partly upon the ac- 
 curacy with which the milling cutter is made. Theo- 
 retically, there should be a cutter of a different shape 
 for each number of teeth required for every pitch, or 
 size. Practically, however, the true form of the tooth 
 changes so little that for ordinary work eight cutters 
 for each pitch may be used for everything from a 
 twelve-toothed pinion to a rack. The commercial 
 cutters on the market are the following: 
 
 No. 1 will cut wheels from 135 teeth to a rack 
 
 ■» %^» 
 
 2 
 
 
 
 
 55 
 
 
 
 134 
 
 teeth 
 
 
 3 
 
 
 
 
 35 
 
 
 
 54 
 
 
 
 4 
 
 
 
 
 26 
 
 
 
 34 
 
 
 
 5 
 
 
 
 
 21 
 
 
 
 25 
 
 
 
 6 
 
 
 
 
 17 
 
 
 
 20 
 
 
 
 7 
 
 
 
 
 14 
 
 
 
 16 
 
 
 
 8 
 
 
 
 
 12 
 
 
 
 13 
 
 
r^is 
 
 n ■' 
 
 ! . 
 
 340 
 
 THE MECHANICAL EQUIPMENT 
 
 GEAR-CUTTING 
 
 341 
 
 i 'Iv 
 
 For work requiring more accurate teeth, half num- 
 bers may be obtained: 
 
 No. V/z will cut wheels from 80 teeth to 134 teeth 
 
 '' 2y2 
 
 
 
 
 ' 42 '' 
 
 < ( 
 
 54 
 
 
 '' sy2 
 
 
 
 
 ' 30 *' 
 
 (< 
 
 34 
 
 
 " ^y2 
 
 
 
 
 ' 23 '' 
 
 < < 
 
 25 
 
 
 *' hy2 
 
 
 
 
 ' 19 *' 
 
 (< 
 
 20 
 
 
 " 65^ 
 
 
 
 
 * 15 and 
 
 
 16 
 
 
 " 7M 
 
 
 
 
 ' 13 teeth 
 
 • 
 
 
 
 If the holes in the blanks are straight and the 
 hubs do not project beyond the face, a number of 
 blanks may be fastened together on the arbor and 
 cut at the same time (see Figure 125). Care must 
 be taken to make sure that the sides of the blanks are 
 truly parallel; otherwise, when the blanks are clamped 
 together, they will spring the arbor and cause it to 
 run out making it impossible to produce accurate 
 teeth. Machines using formed milling cutters are 
 often automatic, and several may be operated by one 
 attendant. When stock gears are made in large quan- 
 tities, the machines may be simplified if a separate 
 one is used for each size and kind of gear, for such 
 an arrangement permits of using a plain index wheel 
 that has the same number of holes as there are teeth 
 to be cut. With this arrangement, teeth may be cut 
 at random around the wheel to avoid uneven heating. 
 The cutting of spur gears by means of formed milling 
 cutters is the cheapest method, and is accurate 
 enough for all ordinary work. 
 
 Formed milling cutters are also widely used for 
 cutting bevel gears, but are not so satisfactory with 
 bevels as with spur gears. Since bevel-gear teeth 
 taper down toward the apex of the pitch cone, the 
 
 sides of the cut between them can never be parallel 
 (see Figure 116), and it is therefore impossible, with 
 a formed cutter that has fixed curves, to give the cor- 
 rect shape to the tooth throughout its entire length. 
 The practice is to use a cutter that is correct for the 
 large end of the tooth, and to set the work so that 
 the tooth is cut to the proper thickness on the pitch 
 line at the small end. The tops of the teeth are then 
 too thick at the small end, and they are filed off. The 
 milling process is more satisfactory with narrow- 
 faced bevel gears than with wide ones, as the devi- 
 ation from the correct form is not so marked. Since 
 the teeth approach one another, the cut between them 
 must narrow down, and it is evident that but one side 
 of the tooth space can be cut at a time; accordingly 
 at least two cuts must be taken for each space, the 
 two cuts matching up on the bottom. Figure 116 
 shows a milling cutter cutting the left-hand side of 
 a bevel-gear tooth; the opposite cut on the other side 
 of the groove has been made. 
 
 Template Principle.— The second, or template prin- 
 ciple, is illustrated in Figure 117, which shows a 
 small portion of a bevel gear with the teeth already 
 cut. The letter o marks the apex of the pitch 
 cone, toward which all the tooth elements, such as a— b 
 and c— d center. A template. A, having a curved por- 
 tion, e — f, of the correct form required for a tooth at 
 the distance a'— o from the apex. If the line a'— o be 
 held at o, and the other end be moved along the tem- 
 plate to c', it would follow the side of the required 
 tooth, a— b— c— d. The principle is applied practi- 
 cally by having a shaper tool mounted in a frame, 
 
 'ill 
 
 * .1 i ♦ 
 
* 
 
 342 THE MECHANICAL EQUIPMENT 
 
 which swings about the point o under the influence 
 ot the former, A, the point of the cutting tool moving 
 backward and forward from a to b across the face 
 of the gear on the line a'-o. A roller, B, on a 
 swinging frame, follows the former from a' to c' and 
 guides the tool in a series of cuts that will produce 
 the surface required. According to this method, the 
 bevel-gear blank is first gashed with grooves which 
 rough out most of the stock, leaving the sides to be 
 limshed. The corresponding sides, x-x, of each tooth 
 are finished, and a new former, curved in the oppo- 
 site direction, is used to form the opposite sides y—y 
 in a second series of cuts. This method is' used 
 mainly m connection with bevel gears, as shown, but 
 may be used for cutting spur gears; the only differ- 
 ence, m the latter case, is that the successive strokes 
 of the cutting tool, instead of centering on the point 
 o, are parallel. In fact, a spur gear is a special case 
 of a bevel gear, in which the point o has moved off 
 toward infinity, and the pitch cone has become a 
 cylinder. The cutting tool is made narrow enough 
 to go through the opening between the teeth at the 
 smallest point, and right- and left-hand cuts match up 
 on the bottom, as in the milling operation illustrated 
 m Figure 116. 
 
 The template method applied to bevel gearing is 
 much more accurate than the formed-cutter method. 
 The only errors possible are inaccuracies in the shape 
 and setting of the former, and the inability of the 
 tool to coincide exactly with the radial line to the 
 apex. These inaccuracies are small, however, and 
 teeth cut on this principle are very .satisfactory. ' 
 
 GEAR-CUTTING 
 
 343 
 
 Describing-Generating Principle. — The describing- 
 generating principle duplicates mechanically the 
 method of drawing the involute curve. This curve, 
 which forms the basis of the sides of involute teeth, 
 is the one traced by a point in a string which is un- 
 wrapped from a cylinder (see Figure 115). The circle 
 corresponding to the cylinder is called the base circle. 
 Suppose that the point of a shaper tool, a, is held 
 against the side of a gear blank mounted on center, 
 b, below it, and that it touches the gear at the top 
 of the base circle. If the base circle of the gear blank 
 is rolled to the right along a horizontal line, c — d, 
 through the point of the tool, the tool will trace an 
 involute curve, a — e, on the side of the gear. If, dur- 
 ing this process, the shaper tool is given a recipro- 
 cating motion across the face of the gear, it will cut 
 a true involute surface that may be used as one side 
 of the tooth. In practice, the side of the tooth would 
 be cut in the reverse direction, from e to a, but the 
 principle is the same. By indexing the blank all 
 around, the corresponding sides of each tooth may be 
 similarly generated. By setting the blank over the 
 thickness of a tooth and making the sidewise motion 
 to the left instead of to the right, the opposite sides 
 of the teeth may be formed. This method may be used 
 for cutting either spur or bevel gears. In the case 
 of spur gears, the strokes of the cutting point, a, will 
 all be parallel. In the case of bevel gears, they will 
 center down to a common point corresponding to o 
 in Figure 117. 
 
 Perm-Generating Principle. — The fourth principle 
 — ^the form-generating — is based upon the fact that 
 
344 
 
 THE MECHANICAL EQUIPMENT 
 
 GEAR-CUTTING 
 
 345 
 
 any gear in an interchangeable set will run with any 
 other gear of the set. This is true no matter what 
 the number of teeth may be, and applies to racks as 
 well as to gears of any diameter. The operation of 
 this principle may be reversed and utilized to make 
 one gear form cut another. If one of the gears is of 
 hardened tool steel, and has the edges along one side 
 of the teeth sharp enough to act as cutting edges, 
 that gear may reciprocate sidewise across the face 
 of the other, the cutting gear and the blank being 
 rotated, meantime, as if they were in mesh. The 
 result of this action is that the teeth of the cutting 
 gear forms grooves in the other which will conform 
 exactly to the space between the teeth that a mating 
 gear should have. This action is illustrated in Figure 
 119. The successive positions shown represent the 
 position of the tooth, a, with reference to the work; 
 the shaded portion, b, shows the material that would 
 be cut out by one of the transverse passes of the cut- 
 ting gear. The distance between the successive posi- 
 tions in the figure is, of course, far greater than it 
 would be in actual practice. This principle is em- 
 bodied in a Fellows gear-shaper. Figures 125 and 126, 
 and may be used in cutting either spur or spiral 
 teeth. In the former case, the gears have no rotation 
 during the cutting stroke; in the latter instance, they 
 are given a uniform rotation during the cutting ac- 
 tion, which results in a spiral tooth instead of a 
 straight one. This form-generating principle gives 
 very accurate work. The operation known as bob- 
 bing, which will be described later, is based on this 
 principle. 
 
 The cutting gear may have any convenient number 
 of teeth, or may be part of a rack. The teeth of a 
 rack are often used to do the forming, as the side of 
 a rack tooth is a straight line, and therefore easier 
 to originate. Figure 120 shows the generating prin- 
 ciple applied in four ways. At A the rack is 
 rolled past a plastic gear and the teeth are moulded 
 by impression. x\t B the tool, T, to the right, has 
 a straight cutting edge, which conforms to one side 
 of a tooth in an imaginary rack. If this is made to 
 travel to the right, as the rack did in A, and if at 
 the same time it has a sidewise reciprocating mo- 
 tion, it will cut out the side of the tooth which it 
 touches. If the cutting tool has two cutting edges, 
 corresponding to the opposite sides of a tooth on the 
 rack, as at T', it will cut out both sides of the 
 tooth space. Instead of a reciprocating cutter, a 
 milling cutter may be used, as at C, the side of the 
 cutter conforming to the imaginary tooth rack and 
 duplicating in every way the action of the shaper 
 cutter, T, in B. In D the side of an emery wheel 
 is substituted for the milling cutter of C; the action 
 is the same in both cases. Of these four means, the 
 first, or impression, method is of course impractic- 
 able; it is mentioned only to help to illustrate the 
 principle. The shaping and milling methods, shown 
 at B and C, are widely used. The grinding method, 
 shown at D, is used to true up the surfaces of gears, 
 which have been cut by one of the previous methods, 
 and then hardened; it is the most accurate of all. 
 
 Spur-Gear-Cutter. — Only a few of the typical gear- 
 cutting machines can be shown, as there are literally 
 
w 
 
 15 
 
 346 
 
 THE MECHANICAL EQUIPMENT 
 
 scores of designs. The most generally used is the 
 automatic spur-gear-cutter, similar to those shown 
 in Figures 121 and 123. In the machine shown in 
 figure 121, the gear blanks are mounted on a hori- 
 zontal arbor, which is carried in the spindle, a, and 
 IS provided with an adjustable outboard support, b, 
 in order that the greatest possible firmness may be 
 given to the work. This arbor is capable of rotation, 
 but IS under the control of a large and very accurately 
 divided index wheel, in the casing c, which controls 
 the spacing of the cut around the rim. A formed 
 milling cutter, like that shown in Figure 122, is 
 carried on a spindle, d, and is given a feed across the 
 tace of the gear. As each cut is completed the car- 
 nage, e, IS returned, the work is indexed to the next 
 position, and the next cut is made. All the motions 
 ot the machine are automatic; the speed of indexing 
 IS independent of the rate of feed and speed of the 
 cutter, and the indexing is done as rapidly as it is 
 possible to do it without causing shock. The feed 
 mechanism of the cutter is disengaged during the 
 indexing, and becomes operative only on its com- 
 pletion. FigTire 123 shows the position of the cutter 
 and the work reversed; the gear blanks are held on 
 the vertical arbor, a, carried by a saddle, b, on the 
 i, 1 machine. The index wheel is inside the 
 saddle. The cutter spindle, c, is carried by the up- 
 right, and has a vertical travel instead of a horizontal 
 one. The principles of action are not altered by this 
 change m arrangement. 
 
 Machine Embodying Template Principle-Figure 
 124 shows a machine embodying the template prin- 
 
 .:^i 
 
 m 
 
346 
 
 THE AlHcilAXUAI. IXjLlPMENT 
 
 scores of (lo^^igns. Tlio n.osl Kvn<.rallv usod is the 
 autoniatic spur-gear-cuttor, similar to those sliown 
 in Hgurcs 121 and 123. In tlic inaoliine sliown in 
 l^igure 121, the gen,- l.lanks arc inoimlwl on a hori- 
 zontal arhor, whi,-], is earrio.l i„ the spin.llo, a, and 
 IS provided with an a.l.justal.l.. oiitlmard support h 
 in order that the greatest possible firmness niav' be 
 given to the work. This arl.or is eapahle of rotation, 
 but IS under the control of a large and verv accurately 
 divided mde.x wheel, in the casing c. which controls 
 the spacing of the cut aroun.l the rim. A formed 
 milling cutter, like that shown in Fi<.ure f-w is 
 carried on a spindle, d, and is given a feed aeross'the 
 tace of the gear. As each cut is completed the car- 
 nage, e, IS returned, the work is indexe.l to the next 
 position, and the next cut is nuul... All the motion.s 
 ot the machine are automatic; the speed of indexin- 
 IS indepen.lent of the rate of feci and speed of the 
 cutter and tlie imle.xing is done as rapidiv as it is 
 possible to do it without causing shock. 'The feed 
 mechanism of the cutter is <lisengage,l during the 
 indexing, and l.ecoines operative onlv on its com- 
 pletion. Figure 1-2?, shows the position of the cutter 
 and the work reversed; the gear blanks are held on 
 the vertical arbor, a, carrie<l by a saddle, b, on the 
 ..., Z "i''f'l'i"<^- The index wheel is inside the 
 saddle. The cutter spindle, c, is carried bv the up- 
 right, and has a vertical travel instead of a horizontal 
 one. The principles of action are not altered by this 
 change in arrangement. 
 
 Machine Embodying Template Principle.-Figure 
 124 .shows a machine embodying the template prin- 
 
 s 
 
 i < 
 
 s -• ^ 
 ■^ p 
 
 >:^ S3 H^ 
 
 < - 
 
 OS -' 
 
 Oh = 
 
 — fc- 
 
 
 < . J 
 
 O - ^ 
 
 • i: O 
 
 CO X fa 
 
 < ? 5 
 
 — tt 
 
 01 '* 
 
 A 
 
 -,5 
 
 5^1 
 
 
 CO 
 
348 
 
 THE MECHANICAL EQUIPMENT 
 
 l! 
 
 
 »' 
 
 ciple. The upright portion of this machine is a 
 specialized form of the vertical slotter described on 
 page 000. In fact, it will be seen that the slotter 
 illustrated in Figure 97 might be rigged up to per- 
 form the functions of this tool. The column is mounted 
 on a long base plate, a, and may be moved in and out 
 to accommodate different diameters of gears. The 
 gear blank is supported on an arbor, b, on a rotating 
 table, which is indexed by a worm and a worm wheel 
 operated through change gears by an electric motor 
 provided for that purpose. The machine is large 
 enough to swing work forty feet in diameter. The tem- 
 plates for shaping the tooth outline are mounted in 
 brackets, c,c, on the tool head on either side of the tool 
 post. The tool post is pressed tow^ard the right- or left- 
 hand former by a spring, as may be required, and is 
 provided with a feeding mechanism for moving it out- 
 ward. It is thus used to reproduce the outline of the 
 template and to form each side of a space between two 
 teeth. This type of machine is used for coarse-pitch 
 gears that are too large to be cut by a formed tool. It 
 has the advantage over the formed cutter process of 
 being comparatively simple in operation and adapt- 
 able to special w^ork; gears of this size are never 
 made in quantity. 
 
 Fellows Gear-Shaper. — The Fellows gear-shaper, 
 shown in Figures 125 and 126, is a successful appli- 
 cation of the form-generating method. Figure 125 
 shows three gear blanks mounted on the work spindle. 
 The cutter has the form of a complete gear, and is 
 carried on the end of a reciprocating vertical ram 
 or slide, a, in the saddle, b. The saddle is adjustable 
 
348 
 
 THE MRC4IA\l(^\Ti h:Q( II>A1K\T 
 
 Ik 
 
 (']j)](\ Tlio ii])ri<;'lit poi'tioH of tliis inacliinc is a 
 six'cializod form of tho vortical slottor doserihod on 
 ]}i\iro ()()(). In fact, it will 1h» scon that the slotter 
 illustrat(Ml in Fignro 07 nii.i»lit he i-iggcd np to per- 
 form tin* fnnclions of this tool. Tin* column is mounted 
 on a lon,ti,' hasc plate, a, and may he moved in and out 
 to accommodate different diameteis of .i»ears. TIk^ 
 .U'cai- hiank is supported on an arhor, h, on a rotatinij; 
 tahle, whicli is indexed hv a worn) and a worm wheel 
 o[)erated tlirongh clian<;e gears hy an electric motor 
 provided for that purpose. The machine* is lar^-e 
 enou,<;h to swin.!*' work forty feet in diameter. The tem- 
 plates for shaj)in.i;- the tooth outline an* mounted in 
 l)!-ackets, c,c, on the tool head on either side of the tool 
 post. The tool post is pressed towarci the right- or left- 
 hand foinier hy a spring, as may he recpiired, and is 
 I)r()vided with a feeding mechanism for moving it out- 
 ward. It is thus nsed to reproduce the outline of the 
 template and to form each side of a space hetween two 
 teeth. This ty])e of machine is used for coarse-|)itch 
 gears that are too large to ])e cut hv a formed tool. It 
 has the advantage over the formed cutter process of 
 heing compai'atively sim])le in operation and adapt- 
 ahl(» to special work; gears of this vsize are never 
 made in quantity. 
 
 Fellows Gear-Shaper. — The Fellows gear-shaper, 
 shown in Figures 12-") and 12(), is a successful appli- 
 cation of the form-generating method. Figure 125 
 sliows tliree gear l)lanks mounted on the work spindle. 
 The cutter has the foi'm of a eomph'te gear, and is 
 carried on the end of a reciprocating vertical ram 
 or slide, a, in the saddle, b. The saddle is adjustable 
 
r7 
 
 
 
 350 
 
 THE MECHANICAL EQUIPMENT 
 
 sidewise to accommodate work of different diameter, 
 and the stroke of the ram is adjustable to suit dif- 
 ferent widths of face on the work to be cut. The 
 action of the machine is as follows: 
 
 The saddle with the cutter is withdrawn from the 
 work spindle, and the blanks are set in place. With- 
 out rotating either the cutter or the work, the head 
 is fed inward toward the center of the blank. This 
 feed is continued until the cutter has cut its way 
 into the blank to the proper depth. The inward feed 
 is then stopped, and the cutting tool and the blanks 
 are rotated slowly at the same pitch velocity. The 
 rotation takes place intermittently at the end of each 
 stroke of the cutter. As this action is continued, the 
 cutter will gradually generate the teeth around the 
 surface of the blank until the gear is finished. An 
 adjustable stop, c, is shown on the side of the head, 
 which is set down against the side of the gear or the 
 supporting device and locked in position. The stop 
 takes the reaction of the cut, and relieves the driving 
 mechanism of any tendency to spring. The cutting 
 stroke is usually upwards, so that it forms a draw cut 
 — the thrust taken up by the stop. The cutter may be 
 reversed and work on the downward stroke when it 
 is necessary to plane into a recess, as in automobile 
 transmission gears. This type of machine, which is 
 used for medium-sized gears, produces very accurate 
 work. The sides of the cutter are relieved so that 
 the tool may be ground on its upper face without 
 losing the correct shape, and the cutter is trued up 
 by grinding after it is hardened, by the process illus- 
 trated in C, Figure 120. 
 
 GEAR-CUTTING 
 
 351 
 
 Hobbing^ Machines. — The form-generating principle 
 may be used for machines of the milling type as 
 well as for those of the shaper type. A case 
 in point is the bobbing process. Figure 127 shows 
 
 >ri 
 
 m 
 
 ^ Upper IndcK Worm-g 
 
 Saddle 
 
 ^Upper Index 
 Whetl 
 
 FIG. 126. SECTION OF GEAR SHAPER HEAD 
 Fellows Gear Shaper Co. 
 
GEAR-CUTTING 
 
 353 
 
 
 an automatic bobbing machine that may be used for 
 cutting either spur, helical or worm gears, according 
 to the angle at which the cutter head, a, is set. The 
 cutting tool used is a **hob," (see a. Figure 99), a 
 special type of formed milling cutter, in which the 
 teeth are shaped and relieved, as in Figure 122, but 
 are arranged in a helix, like a screw thread, instead 
 of in a circle. Every one has noticed how a screw 
 thread appears to travel along its axis as the screw 
 is revolved. If the hob is mounted on the spindle, b, 
 and the axis is tipped up at an angle equal to the 
 helix angle, the cutting motion of the edges will be 
 parallel to the axis of a gear blank mounted on the 
 arbor, c; the action of the edges will have the same 
 effect as that of the milling cutter in C, Figure 120, 
 as it moves past the face of the blank. In operation, 
 the gear blanks mounted on the arbor, are first fed 
 inward toward the cutting tool, and are rotated 
 by a power feed meantime, in order that they may 
 have the rolling action required. When the proper 
 depth of cut is reached, the cutting head is given a 
 gradual downward feed across the face of the gears 
 until the work is completed. In some respects this 
 type of machine is better than the ordinary one 
 shown in Figures 121 and 123, since a greater num- 
 ber of teeth are cutting at once, but absolute rigidity 
 is more important in this type and the motions are 
 more difficult to control. 
 
 Cutting Helical Gears. — Helical gears may be cut 
 by either the shaping or the milling process. The 
 Fellows gear-shaper, shown in Figures 125 and 126, 
 may be used to cut them. If the Fellows machine is 
 
 
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 .'111 (intonmtic lioUhini;- niacliinc that may he used for 
 ('iittiii.u- cithcM- spur, hi^lical oi* worm ^^ears, according 
 to the aiii;lc at which tlic cutter head, a, is set. The 
 (•uttiu,i>- tool used is a 'Mioh," (see a. Figure 90), a 
 sjxH'ial type ot* formed milling cutter, in wiiich the 
 te(*th are shaped and relieved, as in Figure 12:^, but 
 ai-e arranged in a helix, like a screw thread, instead 
 of in a circle. Evei'v one has noticed how a screw 
 thread a|)peais to ti'avel along its axis as the screw 
 is revolved. .11* the hoh is mounted on the spindle, b, 
 and the axis is tipped up at an angle equal to the 
 helix angle, the cntting motion of the edges will be 
 parallel to the axis of a gear blank mounted on the 
 arbor, c: the action of the edges will have the same 
 elTect as that of the milling cuttei* in C, Figure 120, 
 as it moves past the face of the blank. In operation, 
 the geai' blanks mounted on the arbor, are first fed 
 inwai'd toward the cutting tool, and are rotated 
 hy a ])ower feed meantime, in order that they may 
 have the i-olling action re<piired. WIhmi the proper 
 depth of cut is reached, the cutting head is given a 
 gradual downward feed across the face of the gears 
 until the work is com|)leted. In som(^ r(^<pects this 
 type of machine is better than the ordinarv one 
 shown in Figures 121 and 12o, sinc(^ a greater nnm- 
 hc?" of teeth ar(^ cuttini»- at once, but absolute rigidity 
 is more impoi'tant in this type and the motions are 
 more difficult to control. 
 
 Cutting' Helical Gears. Helical g(»ais inay be cut 
 by either tlu' shaping or the milling })f•oc(^^s. Tln^ 
 l^'ellows gear-shapei-, shown in Figures 12.") and 12(>, 
 niay be used to cut tlirm. \{ the Fellows machine is 
 
T' 
 
 354 THE MECHANICAL EQUIPMENT 
 
 used, the cylindrical guide, k, in Figure 126, is given 
 an additional rotary motion by means of the helical 
 cam surface, a. Figure 128, which has the same lead 
 as the helix of the cutter, b, at the other end of the 
 shaft, c. The camming action of the surface, a, on a 
 fixed pin, not shown, gives the cutter the correct 
 helical motion required. The bobbing machine. Fig. 
 nre 127, may be used to cut helical gears; the head 
 may be set around so that the teeth of the hob will 
 move past the pitch surface of the gear blanks at the 
 required helical angle, and the rotary feed of the 
 blanks may be suitably adjusted. In other respects, 
 the action of the machine is the same as for cutting 
 straight teeth. If the axis of the cutting hob is set 
 horizontal, the machine may be used to cut a worm 
 gear. 
 
 Cutting Bevel Gears.— Figure 129 shows a machine 
 that is used to cut bevel gears according to the 
 formed-cutter method. In many respects it is like 
 the machine shown in Figure 121, but the slide, a, 
 Figure 129, carrying the cutters (not shown) is in this 
 case provided with an angular adjustment, b, in the 
 vertical plane, to give a feed along the pitch cone. 
 The action of the machine is similar in other respects 
 to the spur-gear cutter— if the saddle is dropped to 
 a horizontal position, it may be used for spurs. 
 
 Figure 130 shows a bevel-gear cutting machine that 
 embodies an application of the former, or template, 
 principle illustrated in Figure 117. The blank is 
 mounted on a horizontal indexing arbor, a. The cut- 
 ting tool, b, is carried in a shaper head sliding on a 
 carriage, c, which has a horizontal angular adjust- 
 
 GEAR-CUTTING 
 
 f;r; 
 
 PIG. 129. AUTOMATIC BEVEL-GEAR MILLING MACHINE 
 
 Brown & Sharpe Mfg. Co. 
 
 ment so that it may be set parallel to the side of the 
 theoretical pitch cone of the bevel gear to be cut. 
 In the view shown, it is seen nearly **end on," and 
 the stroke of the tool-carrying head is forward along 
 the sliding surface, c. The path of the cutting tool, 
 b, as it is slowly fed in toward the center of the blank 
 
 .>^k 
 
354 THE MECHANICAL EQL'llWlENT 
 
 used, the cylindrical guide, k, in Figure 126, is given 
 an additional rotary motion by means of the helical 
 cam surface, a. Figure 128, wliicli lias the same lead 
 as the helix of the cutter, h, at the other end of the 
 shaft, c. The camming action of the surface, a, on a 
 fixed pin, not sliown, gives tlie cutter the correct 
 helical motion re(iuired. The hobhing nuichine. Fig- 
 ure 127, may be used to cut helical gears; the head 
 may be set around so that the teeth of the hob will 
 move past the pitch surface of the gear blanks at the 
 required helical angle, and the rotary feed of the 
 blanks may ])e suitably adjusted. In other respects, 
 the action of the machine is the same as for cutting 
 straight teeth. If the axis of the cutting hob is se't 
 horizontal, the machine may be used to cut a worm 
 gear. 
 
 Cutting Bevel Gears.— Figure 129 shows a machine 
 that is used to cut bevel gears according to the 
 formed-cutter method. In many respects it is like 
 the machine shown in Figure 121, but the slide, a, 
 Figure 129, carrying the cutters (not shown) is in this 
 case provided with an angular adjustment, b, in the 
 vertical plane, to give a feed along the pitch cone. 
 The action of the machine is similar in other respects 
 to the spur-gear cutter— if the saddle is dropped to 
 a horizontal position, it may l)e used for spurs. 
 
 Figure 130 shows a bevel-gear cutting machine that 
 embodies an application of the former, or template, 
 principle illustrated in Figure 117. The blank is 
 mounted on a horizontal indexing arbor, a. The cut- 
 ting tool, b, is carried in a shaper head sliding on a 
 carriage, c, which has a horizontal angular adjust- 
 
 GEAK-crTTTNTJ 
 
 :]:>:> 
 
 FIG. 129. AUTOMATIC BE\'EL-r,EAR MILLING MACHINE 
 
 Brown & Sharp<^ Mfjr. Co. 
 
 ment so that it may be set parallel to the side of the 
 theoretical pitch cone of the bevel gear to be cut. 
 In the view shown, it is seen nearly *'end on,'' and 
 the stroke of the tool-carrying head is forward along 
 the sliding surface, c. The path of the cutting tool, 
 b, as it is slowlv fed in toward the center of the blank 
 
i 
 
 If 
 
 iri 
 
 GEAR-CUTTING 
 
 357 
 
 between each cutting stroke, is controlled by the 
 roller, d, corresponding to the one, B, shown in Figure 
 117. Three former plates, e, f, g, are mounted on the 
 triangular plate, h. The first one, e, on which the 
 roller now rests, is straight, and is used for a plain 
 roughing cut once around, which removes most of the 
 stock between the teeth. The plate, h, is then rotated 
 one-third of a turn, and the former, f, is used to fin- 
 ish one side of the teeth. When this has been done 
 around the blank, the third former, g, is used to 
 finish the opposite side of the teeth. 
 
 Machine Embodying^ Form-Generating Principle. — 
 The form-generating principle is used in the machine 
 shown in Figure 131, which is built by the same firm 
 as the one that builds the machine just described. 
 If the height of the pitch cone of a bevel gear is 
 shortened, the gear grows flatter until the limit is 
 reached in one of zero height, in which the teeth are 
 ranged around in a circle on a pitch surface that is 
 a plane. Such a gear, called a crown gear, bears the 
 same relation to bevel gears that the rack does to 
 spur gears; and the teeth, like those of a rack, have 
 straight sides. Just as the cutter, T, in B, Figure 
 120, replacing the side of an imaginary rack tooth, 
 may be used to generate a spur tooth, so a straight- 
 sided cutting tool, replacing the side of a crown gear 
 tooth, may, when properly rolled in relation to a 
 bevel gear blank, be used to cut the proper tooth 
 form. The gear to be cut is shown at a. Since there 
 are two cutters, both sides of a tooth are finished at 
 once. The upper cutter, b, is shown just clear of the 
 work; the lower one is hidden. Those sectors of the 
 
 mi 
 I 
 
GKAU-CrTTLXG 
 
 o57 
 
 hotwoon cacli cutting' strok(\ is tduI rolled hy tlio 
 rollor, (1, C'orrospondiii^- to tin one, 1>, shown in Figure 
 117. Tliree lormoi- plates, e, f, g, are mounted on the 
 triangular plate, h. The first one, e, on which the 
 roller now rests, is straight, and is used for a plain 
 roughing cut once around, which removes most of the 
 stock between the teeth. The plate, h, is then rotated 
 one-third of a turn, and the former, f, is used to fin- 
 ish one side of the teeth. AVhen this has been done 
 around the ])lank, the third former, g, is used to 
 finish tlie opposite side of the teeth. 
 
 Machine Embodying Form-Generating Principle. — 
 The t'oi'm-gcMierating j)rincii)le is used in the machine 
 sliown in P'igure 131, which is l)uilt l)y the same firm 
 as the one that builds the machine just described. 
 If the heiglit of the pitch cone of a bevel gear is 
 shortened, the gear grows flatter until tlie limit is 
 reached in one of zero heiglit, in which the teeth are 
 ranged around in a circle on a pitch surface that is 
 a plane. Such a gear, called a crown gear, bears the 
 same relation to bevel gears that the rack does to 
 spur gears; and the teeth, like those of a rack, have 
 straight sides. Just as the cutter, T, in B, Figure 
 120, replacing the side of an inmginary rack tooth, 
 ?uay be used to generate a spur tooth, so a straight- 
 sided cutting tool, replacing the side of a crown gear 
 tooth, nuiy, when properly rolled in relation to a 
 bevel gear blank, be used to cut the proper tooth 
 form. The gear to l)e cut is shown at a. Since there 
 are two cutters, l)oth sides of a tooth an» finished at 
 once. The ui)per cutter, b, is sliown just clear of the 
 work; the lower one is hidden. Tliose sectors of the 
 
GEAR-CUTTING 
 
 359 
 
 crown gear and the master gear which are control- 
 ling the motion are seen at c and d. 
 
 The same firm has developed a machine for gener- 
 ating with a milling cutter a bevel gear that corre- 
 sponds to the helical spur gear. In this gear the 
 teeth are curved on the arc of a circle. 
 
 There are so many types of gear-cutting machines 
 that it is impossible to consider all of them here; 
 enough have been shown, however, to illustrate the 
 more general principles involved. 
 
 
II 
 
 GEAR-CUTTJNG 
 
 850 
 
 crown gear and the master gear whicli are control- 
 ling the motion are seen at c and d. 
 
 The same firm has developed a machine lor gener- 
 ating with a milling cutter a bevel gear that corre- 
 sponds to the helical spur gear. In this gear the 
 teeth are curved on the arc of a circle. 
 
 There are so many types of gear-cutting machines 
 that it is impossible to consider all of them here; 
 enough have been shown, however, to illustrate tlu* 
 more general principles involved. 
 
I; I 
 
 SCREW-THREAD-CUTTING 
 
 361 
 
 'I! If 
 
 i 1 1 
 11 
 
 I 
 
 ( '. 
 
 f ! 
 1 1 
 
 (! 
 
 CHAPTER XX 
 SCEEW-THEEAD-CUTTING 
 
 Early Methods of Cutting Screw Threads.— Screw- 
 thread-cutting, like gear-cutting, is one of the funda- 
 mental operations found in every machine shop, how- 
 ever crude. The early screws were large, and made 
 of wood, because such screws could be *^ chased" by 
 hand on the rough speed lathes then used. The first 
 metal screws were formed by means of hardened dies 
 of the crudest kinc^, without cutting edges, which 
 were turned and forced onto the bar to be threaded. 
 Ihey were, of course, wretchedly inaccurate, and 
 many attempts were made to originate threads with 
 some pretense to accuracy. Many of these early at- 
 tempts were very ingenious; in one instance, two wires 
 side by side were wound around the bar and soldered 
 to It. One of them was then removed, leaving a space 
 between the coils of the other, and forming a screw 
 thread. 
 
 Another method was to chase the thread with a 
 cutting tool, which was fed forward by a knife-like 
 edge held against the work at the required thread 
 angle and allowed to run freely, carrying the cutting 
 tool with it as the work was revolved. This method 
 was better, and it was the one used by Maudslay in 
 generating the lead-screw threads for his first lathes 
 The invention of the slide-rest soon led to the de- 
 velopment of the lead screw and the screw-cutting 
 
 360 
 
 lathe. As pointed out elsewhere, Maudslay at first 
 used a different lead screw for each size of thread, 
 but he soon developed the combination of a single 
 lead-screw with change gears to vary its speed in 
 relation to the work; this is used today. 
 
 Standardization of Screw Threads. — There is no 
 detail in machine construction in which standardiza- 
 tion is more essential than in connection with screw 
 threads. We are so used to standard practice in this 
 respect that the modern mechanic does not realize 
 the chaos that existed in the early machine shops. 
 Every nut had to be fitted to its respective bolt, and 
 both were marked in order that they might be iden- 
 tified if they were taken apart. The first attempt at 
 standardization was made by Maudslay, who settled 
 upon a set of standard taps and dies for use in his own 
 shop. Joseph Clement, a mechanic who worked for 
 Maudslay, took up his work, standardized it still 
 further, and began manufacturing it for the market. 
 Joseph Whitworth, who worked for both Maudslay 
 and Clement, standardized the screw-thread practice 
 of England, and in 1841 brought out what is still 
 known as the *' Whitworth thread." 
 
 Types of Screw Threads. — Since screw threads are 
 used for a wide variety of purposes, it is not possible 
 to standardize them completely, but standardization 
 has been made to the extent of reducing them to a 
 few well-known types, which are differentiated partly 
 by their use and partly by their historical origin. 
 
 The simplest thread is the V-thread, a cross-section 
 of which is shown at A, in Figure 132. This is formed 
 by straight sides, which are on an angle of 60 degrees 
 
 1 " J 
 
 'i 
 
I 
 
 III 
 
 1 ; ■ ( 
 
 362 
 
 THE MECHANICAL EQUIPMENT 
 
 
 A- V- THREAD 
 
 014P 
 
 B- US. STANDARD 
 
 C -WHITWORTH 
 
 r Pitch. P — ^ 
 JhU7/H 
 
 D * SQUARE THREAD 
 
 E - ACME STANDARD 
 
 FIG. 132. SECTIONS OP STANDARD SCREW THREADS 
 
 to each other, and which have sharp corners at top 
 and bottom. This thread is the simplest to make, 
 but It has many disadvantages. The sharp point on 
 ^e outer end of the thread is easily bruised, while 
 the sharp corner at the root of the thread weakens 
 the bolt greatly, and is difficult to maintain on ac- 
 count of the wearing of the point of the tool that 
 makes the cut. This form, however, is well adapted 
 to the making of pressure-tight joints and in slightly 
 modified form, is the basis of the Briggs thread, 
 which IS standard for pipes and pipe fittings. This 
 IS almost its only commercial use. 
 
 .J^^ F""'*^"^ ^^^^^^ standard thread, B, is similar to 
 the V-thread, except that the top and the bottom are 
 flattened for a distance equal to one-eighth of the pitch. 
 The depth is therefore three-quarters that of the cor- 
 
 SCRBW-THREAD-CUTTING 
 
 363 
 
 responding V-thread. This standard was developed 
 by William Sellers, of Philadelphia, in 1864, and 
 is the one most widely used in the United States. 
 It is less liable to injury than the V-thread, and is 
 much stronger. The tools for cutting it are quite 
 as easily made, and much more easily maintained. 
 
 The standard thread used in England is the Whit- 
 worth thread, C, the sides of which have an angle 
 of 55 degrees instead of 60; the top and bottom are 
 rounded instead of flat. In some respects this thread 
 is better than the United States standard, as it has 
 no sharp corners and wears well; it is not, however, 
 so easy to originate. The metric screw thread used 
 on the continent of Europe was adopted in 1898 by an 
 international congress which studied all the standards 
 then in existence. This thread is similar to the 
 United States standard, but a slight clearance is per- 
 mitted, which is obtained by rounding the corner at 
 the root of the thread. 
 
 All of these standards have not only a specified 
 cross-section, but a definite number of threads per 
 inch for each size of bolt. The United States stand- 
 ard has larger threads for small screws than has been 
 found the best in practice. An additional standard 
 has therefore sprung up, known as the S. A. E. stand- 
 ard, for the smaller sizes, which conforms to the 
 shape of the United States thread, but contains more 
 threads per inch. 
 
 In all these standards the angle between the sides 
 of the thread is 55 or 60 degrees. An angle as steep 
 as this produces a considerable side thrust on the 
 nut, which increases the friction. When the threads 
 
364 
 
 (ii 
 
 I! ;;'!l 
 
 '■r 
 
 THE xMECHANICAL EQtnPMENT 
 
 SCREW-THREAD-CUTTING 
 
 365 
 
 are nsed for holding-down purposes— as in the case 
 of bolts and nuts, this friction is an advantage. When 
 the thread is used to transmit running motion, fric- 
 tion IS a detriment; hence, square threads, as shown in 
 D, were developed for this purpose. In these, the 
 space and the tooth have the same thickness. Such 
 threads are little more than half as strong as United 
 States threads, and cannot be cut in dies. 
 
 For transmitting motion intermittently— as in the 
 traversing of a lathe carriage by the lead-screw- 
 the nut IS made in halves, to be clamped on the 
 thread when desired. For such a purpose, the square 
 thread is difficult to enter, and has no take-up for 
 wear. To overcome these difficulties, the Acme 
 Standard thread, shown at E, is now generally used. 
 The angle between the sides of this thread is 29 de- 
 grees, and the flat place at the top is about one- 
 third of the pitch. The widths of the thread and 
 the space are equal at a point midway of their height. 
 This thread is a compromise between the United 
 States and the square thread, and is generally used 
 for lead screws and other forms of working screw. 
 It is stronger than the square thread, allows take-up 
 for wear, is easily clamped by a split nut, and may 
 be cut by ordinary taps and dies. 
 
 Other forms of threads are used for special pur- 
 poses, but need not be considered here. 
 
 Cutting Screw Threads.— Modern methods of cut- 
 ting screw threads are: first, by means of taps and 
 dies, operated by hand or in a machine; second, by 
 means of lathe and lead screw; third, by cam control 
 in automatic turret lathes; and fourth, by milling. 
 
 For thread-cutting, the first method is used more 
 than any other. Hand taps and dies are described 
 and illustrated in Chapter XII. For light special 
 work and for rough outside work — such as construc- 
 tion work, country blacksmithing, etc.— these are 
 used in holders provided with two handles. For the 
 smaller sizes of screw threads, the taps must be solid; 
 they are practically like those illustrated in Figures 
 42 and 43. 
 
 In the larger sizes of taps, which are used with 
 machines, the cost of making the entire tool of tool 
 steel would be prohibitive, so the cutters are made 
 separate and inserted in the body. This method has 
 a further advantage in that the cutters may be set 
 out to allow for wear. A great variety of taps and 
 dies has been developed for use on the various ma- 
 chine tools that do threading work. 
 
 Bolt-Threading Machines.— The machines most used 
 for this purpose are the drill press and the turret 
 lathe, both hand and automatic types. Drill presses 
 that are used for this work are equipped with change- 
 gear feeds to give the spindle a lead corresponding 
 to that of the thread to be cut. The holder which 
 carries the tap may be equipped with a friction drive 
 which slips if the tap sticks or strikes the bottom of 
 the hole. Drill presses are also fitted with an auto- 
 matic reverse on the drive, which may be set for a 
 certain depth, so that when the tap has reached this 
 point the spindle is reversed and the tap is backed 
 out. The drill press is generally used for tapping, 
 or threading, rough holes, such as those used for stud 
 bolts in valves, fittings, and general machinery. 
 
 
 i* 
 
 I' 
 
366 
 
 ■f 
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 m 
 
 !■' 'Ii 
 
 '^ ll 
 
 !' -i, I 
 
 J, f 
 
 f 
 
 1 
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 1 * 
 
 i ■ 
 
 I 
 
 THE MECHANICAL EQUIPMENT 
 
 fW. -?'^ "•'' ^, ''^'" produced in quantities, are 
 threaded in a bolt-threading machine, such as that 
 shown m Figure 133. which is specially designed for 
 this purpose. Machines of this character have a 
 power-driven spindle that carries the threading die, 
 a; the bolt, b, to be threaded, is carried in a s^table 
 holder, c, mounted on the slide, d, which is free to 
 
 ZIL"^ ""*• 7^'^'^ ^'^^' «' *hich does the 
 
 threading is opened and closed by a trip rod, e, pro- 
 vided with two adjustable stops. One of these kops, 
 operated by the in-and-out^motion of the slide, is set 
 to open the die when the bolt has been threaded the 
 required length; thus it is possible to withdraw the 
 work quickly without reversing the machine. When 
 the carriage has moved backward, the other stop 
 closes the head and is ready to cut the next bolt. 
 
 Opemi^ Die Heads—There are many types of 
 opening die heads used on machines of this style and 
 
 ;^/°'r!;f* ^ v5f'- ^"« °f *!»««« is shown in Figure 
 134 The sliding cutters, or chasers, a, of carbon or 
 high-speed steel, are clearly shown on the face of 
 the die. They are held in correct register with each 
 other by a spline, or key, b, on the side. The first 
 few threads of the cutters are ground away at c in 
 order that the work of cutting may be distributed 
 over several teeth instead of being concentrated on 
 the first tooth, as would be the case if the full sec- 
 tion were retained. The middle section of the die 
 d, carries on the side next the cutters four proiect- 
 ing spiral cams, e, one for each cutter, which engage 
 corresponding notches, f, in the rear edge of the cut- 
 ters. When the handle, g, is pulled down, these pro- 
 
 FIG. iSS. BOLT-THREADING MACHINE 
 
 367 
 
''^4 
 
 366 
 
 THE MRf'HANICAL EQUIPMENT 
 
 Studs or bolts, when produced in quantities, are 
 
 w„ t P- ' ''t^'""''"^ rnachine,\uch as that 
 shoun m l.,s„re 133, which is specially designed for 
 this purpose. Machines of thi; chai-acter W a 
 power-driven spindle that carries the threading die 
 a; the Mt, b, to be threaded, is carried in a sJtable 
 holder, c, mounted on the slide, d, which is free to 
 
 tTZw'" ""*• ?^' ^'' ^^^''' •'' ^^■'"'^h does the 
 
 h eading is opened and closed by a trip rod, e, pro- 
 xided w,th two adjustable stops. One of these ^tops, 
 operated by the an-and-out-motion of the slide, is set 
 to open the die when the bolt has been threaded the 
 required length; thus it is possible to withdraw the 
 work quickly without reversing the machine. When 
 the carnage has moved backward, the other stop 
 closes the head and is ready to cut the next bolt. 
 
 Opemng Die Heads.-There are many types of 
 opening die heads used on machines of this st^ie and 
 
 ;i ^f r5- '• ^"' "^ ^^'''^ '' «^°^^" i" "Figure 
 l-\ ^''^'''^'"g <^»«ers, or chasers, a, of carbon or 
 high-speed steel, are clearly shown on the face of 
 the die. They are held in correct register with each 
 other by a spline, or key, b, on the side. The first 
 few threads of the cutters are ground away at c in 
 order that the work of cutting may be distributed 
 over several teeth instead of being concentrated on 
 the first tooth, as would be the ease if the full sec- 
 tion were retained. The middle section of the die 
 _d, carries on the side next the cutters four proiect- 
 mg spiral cams, e, one for each cutter, which eno-ao-e 
 corresponding notches, f, in the rear edge of the'cirt- 
 ters. W hen the handle, g, is pulled down, these pro- 
 
 f,'t 
 
 FiG. 133. 
 
 BOLT-THRE.\DIXG MACHINE 
 3G7 
 
llfll I 
 
 SCREW-THREAD-CUTTING 
 
 369 
 
 FI^S. 134 AND 135 
 
 COLLAPSING DIE HEAD AND COLLAPSING TAP 
 Geometric Tool Co. 
 368 
 
 jectioiis cam the cutters into the working position. 
 The die opens automatically by simply stopping the 
 forward travel of the die when the desired length of 
 thread has been cut. This throws the cutters back so 
 that the die head may be withdrawn without having 
 to be unscrewed from the work. 
 
 The cutters may be thrown in again by using the 
 handle or by having a steel tripping-piece strike 
 the pin, g', opposite. They may be adjusted to cut 
 tight or loose threads by means of the adjusting 
 screws, h', the amount of adjustment is read directly 
 on the micrometer scale, i, on the side of the head. 
 Roughing and finishing cuts may be taken by throw- 
 ing the lever, j, forward. This moves the cutters out 
 0.01 inch. The return of the lever to its backward 
 position closes the cutters and locks them in position 
 for the finishing cut. There is a clear hole through 
 the center of the die head and the shank, somewhat 
 larger than the maximum diameter to be threaded, 
 which permits threading any length required. 
 
 P'igure 135 shows a collapsing tap corresponding 
 in size to the die, Figure 134. In this case, the cut- 
 ters, a, are held out in working position by the wedge, 
 b. When the proper depth has been reached, the face 
 of the work pushes back the contact plate, c, and 
 releases a trip, so that the spring withdraws the 
 wedge and allows the cutters to disappear into the 
 holder. There are a great many collapsing taps and 
 dies, but those shown are sufficient in number to illus- 
 trate the principle involved. 
 
 Pipe-Threading Machine.— Figure 136 shows a ma- 
 chine for threading pipe. In this machine the posi- 
 
 4 
 
 ^k_ 
 
SCRKW-TUh'KAn-CrTTIXG 
 
 309 
 
 FIGS. 134 AND 135 
 
 corj.APsixc; die ukad and collapsing tap 
 (Jeometric Tool Co. 
 3GS 
 
 jectioiis cam tlio cutters into the workiii.i;' position. 
 The (lie opens automatically hy simply stopi)ing the 
 forward travel oi* the die when the desired length ol* 
 thread has been cut. This throws the cutters hack so 
 that the die head may be withdrawn without having 
 to he unscrewed from the work. 
 
 The cutters may be thrown in again by using the 
 handle oi' by having a steel tripping-])iece strike 
 the pin, g', opposite. They may be adjusted to cut 
 tight or loose threads by means oi* the adjusting 
 screws, h', the amount of adjustment is read directly 
 on the micrometer scale, i, on the side of the head. 
 IJoughing an<l linishing cuts nuiy be taken by throw- 
 ing the lever, j, forward. This moves the cutters out 
 0.01 inch. The return of the lever to its backw^ard 
 position closes the cutters and locks them in position 
 for the linishing cut. There is a clear hole through 
 the center of the die head and the shank, somewhat 
 laruer than the maxinuim diameter to be threaded, 
 wdiich permits threading any length required. 
 
 Figure 13') shows a collapsing tap corresponding 
 in size to the die, Figure 134. in this case, the cut- 
 ters, a, are held out in working position by the wedge, 
 b. When the proper dejith has been reached, the face 
 of the work pushes back the contact plate, c, and 
 n^leases a trip, so that the si)ring withdraws the 
 wedge and allows the cutters to disappear into the 
 holder. There are a great many collapsing taps and 
 dies, but those shown are sufficient in numl)er to illus- 
 trate the ])rincii)le involved. 
 
 Pipe-Threading Machine.— Figure LKi shows a ma- 
 chine for threading ])ipe. In this nuudiine the posi- 
 
7/ 
 
 \\ 
 
 SCKEW-THREAD-CUTTING 
 
 371 
 
 tions of the work and the die are reversed from 
 those shown in Figure 133. Pipe comes in lengths of 
 20 feet or more, and is large in diameter. The 
 spindle, a, which is used to carry the work, is of 
 east iron, long, hollow, and large enough to take m 
 the maximum size to which the machine is adapted. 
 Clamping jaws, b, provided at each end to be as far 
 apart as possible, give the work a firm support and 
 center it with the dies. The cutters, c, shown mside 
 the die head, are arranged so that they will collapse 
 into the head when the thread is completed. Special 
 devices are provided for holding short lengths ot 
 pipe— such as nipples— and extra steps, similar to 
 those shown at d on the rear clamping jaws, are used 
 to hold pipe flanges for threading. 
 
 Thread-Cutting on Lathes.— While nearly all com- 
 mercial thread-cutting is done in dies, special threads 
 wanted singly or in small numbers would be cut on 
 the engine lathe. Long and accurate threads, also, 
 such as those required for the various machine tool 
 feeds— shown in the foregoing pages— are cut on 
 lathes. The operation is a skilful one, and the degree 
 of accuracy obtainable is in a large measure con- 
 trolled by the precision of the lead screw that is 
 used. Master lead screws used by tool-builders for 
 cutting their own product, are very expensive and 
 have to be handled with great care. 
 
 The w,ork is mounted on the lathe centers, and a 
 cutting tool that has a cross-section of the groove be- 
 tween the threads, is mounted in the tool post. The 
 proper change gearing is used which will give the 
 lead required— or distance traveled longitudinally for 
 
SCKM'AVTIlKKADCrTTlNr! 
 
 .»7 I 
 
 lions of the work niirl tlir iVw aiv ivvrrscd Irom 
 liiose shown in Figure 133. Pipe conies in lengths ot 
 20 feet or more, and is large in diameter. The 
 si)indle, a, which is used to carry the work, is of 
 cast iron, long, hollow, and large enough to take in 
 the maximum size to which the machine is adapted. 
 Clamping jaws, b, provided at each end to be as tar 
 apart as possi])le, give the work a firm support and 
 center it with the dies. The cutters, c, shown mside 
 the die head, are arranged so that they will collapse 
 into the head when the thread is completed. Special 
 devices are provided for holding short lengths of 
 pipe—such as nipples— and extra steps, similar to 
 those shown at d on the rear clamping jaws, are used 
 to hold pipe flanges for threading. 
 
 Thread-Cutting on Lathes.— While nearly all com- 
 mercial thread-cutting is done in dies, special threads 
 wanted singly or in small numbers would be cut on 
 the engine lathe. Long and accurate threads, also, 
 such as those required for the various machine tool 
 feeds— shown in the foregoing pages— are cut on 
 lathes. The operation is a skilful one, and the degree 
 of accuracy obtainable is in a large measure con- 
 trolled by the precision of the lead screw that is 
 used. Master lead screws used by tool-builders for 
 cutting their own product, are very expensive and 
 have to be handled with great care. 
 
 The work is mounted on the lathe centers, and a 
 cutting tool that has a cross-section of the groove be- 
 tween the threads, is mounted in the tool post. The 
 proper change gearing is used which will give the 
 lead required— or distance traveled longitudinally for 
 
/ -' 
 
 372 
 
 THE MECHANICAL EQUIPMENT 
 
 m 
 
 i .:■ 
 
 each turn of the screw to be cut— and a light cut 
 with the point of the tool is made along the surface 
 to be threaded. The tool is then withdrawn from the 
 work, returned to its starting position, and fed in a 
 httle deeper for the second cut. This process is re- 
 peated, and each time the tool is fed in a little more, 
 until the proper depth has been reached. Figure 35 
 shows a tool-holder with a separate formed cutter 
 that has the required shape. One disadvantage of 
 ^this method is that the greatest wear comes on the 
 point of the tool, which can least afford to bear it. 
 
 Figure 137 shows a special threading tool which 
 has been developed to overcome this difficulty, and 
 which simplifies the making of the successive cuts'. 
 It shows an application of the turret principle, but 
 it is used on the carriage of a standard engine lathe 
 in place of the regular tool post. It consists of a cut- 
 ter with ten cutting edges, which are used in succes- 
 sion. After the tool has been set to cut the proper 
 size, the first of these cutting edges, a', is used to 
 make the first cut. The handle is then operated 
 which indexes the second cutting edge, a^ into po- 
 sition. This makes a second and slightly deeper cut. 
 
 All the cutting edges are brought into action suc- 
 cessively, each one deepens the cut, and the last one 
 brings it to the correct size. The condition of the 
 work after cuts 1, 5, and 10 have been made, is shown. 
 The first cutting edges have broad blunt points— only 
 the last one or two need have sharp points, for the 
 cut is practically completed before they do their work. 
 These last edges therefore retain their shape for a 
 long time. The sides of the cutter are made on the 
 
 AFTER CUT NO. 5 
 
 AFTER CUT NO. 10 
 
 FIG. 137. INDEXING THREADING TOOL 
 
 Rivett Lathe & Grinder Co. 
 
 373 
 
Hi ^"' 
 
 hi! 
 
 
 1. 'I'l 
 1" ■ 
 
 . I 
 
 I i 
 
 374 THE MECHANICAL EQUIPMENT 
 
 formed principle, so that the various edges may be 
 ground on the face and still retain their correct shape. 
 Milling Screw Threads.-In Figure 111 is shown a 
 standard milling machine set up to mill a short 
 screw thread. For milling screw threads special ma- 
 chines have been developed which are also very use- 
 ful for cutting long threads, especially those that are 
 of large diameter. Figure 138 shows a machine of 
 this character. The work is mounted on the spindles, 
 as m an ordinary lathe, but revolves only for the 
 feed, and a milling cutter is carried on a suitable 
 spindle m the traveling carriage. The cutting and 
 feeding motions of the ordinary lathe are reversed, 
 as the cutting motion is given to the milling cutter, 
 which is in the head, a, next the work, and not visible 
 m the picture. It has a travel lengthwise correspond- 
 mg to the lead of the screw to be cut. 
 
 The carriage and head, a, with the cutter start at 
 one end and are gradually fed lengthwise while the 
 work is given a slow rotary feed. The traveling 
 head carries a rest, which takes the thrust of the 
 milling cutter. The spindle that carries the cutter 
 has an adjustment in the vertical plane, so that the 
 cutter may be tipped to the angle corresponding with 
 that of the thread. A special milling cutter is used, 
 the teeth of which are staggered. One tooth is left 
 full for the purpose of gauging. This type of ma- 
 chme is used for lead- and feed-screws, worms, spiral 
 gears, and high grade, solid-end helical springs. The 
 quality of work obtainable by this method is very 
 satisfactory, and, as the cutting action is continuous, 
 the method is efficient for manufacturing purposes. 
 
 FIG. 138. THREAD MILLING MACHINE 
 
 Pratt & Whitney Ck). 
 
 PIG. 139. THREAD ROLLING MACHINE 
 E. W. Bliss Co. 
 
 375 
 
374 THE MECHANICAL EQUIPMENT 
 
 formed principle, so that the various edges may be 
 ground on the face and still retain their correct shape 
 Milling Screw Threads.-In Figure 111 is shown a 
 standard milling machine set up to mill a short 
 screw thread. For milling screw threads special ma- 
 chines have been developed which are also very use- 
 ful for cutting long threads, especially those that are 
 of large duimeter. Figui'e 138 shows a machine of 
 this character. The work is mounted on the spindles, 
 as m an ordinary lathe, hut revolves oulv tor the 
 feed, and a milling cuttei- is carried on a suitable 
 spindle in the traveling carriage. T]w cutting and 
 leeding motions of the ordinaiy lathe are reversed, 
 as the cutting motion is given to the milling cutter,' 
 which is in the head, a, next the work, and not visible 
 111 the picture. It has a travel lengthwise correspond- 
 ing to the lead of the screw to be cut. 
 
 The carriage and head, a, with the cutter start at 
 one end and are gradually fed lengthwise while the 
 work is given a slow rotary feed. The traveling 
 head carries a rest, which takes the thrust of the 
 milling cutter. The spindle that carries the cutter 
 has an adjustment in the viM'tical plane, so that the 
 cutter may be tipped to the angle coiwTsponding with 
 that of the thread. A special milling cutter is used, 
 the teeth of which are staggered. One tooth is left 
 full for the purpose of gauging. This tvpe of ma- 
 chine is used for lead- and feed-screws, worms, spiral 
 gears, and high grade, solid-end helical spi-ings. The 
 quality of work obtainable by this method is very 
 satisfactory, and, as the cutting action is continuous, 
 the method is effieient for manufacturino' purposes. 
 
 FIG. 138. THREAD MILLING MACHINE 
 
 Pratt & Whitney Co. 
 
 FIG. 139. THREAD ROLLING MACHINE 
 
 E. W. Bliss Co. 
 
 .375 
 
I 
 
 376 
 
 THE MECHANICAL EQUIPMENT 
 
 
 m 
 
 Rolling Threads.— For certain uses, threads are 
 sometimes rolled instead of cut on solid stock. This 
 process can be employed only for small work, such 
 as the threading of bicycle spokes. It has certain 
 advantages. With cut threads, the diameter of the 
 stock used has to be the outside diameter of the 
 thread. With a rolled thread, it need be only about 
 the mean diameter of the thread, since the material 
 that is rolled out at the root of the thread goes up to 
 form the top. When the thread, as in a bicycle spoke, 
 occupies only a short length at the end, this advan- 
 tage may mean a considerable saving of material. 
 However, threads formed in this way can never be 
 theoretically correct, and the process weakens the 
 material so that a rolled thread is not so strong as 
 a cut thread of the same size. 
 
 Figure 139 shows a machine for rolling threads on 
 the tops of cans. Here the method is practical and 
 very economical, since accuracy in form is not re- 
 quired and the material is too thin to be cut. Sev- 
 eral of the threaded tops are shown in the foreground. 
 The threading dies, a, are circular, and the grooves 
 that form the threads are on the circumference of the 
 roller. The top is inserted sidewise between the rolls 
 and finished almost instantly, in a few turns. 
 
 CHAPTER XXI 
 GRINDING, AND GRINDING MACHINERY 
 
 Development of the Grinding Process.— The field 
 of grinding in machine-shop practice has been chang- 
 ing'' steadily for the last forty years. Formerly the 
 process was used only for sharpening the edges of 
 tools that had been hardened. This sharpening was 
 (lone by means of soft grinding wheels which were 
 made of natural stone, and which of necessity ran 
 at a comparatively slow speed. About 1873, Mr. 
 F. B. Norton, of Worcester, Mass., began experiment- 
 ing on vitrified emery wheels; he put them on the 
 market a few years later. Since that time, other 
 forms of abrasive have been developed, and their 
 use has steadily increased. The first use was in con- 
 nection with rough work on simple grinding stands, 
 to remove sprues, fins, and so on. From this phase, 
 grinding jumped to the other extreme and became 
 an accurate tool-room process. And now it is being 
 used more and more for economical precision work 
 on a manufacturing basis. In the last of these uses, 
 it is ordinarily a finishing operation on pieces that 
 have been machined with edged tools, of either the 
 lathe or the milling type. 
 
 Special Advantages.— Grinding has several advan- 
 tages possessed by no other cutting process. It is 
 
 377 
 
378 
 
 THE MECHANICAL EQUIPMENT 
 
 II 
 
 If M 
 
 the only method of machining steel after it has been 
 hardened. Hardening and tempering almost invar- 
 iably distort the pieces treated. When accurate 
 shapes are required, as, for instance, in milling cut- 
 ters, the pieces are machined slightly large, to allow 
 for this distortion, and are then ground accurately 
 to size m a finishing process after the heat treatment 
 Another advantage of the grinding process is that 
 it works with the lightest known tool pressure, and 
 can be used on delicate pieces that would have a 
 tendency to spring away from the cutting edge of an 
 ordinary tool. This advantage is of particular value 
 m the grinding of long spindles, shafts, and so on. 
 btill another advantage is that the scale on cast- 
 ings and forgings, which destroys the cutting edge 
 of an ordinary tool, does not interfere with grinding 
 and, whereas one-eighth inch is the usual allowance 
 tor finish with an edged tool, one sixty-fourth or 
 one thirty-second of an inch, only, need be allowed 
 tor grinding— just enough to insure that the surface 
 will be properly cleaned up. A disadvantage for 
 accurate sliding surfaces in machine tools is the fac! 
 that such surfaces, when ground, may retain some 
 ot the emery and therefore cut each other. For this 
 reason, grinding is not used in certain places where 
 otherwise it would be of great advantage. 
 
 Grinding Abrasives.— Modern abrasives are of two 
 kinds, natural and artificial. The natural abrasives 
 are emery and corundum. Emery is a mineral, and a 
 mixture of aluminum oxide and iron oxide in a ratio 
 of about 60 per cent to 40 per cent. Corundum is a 
 purified form of emery, with from 80 to 85 per cent 
 
 GRINDING, AND GRINDING MACHINERY 379 
 
 of aluminum oxide. The iron oxide present in these 
 two materials is undesirable, and has no abrasive 
 quality. Because of this, emery in particular is little 
 used on automatic grinding machines at the present 
 time. . 
 
 The artificial abrasives are the following: car- 
 borundum, which is carbide of silicon made in the 
 electric furnace from coke and sand, with salt and 
 sawdust added to facilitate the reducing process; 
 alundum, which is the trade name for a material 
 consisting chiefly of oxide of aluminum, made from 
 bauxite, a clay mined in Arkansas, and similar in 
 chemical composition to the ruby and the sapphire; 
 and crystolon, which is carbide of silicon, and which, 
 like carborundum, is made from coke, sand, sawdust, 
 and salt. Unlike alundum, crystolon has no counter- 
 part in nature. It is most efficient when used on 
 materials of low tensile strength, such as cast iron, 
 brass, bronze, and aluminum. Aloxite, carbolite, and 
 carbondite are recent materials, and are compounds of 
 aluminum or silicon. All the artificial abrasives are 
 made by fusing the raw materials at high temperatures 
 in an electric furnace. 
 
 The natural abrasives are tougher than the artifi- 
 cial, but not nearly so hard. The shape and form of 
 fracture of the abrasive particles are of importance, 
 as well as their hardness. The diamond is the hardest 
 substance known, but a grinding wheel made up of 
 smooth, round diamonds would be of little use for 
 cutting purposes. One of the great advantages of 
 the artificial abrasives is that they break with a 
 clean crystalline fracture which gives the particles 
 
380 
 
 THE MECHANICAL EQUIPMENT 
 
 m 
 
 sharp cutting edges. When the steel dust produced 
 by these wheels is examined under a microscope, it 
 IS found to consist of small, curled chips, which are 
 similar to the large ones produced by an ordinary 
 . steel cutting tool. 
 
 Grinding Wheels.~A grinding wheel is practically 
 a milling cutter with an infinite number of very small 
 cutting edges. The abrasive used in grinding wheels 
 IS ground, screened through sieves, and graded ac- 
 cording to the number of the finest meshed screen 
 through which it will pass. For instance, a 36-grain 
 wheel contains abrasive which passes through a 36- 
 mesh screen. 6 a ou 
 
 The bond, or adhesive substance that binds the 
 abrasive together, is usually composed of clay, silicate 
 of soda, or shellac. Kubber, celluloid, or an oxidiz- 
 ing oil are also employed in some instances. Four 
 types of bonded wheels are used, known as vitrified, 
 silicate, elastic, or vulcanite-according to the process 
 of their manufacture and the nature of the bond 
 used-and finally, disc wheels. In vitrified wheels 
 the bond IS a mineral and clay mixture fused into a 
 porcelain. These wheels are the most commonly used 
 today as they are not affected by heat, cold, water, 
 oils, or acids. They are porous, and free from hard 
 and soft spots. Their porous texture allows the 
 particles of abrasives to be torn out readily in the 
 grinding process, and the wheel does not clog up so 
 easily with the material being worked upon. On the 
 other hand, a vitrified wheel is not so strong as an 
 elastic wheel and is more easily broken. Cons(«- 
 quently the vitrified process cannot be used for thin 
 
 GRINDING, AND GRINDING MACHINERY 381 
 
 wheels, and it is not advisable to attempt very heavy 
 side cuts with them. • : 
 
 Silicate wheels derive their name from the silicate 
 of soda which constitutes the bond. These are known 
 also as semi-vitrified wheels. They cut smoothly 
 and with little heat; and they are lised for grinding 
 tools, when the temper must not be .drawn. Their 
 grade is dependable for the process of manufacture 
 and can be easily controlled; they may be made in 
 large sizes. Vitrified wheels are rarely made above 
 36 inches in diameter, while silicate wheels can be 
 obtained up to 60 inches. In elastic wheels, shellac 
 forms the bond, and in vulcanite wheels, rubber. The 
 elastic wheels are strong, and consequently very thin 
 wheels may be made which are not only elastic but 
 which have smooth-cutting qualities; they can be 
 used for deep sid« cuts. The disc wheel is wholly 
 different; it consists of an accurately balanced steel 
 disc on which is cemented a cloth or paper impreg- 
 nated with powdered abrasive of the grain or fine- 
 ness required. 
 
 Grading.— The nature of the bond of the grinding 
 wheel determines how strongly the particles of 
 abrasives will be held together— a question of great 
 importance in grinding practice. Wheels from which 
 the abrasive is readily torn are known as soft-grade 
 wheels, and those which retain the grit strongly are 
 called hard-grade wheels. The word ** grain" in 
 connection with grinding wheels refers to the size 
 of the -particles of abrasive; the word *^ grade'' refers 
 to the hardness or softness of the bond. The former 
 is given in numbers and the latter usually by letter 
 
 I 
 
 ii 
 
 ■ ' 
 
 111* 
 
 ; 
 
 \'U 
 
382 
 
 THE MECHANICAL EQUIPMENT 
 
 I' !| 
 
 
 for vitrified and silicate wheels. For the grades of 
 elastic wheels, numbers are usually used. 
 
 Selection of Wheels.— The following elements must 
 be considered in selecting the proper grinding wheel 
 for any given work: material to be ground, degree 
 of accuracy required, quality of finish required, size 
 and shape of the work, whether it is to be ground 
 wet or dry, whether the work calls for external, in- 
 ternal, or surface grinding, and the speed of the 
 work, the rapidity of the side traverse speed, and the 
 depth of the cut. It is apparent, then, that no specific 
 rules can be given in regard to the selection of grind- 
 ing wheels. In general, corundum and alundum 
 wheels are most efficient for hard and soft steel, and 
 carborundum and crystolon for cast and chilled iron. 
 Soft bonded wheels are generally used for very hard 
 materials, and hard bonded wheels for medium and 
 soft materials. It is best to use a medium-grade 
 wheel for grinding brass or bronze. One of the fac- 
 tors that must be taken into consideration when a 
 wheel is selected, is the arc of contact between the 
 work and the grinding wheel. Harder bonded wheels 
 must be used for grinding small diameters than for 
 grinding large ones, and soft wheels are the best for 
 surface grinding. 
 
 The harder grades of corundum and alundum 
 wheels may be run at speeds from 5000 to 7000 feet 
 surface-speed per minute; the softer grades should 
 not be run at a rate exceeding 5000 feet. Carbor- 
 undum and crystolon wheels should be run a little 
 more slowly. For cylindrical grinding, wheels should 
 usually be run from 5000 to 7000 feet per minute; 
 
 GRINDING, AND GRINDING MACHINERY 383 
 
 for surface grinding, about 5000 feet per minute, and 
 for cutter grinding, from 4000 to 5000 feet per 
 minute. 
 
 Since the proper selection of grinding wheels is 
 closely related to their efficiency, it is desirable that 
 the choice of grade and grain and of the various 
 speeds and feeds should be referred to the makers 
 of the wheels, wherever there is much grinding to be 
 done. As grinding is a specialized field, these firms 
 have experts whose entire time is given to advising 
 customers as to just what will best suit their needs, 
 and naturallv such help is of the verv greatest value. 
 
 Mounting of Wheels.— In view of the high speeds, 
 just mentioned, it is obvious that the wheels should 
 be absolutely steady in order that there be no ex- 
 cessive vibration, with its accompanving danger. As 
 therp is always the possibility that bonded wheels 
 mav become ruptured, however well mounted they 
 may be, the operator should be protected, whenever 
 possible, by a hood like that shown at a. Figure 141. 
 This is made in such a wav that if the wheel should 
 break, the operator would be practically secure 
 against injure-. Wheels should be mounted, as shown 
 in Figrure 140, between two safety flanges, which 
 preferably should not be less than one-half or one- 
 third the diameter of the wheel. These flanges 
 should bear on the wheel onlv at their outer edg:e, 
 and a comnressible washer of rubber or blotting 
 paper should be interposed between them and the 
 wheel. 
 
 A wheel so mounted is held near the rim: conse- 
 quentlv the centrifugal strains are much less than 
 
 . 
 
 ^. 
 
384 
 
 i 
 
 I 
 
 I 
 
 I 
 
 THE MECHANICAL EQUIPMENT 
 
 
 . • T/7/S Flange ffey^c/ o r Pressed 
 
 Leo a Bushing 
 
 Con^pressible Washer of 
 .-•'Rubber or B/offing Paper 
 
 ^Central PorHon of Flange 
 re/eiyec/ f-o git^e bearing surface 
 Only near P/m. 
 
 FIG. 140. CORRECT MOUNTING FOR A GRINDING WHEEL 
 
 they would otherwise be. When the wheel wears 
 down toward the edge of the flanges, a smaller pair 
 may be used. Many grinding wheels have straight 
 sides, but those with sloping sides are naturally some- 
 what stronger against bursting, since the flanges have 
 a better hold. Even when there are safety flanges, 
 protection hoods should be used. The laws of most 
 states require the removal of the dust— which is a 
 menace to the health of the workman— by means of 
 some exhaust system. In such instances a hood is 
 required anyway, and it can easily be made strong 
 enough to furnish complete protection. The working 
 speeds, as given by the good makers, allow a factor 
 of safety of from 6 to 12, and all wheels over five 
 inches in diameter are tested at a speed nearly twice 
 that for which they are recommended. 
 
 FIG. 141. NORTON GRINDING WHEEL STAND 
 
 FIG. 142. GARDNER HORIZONTAL DISC AND RING GRINDER 
 
 385 
 
f ^ 
 
 384 
 
 TirK MECHANICAL EQCIPMENT 
 
 
 'iv ' 
 
 «C3% 
 
 Leod Bushinq 
 
 Cornpressible Washer of 
 ■ ■' Rubber or B/o/fmr^ Paper 
 
 yThis Ffange Keyec/ or Prf^sec/ 
 T/(^ht on SpincJJe 
 
 m 
 
 m 
 
 ^ Centra I Porfion of Flange 
 re/ei\^ej/ /o gi>^e bearing surface 
 Only near Rim. 
 
 FIG. 140. CORRECT MOTJXTINd FOR A (JRIXDIXiJ WHEEL 
 
 they would otlierwiso be. W'Ikmi tlio wlieel wciu-^ 
 down toward tlie edge of tlie llaiioes, a smaller pair 
 may be used. Many grinding wlieels liave straight 
 sides, but those with sh)ping sich's are naturally some 
 what stronger against l)ursting, since the flanges have 
 a better hold. Ev<'n when there are safetv llanues, 
 protection hoods should be used. The laws oi* most 
 states require the removal ol' the dust— which is a 
 Tuenace to the health of the woikman— bv means ot 
 some exhaust system. In such instances a hood is 
 required anyway, and it can easily be made stroiii; 
 enough to furnish com|)lete protection. The workini! 
 speeds, as given by the good makers, allow a factor 
 of safety of from (i to 12, and all wheels over tive 
 inches in diameter are tested at a speed nearly twic 
 that for which thev are recommended. 
 
 FIG. 141. NORTOX r.RIXOlXC. WHEEE STAXO 
 
 FIG. 142. GAnnNKR noiMZoxTAT- DISC AXi) Rixc. «;inNm:R 
 
 3S5 
 
K 
 
 I*' 
 
 386 
 
 THE MECHANICAL EQUIPMENT 
 
 
 Types of Grinding Machines.— The simplest type of 
 grinding machine is a plain emery-wheel stand, one 
 of which is shown in Figure 141. These may mount 
 one or two wheels. The commonest way of using 
 a wheel is shown on the right. The wheel is used 
 on the outer surface, and the work, which is pressed 
 up against it by hand, is supported by the adjustable 
 rest, b, which is set up as close to the wheel as pos- 
 sible without bringing it into contact. When wet 
 grinding is done, the pan, c, is made to catch the 
 water. Another way to arrange a wheel is to have 
 the top of it project slightly up through an opening, 
 d, m a surface plate, e. Then if the work is passed 
 'backward and forward over the wheel, an approx- 
 imately flat surface can be obtained. 
 
 Another and much more accurate way of obtain- 
 ing a flat surface is to use the side of the wheel, as 
 shown in Figure 142. In this case, also, there is a 
 double-ended stand with a horizontal, ball-bearing 
 spindle that has on the right a vitrified ring wheel, 
 which grinds on the face, a. The work is supported 
 on the table, b, either directly or by a suitable fix- 
 ture. The table and the carriage, c, may be swung 
 backward and forward across the face of the wheel 
 on the rocker shaft, d. The table may be set square, 
 as shown, or tilted on an angle and locked in that 
 position by the bolt, e; it may also be raised and 
 lowered. The work is pressed up against the wheel 
 by the handle, f, and the amount of forward motion 
 may be controlled by the micrometer stop, g. On 
 the other end of the machine is a disc wheel, h. This 
 wheel, which is of steel, has an abrasive cloth or 
 
 GRINDING, AND GRINDING MACHINERY 387 
 
 paper mounted on its face. Very large wheels of 
 this type are made which run in a horizontal plane. 
 The pieces to be ground are placed on top of the 
 wheel, but they are kept from rotating with it. Their 
 own weight furnishes the necessary pressure. There 
 is no danger that the disc wheel will burst. This 
 wheel is being widely used for many kinds of sur- 
 face grinding. 
 
 For still more accurate surface grinding, machines 
 of the types shown in Figures 143 and 144 are used. 
 The vertical grinder, Figure 143, uses the face, a, of 
 a cup-shaped wheel. This type of machine is both 
 accurate and very efficient for work on large flat 
 surfaces; it is made in sizes large enough to grind 
 faces 25 inches wide and 6 feet long, or circular ones 
 30 inches in diameter. Such a machine will finish 
 many kinds of work formerly done on the planer or 
 milling machine with greater accuracy and at less 
 cost. The ring wheel is clamped to a circular flange 
 at the lower end of a vertical spindle. It is rein- 
 forced against bursting by an adjustable steel band, 
 which may be set up as the wheel wears. 
 
 The wheel spindle is carried in an adjustable 
 counterbalanced head, b, which has a sensitive ver- 
 tical feed operated either by hand or automatically. 
 Provision is made for automatically disengaging the 
 feed when the proper depth of cut has been reached. 
 A pump supplies an abundance of water, which is 
 delivered through the spindle; the centrifugal force 
 drives the water out between the wheel and the work, 
 keeping both cool and free from dust. A stream is 
 also provided outside the wheel for cleansing pur- 
 
II 
 
 FIGS. 143 AND 144. SURFACE GRINDERS 
 The vertical grinder in the upper view is built hv Pr«ff a. xnrhi^^r, 
 Co. The horizontal grinder be^L is buiirbyTlle Norton" rlnZrcJ^ 
 
 388 
 
 GRINDING, AND GRINDING MACHINERY 389 
 
 poses. The table is provided with a high water 
 guard, c, which catches the water and returns it to 
 the supply tank. 
 
 Various forms of chucks are used to hold the work. 
 These may be circular with an automatic rotary feed, 
 in which case the table is partly under the wheel, as 
 shown in the illustration. This arrangement permits 
 of setting the work on the exposed portion of the 
 table while the grinding operation is going on; thus 
 the action of the machine is continuous. For plain 
 flat pieces, especially when they are thin, as in the 
 case of saw blades, magnetic chucks are used to 
 great advantage. When rotary chucks are used, 
 the table remains stationary, and the only feed i.s 
 rotary; for long work, the table may be given a trans- 
 verse feed motion along the bed. The length of 
 travel is governed by means of suitable dogs, d, at 
 the front of the table, which act like those described 
 in connection with the planer. Figure 86. In this 
 machine, as in other types of grinding machines, the 
 table is provided with extensions, e; these protect 
 the ways from water carrying abrasive dust, which 
 would tend to wear them away. 
 
 In the open-side surface grinder, shown in Figure 
 144, the grinding is done on the edge of the wheel 
 instead of on the face. This machine can therefore 
 be used for finishing grooves, irregular shapes, and 
 surfaces that have projections. The work is carried 
 on a slotted surface on the table, which is between 
 the sides of the water guard and does not show in the 
 photograph. This surface is 15 inches wide, and 
 from 6 to 14 feet long according to the length of 
 
FIGS. 143 AND 144. SURFACE GRINDFRS 
 The vmical jrri.Mler in the upper v.Vw is J.nilr hv Prntt & WhitnPV 
 Co. Uhe horizontal ^^-inder hHow is huilt l,v the Norton (^Hn'linrCV 
 
 ;;ss 
 
 GRINDING, AND GKINDINC; MACIIINKKY 389 
 
 poses. Tlic ta])l(' is provided witli a lii^b water 
 o-uard, (', wliicli calclK^s llic watei- and returns it to 
 the supply tank. 
 
 Various forms of eliueks are used to hold the work. 
 'Piiese nuiy Ix^ cireulai" with an autoinatie rotary feed, 
 in whieh ease the table is ])artly under the wheel, as 
 shown in the illustration. This arran.i»enient permits 
 of setting the work on the exposed portion of the 
 table while the grinding operation is going on; thus 
 the action of the maehine is eontinuous. For plain 
 Hat pieees, especially when they are thin, as in the 
 ease of saw blades, nuignetie ehueks are used to 
 great advantage. AVlien rotary ehueks are used, 
 the table remains stationary, and the only tecnl is 
 rotary; for long work, the table may i)e given a trans- 
 verse feed motion along the bed. The length of 
 travel is governed by means of suital)le dogs, d, at 
 tlie front of the table, whieh aet like those described 
 in connection with the i)laner, Figure 86. In this 
 machine, as in other types of grinding machines, the 
 table is provided with extensions, e; these protect 
 the ways from water carrying abrasive dust, which 
 would tend to wear them away. 
 
 in the open-side surface grinder, shown in Figure 
 144, the grinding is done on the iHhj;(' of the wheel 
 instead of on the face. This machine can therefore 
 be used for tinishing grooves, irregular shapes, and 
 surfaces that have projections. The work is carried 
 on a slotted surface on the table, which is between 
 the sides of the water guard and does not show in the 
 photograph. This sui"face is 15 inches wide, and 
 from () to 14 feet long according to the length of 
 
II 
 
 J 
 
 I 
 
 I 
 
 i^ 
 
 i* ' 
 
 390 
 
 THE MECHANICAL EQUIPMENT 
 
 the machine. The wheel head mounted on the up- 
 right carries a wheel 14 inches in diameter, which 
 can be raised to give a clear distance of 17 inches 
 to the surface of the table; when it is raised, a mag- 
 netic chuck can be used on a supplementary table. 
 The work has a horizontal traverse under the wheel, 
 and there are accurate adjustments for controlling the 
 depth of cut. The travel of the table is controlled by 
 adjustable dogs, as in the machine just described. 
 
 Figure 145 shows a plain cylindrical grinding ma- 
 chine used for producing cylindrical and conical sur- 
 faces. This type is used for finishing surfaces that 
 have been roughed off in a lathe to within 1/64 or 
 1/32 of an inch of the required size. .In addition to 
 the rapid rotation of the grinding wheel, these ma- 
 chines have the following motions: a slower rotation 
 of the work, as in a lathe, of from 25 to 75 feet per 
 minute; a traverse of either the wheel or the work 
 longitudinally of from one-fourth to three-fourths the 
 width of the emery-wheel face for each revolution 
 of the work; a cross feed or adjustment for setting 
 the wheel to give the proper diameter of work. Most 
 machines have also a horizontal swiveling adjustment 
 that can be used in the grinding of tapers. 
 
 The feeds that govern the depth of cut have a 
 range from .00025 inch to .004 inch with each re- 
 versal of the table, and are automatically thrown out 
 when the work is down to size. The wheel spindle 
 is of chrome-nickel steel, hardened, ground and 
 lapped, and is capable of carrying a wheel 20 inches 
 in diameter and 3 inches thick. The speeds of the 
 wheel, the work, and the feed of the table are en- 
 
 FIGS. 145 AND 146. GRINDING MACHINES 
 
 The plain cvlindrical grinder above is built by the Norton Grinding 
 
 Co. The universal j?rinder below is bnilt by Brown & Sharpe Mfg. Co, 
 
 391 
 
390 
 
 THE ME( HANICAL EQUIPMENT 
 
 the machine. The wheel head mounted on the up- 
 right carries a wheel 14 inches in diameter, which 
 can be raised to give a clear distance of 17 inches 
 to the surface of the table; wlien it is raised, a mag- 
 netic chuck can be used on a supplementary ta])lc. 
 The woi-k has a horizontal traverse under the wheel, 
 and there are accurate adjustments for controlling the 
 depth of cut. The travel of the table is controlled by 
 adjustable dogs, as in the machine just described. 
 
 Figure U.! shows a plain cylindrical grinding ma- 
 chine used for producing cylindrical and conical sur- 
 faces. This type is used for finishing surfaces that 
 have been roughed oflP in a lathe to within l/()4 or 
 1/32 of an inch of the re(|uired size, in acklition to 
 the raj)id rotation of the grinding wheel, these ma- 
 chines have the following motions: a slower rotation 
 of the work, as in a lathe, of from '2^) to '.'» feet per 
 minute; a traverse of either the wheel or the work 
 longitudinally of from one-fourth to three-fourths the 
 width of the emery-wheel face for each revolution 
 of the work: a cross feed or adjustment for setting 
 the wheel to give the pro|)er diameter of work. Most 
 machines have also a horizontal swiveling adjustment 
 that can be usinl in the grinding of tapers. 
 
 The \'vv(y that govern the depth of eut have a 
 range from .()()()2:) inch to .004 inch with each re- 
 versal of the table, and are automatically thrown out 
 when tlie work is down to size. The wheel spindle 
 is of chrome-nickel steel, hardened, ground and 
 lapped, and is capable of carrying a wheel 20 inche> 
 in diameter ami :{ inehes thiek. The speeds of tin- 
 wheel, the work, ;ni(l the {'vOi\ of \hr table are en 
 
 .viSMfSy 
 
 FIGS. 145 AND 146. GRINDING MACHINES 
 Tilt' ithiiii cvIiiKn-ii'jH Ln'iii<1<M- mIh.vo is huili l>y ilu' Norion (Iriiidinj: 
 Co. Tlic mii"vt'rs:il irrindrr hclow i< l.iiili l.y I'mwii ,K: Sliiir]..' .Mlu. < '<», 
 
 :i'.ti 
 
Mfpi 
 
 392 THE MECHANICAL EQUIPMENT 
 
 tirely independent of one another; the wheel speed 
 varies from 1360 to 1630 r.p.m., the work speed from 
 27 to 207 r.p.m., and the feed of the table from 21 
 inches to 126 inches a minute. Three steady-rests 
 are provided for supporting slender work, and pro- 
 vision is made for an abundant supply of water— 
 the tank and pump are located inside the bed of the 
 machine. In this machine, as in all other high-grade 
 grinding machines, all the working surfaces are pro- 
 tected from grit-bearing water, which would soon 
 destroy their accuracy. All changes are effected from 
 the front of the machine. 
 
 Figure 146 shows a universal grinding machine that 
 has a wider range of work. The wheel stand in this 
 type of machine has a horizontal swiveling adjustment, 
 a, so that the wheel can be set in any position without 
 interference. The upper portion, b, of the table has 
 a swiveling motion about a central stud in the lower 
 part, c, and the headstock also swivels, at d. By 
 means of these adjustments, any taper to be ground 
 may be handled accurately. In addition to the swivel- 
 ing adjustment, the wheel stand has a hand-operated 
 transverse adjustment that can be set to thousandths 
 of an inch, and an automatic cross feed of from 
 .00025 to .004 inch, which operates at each reversal 
 of the table and throws out when the work is to 
 size. In Figure 146 the steady-rests and the other 
 equipment necessary are shown on the floor. An in- 
 ternal grinding fixture, f, consists of a separate head 
 with an independently driven spindle, on the end of 
 which a small wheel may be mounted for grinding 
 out small holes and cylinders. 
 
 GRINDING, AND GRINDING MACHINERY 393 
 
 Figures 147 and 148 show two machines designed 
 especially for internal grinding. The Bryant grinder, 
 shown in Figure 147, has a chuck, a, in which is 
 mounted the piece to be ground, b. This chuck, with 
 the work, is given an independent rotation by the 
 pulley, c, in the fixed head of the machine, and the 
 grinding wheel, d, is carried on the end of a shaft 
 mounted in the head, or box, e, which depends from 
 the heavy bar, f. A belt, not shown, drives the 
 grinding spindle from a pulley, which is inside the 
 box, e. For the longitudinal motion of the grinding 
 wheel a traverse is given to the bar, f, by the mech- 
 anism at the right, operated either automatically or 
 by hand. An arm projects downward from the 
 swinging box, e, and by bearing against a former, or 
 control-plate, inside the frame, controls the forward 
 and backward position of the wheel, as well as the 
 diameter being ground. 
 
 The control-plate against which the arm bears may 
 be straight and set parallel with the axis for cylinder 
 grinding, or on a taper for taper grinding, and its 
 position may be adjusted by a feed screw under con- 
 trol of the mechanism, g, at the front of the machine. 
 The control-plate need not necessarily be straight 
 and by giving it a curved contour irregular shaped 
 holes may be ground. By turning the feed screw the 
 control-plate inside may be moved in and out for 
 varying the depth of cut. A stop-pin, h, prevents 
 the wheel from swinging forward far enough to strike 
 the opposite side of the hole. 
 
 In the machine shown in Figure 148, the work is 
 mounted on a table that carries the work across the 
 
 if 
 
 il 
 
I 
 
 i 
 
 TIG. 147. BRYANT CHUCKING GRINDER 
 MG. 148. HEALD INTERNAL GRIXDINiJ MACHINE 
 
 3i)4 
 
 GRINDING, AND GRINDING MACHINERY 395 
 
 wheel with an automatic transverse movement to and 
 fro. The wheel is mounted on the end of a spindle, 
 a, which is driven from the small pulley at the ex- 
 treme left. This spindle is adjustable eccentrically 
 in a larger one, b, which rotates about a fixed axis 
 in the main bearings, c, of the head. The outer 
 spindle, b, has a slow rotation that carries the axis 
 of the spindle, a, around in a circle, the diameter of 
 which is determined by the amount of eccentricity 
 between the two axes. The grinding wheel there- 
 fore has two motions: a rapid rotation about the axis 
 of its own spindle, a, which gives the cutting speed; 
 and a slower one about the axis of the spindle, b, 
 which gives a circumferential motion of the wheel 
 as a whole around the inside surface of the work. 
 The degree of eccentricity can be varied, by means 
 of an adjustment at d, to suit the amount of travel 
 that it is necessary to give the wheel. The depth of 
 cut is controlled by the micrometer screw, e. 
 
 This form of internal grinder is useful for finishing 
 the bores of automobile cylinders and other parts 
 that cannot be convenientlv mounted for rotation. 
 When the work can be easily turned, it can be 
 mounted in a chuck on the head of the machine, and 
 the wheel can be mounted at the end of a spindle 
 carried by the sliding table. The work spindle and 
 the wheel spindles are given independent rotations 
 by means of separate belts, and the depth of cut is 
 controlled by an adjusting screw on the side of the 
 table, as shown in Figure 148. 
 
 Tool Grinders. — Grind stones are used only for 
 thin-edged tools, such as cutlery and wood-working 
 
TIC. 147. BRVAXT CUVCKlSr. r.RlSUKK 
 
 fk;. 14S. Ml \[j, ixTKKNM. .;mxnix<, aiachixh 
 
 :i:'i 
 
 w 
 
 (JRIXDING, AM) (;RIM)1N(J MACHINERY :J05 
 
 ..lu'c'l Willi an autoinatic Iraiisvt'isc inovcnu'iit to ami 
 fro. The wIkh'I is moiniliMl on tlir end of a spindle, 
 .,, wliich is (IriviMi from tin' sinall pullry at tlii» ox- 
 livinc left. This sj)in(ll(' is adjustahlc (M-ccntrically 
 ill a lar^ci- one, 1), wliicli I'otatcs ahont a lixcd axis 
 in the main hcarini-s, c, of the head. Tin' outer 
 spindle, I), lias a slow rotation that carries the axis 
 of the spindle, a, aronn<l in a circle, the diameter of 
 which is detei-mined by tln^ amount of eccentricity 
 h<*tw(H^u the two axes. The .t»i-indin,i'- wheel there- 
 fore has two motions: a rapid rotation about the axis 
 of its own spin<lle, a, which liivcs the cutting- speed; 
 and a slower one ahont tin* axis of the spindle, h, 
 which uivcs a cii-cumferential motion of the wheel 
 as a whole around the inside sui'face of the work. 
 The dcm*cc of eccentricitv can he vai'ied, hv nu^aus 
 of an adjustment at d, to suit the amount of travel 
 that it is necessary to i;ive the wheel. The depth of 
 cut is controlled hv the mici-ometei" sci'ew, e. 
 
 This form of internal .grinder is useful for finishin<; 
 the hores of automobile cylindei-s and otluM* parts 
 that cannot be conveniently moulded foi* rotation. 
 When the work can be easily tui'ne(l, it can be 
 nionnted in a chuck on the head of the machine, and 
 the wheel can be moulded at th.e end of a spindle 
 carried by the slidin.n' table. The work spindle and 
 the wheel spindles are liiven independent i-otations 
 by ni(»ans of separate belts, and the depth of cut is 
 «'ont rolled bv an adiustini;- screw on the side of the 
 table, as shown in Fi.i;ure 14S. 
 
 Tool Grinders. — Grind stones are usimI only for 
 tliin-edo:ed tools, such as cutler\ and wood-workin?,' 
 
( 
 
 396 
 
 n •; 
 
 THE MECHANICAL EQUIPMENT 
 
 tools. In modern shop practice, cutting tools are no 
 longer ground by hand on an emery wheel as for 
 merly Correct shape and proper cutting angles are 
 essential factors in good tool performance, and these 
 can be had only if grinding machines are used 
 furthermore, in milling cutters and reamers it is 
 essential that all the teeth be ground uniformly, and 
 this cannot be done by hand. 
 
 For this work a large number of tool grinders have 
 been developed, which fall into three general classes: 
 I^irst, cutter and reamer grinders, for sharpening the 
 multiple edges of milling cutters and reamers. In ^ 
 this type the tool is mounted on centers or an an 
 arbor and each face is brought for grinding, up to a 
 delmite position, which is determined by a stop In 
 this way uniformity is obtained for the various teeth 
 Second, twist-drill grinders. In these, the drill is 
 carried on a holder, which is set at an angle of about 
 60 degrees to the face of the wheel, and which is 
 then given a rocking and sliding motion as it is 
 inoved past the wheel. Thus a slightlv relieved con- 
 ical surface is produced. The drill is then turned 
 oveT and the other flute is ground, provision being 
 made that the two surfaces shall be alike. Third 
 umyersal tool grinders, which are used to sharpen' 
 all kinds of lathe, planer, and shaper tools. The tool 
 IS clamped into a holder, which can be rotated about 
 horizontal and vertical axes, which is also capable of 
 sliding. The relationship between the various move- 
 ments is complex, but they are under the control of 
 adjustments that can be so set that exact shapes and 
 angles can be ground by comparatively unskilled 
 
 GRINDING, AND GRINDING MACHINERY 397 
 
 labor. With them it is possible to grind any face at 
 any angle, and to duplicate the pattern indefinitely. 
 
 Polishing and Buflfing. — Polishing and buffing are 
 finishing operations somewhat allied to grinding. No 
 attempt is made, however, by means of them to alter 
 or control the form of the piece; they are used merely 
 in polishing the surface or in preparing it for plat- 
 ing or for some other surface finish, such as blueing 
 or lacquering. Polishing wheels often are made of 
 wood and have around their circumference leather 
 strips that are impregnated with emery or other 
 abrasive material. Another type of wheel is made of 
 steel, and is about 12 inches in diameter and 21/2 
 inches across the face; over the face is a strip of cloth 
 carrying the abrasive, which may be changed from 
 one grade to another or renewed when worn. Wooden 
 and steel wheels are used on work where it is neces- 
 sary to maintain good edges. The steel wheels, 
 which are safer and generally more economical, are 
 used largely in cutlery manufacture. 
 
 Buffing wheels are made of disks of leather — or some- 
 times of cloth, such as canvas, muslin, or felt. They 
 are clamped between two steel plates, and their outer 
 edges are impregnated with grinding material, rouge, 
 and the like. Wheels of this kind are used in plain 
 stands, similar to those shown in Figure 141, and the 
 work is manipulated by hand. Canvas and muslin 
 wheels are used for polishing irregular pieces, as the 
 wheels are soft and when the work is pressed against 
 them they will conform to a curved surface. Belts 
 faced with grinding dust, which run from 2000 to 
 2500 feet per minute, are also used with good results. 
 
Ji, :^I 
 
 BROACHING AND PRESS WORK 
 
 399 
 
 CHAPTER XXII 
 BROACHING AND PRESS WORK 
 
 The Broaching: Process.— In its usual application 
 the broaching process consists in forcing an elongated 
 cutting tool, which has a varying cross-section, and 
 multiple cutting edges along the sides, through a 
 hole already formed, thereby changing the shape of 
 the hole. Formerly the broaching tool was pushed 
 through by a press, and for some purposes— provided 
 the tool can be very short— this is still done. Nearly 
 all broaching, however, is now done bv pulling the 
 broach through the hole. The initiafhole is ordi- 
 narily drilled at right angles to some face already 
 machined, as in the majority of the samples shown 
 in Figure 150, but it may be forged or rough-cored 
 and of rectangular or other shape, as in the case of 
 the steel revolver-frame and the cast iron stand, shown 
 at the left. Typical broaching tools for pulling cuts 
 are shown at each side of the illustration. 
 
 The broaching process is applicable in finishing 
 square, hexagonal, or odd-shaped holes, in cutting 
 single or multiple key-ways in hubs, and in forming 
 the teeth of small internal gears, ratchets, and the 
 like. It was formerly used almost entirely for in- 
 terior work, but recently has been extended to ex- 
 terior work; it may be used in broaching the teeth on 
 
 398 
 
 small spur gears when the quantities required are 
 large enough. The chief disadvantages of the process 
 are the high cost of the broaching tools and the un- 
 certainty of their life, but these are much more than 
 offset by its speed and accuracy, and its adaptability 
 in connection with a wide variety of irregular forms, 
 as well as by the fact that the work can be done by 
 comparatively unskilled labor. 
 
 It is said that broaching was first used by Mr. 
 R. S. Lawrence, at the Sharps' Rifle Works, in Hart- 
 ford, about 1853, and for many years it was employed 
 only in the manufacture of guns and similar articles. 
 All of the early broaching tools were pushed through 
 the work by a press; consequently, since the tools 
 were under compression, they had to be short and 
 of fairly large cross-section, or they would buckle and 
 break. In good practice not more than from .001 to 
 .003 inch of the metal should be removed per cutting 
 edge, and sufficient space should be left between the 
 tools for the chips to accumulate during the cut, 
 which means that they cannot be much less than 
 five-eighths of an inch apart. Therefore, when there 
 is a marked change in the shape of the hole, a long 
 succession of cutting edges is required. 
 
 Since push-broaches cannot be made over a foot 
 long, however, in the early days of broaching the 
 work had to be divided among a number of broaches 
 which were used in succession; the first one started 
 with the original round hole, and each succeeding one 
 continued the operation from where the previous one 
 had left it. Sometimes as many as ten or a dozen 
 broaches were required. The handling of so many 
 
400 
 
 THE MECHANICAL EQUIPMENT 
 
 tools involved considerable labor, and more or less 
 danger of breaking them if they were used in a 
 wrong order. Even under these handicaps the 
 broaching process produced certain kinds of work 
 much more cheaply and satisfactorily than any other 
 method In modern manufacture the broach is pulled 
 through the work; consequently it is under tension 
 only, and may be any length convenient to handle. 
 Ihus the danger of breakage is lessened, and the 
 number of tools to be handled is reduced. This mod- 
 ern type of broach has practically superseded tho 
 other and less convenient one. 
 
 The Broaching Machine.-The modern form of 
 broaching machine is shown in Figure 149 It con 
 sists of a square, box-like upright or standard, a, 
 which contains the operating mechanism, and a Ions 
 horizontal extension, b, of U-shaped cross-section 
 Between the upper ends of the U are guides carrv- 
 mg a draw-head, c, which slides backward and for- 
 ward along the top of the extension. Secured to this 
 head IS a long screw, d, which can just be seen be- 
 tween the guides. The screw is fixed in the draw-hea<l 
 and does not rotate. The power to operate the ma- 
 chine is carried from the pulleys at the extreme 
 right through a shaft to a pinion in the casing whiel. 
 drives the large gear, e, to which is secured a 
 threaded sleeve, engaging the screw, d 
 
 The revolution of this gear and its sleeve moves 
 the screw and the draw-head to the right to make a 
 cutting stroke. At the end of the extension, b, is an 
 annular finished face, f, which is perpendicular to 
 the motion of the draw-head. This face carries a 
 
 BROACHING AND PRESS WORK 
 
 401 
 
 FIG. 149. BROACHING MACHINE 
 
 suitable work-holder, g, one kind is shown in place, 
 and others are shown in the pan below. The work to 
 be cut is set into the work-holder, g, and a broach- 
 ing tool similar to the one shown at a. Figure 150, 
 is inserted through the initial hole in the piece and 
 keyed to the draw-head by means of a loose key 
 slipped through the slot, b, Figure 150. 
 
 Broaching Tools.— Figure 150 shows four broaches; 
 in the one at a, the shape gradually changes from 
 round at the upper end to square at the lower end. 
 This type would be used for such a hole as that 
 shown at c. The broach, d, would be used for cutting 
 a series of notches or splines, as shown at e. For a 
 single key-way, as at f, a broach of the type shown 
 at g would be used. This is rectangular in cross- 
 
400 
 
 THE MKrHAXlfAL KQUIPMENT 
 
 tools involved considerable labor, and more or les. 
 danger of breaking them if thev were used in u 
 wrong order. P>en under ti.es.. handioaps 11,. 
 broaching process produced certain kin.is of work 
 much more cheaply and satisfactorily than anv oth(.r 
 metho. . I„ modern manufacture the broach is" pulled 
 througl, (be work; consecpiently it is nn.l.M- t<.nsi«„ 
 o^'ly, and may b,. any length convenient to han.H,. 
 I bus the danger of breakage is less,.,,...!, an.l ll„. 
 number of tools to be han.lled is red,„-ed. Tbi< nu..i 
 ern type of broach has practically supersede.l Ih,. 
 other and less convenient one. 
 
 The Broaching Machine.-The modern form oi 
 broaching machine is shown in Figure 14!). It ,-,„, 
 s.sts of a square, box-like upright or stan.ianl, a. 
 which contains the operating mechanism, an.! a ion- 
 horizontal extension, b, of IJ-shape.l cross-s,.ctio,r 
 Betwe,.,, the n,,per eiuls of the V are gui.les earrx ' 
 ing a draw-iiead, c, uhicli slides backward and foV 
 ward along the top of the extensi<.n. Seenred to thi< 
 head IS a long screw, .1, whi<-b can just be seen be 
 tween the guides. The .«crew is fixe.l in the draw-hea,l 
 and does not rotate. The power to operate the ma 
 cb.ne ,s earried from the pulleys at the ..xtrem. 
 right through a shaft to a pinion in th,. casing- wbieh 
 drives the large gear, e, to wbi(-h is s.-einvd a 
 Ihreaded sleeve, engaging the screw, d. 
 
 The revolution of this gear ami its sleeve move 
 the screw and the .Iraw-h<.ad to the ri-ht to mak.. . 
 cutting stroke. .\t the <.nd of the extension, 1, i. ,, 
 annular finished face, f, whieh is perpendicular U 
 the molion of the draw-head. This face carries , 
 
 BKOACHINf! AND PHKSS WOUK 
 
 401 
 
 FlU. 149. BKOACHINd MACHINE 
 
 suitable work-holder, g, one kind is shown in place, 
 and others are shown in the i)an below. The work to 
 be cut is set into the work-holder, g, and a broach- 
 ing loo! similar to the one shown at a. Figure l.'jO, 
 is inserted through the initial hole in the piece and 
 keyed lo llie draw-head by means of a loose key 
 sjipjied tiirougii th(> slot, 1), Figure 150. 
 
 Broaching Tools.— Figure laO shows four broaches; 
 in the one at a, the shape gradually clianges from 
 round at the upper eiul to scpiare at the lower end. 
 This type would be used for sucli a hole as that 
 shown at c. The broach, d, would be used for cutting 
 a series of notches or syilines, as shown at e. For a 
 siiigl(. key-way, as at f, a broach of the type shown 
 at g would be used. This is rectangular in cross- 
 
BROAC KING AND PRESS WORK 
 
 403 
 
 FIG. 150. BROACHES AND SAMPLES OF BROACHING WORK 
 
 402 
 
 section, with the cutting teeth along one edge only. 
 The piece to be cut is mounted on a projecting stud, 
 a, Figure 151, on the work holder, which is slotted 
 at b to receive the broach and guide it so that only 
 the cutting edges can project. The small end of the 
 broaching tool is inserted through the work and the 
 slot, b, in the supporting stud, and secured to the 
 draw-head. The handle, i. Figure 149, ife then thrown 
 over, and the h«ad, carrying the broach with it, 
 moves to the right. The teeth are set on an incline; 
 as the motion starts, the teeth begin to appear above 
 the surface of the stud, a, and cut deeper and deeper 
 until the full depth is reached. The last few teeth, 
 c, are the final shape required, and serve to bring 
 the work accurately to size. 
 
 This feature in broaching tools accounts in large 
 measure for the accuracy of the process. The 
 previous cutting edges leave little work for the siz- 
 ing edges to do and if the first of these wears, the 
 second can take up its work, and so on, until the 
 last one has been worn out. When the broach has 
 been pulled all the way through the work and holder, 
 it lies in the extension, b. Figure 149. It is removed 
 from the draw-head; then the handle, i, is reversed, 
 .and the draw-head is brought back to the starting 
 position by a rapid return traverse. A new piece 
 is set in place, the broach is inserted through the 
 hole in the work and secured once more to the head, 
 and the machine is again ready to start. The broach- 
 ing process is not confined to straight cuts; helical 
 cuts also may be made, provided the pitch of the 
 helix is not too steep. 
 
HROAcniNCJ AM) PKKSS WORK 
 
 40:; 
 
 Fir,. 150. BROACHES AND SAMIM.FS OF BROArHIXr; WORK 
 
 402 
 
 xcclion, with the ('ntt'ni,u Icctli alon^ one (mI^o only. 
 Tlie piece to bo cut is mounted on a projecting stud, 
 a, Figure 151, on the work liolder, which is slotted 
 at ]) to receive the broach and gui(h» it so that only 
 the cutting inhj^ea can project. The small end of the 
 hroaching tool is inserted through the work and the 
 slot, b, in the supporting stud, and secured to the 
 draw-head. The handle, i, Figure 149, is then thrown 
 over, and the head, carrying the broach with it, 
 moves to the right. The teeth are set on an incline; 
 as the motion starts, the teeth begin to api)ear above 
 the surface of the stud, a, and cut deeper and deeper 
 until the full depth is reached. The last few teeth, 
 c, are the tiiud shape recjuired, and serve to bring 
 the work accui*ately to size. 
 
 This feature in broaching tools accounts in large 
 measure for the accuracy of the process. The 
 previous cutting edges leave little work for the siz- 
 ing i'iUfj!:i^ii to do and if the tirst of these wears, the 
 second can take up its work, and so on, until the 
 last one has been worn out. When the broach has 
 l)een pulled all the way through the work and holder, 
 it lies in the extension, b. Figure 149. It is removed 
 from the draw-head; then the handle, i, is reversed, 
 and the draw-head is brought back to the starting 
 position by a rapid return traverse. A new piece 
 is set in place, the broach is inserted through the 
 hole in the work and secured once more to the head, 
 and the nuichine is again ready to start. The broach- 
 ing process is not confined to straight cuts; helical 
 cuts also may be made, provided the pitch of the 
 helix is not too steep. 
 
BROACHING AND PRESS WORK 
 
 405 
 
 404 
 
 Broaching machines of the draw-head type are 
 capable of making strokes np to 50 inches, so that 
 long broaches can be used with the resulting saving 
 in both tool expense and operation. This process 
 is being applied to larger and heavier work, since 
 its economy of operation and accuracy of output 
 make it a valuable method wherever there are quan- 
 tities sufficient to justify the expense of the tools. 
 
 Punches and Dies. — ^Press operations, which are 
 done with punches and dies, may be either cutting 
 or forming, or a combination of both. The cutting 
 is always a shearing action, as in cutting up bar 
 or sheet stock, punching holes of almost any shape, 
 or trimming off the raw edges of pieces after they 
 have been formed. The shaping or forming opera- 
 tions are in reality cold forging, and comprise bend- 
 ing, forming, bulging, embossing or coining, cupping 
 and drawing, or heading and upsetting. Nearly every 
 operation calls for a different die, and we can describe 
 here only a very few of the better known types. These 
 are used generally on sheet-metal stock of steel, 
 wrought iron, brass, copper and, in the case of 
 jewelry, of the precious metals. The tools consist 
 of two main parts, a die of one or more pieces, which 
 is secured to a fixed bed in the machine, and a punch 
 carried in a reciprocating head, the motion of which 
 is controlled by some form of clutch. 
 
 One of the simplest forms is the plain blanking 
 die. Figure 152, which consists of a die, a, with cut- 
 ting edges, b, formed to give the proper shape, and 
 the corresponding punch, c. The strip from which 
 the blank is to be cut is laid over the opening; the 
 
 » ; 
 
 i 
 
406 
 
 THE MECHANICAL EQUIPMENT 
 
 BROACHING AND PRESS WORK 
 
 407 
 
 I 
 
 punch descends through the die, carrying the blank 
 with it. Generally there must be a stripping piece, 
 d, which reaches over the top of the sheet metal and 
 holds it in place as the punch rises. This piece strips 
 the metal off the punch and leaves the sheet free to 
 be fed along for the next piece. Several punches may 
 be combined in one fixture and all do the same kind 
 of work, or they may perform a succession of opera- 
 tions one after the other. When they perform the 
 same kind of work, they are known as gang dies; 
 when they work in series, each punch making its own 
 cut, they are known as follow dies. The simplest 
 form of bending die is shown in Figure 153. The 
 face of the die is shaped to conform to the contour 
 desired, and the punch forces the work down into it. 
 The action is so simple that it needs no explanation. 
 
 Two or more bending operations may be performed 
 in a compound bending die, as shown in Figure 154. 
 In the one shown, the work is carried down into the 
 die by the punch, a, and held there while the beveled 
 fingers, b, acting upon slides, c, in the die, force them 
 inward and produce the bend, d. On the upstroke 
 of the head the slides, c, are thrown out by springs; 
 the finished piece rises with the punch, and may be 
 slipped off when it is clear of the die. When the 
 punch performs several operations, as in this case, 
 it IS usually necessary to introduce a spring connec- 
 tion, e, which will allow the main portion of the 
 punch to descend and effect the second motion while 
 the punch stays at rest. Remarkable ingenuity is 
 displayed in the design of dies of this character, 
 which are sometimes quite intricate. 
 
 Figure 155 shows a double-action die combining 
 cutting with drawing, which is but a form of bend- 
 ing. In this instance there are two sliding heads, 
 one of which carries the punch, a, which cuts out a 
 round disc by shearing against the cutting edges, b, 
 of the die, c. The punch, d, then descends and 
 pushes the blank through the hole, e, forming the 
 
 shell as shown. 
 
 Plain drawing dies repeat the action of the parts 
 c and d as the shell is progressively forced through 
 holes— each smaller than the one immediately preced- 
 ing—and drawn out from the shallow cup into a 
 longer one and even into a tube. Such redrawmg 
 dies are characteristic tools in the manufacture ot 
 cartridge shells. All materials drawn in dies m this 
 way must be annealed from time to time as the work 
 progresses, because after a certain percentage of 
 *^ drawing down" they become brittle and their duc- 
 tility must be restored. This is done by heating 
 them to a red heat and allowing them to cool. 
 
 Figure 156 shows a combination die used for cut- 
 ting a blank and, at the same stroke, turning down 
 the edge and drawing the piece into the required 
 shape. The work is blanked by the cutting punch 
 a, and formed to the right shape by b and c. The 
 former holds the piece by spring pressure against 
 the block, c, while the punch, a, continues to descend, 
 and draws the work into the required shape. The 
 ring, d, acts as an ejector, throwing out the piece 
 as the punch rises on the return stroke. The flange 
 or edge, e, which is left turned out, is sure to b6 
 irregular in shape. When it is necessary to have 
 
BROACHING AND PRESS WORK 
 
 409 
 
 I' I 
 
 I 
 
 I 
 
 this smooth, the edge is cleaned off in a trimming 
 die somewhat similar to that shown in Figure lol. 
 
 Figure 157 shows a bulging die which enlarges a 
 cup, similar to that formed in Figure 155, to the 
 rounded shape shown. The drawn shell is placed 
 over the mushroom plunger, a, in the die and when 
 the punch descends the rubber disc, b, is forced out, 
 expanding the shell into the curved chamber formed 
 hy the punch and the die. As the punch rises, the 
 rubber returns to its original form and the expanded 
 
 work is then removed. , r, jjo, 
 
 The most accurate type of die is the sub-press die, 
 shown in Figure 158. In all the dies above described, 
 the machine is depended upon for the accurate regis- 
 tering of the punch with the die. The sub-press die 
 is self-contained; the punch, a, slides in an upright, 
 b, which is secured to the base, c. The only function 
 of the machine is to depress the top of the punch, a; 
 correct alignment is obtained from the proper regis- 
 tering of the pieces a, b, and c. Dies of this char- 
 acter are used in the manufacture of watches, for 
 punching out wheels and other parts, and they can 
 be made to do work requiring extreme accuracy. 
 The finer parts (not shown) are secured to the taces 
 e and f of the punch and die. 
 
 Types of Presses.— The simplest form of press is 
 the foot press, shown in Figure 159. These machmes 
 are used in jewelers' work, and for light operations 
 on small pieces. They may be mounted on independ_ 
 ent stands, as shown, or in rows along a bench, and 
 are usuallv operated by girls or boys. The die is 
 set on the base, and the punch is carried in the slid- 
 
410 
 
 THE MECHANICAL EQUIPMENT 
 
 ing head, a, mounted in the frame of the machine. 
 The motion is derived from a toggle joint actuated 
 by a heavy pendulum, b, which is pushed back by 
 the foot treadle, c. By means of the adjusting screw, 
 d, the head may be raised or lowered to accommodate 
 different heights of work. In another type of hand 
 press which is widely used, the head is forced down 
 by means of a sharp-pitched screw, which occupies 
 the place of the adjusting screw, d. Across the top 
 of this screw is a horizontal arm, which carries at 
 each end a heavy cast-iron ball. A handle drops 
 down from the arm to a point within reach of the 
 operator, who, by pulling this handle, revolves the 
 screw and the heavy weights and forces the head 
 down against the work. 
 
 For larger work the belt-driven press. Figure 160, 
 is used. This consists of a heavy C-shaped frame 
 which leaves the sides clear so that strip stock can 
 be fed across the die from side to side. When the 
 back is open, as at a, the press is known as an open- 
 back press. The opening permits light from the back 
 of the machine to fall on the die, and also provides 
 an egress through which the stamped articles may 
 be discharged. In this type of press the main frame, 
 b, is usually separate from the legs, c, and is clamped 
 to them by means of a fitted connection, d, which 
 is on the arc of a circle. 
 
 By the turning of the worm, e, in the base, the 
 frame, b, may be tilted backward at an angle, an 
 advantage often convenient in connection with cer- 
 tain types of work, since the finished piece will then 
 slide away from the opartor and out through the 
 
 FIG. 159. FOOT PRESS 
 
 FIG. 160. BELT-DRIVEN OPEN 
 BACK PRESS 
 
 I 
 
 FIG. 161. BACK-GEARED 
 PILLAR PRESS 
 
 PIG. 162. KNUCKLE-JOINT 
 
 PRESS 411 
 
410 
 
 ing head, a, niountod in fho frame ol' tlie 
 
 The motion 
 by a heavy 
 the foot treadl 
 
 machiu< 
 
 is derived from a toaal 
 
 r^rt 
 
 diffe 
 
 lo joint actuated 
 
 pendnhim, b, whicJi is pushed back by 
 
 c, c. By means of the adjusting screw, 
 
 owered to accommodate 
 
 d, the liead mav be raised or 1 
 
 i-ent lieights of work. I 
 
 press whicli is wi(k-lv 
 
 n anotlier tyi)e of han<i 
 
 I 
 
 usi'd, tlie liead is forced d 
 
 own 
 
 )y means of a sharp-pitched scr 
 
 ew 
 
 w 
 
 the pi, 
 of tl 
 
 ice of the adjusting screw, d. A 
 
 hicli occupie 
 the t 
 
 cross 
 
 on 
 
 lis 
 
 I 
 
 crew IS a horizontal arm, wliicli carries at 
 
 each end a lieavv east- 
 d 
 
 iron ball. A handh' drops 
 down from the arm to a point witliin reacli of Uw 
 
 e, revolves the 
 eavy weiglits and forces \]w luwid 
 
 operator, wlio, hy ])ulling this liandl 
 screw and tlie h 
 
 down against the worl> 
 
 For I 
 
 irger work the belt-driven press, F 
 
 IS used. Thi 
 
 'iiiure Kid. 
 
 which leaves tlie sides cI 
 
 s consists of a heavy C-shaped fi 
 
 amc 
 
 ear so that strip stock can 
 be fed across the die from side to sid(^ AVlien the 
 
 bad 
 
 back 
 
 k is open, as at a, the press is known a: 
 
 pre 
 
 ss. 
 
 ^ri 
 
 an open 
 le opening i)ermits light from the back 
 
 of the machine to fall cm the d 
 
 an eirress 
 
 tl 
 
 ie, and also provide 
 
 irougli which the stamped articl 
 
 be dischai'ged. Jn this tyj)e of 
 
 es ma\ 
 
 press the main fram 
 
 , "■^^'.. ... i.M.- i^|M' ui (jiess riie main Trame, 
 
 b, is usually separate from the legs, c, and is clamped 
 
 to them by means of a fitted connection, d, whicl 
 is on tlie arc of a circle. 
 
 By the turning of the w 
 frame, b, may be tilted backw^ard at 
 
 orm, e, in the base, the 
 
 an angle, an 
 
 in connection with cer- 
 
 advantage often convenient 
 
 tain types of work, since the finished piece will then 
 
 slide away from the opartor and out throuah tin 
 
 iKi. IT)!). FOOT r-in:ss 
 
 fk;. IfiO. rklt-dkivi:n oim:n 
 
 BACK PRESS 
 
 Fir,. 161. BACK-iiKARF.n 
 IMl.LAR PRF.SS 
 
 Fir,. 162. KN'T'CKLE-.IOINT 
 PRESS 411 
 
412 
 
 Tlli: MECHANICAL EQUIPMENT 
 
 BROACHING AND PRESS WORK 
 
 413 
 
 !| 
 
 g 
 
 opening in the back into a drum or receptacle behind 
 the machine. The punch head, f, is operated through 
 a connecting rod from the crank, g, between the 
 housings on the top of the frame. This crank is part 
 of shaft, which extends to the right and carries the 
 driving pulley. The pulley is generally made with a 
 heavy rim, so that it acts as a flywheel as well. It 
 is not keyed to the shaft but rotates freely, except 
 when a clutch on the side of the machine between the 
 pulley hub and the frame is thrown in. 
 
 This clutch does not show in the figure. It is 
 operated by the foot treadle, h, shown below. Much 
 thought has been given to the subject of press 
 clutches, as the work they are called upon to do is 
 very severe. They are usually arranged to lock the 
 pulley to the shaft when the treadle is depressed and 
 held there. If the treadle is depressed and the foot 
 is removed at once, the crank shaft will make one 
 revolution and stop automatically at the top of the 
 return stroke, in the position shown. The work is 
 then fed forward and the treadle is depressed again. 
 For continuous operation it is necessary only to keep 
 the treadle depressed. The connecting rod is made 
 in two sections, which may be clamped together by 
 the screw, i. Thus an adjustment for length is given 
 which allows setting the head to different heights for 
 varying jobs. 
 
 Figure 161 shows a straight-sided or pillar press, 
 which is much stronger than the one just shown, but 
 in general not so convenient. Here the connection 
 between the base which carries the die and the bear- 
 ings above, is made by two straight members a, a, 
 
 which are free from the bending strain incident to 
 the open-back type. This press is back-geared, the 
 belt runs on tight and loose pulleys at the left, and 
 the flywheel is separate from the pulleys. The pul- 
 leys and the flywheel are carried on a separate shaft 
 at the back of the machine, and this shaft has a 
 pinion at the opposite end engaging with the large 
 spur wheel at the right. The clutch is located, as 
 in the machine just described, at b, between the 
 frame and the hub of the large gear. 
 
 Figures 160 and 161 both show single-action 
 presses; that is, there is one head with its connect- 
 ing rod and crank. In a double-action die, such as 
 that shown in Figure 155, it is necessary that there 
 be two heads. One of these is usually arranged to 
 slide inside the other, and the shaft above has three 
 crank pins — one in the middle, which operates one 
 head; and one on each side, which act together and 
 operate the other head. Such presses are known as 
 double-action presses. Triple-action presses are also 
 made, in which the third motion is usually given to 
 an independent head that acts upward through the 
 lower die. 
 
 A still more powerful type of press is the knuckle- 
 'joint press. Figure 162, which usually has the pillar 
 type of frame. The shaft, however, instead of driv- 
 ing directly down to the head, operates a toggle or 
 knuckle joint. The upper member, a, connects with 
 the arch of the frame, and the lower member, b, with 
 the head, c. A short link extends forward from the 
 crank on the main shaft, d, to the joint between the 
 toggle members, a and b. Presses of this type have a 
 

 lIBii'' 
 
 ll 
 
 11 
 
 r 
 
 i 
 
 414 
 
 THE MECHANICAL EQUIPMENT 
 
 very short stroke, but tremendous power; they are 
 used for embossing, coining, and so on. Hydraulic 
 presses, also, are used for heavy work, especially 
 where the stroke is long. These, however, are not 
 used so much for cold pressing as for hot forging. 
 A heavy forging press is shown in Figure 20. 
 
 The types of presses are often subdivided accord- 
 ing to the use to which they are put and the methods 
 of feeding the work. A coining press is a knuckle- 
 joint press especially adapted, as the name implies, 
 for coining work. Trimming presses are used to cut 
 off the ragged edges of pieces that have been blanked 
 and formed. Other types are called multiple-punch- 
 ing, notching, or perforating presses, according to 
 their use. A cut-and-carry press has multiple plung- 
 ers, each of which does a different operation. The 
 stock is fed in from one side and moved across from 
 station to station with each stroke of the head, and 
 a finished piece comes out on the other side at every 
 stroke. In a dial-feed press a circular work-holder, 
 or dial, rotates about a central stud on the base; it 
 has openings or stations around the rim. The dial is 
 operated automatically by the punch, and the oper- 
 ator feeds the stations on the side toward him while 
 work is being performed on the pieces that are on 
 the other side. This is a safe and rapid form of feed, 
 well adapted to long runs of standard work. 
 
 Safety.— Increasing attention is being given to the 
 the question of the safety of the operator in feeding 
 punching machinery. With no class of machines have 
 accidents been more frequent. They usually come 
 from the accidental throwing in of the clutch, from 
 
 BROACHING AND PRESS WORK 
 
 415 
 
 tlie failure of the operator to get his hand away from 
 the die quickly enough after he has thrown the 
 clutch, or from an attempt to readjust the work on 
 the die while the head is descending. Many safety 
 devices have been developed. Some of them provide 
 an automatic stop which locks the head so that it 
 cannot descend until the operator's hands are clear 
 of the die. Others hold the clutch until the operator 
 throws a releasing mechanism which requires the 
 use of both hands. And in another form, a guard is 
 automatically interposed between the operator and 
 the die by the clutch-throwing mechanism or by the 
 head as it descends. 
 
 V 
 
' 
 
 ;! 
 
 I II 
 
 §l| 
 
 
 ^ 
 
 CHAPTER XXIII 
 WOODWORKING MACHINERY 
 
 Types of Machines Few; Modifications Many. — The 
 natural peculiarities of wood constitute a factor that 
 has strongly influenced the design of the machinery 
 used for working it into useful shapes. Obviously 
 wood cannot be cast or forged; hence woodworking 
 machines are nearly all cutting machines. Wood is 
 comparatively soft and brittle, and the chips clear 
 themselves easily; therefore high speeds (5000 to 
 10,000 feet a minute) are the rule, with correspondingly 
 fast feeds and high power consumption. Such speeds 
 preclude reciprocating motion between the cutter and 
 the work; the lathe, drill, milling and grinding ma- 
 chines are the only machine tools that have their 
 counterparts in woodworking. 
 
 In spite of the small number of fundamental ma- 
 chines, each type has been modified in many ways 
 to suit special conditions, so that today there is wide 
 variety in the methods of holding and feeding the 
 work, and in the arrangement of the cutting tools. 
 Thus, the surfacer, the matcher, the moulder and the 
 shaper* are developments of the planer; the hollo w- 
 
 * Note.— These names must not be confused with those of metal- 
 working machine tools, with which the tools here mentioned have no 
 connection. 
 
 416 
 
 WOODWORKING MACHINERY 
 
 417 
 
 chisel mortiser is a form of borer; the circular saw, 
 in effect a fast-running milling cutter, is used in 
 plain and universal benches, swing frames, tenoning 
 machines, log mills, and so on. 
 
 Saws.— Some form of saw is invariably used for 
 cutting lumber roughly to shape. The circular saw 
 has been used in the past to do most of this work, 
 especially when straight cuts were required. The 
 band saw has now superseded it in many cases. The 
 great advantages of the band saw are its thinness, 
 by virtue of which it wastes only one-third as much 
 material as the circular saw, and its narrowness, 
 which makes it suitable for use on curves and easy 
 scroll work as well as for straight lines. A plain 
 band saw for general purposes is shown in Figure 163. 
 The cast-iron C-frame carries an upper and a lower 
 wheel, a and b, each about 3 feet in diameter and 
 faced with leather; the upper wheel bearing slides in 
 vertical ways, and is pushed upward by a spring that 
 keeps the correct tension in the saw, c, which passes 
 over the wheels. The lower wheel shaft carries both 
 tight and loose pulleys on the rear end, over which 
 the driving belt passes; the belt shipper for starting 
 and stopping the saw is operated by the handle, d. 
 
 The work is laid on the table, e, which can be 
 tilted from zero to 45 degrees, by a hand wheel (not 
 shown), and which is fed by hand against the front 
 edge of the saw. The thrust is borne by the roller 
 guides, f, the upper one of which can be placed as 
 close to the work as convenient by lowering the post, g. 
 For safety's sake both wheels, and all except the work- 
 ing portion of the saw, should be inclosed, as shown 
 
418 
 
 THE MECHANICAL EQUIPMENT 
 
 I 
 
 I 
 
 in the figure. The saws used vary from 1/2 to 21/2 
 inches in width, have a brazed lap joint, run at a 
 speed of 5000 feet a minute, and consume 3 to 5 
 horsepower. 
 
 For ripping and straight-edging, a heavier ma- 
 chine is used, with a saw 4 inches wide, and an ad- 
 justable guide or ** fence'' is attached to the left side 
 of the table. The work is fed automatically, from 
 30 to 125 feet a minute, by two fluted rolls carried 
 at the lower end of the post, g. 
 
 Band Saw.— The band saw is desirable for re-saw- 
 ing timbers into boards, or a thick board into two 
 thin ones, on account of its narrow slot, or kerf. For 
 this purpose an in-feeding and an out-feeding pair 
 of vertical feed rolls are used. All the rolls are 
 power-driven and can be adjusted by a hand wheel 
 for different thicknesses of work. For sawing 
 warped surfaces, such as ship timbers, a special saw 
 is used, both wheels of which are mounted on a cir- 
 cular housing carried on roller bearings by the main 
 frame. The saw can be tipped 45 degrees to the right 
 or left while working, so that it is possible to cut 
 almost any skew shape with it. 
 
 Circular Saw.— In spite of the fact that the band 
 saw can be used in a variety of ways, the circular 
 saw is very often used in preference, especially when 
 many long, straight cuts must be made. In its 
 simplest form it is used in a plain saw bench, which 
 consists of a four-legged, or box, frame supporting 
 a smooth iron or wooden table, about 4 feet by 6 feet, 
 and carrying a horizontal arbor on which is mounted 
 a circular saw whose upper edge projects through 
 
 .'•i .1 
 
 I* .1 
 
418 
 
 THE ME(iIAXI('AI. EQUIPMENT 
 
 in the figure. Tlie saws used vary fi-oin i/^ to 2^. 
 inches in widtli, liavc a hrazed lap joiut, run at a 
 speed of nooO feei a uiiuute, and consume 3 to :> 
 liorsepowcr. 
 
 For ripping and straight-edging, a Invivier ni;i- 
 ehine is used, witli a saw 4 inches wi(h', and an ad 
 justahk^ gui(h' or ''fence" is attached to tlie left si^lc 
 of tlie table. Tlic work is Uh] autonudically, from 
 :^0 to 12.") IV(»t a ininut(\ hy two fluted rolls carried 
 at the lower end of the post, g. 
 
 Band Saw. — The hand saw is (h^sirahle for re-saw- 
 ing timbers into ])oards, or a thick board into two 
 thin ones, on account of its narrow slot, or kerf. For 
 this purpose an in-feeding and an out-fe(Mling pair 
 of vertical feed rolls are used. All tlu^ rolls aro 
 power-driven and can be adjusted by a hand wIkmI 
 for different thicknesses of work. For sawin- 
 warped surfaces, such as ship tim])ers, a special saw 
 is used, botli Avhec^ls of which are mounted on a cir 
 cnlar housing carried on roller bearings by the main 
 frame. Tlu' saw can be tij)])ed 45 d(»grees to the riglil 
 or left while working, so that it is possible to cul 
 almost any skew shape with it. 
 
 Circular Saw.— In spite of the fact that the baii<l 
 saw can be used in a variety of ways, the circid.'ir 
 saw is very often used in preference^, especially when 
 many long, straight cuts must be made. In its 
 simplest form it is used in a plain saw bench, whidi 
 consists of a four-legg<'d, or box, frame supportinu^ 
 a smooth iron or wooden table, about 4 feet by () feel, 
 and carrying a horizontal arbor on which is mountcMl 
 a circular saw whose upper o(\o;^. projects throucrli 
 
420 
 
 THE MECHANICAL EQUIPMENT 
 
 WOODWORKING MACHINERY 
 
 421 
 
 3 11 
 
 ii 
 
 1' 
 
 a narrow slot in the table. A long fence for guiding 
 the work is clamped to the top of the table; it can 
 be shifted for ripping different widths, and can be 
 tilted for sawing bevels. 
 
 The table can be elevated by a hand wheel or by a 
 lever, so that the saw blade will protrude through 
 the top of the work no further than is necessary to 
 make a clean cut. The smaller sizes are hand-fed, 
 but for heavy ripping and edging a two-roll feed is 
 used, similar to that on band saws. A chain feed is 
 sometimes used when a straight cut is absolutely 
 essential. Such a feed consists of two endless chains 
 which travel the length of the table, one on each side 
 of the saw, in a recess made for the purpose, and 
 return underneath through the frame. Each link has 
 a serrated surface, against which the work is pressed 
 by a row of weighted idlers acting from above. 
 
 Universal Saw Bench.— Gradual development of 
 this type has evolved the universal saw bench, shown 
 in Figure 164. The table consists of a stationary 
 section, a, and a moving section, b, carried on rollers 
 c. Both the stationary section and the moving sec- 
 tion are carried on a rocker, so that the whole table 
 can be tilted about a longitudinal horizontal axis 
 through the saw slit, d. Two saws, a cross-cut, e, 
 and a rip, f, are provided; they are mounted at each 
 end of a yoke (not visible) carried in bearings in the 
 main frame. 
 
 By the turning of a handwheel the yoke is swung 
 in its bearings and either saw is brought into operat- 
 ing position. Two types of fence are provided: the 
 ripping fence, g, which can be clamped at any angle 
 
 and at any distance from the saw; and the cut-off 
 gauge, h, which may also be clamped at any angle, 
 and which is provided with a guide strip that slides 
 in the groove, i. All fences and gauges have scale 
 and micrometer adjusting screws for making accurate 
 settings. This machine is most useful m cabinet- 
 making and pattern shops, where the degree of 
 accuracy approaches that required in metal working. 
 Swing-Frame Saw.— The swing-frame saw is pecu- 
 liarly fitted for cutting off to standard lengths, as m 
 door, sash, and box factories. The work rests m a 
 fixed position on a table, and the saw, whose arbor is 
 supported in the lower end of a frame that hangs 
 from the ceiling, is pulled through the work from 
 
 back to front. 
 
 Log Mill.— A special apparatus, known as a log 
 mill, is used for ripping logs and rough timbers into 
 boards. It has two main parts: the husk, a, and the 
 carriage, b (Figure 165). The former si:,.ports the 
 saw, the arbor, and the feed mechanism; the latter 
 holds the log and feeds it past the saw. The arbor 
 is driven directly by the pulley, c; the forward feed 
 is obtained by pulling the lever, d, to the right. This 
 motion feeds the frame forward by means of a pinion 
 meshing with the rack, e. For the return feed, or 
 ''gig,'' which is considerably faster than any of the 
 forward feeds, the lever d is pushed to the left. 
 The gauge-roll, f, with graduated adjustment, sup- 
 ports the left-hand side of the timber as it approaches 
 the saw, and the spreader wheel enters the kerf and 
 opens it enough to prevent the binding of the- saw. 
 The carriage is a timber frame which travels on 
 
lit 
 
 II 
 
 WOODWORKING MACHINERY 
 
 423 
 
 rolls that are either stationary, as shown in the illus- 
 tration, or fastened to the under side of the carnage 
 stringers. Bolted to it are a number of head-blocks, 
 h spaced about five feet apart, which support the 
 log on its under side; its right-hand side rests against 
 the uprights, i, fastened to the set beam, j. The log 
 is clamped rigidly to the uprights by hooks, or 
 ^^dogs," of various styles, and is **set" or shifted 
 across the carriage by the handle, k. The scale, 1, 
 indicates the distance between the uprights and the 
 saw. The foot lever, m, brings into action a device 
 that ** backs" the set beam to take on a new log 
 while the carriage is gigging. 
 
 Gang Saw.— The gang saw, for cutting logs into 
 lumber, constitutes an exception to the general rule 
 that reciprocating tools are not used in woodworking 
 machinery. Aside from the fact that it is one of the 
 oldest types of saw used in this connection, the 
 features that especially commend it are narrow saw 
 blades, ability to cut up a log completely in one 
 operation, without occasioning loss of time in gig- 
 ging, and possibility of direct connection to a steam 
 engine. The gang saw consists of a heavy vertical 
 frame in which a saw-bearing sash slides rapidly up 
 and down. A number of parallel saw blades are 
 stretched between the top and the bottom girts of 
 the sash, and since they are under tension only they 
 can be made very thin. The cut is taken on the down 
 stroke, and the teeth are drawn back slightly on the 
 up stroke in order that they may not drag; this back- 
 ward motion is given by a device which oscillates 
 the lower end of the sash, Feed rolls (two above and 
 
WOOnWORKINCJ MACHINERY 
 
 423 
 
 roll^ that aro (Mther stationary, as shown in tho ilhis- 
 nation, or fastened to the under side of the earria-e 
 .irins-ers. Bolted to it are a number of head-blocks, 
 1, spliced about five feet apart, which support the 
 l(,o on its under side; its right-hand side rests against 
 tlM' uprights, i, fastened to the set ))eani, j. The log 
 is clamped rigidly to the uprights by hooks, or 
 -dogs," of various styles, and is ^*set" or shifted 
 across the carriage by the handle, k. The scale, 1, 
 indicates the distance between the upriglits and the 
 saw. The foot lever, m, brings into action a device 
 tliat 'Miacks" the set beam to take on a new log 
 while the carriage is gigging. 
 
 Gang Saw.— The gang saw, for cutting logs into 
 Uiniber, constitutes an exception to the general rule 
 that reciprocating tools are not used in woodworking 
 machinery. Aside from the fact that it is one of the 
 ()ld(»st types of saw used in this connection, the 
 features that especially conmumd it are luirrow saw 
 hlades, ability to cut up a log completely in one 
 operation, without occasioning loss of time in gig- 
 ging, and possibility of direct connection to a steam 
 engine. The gang saw consists of a heavy vertical 
 frame in which a saw-bearing sash slides rapidly u}) 
 and down. A number of parallel saw blades are 
 stretched between the top and the bottom girts oT 
 the sash, and since they are under tension only they 
 can be made verv thin. The cut is taken on the down 
 stroke, and the teeth are drawn back slightly on the 
 up stroke in order that they may not drag; this back- 
 ward motion is given by a device which oscillates 
 the lower end of the sash. Feed rolls (two above and 
 
424 
 
 THE MECHANICAL EQUIPMENT 
 
 WOODWORKING MACHINERY 
 
 425 
 
 IH 
 
 
 two below the work) carry the logs through the 
 frame, and deliver the rough-cut lumber on the out- 
 feeding side. 
 
 Power Consumption of Saws.— The power consump- 
 tion of saws varies greatly according to the coarse- 
 ness of the teeth, width and depth of cut, and rate 
 of feed. The usual cutting speed is 10,000 feet a 
 minute. With hand feed 3 to 5 horsepower is re- 
 quired. Heavy power-fed saw benches take 10 to 20 
 horsepower, and feed from 20 to 150 feet a minute; 
 log mills require 25 to 50 horsepower, and the feeds 
 range from 50 to 300 feet a minute. 
 
 Planers, Surfacers, Moulders and Shapers.— On ac- 
 count of vibration, fast cutting speed and feed, and 
 the fact that a rip-saw tooth cuts only on the front 
 and tears on the side, all rip-sawed surfaces must be 
 planed by being passed over a rapidly revolving 
 cylinder carrying two or more thin knives, which 
 make a series of light, broad cuts as nearly parallel 
 to the grain as possible. The knives must be longer 
 than the width of the surface to be planed, and the 
 feed and the cutting speed must be so related that 
 no visible corrugations will.be produced. Irregular 
 surfaces may be obtained by varying the contour of 
 the knife-edges — in every case the surface will be a 
 counterpart of their contour. By the process just 
 described, flooring is matched and beaded, and mould- 
 ings are made. 
 
 The hand planer, Figure 166, consists of the box 
 frame, a, front and rear carriages, b and c, front and 
 rear tables, d and e, and cutter-head or cylinder, f. 
 A section of one of these cylinders in a somewhat 
 
 FIG. 166. HAND PLANER 
 H. B. Smith Machine Co. 
 
 I I 
 
 FIG. 167. SECTION OF A SURFACER HEAD 
 
424 
 
 THE MECIIANK AL EQrn>MI^:NT 
 
 WOODWORK! N( I AIACIILXERY 
 
 425 
 
 two Ix'low Uw work) carry Uw lo^s tlir()u.t»']i Ww 
 frame, and (IHiv(>r tlie roii^i-ii-rut limibcr on the out 
 feeding side. 
 
 Power Consumption of Saws.— The powiM- eonsunip 
 tion of saws varies greatly aeeording to the coarse 
 ness of the teeth, widtli and (h'pth of eut, and 7-at<' 
 of feed. The usual cutting speed is 1(),()()() feet a 
 minute. With hand feed .*) to o horsepower is re 
 quired. Heavy power-fed saw henches take 10 to 2n 
 horsepower, and fec^l from 20 to loO feet a minute; 
 log mills require 25 to 50 hors(7)()\\er, and the feed> 
 range from 50 to 800 feet a minute. 
 
 Planers, Surfacers, Moulders and Shapers.— On ac- 
 count of vihration, fast cutting spcM'd and feed, and 
 tlie fact tliat a rip-saw tooth cuts only on the front 
 and tears on the sid(\ all rip-sawed surfaces nmst !).■ 
 planed by being passed over a rapidly revolving 
 cylinder carrying two or mon^ thin knives, which 
 make a series of light, broad cuts as nearly parallel 
 to the grain as possible. The knives must be longer 
 than the width of the surface^ to be planed, and the 
 r^ed and the cutting speed nmst l>e so relatc'd thai 
 no visible corrugations will be ])roduc(Ml. lrreii:ular 
 surfaces may be o])tained by varying the contour of 
 the knife-edg(»s— in every case the surface will be n 
 counterpart of their contour. By the ])rocess jus! 
 described, flooring is matched and l>eaded, and mould- 
 ings are made. 
 
 The hand planer. Figure Kiti, consists of the l)o.v 
 frame, a, front and rear carriages, b and c, front and 
 rear tables, d and e, and cutter-head or cvlinder, f. 
 A section of one of these cylinders in a somewha' 
 
 Fl(i. IGtJ. HAND PLANKR 
 11. ii. yiiiiili Macliiue Co. 
 
 FKl. 107. SECTION OF A SUKFACER HEAD 
 
426 
 
 THE MECHANICAL EQUIPMENT 
 
 .WOODWORKING MACHINERY 
 
 427 
 
 different machine is shown in Figure 167. Either 
 table may be raised or lowered for cuts of different 
 thicknesses by a turning of the hand wheel g or h, 
 as the case may be, which slides it over inclines on 
 the carriage. The adjustable fence, i, acts as a guide 
 for the work; the bracket, j, which is ordinarily re- 
 moved or swung downward, is used when work is to 
 be rabbeted. 
 
 It was customary to use on early planers a cutter- 
 head of rectangular section, with a knife bolted to 
 each face. Necessarily there was much clearance 
 between head and table, so that operators frequently 
 lost some of their fingers in feeding the tail end of a 
 board over the knives. Today circular cutter-heads 
 with inserted knives are used on all hand-feed plan- 
 ers, and a guard, k (Figure 166), is set directly over 
 the cutters. 
 
 For planing long boards in quantities a power feed 
 is required. The cutter-head is mounted on an ex- 
 tension about ten inches above the table. Two feed 
 rolls, also, are mounted on this extension, one in 
 front of the cutter-head and the other behind it. The 
 feeding-in roll is fluted, and so supported as to have 
 considerable vertical play to allow for unevenness in 
 the rough stock. Directly under the feed rolls are 
 two other rolls, which work through slots in the 
 table. The table is in one piece, and can be raised 
 or lowered so that varying thicknesses of stock and 
 depths of cut can be obtained. Front- and back-pres- 
 sure bars— a and b. Figure 167--hold the stock firmly 
 to the table immediately before and after it passes 
 the cutters. A machine of this type is called a oingie- 
 
 cvlinder surfacer. If another cutter-head is added, 
 it is possible to surface both the upper and the lower 
 side of a board at the same time; a machine that has 
 this extra cutter-head is called a double-cylinder sur- 
 facer. 
 
 The efficiency of these machines is still further in- 
 creased by the use of sectionalized feeding-in rolls 
 and pressure bars, each section being pressed down 
 independently by a weight or spring device (see 
 Figure 167). A number of narrow boards which are 
 twisted, or whixih have slightly different thicknesses, 
 can then be fed simultaneously, and the full width of 
 the machine can be utilized. In a double-cylinder sur- 
 facer, the upper cutter-head is placed ahead of the 
 lower one, so that the stock has a firm support as 
 it passes each head. The table can be raised or low- 
 ered for different thicknesses of material and vary- 
 ing cuts of the upper head; while the lower head, car- 
 ried in the table, can be raised or lowered independ- 
 ently to vary the cut on the under side of the work. 
 On all except the smallest of these machines, a rapid 
 adjustment of the table-elevating mechanism can be 
 
 made by power. 
 
 For cutting . mouldings, hexagons, full and sec- 
 tional rounds, and other strips of irregular cross- 
 section, one or two vertical cutter-heads are desirable 
 in addition to the horizontal heads of the surfacer. 
 A machine that has these additional attachments is 
 called a moulder. There are two distinct styles: the 
 outside type, in which the table is supported in ver- 
 tical slides on the side of the frame; and the inside 
 type, in which the table is supported as it is in a 
 
428 
 
 THE MECHANICAL EQUIPMENT 
 
 r*' 
 
 ^1 
 
 surfacer. The outside moulder is not rigid enough 
 to be used for wide work, but it is more accessible 
 than the inside moulder, on account of the more 
 open construction. In both types, the vertical, or 
 *' matcher," heads have vertical, transverse, and 
 swiveling adjustments, and the feeding-out rolls are 
 dispensed with. 
 
 Figure 168 shows a six-head planer or matcher 
 specially adapted for finishing boards simultaneously 
 on all sides, and used in the manufacture of matched 
 flooring. The lower cutter spindle, a, has a slight 
 vertical adjustment to compensate for wear of knives, 
 while the upper spindle and pressure bars can be 
 raised and lowered on the guides, b. The table con- 
 sists of a feeding-in extension, c, with adjustable 
 fence for lining up the rough stock, and a platen 
 which supports the work under the top cutter-head. 
 
 On some machines the platen and the lower feed- 
 ing-in rolls have a wedge adjustment for raising and 
 lowering them slightly, so that the thickness of the 
 upper and the lower cuts can be varied without 
 changing the thickness of the finished piece. A ma- 
 chine of this type is said to have a 'Svedge platen.'' 
 The four feeding-in roll centers are at d, and the 
 two feeding-out rolls at e. These rolls give a positive 
 feed, and yet permit a wide variation in the thickness 
 of stock. The side, or matcher, heads are located 
 at f. In the illustration one of the driving spindles 
 may be seen through a hole in the frame below; the 
 two heads at the left end are used for beading and 
 for other narrow cuts. 
 
 The power consumption of machines of the planer 
 
428 
 
 TIIK MKCHAXK'AI. lOQllPxAIENT 
 
 snrfacor. Tlic outsiile moulder is not rio'id oiioiip^h 
 to ho us(m1 for wide work, hiil it is more accessible 
 than the insich^ inonhhM-, on account of the more 
 open construction. In hoth tyjM's, the vertical, or 
 *'matclicr/' heads jiave veitical, transverse, and 
 swivelini;- adjustments, and the Feedino-out rolls arr 
 disi)ensed with. 
 
 Figure 1()8 shows a six-liead planer or matcher 
 specially adapted for linishini;- hoards siimdtaneously 
 on all sides, and nsed in the manufactui'e of matched 
 flooring. The 1ow(m- cutter spindle, a, has a slight 
 vertical adjustment to compensate fo!' wear of knives, 
 while the upper s])indle and pr(\<sure hai-s can hr 
 raised and lowen^l on the guides, h. The table con- 
 sists of a feeding-in extension, c, with adjnstabl.' 
 fence for lining up the rough stock, and a platen 
 which supports the work nnder the top cutter-head. 
 On some machines the platen and the lower feed- 
 ing-in rolls have a wedge adjustment for raising and 
 lowering them slightly, so that the thickness of the 
 upper and the lower cuts can be varied without 
 changing the thickness of the finished piece. A ma- 
 chine of this type is said to have a "wedg(. platen." 
 The four feeding-in roll centers are at d, and the 
 two feeding-out rolls at e. These rolls give a positive 
 feed, and yet permit a wide variation in the thickness 
 of stock. The side, or matcher, heads are located 
 at f. In the illusti-ation one of the driving spindles 
 may be seen through a hole in the frame Ixdow; the 
 two heads at th<' left <'nd are us(»d for beading arnl 
 for othei- narrow cuts. 
 
 The power consumption of ma(diines of the f)lane 
 
 C5 
 
 
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 rt 
 
 fc: 
 
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 430 
 
 THE MECHANICAL EQUIPMENT 
 
 WOODWORKING MACHINERY 
 
 431 
 
 ill 
 
 type varies with the feed, width, and depth of cut, 
 and with the number of cutter-heads. Hand planers 
 require 1 to iy<^ horsepower, single-cylinder surfacers 
 5 to 20, double-cylinder surfacers 15 to 25, and four- 
 and six-head machines up to 40 horsepower. These 
 figures are for the usual feeds of 20 to 60 feet a 
 minute; ** fast-feed ' ' machines, with feeds up to 250 
 feet a minute, require up to 60 horsepower. The 
 usual cutting speed for planers is 5000 feet a minute. 
 
 For curved work, such as brush backs, and handles 
 for hand saws, planes^ and so on, a vertical spindle 
 machine with hand feed is desirable. In the variety 
 moulder or shaper. Figure 169, each spindle has an 
 independent vertical adjustment for varying the 
 height of the cut, and can be depressed entirely below 
 the table so as not to interfere with large work. 
 Ordinarily the shaper has a solid fixed table; but 
 when it is necessary to cut profiles — such as column 
 flutings — at some height from the table, the front 
 half can be dropped, as shown, and the work can be 
 suppported on the lower level. 
 
 Lathes. — For general manufacturing the lathe is 
 much less useful than the planer and the moulder; 
 it cannot attain the high cutting speeds of the planer 
 without causing excessive vibration of the work, and 
 is only useful for producing cylindrical and other 
 surfaces, of revolution, whereas the planers and the 
 moulders can be used for both plane and cylindrical 
 surfaces. The best work for the wood-turning lathe 
 is pattern-making, the turning of table legs, stair 
 balusters, and pieces of varying diameter, and the 
 manufacturing of elliptical and irregularly curved 
 
 FIG. 169. DROP TABLE MOLDER 
 S. A. Woods Machine Co. 
 
 articles, such as hammer handles, wagon-wheel spokes, 
 gun stocks, and so on. 
 
 For plain turning, a light ''speed lathe" is used, 
 with bed, legs, headstock, and tailstock like those ot 
 an engine lathe. No back gears are necessary, for 
 sufficient speed variation is obtained by means of a 
 three-stepped cone pulley. The live spindle is 
 threaded to receive a face plate, and is reamed to 
 take a three-pronged spur center for driving long 
 work that must be supported at both ends. The tool 
 is usually held against an adjustable rest and fed 
 
430 
 
 THE :\li:('lIAMC'AL KQl IPMENT 
 
 WOUDWOKKIMJ MACHINKIJV 
 
 4:;i 
 
 type varies with tlie feed, width, and depth of cut, 
 and with the number of eutter-heads. Hand planers 
 require 1 to 7 to horsepower, single-cylinder surfacers 
 ') to 20, double-cylinder surfacers 15 to 25, and foui- 
 and six-head machines up to 40 horsej)ower. Theso 
 figures are for the usual feeds of 20 to 60 feet a 
 minut(»; ^* fast-feed'' machines, with feeds up to 25(1 
 feet a minute, require up to (iO horsepower. Tlio 
 usual cutting speed for planers is 5000 feet a minute. 
 
 For curved work, such as brush backs, and handles 
 for hand saws, planes, and so on, a vertical spindle 
 machine with hand feed is desiral)le. In the variety 
 moulder or shaper, Figure 169, each spindle has an 
 independent vertical adjustment for varying the 
 height of the cut, and can be depressed entirely below 
 the table so as not to interfere with large work. 
 Ordinarily the shaper has a solid fixed table; l)ut 
 when it is necessary to cut profiles — such as colunui 
 flutings — at some height from the table, the fi'oiit 
 half can be dropped, as shown, and the work can be 
 suppported on the lower level. 
 
 Lathes. — For general manufacturing the lathe is 
 much less useful than the planer and the moulder; 
 it cannot attain the high cutting speeds of the planer 
 without causing excessive vibration of the work, an<l 
 is only useful for producing cylindrical and otluM- 
 surfaces of revolution, whereas the planers and th<' 
 moulders can be used for both plane and cylindrical 
 surfaces. The best work for the wood-turning lath<' 
 is pattern-making, the turning of table legs, stair 
 balusters, and pieces of varying diameter, and th'' 
 manufacturing of elliptical and irregularly curved 
 
 FU\. IG9. HKOP TABLK MOLHKli 
 S. A. Wodds MsH-hine (\>. 
 
 articles, such as hammer handles, wagon-wheel spokes, 
 -un stocks, and so on. 
 
 For plain turning, a light ^'speed lathe" is used, 
 xvith l)ed, leo:s, headstock, and tailstock like those ol 
 an engine lathe. Xo back gears are necessary, for 
 snfiicient speed variation is ohtained by means of a 
 lliree-stepped cone pulley. The live spindle is 
 t breaded to receive a face plate, and is reamed to 
 take a three-pronged spur center for driving Ion- 
 work that must be supported at both ends. The tool 
 is usuallv held against an adjustal>le rest and U^d 
 
432 
 
 THE MECHANICAL EQUIPMENT 
 
 WOODWORKING MACHINERY 
 
 433 
 
 m 
 
 by hand; but for accurate pattern making, tool car- 
 riages are provided, as in engine lathes. Face lathes, 
 consisting of a headstock mounted on a suitable base, 
 with tool rest carried on a bracket, are used for turn- 
 ing patterns of wheels, pulleys, cylinder covers, and 
 the like. The tools commonly used for these lathes 
 are the gouge (for roughing), skew, round-nose and 
 straight chisels, and the parting tool. 
 
 Gauge Lathe. — The gauge lathe is used for turning 
 table legs and other irregular surfaces of revolution. 
 The irregular contour is obtained with a roughing 
 tool, which follows a fixed template, or former, 
 secured to the bed. A finishing cut is taken by a 
 formed *'back knife," mounted obliquely in a frame 
 which slides in two vertical guides so that the knife 
 is always in contact with the work just behind the 
 roughing tool. If the former is rotated at the same 
 speed as that of the work, still more irregular shapes 
 can be turned, which need not be surfaces of revolu- 
 tion. 
 
 Blanchard, or Copying, Lathe.— Figure 170 shows 
 a Blanchard, or copying, lathe, used for turning these 
 irregular forms. The essential parts are: the main 
 frame, shaped roughly like that of a speed lathe; and 
 the carriage, a, which travels on the ways of the bed 
 and supports a revolving cutter-head, b. A vibrator 
 frame, c, carries a former or pattern, d, revolving 
 between centers, e, e, and the stock (not shown) be- 
 tween the centers, f, f. The vibrator is supported in 
 bearings in the lower part of the main frame, and is 
 oscillated backward and forward by the irregular 
 pattern, which rotates between the shoe, g, on the 
 
 FIG. 170. BLANCHARD OR COPYING LATHE 
 J. A. Fay & Egan Co. 
 
 carriage, and the shoe, h, on a pivoted arm. As the 
 stock and the former are carried in the oscillating 
 frame and are rotated in the same direction and at 
 the same speed by means of the drive, i, the cutter- 
 head will reproduce in the work the shape of the 
 pattern above it. A lead screw feeds the carriage 
 along the bed until the end of the work is reached, 
 when the pressure of the shoes is automatically re- 
 leased and the carriage is returned at high speed to 
 its starting position. The pattern and the work can 
 be rotated between fixed centers and the cutter-head 
 and shoe can be carried on the oscillating frame; this 
 
4:V2 
 
 THE MECHANICAL EQUIPMENT 
 
 !)>• li;iri<l; hut Tor accurate pattorn makiii.i;', tool eav 
 riai^cs arc provided, as in cn^'iiic latlics. Kacc lathe,-, 
 consist in.i;- of a hcadstock mounted on a suitahle has( . 
 ^vith tool I'cst carried on a hracket, arc used for turn 
 mu; patterns of wliecls, pulk'vs, cylinchM* covers, and 
 the like. The tools coniinonlv used for these lather 
 
 « 
 
 are the gouge (for roughing), skew, round-nose and 
 straight chisels, and the parting tool. 
 
 Gauge Lathe. — The gauge lathe is used for turnini' 
 table legs and other iri'egular surfaces of revolution. 
 The irregular contour is obtained with a roughini; 
 tool, which follows a fixed template, or forme!-, 
 secured to the bed. A finishing cut is taken by a 
 formed *M)ack knife," mounted oblicpiely in a frame 
 which slides in two vertical guides so that the knilV 
 is always in contact with the work just behind the 
 roughing tool. If the former is i'otate<l at the same 
 speed as that of the work, still more irregular shapes 
 can be turned, which need not be surfaces of revolii 
 tion. 
 
 Blanchard, or Copyings, Lathe.— Figui-e 170 shows 
 a Blanchard, or copying, lathe, used for turning thes<' 
 irregular forms. The essential i)ai-ts are: the main 
 frame, shaped roughly like that of a speed lathe; and 
 the carriage, a, which travels on the wavs of the bed 
 and supports a revolving cuttei'-head, b. A vibrator 
 frame, c, cai'ries a former oi* pattern, d, levolvinu 
 between centers, e, e, and the stock (not shown) be 
 tweeii the centers, f, f. The vibrator is supjmrted in 
 bearings in the lower part of the main frame, and is 
 oscillated backwai'd and forward bv the irresular 
 pattern, which rotates between the shoe, g, on the 
 
 WOODWOU'KINC MAClliNKin" 
 
 4.;:i 
 
 no. ITU. BLANCllAKl) OU COPVINO LATiiE 
 .7. A. F;iy & Ejran Co. 
 
 cari'iage, and the shoe, h, on a pivoted arm. As the 
 stock and the former are carried in the oscillating 
 frame an<l are rotated in the same direction and at 
 the same s])eed l)y means of the driv(\ i. the cutter- 
 head will reproduce in the work the shape of the 
 pattern a]>ove it. A lead screw feeds the carriage 
 along the bcnl until the end of the work is reached, 
 when tlie pressure of tlie shoes is automatically re- 
 leased and the carriage is returned at high speed to 
 its starting ])osition. The pattern and the work can 
 be rotated between fixcul centers and the cutter-liead 
 and shoe can be carried on the oscillating frame; this 
 
HI' 
 If.' 
 
 434 
 
 
 THE MECHANICAL EQUIPMENT 
 
 arrangement is utilized in other types of the Blanchard 
 lathe. 
 
 MisceUaneous Machines.-In the manufacture of 
 doors, windows, cars, and framed articles, the borer 
 and the mortiser are used for making round and 
 rectangular holes. The single-spindle borer resembles 
 the plain drill press for metal drilling, except that 
 a hand feed is always used and the table usually has 
 a universal adjustment for positioning, or else is 
 fitted with rollers for handling long timbers. The 
 most satisfactory mortiser is the hollow-chisel type, 
 illustrated in Figure 171. The cutting tool, a, is a 
 square hollow chisel which trims the sides of the 
 mortise, inside of which a bit rotates and clears out 
 the material. The tool is fastened to the plunger,, b, 
 which has a power feed with quick return and an 
 adjustable travel controlled by the dogs, c, c. The 
 bit spindle is carried in bearings in the plunger, and 
 IS driven by a belt passing to the main pulley, e, over 
 the idlers, d, d, which automatically maintain tension 
 m the belt, irrespective of the position of the spindle 
 pulley inside the plunger head. 
 
 The carriage, f, in which the plunger slides, has a 
 forward adjustment on the frame, and the table, g, 
 has vertical and longitudinal adjustments, all oper- 
 ated by hand wheels, for setting the work and vary- 
 ing the depth of mortise. The vise, h, is specially 
 designed to hold down the work while the chisel is 
 rising. Unlike the old-style mortisers, which were 
 simply machine-operated chisels, this machine fin- 
 ishes the hole in one stroke downward. 
 
 The wood-milling machine (P^ignre 172), is a receiil 
 
 >i 
 
4:^4 
 
 Tin-; MKCHAXK/AL EQnPMKNT 
 
 arrangement i.s utilized in other types of the Blanchar,] 
 lathe. 
 
 Miscellaneous Machines.-!,, the manufaeture r.f 
 <loors, window.., ear.s, and framed articles, the borer 
 :ui<l the mortiser are used for making round and 
 '■'■'•ta.|f,u!ar holes. The single-spindle borer reseml.l,.. 
 tlie plain drill pres.s for metal drilling, except thai 
 a luuid feed is ahvay.s used and the table usually lia^ 
 a universal adjustment for i)()sitioniiig, or else i^ 
 titted with rollers for handling long timbers. Tlir 
 most satisfactory mortiser is the hollow-chisel type 
 Illustrated in Figure 171. The cutting tool, a, is a 
 .'square hollow clii.sel which trims the sides of the 
 mortise, inside of which a bit rotates and cleans out 
 the mat.'rial. The tool is fastened to the plunger, 1). 
 which ha.s a power feed with quick return and an 
 adjustable trayel controlled by the dog.s, c, e. The 
 l)it spindle is carried in bearing.s in the plunger, and 
 IS driven by a belt pa.ssing to the main pulley, e, over 
 the Idlers. <1. d. which automatically maintain tension 
 m the belt, irrespective of the position of the spindle 
 pulley inside the plunger head. 
 
 The carriage, f. in which the plunger slides, has a 
 forward adjustment on the frame, and the table, jr. 
 has vertical and longitudinal adjustment.s, all ope'r 
 ated by hand wheels, for setting the work and vary- 
 ing the depth of mortise. The vise, h, is specially 
 designed to hold down the work while the chisel is 
 rising. Tnlike the old-style mortisers, which were 
 Miriply machin.M.peral.'d chisels, (his machine fin 
 ishes (he hole in one stroke downward. 
 The \v(i.M|-nii||ii|o m.-icliiiic (Kiginv 17l'). is a wrm' 
 
1 m 
 
 436 
 
 THE MECHANICAL EQUIPMENT 
 
 WOODWORKING MACHINERY 
 
 437 
 
 M*» 
 
 « 
 
 development in pattern-shop equipment. Like the 
 universal miller for metal-working, it is not a manu- 
 facturing machine, but it can produce an almost un- 
 limited variety of shapes with the accuracy of a ma- 
 chine tool. It corresponds in general design to the 
 vertical die-sinker, Figure 107. The spindle, a, is 
 carried by a head, b, at the end of an adjustable 
 counterbalanced arm, c; the head swivels 90 degrees 
 to the right and 45 degrees to the left, and the 
 spindle has a short vertical travel independent of the 
 arm, controlled by the hand wheel, d. The main bed, 
 e, swivels to any angle desired, and supports a car- 
 riage on which is mounted a table, f, which can be 
 swiveled and adjusted transversely or longitudinally 
 by the hand wheels shown. Graduated scales are 
 provided for facilitating accurate adjustments, and 
 the carriage can be fed along the bed by either hand 
 or power. This machine is very useful in making 
 core boxes, gear patterns, and other complicated 
 shapes. Other wood millers are constructed along 
 simpler lines; they have a horizontal and a vertical 
 spmdle mounted directly in the column, with the 
 table supported in a knee sliding in vertical ways 
 on the front of the column. 
 
 Sanding machines are used for finishing woodwork 
 when a planed or a turned surface is not sufficient. 
 In these, the cutting element consists of discs, drums, 
 or cloth belts covered with sandpaper, against which 
 the work is held until ground smooth and to shape. 
 Usually the work rests on a table provided for the 
 purpose, and is fed by hand. An important exception 
 IS the multiple-drum sander, in which rotating and 
 
 oscillating sanding drums polish the under surface 
 of the work as it slides along the table under the 
 action of feed rolls, which bear down on its upper 
 surface. 
 
PAPER MACHINERY 
 
 439 
 
 CHAPTER XXIV 
 PAPER MACHINERY 
 
 Rag Machinery.— The striking characteristics of 
 paper machinery are: large power consumption in 
 comparison with the amount of labor employed; and 
 the use of water and steam in enormous quantities, 
 the first as a carrier for the paper fibres, and the 
 second for cooking and drying. Census figures show 
 that about 17 horsepower per wage-earner is con- 
 sumed in paper and pulp manufacture; in steel manu- 
 facture and rolling only about half that amount is 
 used, while in typical machine shops only 2 or 3 
 horsepower per wage-earner is employed. The 
 amount of water used is indicated by the fact that 
 for every ton of paper produced, from 12,000 to 
 100,000 gallons of water are needed for such processes 
 as washing and diluting, in addition to which 10,000 
 to 15,000 gallons must be used in the form of steam. 
 
 The principal machinery and apparatus required 
 in the manufacture of paper, is as follows: 
 
 For converting rags into **half stock'*: thresh- 
 ers, rag-cutters, dusters, digesters, washers. 
 
 For converting wood into ''half stock": bark- 
 ers, grinders, chipping machines, digesters for 
 soda or sulphite process. 
 
 For preparing the wet pulp or ''stuff"; beat- 
 ers, refiners. 
 
 438 
 
 For making machine-finished paper: Four- 
 drinier or cylinder machine, including winders 
 and one or more calenders. 
 
 For cutting and finishing: slitters, cutters, 
 super-calenders, plating and glazing rolls, coat- 
 ing machines. 
 
 Auxiliary apparatus: belt conveyors, triplex 
 and centrifugal pumps, blowers, exhausters, and 
 
 so on. 
 Dusters and Cutters.— The purpose of rag machin- 
 ery is twofold: to remove loose dust, and to cut the 
 rags into small pieces. The thresher, which performs 
 the first of these duties, consists of a tightly built 
 wooden chest, about eight feet high and ten feet 
 long, with a side door through which the rags are 
 charged; a wooden cylinder that extends lengthwise 
 through it, is provided with arms or beaters project- 
 ing radially from its surface, and driven by a pulley 
 at one end of the shaft. The cylinder stirs up, pokes, 
 and pulls out the lumpy rags as they come from the 
 bale, while suction ducts connected to the upper part 
 of the machine draw off the loose dust. The "devil" 
 works on the same principle; its shape is more or 
 less cylindrical, instead of rectangular, and the re- 
 volving beaters are aided by stationary beaters fixed 
 on the inside of the casing. 
 
 There are two types of duster. In the railroad 
 duster, from three to six revolving cylinders are set 
 in a row, each covered with hard-wood lagging, and 
 fitted with projecting steel pins which pass between 
 other sets of pins projecting inwardly from the cas- 
 ing. These pins beat and thresh the rags as they 
 
' 
 
 '■ / 
 
 
 IH 
 
 440 
 
 THE MECHANICAL EQUIPMENT 
 
 no. 173. TAYLOR DUSTER piG. 174. RAG CUTTER 
 
 Holyoke Machine Co. 
 
 travel from the feeding hopper to the discharge end 
 of the machine, while the dust is sucked out as in 
 the case of the thresher. The other type, illustrated 
 by the Taylor duster. Figure 173, is of about the 
 same size and shape as a thresher. Inside the chest 
 there is a screen consisting of one or two skeleton 
 cylinders, covered with quarter-inch mesh wire cloth 
 rotated by the pulley, a; there is also a central shaft, 
 fitted with propeller blades and driven in the oppo- 
 site direction by the pulley, b. The rags are fed into 
 the right-hand end of the screen, and as they are 
 driven through to the left-hand end by the screw 
 action of the blades, they are tossed about and 
 dragged over the screen, being thereby freed of all 
 remaining loose dirt, buttons, hooks, and so on. Ma- 
 chines of the usual size can handle about three hun- 
 dred pounds of rags an hour, and a series consisting 
 of one thresher, one railroad duster, and two screen 
 dusters, will remove from 2 to 10 per cent of the 
 weight of the stock in the form of dust. 
 
 Figure 174 shows a medium-sized rag-cutter for 
 cutting threshed rags into strips an inch or less 
 wide. The rags are fed by hand or by a belt con- 
 
 PAPER MACHINERY 
 
 441 
 
 veyor into the trough, a, passing under the toothed 
 feed-roll, b, to a series of revolving knives acting 
 against a fixed knife, as in a lawn mower; these 
 knives cut them, and then they are dropped on to a 
 discharging conveyor (not shown in the figure). The 
 driving pulley, c, is attached directly to the shaft 
 carrying the knives, the feed roll being driven by an 
 open belt running from the knife shaft to pulley, d, 
 and by a crossed belt from pulley e to pulley f; 
 these, together with the gearing shown, give a large 
 reduction in speed. The feed roll does not run m 
 fixed bearings, but rides on the surface of the rags, 
 having sufficient weight to seize them with its teeth. 
 Digesters and Washers.— The digester or boiler for 
 saponifying the glutinous and resinous substances m 
 rag stock and washing out the last of the dust, is a 
 spherical or cylindrical steel tank, built to stand forty 
 to fifty pounds of pressure. It is fitted with a door 
 for charging and discharging the stock, a pipe for 
 supplying steam, another for letting in the wash 
 liquor, and one or more blow-off cocks. It may be 
 stationary or revolving; in the former case, the lower 
 part forms a reservoir for liquor, above which is a 
 perforated plate on which the stock rests. Steam is 
 admitted at the bottom, and circulates the liquor by 
 blowing it up through a central pipe to a spray-head 
 near the top of the boiler, from which it is squirted 
 down over the rags, somewhat as coffee is distributed 
 
 in a percolator. 
 
 Kevolving boilers are supported in trunnions, and 
 are rotated slowly by worm or double-reduction spur 
 gearing. One trunnion forms an inlet for steam, the 
 
 ■\ 
 
440 
 
 rilH ME( IIAMCAL EQl'JPMENT 
 
 PAPER ^iAClIINERY 
 
 441 
 
 FIG. 173. TAYLOR DUSTER FIG. 174. RAG CUTTF-R 
 
 Ilolyoko Macliino Co. 
 
 trnvcl IVoni tlio tVodiii"- lioppor to tlio discliarov ond 
 of the inacliinc, wliil,. the dust is sucked out as in 
 tho case of tlie tlnvslier. Tlie other type, illustrated 
 l)y the Tayh)r dust(M-, Ki-ure 17;), is of ahout tli.' 
 sauie size and shape as a thresher. Iiisich' the ehesf 
 there is a screen consisting of one or two ske'.eton 
 cylinders, covered with (puirter-inch niesli wire cloth 
 rotated hy the pulley, a; tlu^e is also a central shaft, 
 fitted with propeller blades and driven in the opjx) 
 site direction hy the pulley, h. The ra.os are \\h\ int.. 
 the rio-ht-hand end of the screen, and as they are 
 driven through to the left-hand end hy the screw 
 action of the ])lades, they are tossed about and 
 dragged over the scr(>en, being thereby freed of all 
 remaining loose dirt, buttons, hooks, ami so on. Ma 
 chin(^s; of the usual size can handle about three hun 
 dred pounds of rags an hour, and a series consisting 
 of one thresher, one railroad duster, and two screen 
 dusters, will remove from 2 to 10 per cent of th.' 
 weight of the stock in the form of dust. 
 
 Figure 174 shows a medium-sized rag-cutter foi 
 cutting threshed rags inlo stri])s an inch or les.- 
 wide. The rags are i'vd by hand or by a belt con 
 
 V, vor into the trougli, a, passing under the toothed 
 ,,;.a-roll, 1), to a series of revolving kniv(>s acting 
 ,..rmst a iixed knife, as in a lawn mower; these 
 knives cut them, and then tliey are dn^nn'^l ^>^i ['^ '' 
 ai-charging conveyor (not sliown in the figure). 1 he 
 driving pullev, c, is attached directly to the shatt 
 ,arrviiig the knives, the feed roll l>eing driven l>y an 
 ,,uvu belt running from the knife shaft to pulley, d, 
 .„ul bv a crossed belt from pulley e to pulley f; 
 \\u'<v 'together with the gearing shown, givi' a large 
 ,,duction in speed. The Uhh\ roll do^'s not run in 
 fixed bearings, but rides on the surface ot the rags, 
 hnvin- sufhcient weight to seize them with its teeth. 
 Digesters and Washers.— ^fhe digester or boiler lor 
 saponifving tlie glutinous and resinous substaiKvs in 
 rag stock and washing out the last of the dust, is a 
 s]»herical or cvlindrical steel tank, ])uilt to stand forty 
 t(, liftv pounds of pressure. It is titled with a door 
 for cliarging and discharging the stock, a pipe for 
 sui)])lying steam, another for letting in the wash 
 liiiuor, and one or more blow-off cocks. It may be 
 stationary or revolving; in the fornu'r case, the lower 
 part fori'iis a reservoir for fupior, above which is a 
 IK'rforated plate on which the stock rests. Steam is 
 admitted at the bottom, and circulates tlu> fKpior by 
 blowing it up through a central ])i])e to a spray-head 
 near the top of the boiler, from which it is s.iuirted 
 (h)wn over the rags, somewhat as coffee is dislrilmted 
 
 in a percolator. 
 
 devolving boilers are su])port'.Ml in trunnions, and 
 are rotated slowly l)y worm or double-reduction spur 
 gearing. One trunnion forms an inlet for steam, th- 
 
442 
 
 I 
 
 THE MECHANICAL EQUIPMENT 
 
 PAPER MACHINERY 
 
 443 
 
 Other for liquor. The capacities of these boilers vary 
 from 2 to 6 tons of rags. Spherical ones, which 
 rarely exceed 10 feet in diameter, have the smallest 
 capacity; cylindrical ones range in size up to 25 feet 
 in length and 10 feet in diameter, and hold a corre- 
 spondingly greater weight of stock. The steam 
 pressure, weight of liquor, and length of boil vary 
 according to the chemicals used and the quality of 
 the stock; caustic soda requires approximately only 
 half the pressure, length of boil, and chemical per 
 pound of stock that caustic lime demands. 
 
 A washer, or Hollander, as it is frequently called, 
 because of its invention in Holland, is used for re- 
 moving the dirt and coloring matter dissolved from 
 the rags in the digesters, and breaking the rags up into 
 small clumps or knots of fibre, which are still further 
 subdivided in later operations. As seen in Figure 
 175, the washer consists of an oval-shaped tub, about 
 20 feet long, 9 feet wide, and 3 feet high, with a 
 partition or **midfeather'' dividing it into two parts 
 for two-thirds of its length. A roll faced with blunt 
 steel or bronze knives, called the breaker roll, rotates 
 in one part under the semi-cylindrical hood, and one 
 or more wash drums (not visible in the illustration) 
 covered with wire cloth, rotate in the other part. 
 Both roll and drums have their bearings adjustable 
 in vertical slides, so that their depth of immersion 
 can be varied. 
 
 The floor of the tub is smooth and level, except 
 in three places: the *' breast," directly in front of the 
 breaker roll, where it slopes up slightly; under the 
 roll, where it supports a plate carrying 6 or 8 knives 
 
 FIG. 175. WASHER 
 
 E. D. Jones & Sons Co. 
 
 like those on the roll; and behind the roll, where it 
 rises in a curve close to the circumference of the roll, 
 and then slopes down to its normal level — the ' ' back- 
 fall," as it is termed. In operation, the washer is 
 filled with boiled rag stock and water, and the 
 breaker roll paddles the mixture over the back-fall 
 to the wash drums and back again for two to six 
 hours. The fibres are torn apart and brushed length- 
 wise—not cut-— as they pass between the knives of 
 the roll and floor plate, which are brought closer 
 together as the stock becomes more subdivided; at 
 the same time, dirty water escapes to the interior 
 of the wash drum, from which it is withdrawn 
 through one of the bearings either by dippers or by a 
 siphon. 
 
442 
 
 TIIK MECHAXICAL Ki^l ll\\[Ki\T 
 
 otlier for liciiior. Tlie capacities of tliosc ])oil(M-s var\ 
 from 2 to (i tons oi* ra^s. Splicrical ones, wliicli 
 rarely exceed 10 feet in diameter, Iiave tlie smaller 
 capacity; cylindrical ones range in size np to 2') IVhI 
 in length and JO feet in diameter, and liold a coitc 
 spondingly greater weight of stock. The steam 
 pressnre, weight of liqnor, and length of boil vary 
 according to the chemicals used and the quality of 
 the stock; caustic soda requires approximately only 
 half the pressure, length of boil, and clnMuical pei- 
 pound of stock that caustic lime demands. 
 
 A washer, or Hollander, as it is frequently called, 
 because of its invention in Holland, is used foi- re- 
 moving the dirt and coloring matter dissolved from 
 the rags in the digesters, and breaking the rags up into 
 small clumps or knots of fibre, which are still furthci- 
 subdivided in later operations. As seen in Figure 
 175, the washer consists of an oval-sha])ed tub, al)oiil 
 20 feet long, 9 feet wide, and '^ feet high, with a 
 partition or *'midfeather" dividing it into two parts 
 for two-thirds of its length. A roll faced with blunt 
 steel or bronze knives, called the breaker roll, rotatt^s 
 in one part under the semi-cylindrical hood, and one 
 or more wash drums (not visible in the illustration) 
 covered with wire cloth, rotate in the other part. 
 Both roll and drums have their bearings adjustabl*' 
 in vertical slides, so that their depth of immersion 
 can be varied. 
 
 The floor of the tub is smooth and level, excejit 
 in three places: the **breast,'' directly in front of the 
 breaker roll, where it slopes up slightly; under tli- 
 roll, where it supports a plate carrying G or 8 kni\ < - 
 
 PAPER MA( HINERY 
 
 44:j 
 
 FIG. 175. WASHER 
 B. I). Jones & Sons Co. 
 
 like those on the roll; and Lehind the roll, where it 
 lises in a curve close to the circumference of the roll, 
 and tlicn ^]()\h^^ down to its normal level— the ''back- 
 fall," as it is termed. In operation, the washer is 
 lill.Ml with boiled rag stock and water, and the 
 bivak<'r roll paddles tlie niixture over the back-fall 
 to the wash drums and back again for two to six 
 iiours. The libres are torn apart and brushed length- 
 ^vis('— not cut — as they pass between the knives of 
 tlie roll and floor plate, which are 1)rought closer 
 together as the stock becomes more subdivided; at 
 the same time, dirty water esca])es to the interior 
 '.'M the wash drum, from which it is withdrawn 
 through one of the l)earings either by dippers or by a 
 siphon. 
 
444 
 
 THE MECHANICAL EQUIPMENT 
 
 PAPER MACHINERY 
 
 445 
 
 ' 
 
 Wood-Pulp Machinery.— Wood pulp is of three 
 principal kinds: mechanical, soda, and sulphite, each 
 of which requires special machinery. Mechanical 
 pulp, which is simply finely ground wood fibre, is 
 made in a grinder, an example of which is shown in 
 Figure 176. This is an emery or sandstone wheel 
 rotating on a horizontal shaft within the casing, a. 
 Three or more pockets, b, with doors, are built into 
 the casing, over each of which is mounted a hydraulic 
 cylinder, c, whose plunger moves radially in relation 
 to the wheel. The logs to be ground are cut into two- 
 foot lengths, barked in machines (described in the 
 next paragraph), split into boards, and freed as far 
 as possible from knots. These boards are then set in 
 the pockets and pressed by the plunger against the 
 rotating stone, which slowly wears them away. A 
 stream of water keeps the wood from burning, and 
 at the same time washes away the pulp which varies 
 greatly in quality according to the amount of water 
 used. As can be imagined, the friction of these ma- 
 chines consumes a great quantity of power; for ex- 
 ample, a 6-pocket grinder with a wheel whose sur- 
 face speed is 3000 feet per minute, requires 1200 
 horsepower. 
 
 Barkers and chippers are required for preparing 
 logs for the soda and sulphite processes. These 
 machines differ with respect to the method of feeding 
 the logs. In both cases, knives are mounted on the 
 face of an inclosed disc, about 5 feet in diameter, 
 rotating on a horizontal shaft. The casing with its 
 discharge spout for bark and chips, has the appear- 
 ance of a centrifugal pump. The barker has a device 
 
 FIG. 176. WOOD PULP GRINDER 
 The Bagley & Sewall Co. 
 
 m 
 
 on one side which holds the logs (cut to short length, 
 as in the mechanical pulp process) in a horizontal 
 position and forces them against the knives, rolling 
 them over at the same time until the bark is com^ 
 pletely sheared off. The chipper has an inclined 
 chute, through which the logs are fed end on; in this 
 case, the knives break them up into small chips 
 
444 
 
 TIIK MKCIIANirAI, K(,)| ||\MKi\T 
 
 M^ 
 
 Wood-Piilp Machinery.^ Wood |)iilp is of tlm 
 prin('i|)nl kiiuis: niecliimicnl, soda, niid sul|)liit(\ oadi 
 of wliich r(M|uir(>s special inacliinci-y. Mrclianic.il 
 ]>ulp, wliicli is siiii|>ly lincly .i;i-oi']id wood lihr(», is 
 made ifi a i^i'iiidci', an ('xanij)l(' ol wliicli is shown in 
 r'i.U'urc 1<(>. 11iis is an cnicr'v or sandstone wlicc] 
 rolalin.u- on a liorizonial slial'l witliin tlic casini*-, a. 
 TliriM' or moi'c ])o('I<('ls, h, willi doors, ai'c huilt inlo 
 lilt' casin.i;", ovim* each of which is nionntcd a liydi'anlic 
 cylindiM', c, whose ])lnn.i;'er moves i-adially in i-elatiori 
 to the wheel. The h).i;s to be ^ronnd ai'e cnt into two- 
 loot lengths, i)arked in machines (described in the 
 next para,urai)h), split into hoai'ds, and ['vinnl as far 
 as ])ossil)le from knots. These hoai'ds ai-e then set in 
 the po<'kets and ])i-esse(l hy the plnnitcr against tlic 
 rotating- stone, wliicli slowlv weai-s them awav. A 
 stream of water kee])s the wood from ])ni-nin,i;-, and 
 at the same time washes away tlie ])n]p which varies 
 .areatly in (piality according- to tlie amonnt of wat-r 
 used. As can he ima<iine(l, the friction ol* these ma- 
 chines consnmes a .u'reat (plant ity of ])ower; for ex- 
 ample, a (i-pocket i»i'inder with a wheel whose sur- 
 face ^]UH'i] is :U)00 feet per minute, recpiin^s ]2(H) 
 horsepow ci". 
 
 IJarkei's and cliippers are rerpiired for ])i-epari]i,L: 
 lo.iis for the soda and sulphite processes. 'I'hesf 
 machines <liffer with respect to the nietliod of feedin- 
 the lous. Fn both cases, knives are mounted on t1i<' 
 face of an inclosed disc, about 5 feet in (liamet<'r, 
 rotating- on a horizontal shaft. The casino- with ils 
 dischai'Kc spout for bai'k and chips, has the a])pear- 
 ance of a centrifugal i)ump. The barker has ii devi 
 
 IfC 
 
 PAIMHi MAf nii\i:RY 
 
 445 
 
 FIG. 17G. WOOD I'TLP (IRIXDER 
 The Hairley .V: Sew nil < '.i. 
 
 on one side wliicli holds tlie logs (cut to short length, 
 as in the mechanical l)ul]) ])rocess) in a liorizontal 
 position anil foi'ces them against th<' knives, rolling 
 them over at the sanu' time until the hai-k is com- 
 plet(dy sheared off. The chipp(M' has an inclined 
 •'hute, through which the logs are fed end on; in this 
 <'ase, the knives l)reak them up into ifmail chips 
 
/ 
 
 ■*;l 
 
 
 f ■ 
 
 446 
 
 THE MECHANICAL EQUIPMENT 
 
 with an action which corresponds to the blow of an 
 axe in felling a tree. 
 
 The digesters for soda pulp are like those used 
 for rag stock. The capacities are much greater, how- 
 ever, and the ste"^m pressure higher; 20 tons of chips 
 are a usual charge, and require 8 to 10 hours boil- 
 ing at a 100-pound pressure. The sulphite pulp- 
 digester must be lined with lead, brick, or cement, 
 because of the corrosive sulphurous acid that the 
 liquor contains. It is built vertically, about 8 feet 
 in diameter and 45 feet high, and is arranged either 
 to admit steam directly to the liquor at an 80-pound 
 pressure for the rapid process, or to circulate the 
 steam through pipe coils at a 45-pound pressure for 
 the slow process. The sulphite digester requires 
 ovens for burning sulphur with a deficient supply of 
 air. The acid calcium sulphite solution is formed 
 in wooden towers charged with broken limestone 
 which is converted by a current of sulphur dioxide, 
 led in at the base, and a counter-current of w^ter 
 sprayed down from the top. 
 
 A series of riffles, or **sand traps,'' followed by 
 strainers removes knots and pieces of undigested 
 wood from the '^half-stuff" produced in the digest- 
 ers. The stuff is then pumped to the beaters cr, if 
 it is to be shipped to another mill, is concentrated 
 and made into soft, thick sheets of ** air-dry" pulp. 
 The *'slusher," used for the concentrating, is a 
 wooden vat with a partition dividing it into a large 
 and a small part; a cylinder covered with wire clotli 
 rotates in the large part, picks up a coating of fibre 
 from the dilute stuff which surrounds it, and trans- 
 
 PAPER MACHINERY 
 
 447 
 
 fers this fibre to a felt-covered roll, from which it is 
 scraped into the small compartment of the vat hold- 
 ing the concentrated material. 
 
 Beaters and Refiners.— The half stock and the air- 
 dry pulp are mixed in the proper proportions and 
 prepared for the paper machine in a beater, the func- 
 tion of which is to separate the fibres and draw them 
 out to their extreme length without cutting them. 
 This machine is like the. washer for rag stock, pre- 
 viously described; the chief differences are the finer 
 vertical adjustment of the beater roll, the omission 
 of wash drums, and the grouping of the roll knives 
 in sets of three or more with wide space between 
 the sets to make the roll more efficient as a paddle 
 wheel for the stuff, which is much more dilute than 
 in the washer. Sharp knives are used to produce 
 *'free" or *'fast" stock suitable for filter, duplicat- 
 ting, blotting, and news-print papers; medium blunt 
 knives for turning out high-grade writing and print 
 paper, and very blunt ones for the production of 
 bond, strong wrappings, and so on, requiring 
 ** greasy" stock. In the latter case, stone floor plates 
 opposite the knives are sometimes used. 
 
 The capacities of the beaters vary widely. Medium 
 sizes are about 16 feet long, 8 feet wide, and 3 feet 
 deep, with a roll 31/2 feet in diameter, and hold the 
 equivalent of 500 pounds of air-dry pulp; the largest 
 sizes hold from 2000 to 3000 pounds. In all cases, 
 the circumferential speed of the roll is about 2000 
 feet a minute. The power consumption per ton of 
 stuff diminishes as the size of beater increases; it 
 also varies greatly with the clearance between roll 
 
 V 
 
448 
 
 THE MECHANICAL EQUIPMENT 
 
 
 m 
 
 and bed plate, and with rate of circulation of the 
 stuff, 21/2 horsepower per 100 pounds of dry stuff 
 being a fair average. 
 
 The operation of refining or brushing out the fibres 
 straight and parallel, may be performed on the beater 
 by raising the roll shortly before emptying. In the 
 case of high-grade paper, however, this operation is 
 done in a Jordan or Marshall refiner, which consists 
 ot a conical drum carrying longitudinal beater knives 
 revolving mside a conical shell, with corresponding 
 knives set on its inner surface. The clearance be- 
 tween stationary and rotating knives, varied by slid- 
 ing the drum longitudinally, is just sufficient to give 
 the desired brushing action to the fibres as the stuff 
 flows through from the small to the large end of the 
 cone. 
 
 Paper Machines.-By far the greatest tonnage of 
 paper is produced on the Fourdrinier machine, in- 
 vented and patented by a French paper-maker, Louis 
 Robert, m 1799, and perfected some years later by 
 Henry and Sealy Fourdrinier, the proprietors of an 
 English paper mill. The machine has undergone no 
 fundamental changes, but has been improved in de- 
 tails to increase the size, speed, flexibility of drive 
 recovery of stock from the waste water, and safety 
 ot the operators. 
 
 A typical machine is shown in elevation in Figure 
 177, and m plan in Figure 178. It consists of a 
 
 wet end, on which the paper is formed, two or 
 three pairs of press rolls, which reduce it to the cor- 
 rect thickness, a series of drying rolls, one to six 
 stacks of calenders, and one or more reels on which 
 
 PAPER MACHINERY 
 
 449 
 
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450 
 
 THE MECHANICAL EQUIPMENT 
 
 PAPER MACHINERY 
 
 451 
 
 the machine-finished paper is wound. The pulp flows 
 from the beaters to the stuff chests, a and b. 
 Figure 178, where it is kept from settling by paddles 
 attached to vertical rotating shafts. It is then 
 pumped to a regulating box (not shown), in which 
 it is diluted to its final • consistency and maintained 
 at a constant level by means of an overflow pipe, 
 which assures a constant flow into the machine. 
 From here it passes through a regulating cock to the 
 sand tables, a series of long, narrow, inclined troughs 
 covered on the bottom with long-haired felt or with 
 strips of wood set at 45 degrees, which catch any 
 coarse solid particles, as well as sand and dirt that 
 have not yet been separated from the fibre. The 
 lower end of these sand tables appears at c. 
 
 The pulp then flows to the strainers, d, d, to re- 
 move knots and intertwined fibres. The usual type 
 of strainer has a flat plate, about 7 feet long and 21/2 
 feet wide, pierced with fine slits 2 to 3 inches long, 
 a quarter-inch apart, and less than 0.05 inch wide, 
 which allow only individual fibres to pass through. 
 In order that the action may be more rapid, the plate 
 is jogged up and down by a crank and pitman, or 
 else a vibrating diaphragm in the trough under the 
 plate produces an alternating puffing and suction 
 action. Other types of strainers have revolving or 
 oscillating cylinders instead of flat plates. 
 
 The pulp that fails to pass the strainers, d,d, is 
 washed off to the auxiliary strainer, e, and all that 
 passes this one is returned to the regulating boxes 
 for dilution with fresh stuff. That which passes the 
 main strainer is led directly to the '*wire" of the 
 
452 
 
 THE MECHANICAL EQUIPMENT 
 
 machine. This is an endless sheet of wire cloth, f 
 (Figures 177 and 178); 30 to 50 feet long and 100 to 
 250 inches wide, woven with about 70 strands per 
 inch, and passing from the breast roll, g, to the lower 
 couch roll, h, and back again. On its forward travel 
 it is supported by a number of small rolls, i, set close 
 together, returning over and under the rolls j, whose 
 position can be adjusted so that they will regulate 
 the tension of the wire. 
 
 The stuff is fed to the wire on an apron of rubber 
 or waterproof cloth, k, whose edges are folded up to 
 keep the pulp from overflowing, and is spread evenly 
 to the proper thickness by an adjustable gate, or 
 ** slice," at the point where it flows from the apron 
 onto the wire. It is carried along by the wire, re- 
 strained on either side by the endless rubber bands, 
 1,1, called deckle straps, while the water collecting 
 in the meshes of the wire is carried off on the sur- 
 face of the rolls by capillary action and passes 
 into the troughs, m,m. Just before reaching the 
 couch rolls, the wire runs over suction boxes, n,n, 
 where a large amount of water is taken from the 
 pulp by vacuum pumps. This, together with the 
 water from the troughs m, m, and from the strainer, 
 e, drains into the low-box, y, from which it is pumped 
 to the high-box, z, for dilution with fresh pulp. 
 
 The watermark, if one is desired, is produced be- 
 tween the suction boxes by a light wire skeleton 
 cylinder called a ^Mandy roll,'' having the pattern 
 in raised wires on its surface which rests on the sur- 
 face of the paper. From the breast roll to the first 
 suction box, the wire, the deckle straps, and the sup- 
 
 PAPER MACHINERY 
 
 453 
 
 porting rolls are all carried on the deckle frame, o, 
 which is hinged at the left-hand end to a fixed part of 
 the machine and is given a rapid sidewise *' shake'' 
 at the right-hand end, with the object of thoroughly 
 interlacing the fibres as they are formed into a web 
 of paper. This action is the essential characteristic 
 of the Fourdrinier machine. 
 
 The moist paper leaves the wire at the couch rolls, 
 and is immediately picked up by an endless sheet of 
 felt, p, which carries it through the first press rolls, 
 q, q, after which it is turned over and picked up by 
 another felt, r, and carried through the second press 
 rolls, s, s. Thus each side of the paper comes into 
 direct contact with a roll and is smoothed by it. 
 From this point the web passes up and down over 
 steam-heated drying rolls, t, from sixteen to forty 
 in number, being held in close contact by the felts 
 shown in the figure. The pair of steam-heated 
 smoothing rolls, u,u, of polished chilled iron, give 
 the paper a preliminary calendering. The machine is 
 often arranged for sizing by interposing between two 
 batteries of dryers a tank of sizing material into 
 which the paper is passed. 
 
 The calender, v, at the left of the dryers, puts the 
 *^ machine finish" on the web of paper. Pressure is 
 applied by screws or by weights and levers; the 
 paper passes progressively between each roll and 
 the next lower one, and under the combined action 
 of pressure and steam heat is compressed and given 
 a smooth, hard surface. Any number of calenders 
 may be installed in series, the number depending 
 upon the grade of finish desired. The web is finally 
 
454 THE MECHANICAL EQUIPMENT 
 
 trimmed on the edges and slit to the desired widths 
 by rotating disc knives, w; then it is wound on the 
 reel, x. 
 
 Figure 178 shows a typical power drive for a 
 Fourdrimer machine. The shake, couch roll, press 
 ro Is, first and second drying batteries, smoothers, 
 calender, and reel, are driven separately from the 
 mam shaft by the cone pulleys and bevel gears 
 showii m the figure; thus is secured the independent 
 speed regulation necessary for counteracting irreg- 
 ularities in the shrinkage of the paper as it dries, 
 ihe power consumption of medium-sized machines 
 from breast roll to reel with the driving mechanism, 
 is about 8 horsepower per ton of paper per 24 hours 
 To this figure must be added 50 per cent for stuff- 
 pumps, strainers, and other auxiliaries. The tendency 
 IS to make wider machines; whereas 150 inches was 
 about the maximum a few years ago, wires over 200 
 inches wide are in operation today. At the same time 
 speeds have increased; at present a wire speed of 250 
 feet a minute is a fair average, and 700 feet is the 
 upper limit, though that will doubtless be exceeded 
 m the near future. These wide, fast machines re- 
 quire much more power than the amount mentioned 
 above. 
 
 A modified form of Fourdrinier, known as the 
 single-cylinder machine, is sometimes used for very 
 thin paper, or paper to be finished on one side only. 
 The distinguishing feature is a single drying cylinder 
 about 10 feet in diameter, in the place of the battery 
 of smaller cylinders, t, on the Fourdrinier. A ma- 
 chine which is similar in name, but entirely different 
 
 PAPER MACHINERY 
 
 455 
 
 i 
 
 m mrmmmmmmmm}mMiimn f} W )im\ 
 
 FIG. 179. CYLINDER PAPER MACHINE 
 
 in form— called a cylinder machine— is used for the 
 manufacture of low-grade paper, mill board, and air- 
 dry wood pulp. The strained pulp enters a tank, a. 
 Figure 179, in which a skeleton cylinder, b, covered 
 with wire cloth, revolves. The fibres stick to the 
 wire while the water passes through the meshes, 
 under the action of a suction pump; the sheet of 
 paper thus formed is removed from the cylinder at 
 the couch roll, c, by the felt, d, which carries it to 
 the large steam-drying roll, e. After drying, it is 
 wound off on the reel, f; the felt in the meantime 
 returns to the couch roll through the washer, g, over 
 the scraper, h, and between the squeezing rolls or 
 
 wringers, i, i. 
 
 One cylinder cannot make a thick sheet, so that in 
 the manufacture of heavy paper board a number of 
 cylinders are mounted in tandem, the wet webs being 
 taken off in successive layers on the same felt; it is 
 thus possible to obtain different colors on opposite 
 
456 
 
 THE MECHANICAL EQUIPMENT 
 
 PAPER MACHINERY 
 
 457 
 
 FIG. 180. SUPERCALENDER 
 Holyoke Machine Co. 
 
 sides of the same sheet. In a modification of this 
 machine, the drying cylinder, e, is replaced by a pair 
 of press rolls, and the wet web is wound on the upper 
 roll until the required thickness has been obtained, 
 when It IS slit across from side to side, taken from 
 the rolls, laid out flat, and dried in heated lofts. 
 
 Finishing Machinery.— A super-calender is used for 
 obtaining a smoother surface than that which is 
 called '* machine finish.'' A typical machine of this 
 kind is shown in Figure 180, which, with the omission 
 
 of the winding device, would represent an ordinary 
 calender. The rolls are built up in stacks of four to 
 twelve, compressed paper rolls alternating with 
 chilled iron. Pressure is applied by means of levers 
 and tension rods, a, connected to weights. A reel of 
 dampened paper is placed at b, and the paper is fed 
 over the guide rolls, c, to the top calender roll, and 
 then back and forth between the rolls until it reaches 
 the bottom; finally it is rewound at d. The drive is 
 through the shaft, e, to the lowest roll, which can be 
 driven directly or at a lower speed through back 
 gears. The unwinding reel is held back by the brake, 
 f, which keeps a uniform tension in the paper; and the 
 winding reel, belt-driven from g, can be slowed down 
 any desired degree as the roll of paper increases in 
 diameter. 
 
 In contrast with this variable-speed reel, the con- 
 stant-speed winder. Figs. 177 and 178, should be noted. 
 In this case the power is applied to the rolls, a', b', in- 
 stead of to the reel, and since the paper travels at 
 constant speed, the reel, which simply rests on the 
 rolls, will be rotated at the right speed whatever 
 the amount of paper wound upon it. In order that 
 the paper may be wound tightly, b' is driven slightly 
 faster than a'. 
 
 For plate glazing or linen finishing a special two- 
 roll calender is used which is provided with hori- 
 zontal front and back tables level with the top of the 
 lower roll, and a reversing drive is employed. A 
 stack of paper sheets, alternating with copper or zinc 
 plates or sheets of linen, is set on the front table and 
 passed back and forth between the rolls until the 
 
 Mi 
 
456 
 
 THE MECHANICAL EQUIPMENT 
 
 FIG. 180. SUPERCALKXDER 
 Ilolyoko Machine Co. 
 
 sides of the same sheet. In a modification of thi> 
 maehiTHs tlie dryino. cyVuulrv. c, is rephieed hv a ikdi 
 of press rolls, and tln^ uvt wcl, is wound on tile upprr 
 n)ll uiitd the recpiired thickness has hcen obtaincl. 
 wlien It is slit across from si<lc to side, taken from 
 the rolls, laid out flat, and dried in heated lofts. 
 
 Finishing- Machinery.— A super-calender is used f.M 
 o])tainino- a smoother surface than that whicli i< 
 ^'^'"^•^^ 'Mnachine linish.'' A typical machine of tln< 
 kind IS shown in Figure 180, which, with th(i omission 
 
 PAPEK MACHIXEHV 
 
 4; 
 
 ')t 
 
 of the windin.i;' device, wouhl rcprcsrnt an <)r<linai"y 
 calender. The rolls are built n\) in stacks of foui* to 
 iwelve, compressed paper rolls altei-natint;- with 
 cliilled iron. Pressure is ap[)lied l)y means of levers 
 jiiid tension rods, a, connectiMl to weights. A reel of 
 dampened paper is placed at I), and the pajjei* is fed 
 over the guide rolls, c, to the top calendei* I'oll, and 
 tlieii hack and forth between the rolls until it reaches 
 I lie bottom; linallv it is rewound at d. The drive is 
 llirougli the shaft, e, to the lowest roll, which can l)e 
 driven directly or at a lower s})eed through back 
 iiears. The unwinding I'eel is held back bv the bi-ake, 
 r, wliicli keej)s a uniform tension in the ])aper; and the 
 winding reel, belt-driven fi'om g, can be slowed down 
 any desired degree as the roll of pa])er increases in 
 diameter. 
 
 In contrast witli this variable-si3eed reel, the con- 
 slant-speed winder, Figs. 177 and 178, should be noted. 
 In this case the power is applied to the rolls, a', b', in- 
 stead of to the reel, and since the paper travels at 
 constant speed, the reel, which simply rests on the 
 rolls, will be rotated at the right speed whatever 
 the amount of i^aper wound upon it. In order that 
 the paper may be w^ound tightly, b' is driven slightly 
 faster than a'. 
 
 For plate glazing or linen finishing a special two- 
 roll calender is used whicli is pi'ovided with hori- 
 zontal front and hack taldes level with the top of the 
 lower roll, and a reversing drive is em])l()yed. A 
 stack of paper sheets, alternating with c()i)per or zinc 
 plates or sheets of linen, is set on the front table and 
 passed ])ack and forth between the rolls until the 
 
458 
 
 THE MECHANICAL EQUIPMENT 
 
 surfaces are sufficiently finished. Friction glazing is 
 done on a two- or three-roll calender in which one of 
 the rolls is driven much faster than the others by a 
 special spur-and-pinion connection. 
 
 The most highly finished paper is made by coating 
 with a mixture of china clay and thin glue. The 
 apparatus for this process varies in details, but al- 
 ways has these principal parts: a vat for holding 
 the coating fluid; brushes for working out lumps and 
 smoothing the coated surface; an automatic carrier 
 for conveying the coated paper through the drying 
 room; and glazing calenders. The body paper is 
 passed through the vat, between two press rolls which 
 remove the excess coating, and then between tw6 
 sets of brushes, one above and one below, which 
 vibrate across the paper. Each set consists of a 
 coarse, a medium, and a fine brush— the last usually 
 camel's hair— working in series on the web of paper. 
 After leaving the last brushes, the web is picked up 
 at intervals of fifteen to twenty feet by cross bars, 
 which rise toward the ceiling and then travel hori- 
 zontally into the drying room. The web, therefore, 
 hangs in festoons reaching nearly to the floor, and is 
 dried without touching anything except the cross 
 bars. After drying the web is reeled and run through 
 calenders that polish the surface. 
 
 CHAPTER XXV 
 BOOT AND SHOE MACHINERY 
 
 General Characteristics. — The machines used in 
 making boots and shoes are quite unlike those which 
 are to be found in other lines of manufacture. The 
 difference is due to the nature of the principal mate- 
 rial used, to the small size of the parts composing the 
 shoe, and to the kinds of operation performed. In 
 general, shoe machines translate into mechanical 
 processes the manual dexterity of the old-fashioned 
 shoemaker in using the hammer, knife, awl, and 
 needle. The fundamental machines, most of them de- 
 veloped by clever shoemakers, were original in de- 
 sign, and even those now used for pressing, rolling, 
 grinding and buffing are distinctive, for they do not 
 closely resemble the corresponding machinery in 
 wood or metal-working, although they perform the 
 
 same operations. 
 
 History of Shoe Machinery.— The first important 
 shoe machine, which was invented in 1815, made 
 wooden pegs for fastening the soles of shoes to the 
 uppers. In 1845 the rolling machine was introduced, 
 for compressing and hardening sole leather; this 
 mechanical process replaced the hand hammering 
 which had been in vogue up to that time. In 1851 
 a Lynn shoemaker, by the name of Nichols, adopted 
 
 450 
 
'im 
 
 i 
 
 I 
 
 460 THE MECHANICAL EQUIPMENT 
 
 Howe's sewing machine to sewing shoe uppers, and 
 a year later the machine was used in the manufacture 
 of shoes by John Wooldredge, also of Lynn. The 
 introduction of this machine made shoe manufacture 
 distinctly a factory industry. In 1858 Lyman R 
 Blake, another shoemaker, invented a machine for 
 sewing uppers and soles together, which was im- 
 proved by Mathies and built by Gordon McKay, a 
 capitalist and manufacturer. It was first used com- 
 mercially in 1861, and now the name McKay is given 
 to one of the most widely manufactured types of 
 shoe in this countrv. 
 
 A still more important advance was made in 1862, 
 when Aiiguste Destouy, a New York mechanic, in- 
 vented a machine with a curved needle for sewing 
 the soles of turn shoes. This was developed under 
 the direction of Charles Goodyear, son of the in- 
 ventor of the vulcanizing process, and in 1875 was 
 applied to the sewing of welts to insoles in the manu- 
 facture of *' Goodyear welt'' shoes, which are superior 
 to all other tvpes in comfort, wearing quality, and 
 appearance. The manufacture of the rougher grades 
 was made materially easier by the commercial appli- 
 cation, in 1857, of a pegging machine for driving 
 the wooden pegs that hold together the insole, upper, 
 and outsole in pegged shoes. 
 
 The first successful lasting machine, the invention 
 of c Boston lawyer, George Copeland, was exhibited 
 at the Centennial Exposition, in 1876. A machine 
 duplicating the hand method of lasting was invented 
 in 1883 by Matzeliger, an expert machinist who came 
 to Lynn from Dutch Guiana and learned the shoe 
 
 BOOT AND SHOE MACHINERY 
 
 461 
 
 trade. These two machines eliminated the only re- 
 maining hand process in shoe manufacture: that of 
 stretching the upper over the last and securing it 
 temporarily by nails, until the sole was attached. 
 These machines have been supplemented by the puU- 
 ing-over machine, which prepares the shoe for last- 
 ing. A recent invention is the clicking machine, for 
 cutting uppers from the hide or skin; it takes the 
 place of the workman with his patterns and knife, 
 who was known as the hand cutter. 
 
 Machine Operations. — The principal operations 
 performed in shoe manufacture are: cutting, bend- 
 ing and stretching, and stitching. Among the ma- 
 chines for the first of these operations are clicking 
 machines, stripping machines for cutting hides into 
 strips of a width equal to the length of the sole, sole- 
 cutting or **dieing-out" machines, splitting machines, 
 channelers, skiving machines, edge setters, and so on. 
 Some of these work on the principle of the punch, 
 others use either rotary or stationary knives, while 
 still others use revolving cutters similar to milling cut- 
 ters. Some of the machines for the second class .of 
 operations are sole-laying and sole-leveling machines 
 for bending the sole to the proper shape, channel- 
 opening and channel-laying machines for raising and 
 flattening the channels on insoles, and pulling-over 
 and lasting machines for stretching the uppers over 
 the lasts. The third group is made up of sewing 
 machines of different types, some of which— such as 
 the McKay sewing machine, the Goodyear welt, and 
 the Goodyear outsole rapid-lockstitch machine — stand 
 as landmarks in the development of shoe machinery. 
 
7 
 
 i 
 
 462 
 
 THE MECHANICAL EQUIPMENT 
 
 Other operations performed by special machines are 
 rollmg, hammering, pressing, nailing, cementing, iron- 
 ing, grinding, buffing and polishing. 
 
 Arrangement of a Shoe Factory.— The modern shoe 
 factory is composed of six departments: for cutting, 
 stitching, stock fitting, ** making'' or bottoming, finish- 
 ing and treeing, and for packing and shipping. The 
 cutting and stitching rooms are usually on the top 
 floor, and the sole leather room is generally on the 
 ground floor. The bottoming room is on the floor next 
 below the cutting and stitching departments, and the 
 shipping room is generally on the floor next above 
 the sole-leather room. 
 
 Types of Shoes.— The methods now in use for fas- 
 tening the upper to the sole are: (a) McKay, (b) 
 Goodyear welt, (c) Turned, (d) Standard screw, (e) 
 Pegged. 
 
 Figure 181 shows these methods. In the McKay 
 sewed shoe method, a, the upper and the lining are 
 held m the insole by a row of tacks driven from the 
 outsole side and clinched at the points; the outsole 
 IS .then stitched on using a single thread and chain 
 stitch, the channel being opened up during the stitch- 
 mg and closed or ^^aid'' after the stitching is com- 
 pleted. Sometimes an additional seam, known as 
 ''fair stitching,'' is run around the outsole close to 
 the edge in imitation of the Goodyear welt. This 
 method is comparatively cheap, but leaves a row of 
 nail points and a seam of heavy thread inside the 
 shoe; moreover, when it is used it is also impossible 
 to put on a new outsole without sewing through to 
 the inside— a stitch difficult to make by hand. 
 
 BOOT AND SHOE MACHINERY 
 
 463 
 
 McKay Stam 
 
 Uppe> 
 
 •Inseam 
 
 Weft 
 
 i Outsole 
 Channel Filling <Channel 
 
 <a> McKAY SHOE 
 
 Channel Filling "Oufsole ''(^fseam 
 (b> GOODYEAR WELT SHOE 
 
 / \5urface Channel 
 Seam (Open) 
 
 Channel (Laid } ''Sole 
 
 LASTED AND SEWED BEFORE TURHIM6 THE SAME AFTER IT HAS BEEN TURNED 
 
 <C> TURN SHOE 
 
 " yUpper 
 
 .'Lining 
 
 Cd) STANDARD SCREW SHOE 
 
 ■"Peg 
 
 (e> PEGGED SHOE 
 
 FIG. 181. TYPES OF SOLE FASTENINGS 
 
 The Goodyear welt derives its name from the strip 
 or welt of leather which runs around the outsole 
 between the upper and the edge of the sole, uniting 
 the insole, upper leather and outsole by the two rows 
 of stitching shown in the figure. Although appa- 
 
 
 A 
 
464 
 
 THE MECHANICAL EQUIPMENT 
 
 rently complicated, the processes of this method are 
 easily carried out by machinery, and they produce 
 the most comfortable and durable type of shoe. 
 Furthermore the outsoles can be easily repaired 
 either by hand or by machine. 
 
 Turn shoes, e, are sewed together inside out; the 
 stitch used IS similar to the inseam stitch of a welt 
 Shoe. The shoe is then turned right side out and the 
 final operations of heeling, and so on, are performed 
 upon It as in the case of other shoes. Turn shoes 
 are very light and flexible, and the inner surface 
 ot the sole IS smooth and free from nail points or 
 seams of thread. This type of shoe is used for sli«. 
 pers, pumps, and ladies' fine footwear 
 
 Standard screw and pegged shoes resemble the 
 McKay type, in that tacks are used for attaching 
 the upper leather to the insole; in the McKay shoe, 
 however, the outsole is fastened on by threaded wire 
 screws, while in the pegged type pegs of calendered 
 
 wl .r°fl ^ZT^- '^' standard-screw shoes, which 
 lack the flexibility of sewn soles, are used for heavy, 
 rough wear. Nailed shoes are similar to pegged 
 
 r'lono?.* *^^* "^^'^ ^'' substituted for the pegs. 
 
 In 1909 the relative production of these different 
 types in the United States was McKay, 41.5 per cent; 
 Goodyear welt, 32.3 per cent; turned, 16.3 per cent 
 standard screw, 7.9 per cent; pegged and nailed, 2 
 per cent. ' 
 
 Cutting Room Machinery—The essential parts of 
 the clicking machine (see Figure 182) are a frame 
 carrying a cutting block, a, consisting of maple 
 boards set with the grain end on; a vertical plunger, 
 
4G4 
 
 THE MECHANrCAL EQUIPMENT 
 
 rent y oon.pl.cato.l, tlio pro(.oss,.s „f tl,is „i..tI,o<l aro 
 oa.ily ,arno.l ,.ut l.y ,„a.-l,in,.ry an.l Ihov pro,],,.-. 
 !.<■ n.o.t <-o.Mf..rtal.h. a.ul .lural.l,. tvpo'of .l.o. 
 JMirthennoro, tl.e outsolos ,.„. h. oasily repaired 
 t'ltlier by hand or ))y maeliiiu.. 
 
 Turn slices, <•, arc sow.mI toffether inside out; tlio 
 s .t<-l, used IS si.uilar to tl>e insean. slitel, of a welt 
 |;lH.e. Il.e shoe is then turned right side out and the 
 <'"al operations of heeling. an<l so on. are pcM-forn.e.l 
 "po.. .t as ,n the ease of other shoos. Turn shoes 
 a.e very l,g|,t and flexil.le. and the inner surfaee 
 
 1. '" 7 ',' " r"""*'' ■■'""' ^'''' <■'■«'" """ points 0'- 
 seams ot thread. This type of shoe is used for slit,- 
 
 pt'rs. pumps, and ladies' fine footwear 
 
 Stan<lar.l serew an.l pegged shoes resemble the 
 AleKay type, in that taeks are us..l for attaching 
 ''<• upper leather to the insole; in the MeKav shoe, 
 I'owever, he outsole is fastened on bv thread.:,! wire 
 «-.-ews. wlMle in the pegged type pegs of eale„dere,l 
 beeehwood are used. The standard-screw shoes, which 
 lack the flexibility of sewn soles, are used for heavy, 
 rough wear. Kailed shoes are similar to pegged 
 shoes except that nails are substituted for the pegs 
 In ]!)()!) the relative pro.luction of these different 
 .ypcs m the United States was :VlcKay, 41.5 per cent; 
 f.oo.lyear welt, 32.3 per cent; turned. l(i.3 per cent 
 staiKlard screw, 7.!) per cent; peggvd an.l naih.l, 2 
 per cent. ' 
 
 Cutting Room Machinery.-The essential parts of 
 the clicking machine (.see Figure 182) are a frame 
 carrying a cutting block, a, consisting of maple 
 boards set with the grain end on; a vertical plunger, 
 
 'A 
 
 '.1 
 
 7\ 
 
 2 
 EH 
 
 IT 
 
 o 
 
466 
 
 THE MECHANICAL EQUIPMENT 
 
 BOOT AND SHOE MACHINERY 
 
 467 
 
 d; and an arm, c, attached to the plunger, which rises 
 and falls with it and may be swung so as to cover 
 any part of the cutting block. The operator places 
 a skin on the block, sets a light steel die or ring, 
 about three-quarters of an inch thick and sharpened 
 on one edge, on that portion of the skin which he 
 wishes to cut out, swings the arm over it, and then 
 forces the die through the leather and a slight dis- 
 tance into the wooden block. It might seem that the 
 continued forcing of sharp dies into the cutting 
 block would roughen it and soon spoil the surface. 
 This is not the case, for the fibres become spongy 
 and elastic because the surface of the block is kept 
 well oiled. This method of cutting against an elastic 
 surface is characteristic of leather manufacture. 
 
 The cutting of cloth linings is done in a similar 
 way, but "dieingr-ouf machines replace the pressure 
 arm of the clicking machine with a strong beam 
 operated by means of eccentrics from a driving shaft 
 below. The larger sizes have cutting blocks 96 inches 
 long, 16 inches wide, and 10 inches high, and are 
 capable of cutting fifty thicknesses of lining at a 
 stroke. Clicking machines do not require such stroncr 
 construction, since the operator cuts only one thick- 
 , ness of leather owing to the fact that he must select 
 the best parts of each skin and place his dies to leave 
 a minimum amount of scrap. 
 
 The skiving machine bevels or scarfs the upper 
 leather to a thin edge, after which cement is applied 
 to the beveled surface and the edge is folded back 
 upon itself and pressed into place so that nothing 
 but the grain side shows. The Amazeen machine, 
 
 Figure 183, has a feeding device, made up of a 
 knurled roll, a, and a smooth disk, b, at right angles 
 to it and forced against the upper surface of the feed 
 roll by a helical spring, c. An adjustable guide, d, 
 holds the right-hand edge of the leather at the proper 
 point as it passes backward between the feed roll 
 and the feed disk; a rotary disk-knife, set directly 
 back of the feed on an inclined shaft, e, can be ad- 
 justed for various amounts of bevel; and a grinding 
 wheel, f, mounted behind the knife, can be brought 
 into action so as to grind the knife without removing 
 it from the machine. For heavier work machines are 
 used which are similar to this except that they have 
 a stationary knife. 
 
 The skived edges are cemented on the top of a box- 
 shaped bench machine. This has a small metal wheel 
 with roughened surface projecting through a slot in 
 the top which supplies the cement to the work. The 
 inside of the machine is a cement reservoir, the ad- 
 hesive being fed by a screw pump to a well under 
 the wheel, which overflows at a fixed level so that the 
 wheel cannot be flooded. 
 
 After being cemented, the edges are turned or 
 folded on a machine of which there are two types. 
 In the "Boston,'* the leather is laid on the table of 
 the machine and is gripped along its entire length, 
 about a half-inch from the edge, between two clamps 
 that have the same curve as this edge; a block, also 
 shaped to this curve, rises past the clamps and then 
 approaches them, thus folding the edge back upon 
 itself The ''Columbia" machine folds and hammers 
 down* a short length of the edge, and then feeds the 
 
468 
 
 THE MECHANICAL EQUIPMENT 
 
 BOOT AND SHOE MACHINERY 
 
 469 
 
 work a distance equal to the length folded over. This 
 machine is slower than the Boston, but does not re- 
 quire special clamps and blocks for each shape of 
 
 Stitching.Room Machinery.-Uppers and linings are 
 stitched on sewing machines which are adaptations 
 of the sewing machine for cloth. The essentials are 
 the frame, the feed, and the stitching mechanism. 
 A C-trame is used, at the upper end of which is the 
 mechamsm for moving the needle up and down, whil- 
 the lower end forms the table on which the work is 
 laid. This table may be flat and flush with the bench, 
 for sewing flat work; or it may be convex and sup- 
 ported 3 to 6 inches above the bench on a vertical 
 post or a horizontal cylinder which is part of the 
 trame. The principal feeds are the ** four-motion'' 
 and the -rotary." The four-motion consists of a 
 serrated plate set in a slot in the table, which rises 
 to the work, draws it backward the length of one 
 stitch, descends, and returns to its first position; the 
 rotary is a wheel with a serrated edge, which is in- 
 termittently rotated by a rachet and pawl. The work 
 is held against the feeder by a presser foot or a 
 wheel attached to the upper end of the frame. 
 
 The stitching mechanism varies according to the 
 kind of stitch made, which may be one- or two-needle, 
 one- or two-thread, chain stitch; one- or two-needle 
 lock stitch; buttonhole stitch, etc. The commonest 
 are the one-needle, one-thread chain stitch (which is 
 strong and elastic, but has a right and a wrong side 
 and pulls out if broken), and the one-needle lock 
 stitch (which has two threads and does not stretch 
 
 FIG. 184. CHAIN STITCH MECHANISM 
 
 easily, but cannot pull out). Figure 184 shows a 
 common chain stitch and the mechanism that forms 
 it. The needle, a, descends through the work, carry- 
 ing the thread with it; the looper, b, rotating clock- 
 wise, catches a loop of the thread as the needle rises; 
 the work then feeds, the loop c is spread laterally 
 so as to encircle the needle on its next descent; and 
 as the needle takes the position shown in the figure, 
 the loop c is cast off from b by the extension, d, and 
 drawn taut as the needle completes its downward 
 stroke. Another method of forming the chain stitch 
 is described later, in connection with the McKay sew- 
 ing machine. 
 
 A typical lock-stitch mechanism. Figure 185, has 
 a needle, a, the bobbin inclosed in case b, which is 
 supported loosely so that a thread can completely 
 encircle it; the shuttle, c, and shuttle driver, d, oscil- 
 lated by shaft e. Both c and d move in a circular 
 path in the frame, f . As a descends it pulls down a 
 
470 
 
 THE MECHANICAL EQUIPMENT 
 
 BOOT AND SHOE MACHINERY 
 
 471 
 
 a-' 
 
 
 n 
 
 FIG. 185. LOCK STITCH. MECHANISM 
 
 loop of thread which is caught on the hook of the 
 shuttle, c, as it rotates clockwise owing to the pres- 
 sure from d, and is drawn into the position shown. 
 The shuttle rotates slightly farther, while the needle 
 rises and a take-up (not shown) pulls the needle 
 thread off the shuttle hook and over the left side of 
 the bobbin, so as to loop it around the bobbin thread; 
 then d reverses its direction, the needle thread 
 passes out through the space opened up by the back- 
 lash between c and d, and further motion of the 
 take-up draws the stitch taut while the shuttle, c, 
 
 and the driver, d, return to their first positions, 
 ready for the next descent of the needle. All stitch- 
 ing devices, either chain stitch or lock stitch, re- 
 quire a tension regulator for the threads; this is 
 usually a pair of discs or plates held together by a 
 thumbscrew and spring, between which the thread is 
 drawn. 
 
 The eyeletting, the buttonholing, and the making 
 of the decorative perforations along the upper edges 
 of tips, are also done in the stitching room. The 
 eyeletting machine has a table on which the work is 
 placed, a punch which descends upon the work and 
 perforates it, and an eyelet-placing finger which re- 
 ceives the eyelets from a magazine, one at a time 
 and flanged on one end, and inserts them in the per- 
 forations from the under side. A set, or rivetter, 
 descends upon each eyelet and rivets it while the 
 finger holds it in place. The duplex eyeletting ma- 
 chine sets both rows of eyelets on a shoe at the same 
 time; thus perfect alignment is insured. 
 
 The buttonholing machine is a special sewing ma- 
 chine which first cuts the buttonhole with a wedge- 
 shaped punch, and then sews it with a two-thread 
 stitch that covers the raw edge of the hole and in- 
 closes a cord that protects it. The tip perforations 
 are made either on a ** Crown" machine, a bench 
 machine like a miniature sheet-metal punch, which 
 perforates the entire tip at one stroke; or on a 
 *' Royal" machine, which has a C-frame like that 
 of a sewing machine, the needle being replaced 
 by a punch which perforates a single hole or unit of 
 the design and simultaneously feeds the work into 
 
 
 i 
 
472 
 
 THE MECHANICAL EQUIPMENT 
 
 position for making the next perforation. The 
 wooden cutting block of the dieing-out machine is re- 
 placed by a strip of paper which is fed along under 
 the work. 
 
 Machinery of the Stock-Fitting Room.— Stripping 
 machines are used for cutting hides into strips. The 
 individual soles or heel lifts are then cut from the 
 strips on dieing-out machines. 
 
 Rolling machines, which compress the sole leather 
 to make it more durable, consist of a housing for an 
 upper and a lower roll, gearing for driving them, a 
 screw adjustment for varying thicknesses of leather, 
 and a treadle for raising the lower roll. 
 
 The soles are only roughly cut to shape on the 
 dieing-out machines, which are frequently in a sepa- 
 rate factory, so that the accurate form must be ob- 
 tained on a rounding machine. The *' Planet," illus- 
 trated in Figure 186, has a circular table, a, on which 
 is mounted a fixture, b, for holding a wooden pattern, 
 c, shaped to the desired form of the sole. The sole is 
 placed between this pattern and a plate, d, which is 
 pressed down from above and is adjustable for differ- 
 ent thicknesses of stock. A short vertical knife, e, is 
 held in a block at the end of a swinging arm, g, which 
 is pressed against the pattern by a spring. When the 
 power is applied, the table and the knife rotate 
 rapidly in a counter-clockwise direction for a little 
 more than one revolution, to insure a complete trim- 
 ming of the surplus material, and then return to their 
 original position. During this interval the knife block 
 has been in continuous contact with the pattern, and 
 has made an exact reproduction in the leather stock. 
 
 
472 
 
 TUK ME( HANK AL EQlIPMExNT 
 
 position for nuikino- tlio noxt perforation. Tli< 
 wooden vniViuii; ])iock of the dieino:-out nuichine is re- 
 placed ])y a strip of pai)er which is fed along undci 
 tlie work. 
 
 Machinery of the Stock-Fitting Room.— Stripping 
 machines are used for cutting hides into strips. The 
 individual soles or heel lifts are then cut from the 
 strips on dieing-out nuichines. 
 
 Kolling nuichines, wliich compress the sole leatlior 
 to nudve it more durable, consist of a housing for an 
 upper and a lower roll, gearing for driving them, a 
 scn^w adjustnu^nt for varying thicknesses of leather, 
 and a treadle for raising the lower roll. 
 
 The soles are only roughly cut to shape on the 
 dieing-out nuu'hines, wliich are frecjuently in a sepa- 
 rate factory, so that the accurate form must be ob- 
 tained on a rounding nuichine. The **Planet,'' illus- 
 trated in Figure ISfi, has a circular table, a, on which 
 is mounted a fixture, b, for holding a wooden pattern, 
 c, shaped to the desired form of th(^ sole. The sole is 
 placed between this pattern and a plate, d, which is 
 pressed down from al)ove and is adjustable for differ- 
 ent thicknesses of stock. A short vertical knife, c, is 
 held in a block at the end of a swinging arm, g, wiiich 
 is pn^ssed against tlip pattern l)y a spring. When the 
 power is applied, the table and the knife rotate 
 rapidly in a count(M*-clockwise direction for a little 
 more than oue revolution, to insure a complete trim- 
 ming of the surplus uuiterial, and then return to their 
 original position. During this interval the knif(^ block 
 has be,»Ti in continuous contact with the pattern, an<I 
 has made an exact repi'oduction in the leather stock. 
 
474 THE MECHANICAL EQUIPMENT 
 
 It always presents the knife edge squarely to the 
 work; and a cam, f, shaped roughly to the outline of 
 tne sole, helps the spring to keep a uniform pressure 
 ot the swinging arm, g, against the pattern, and 
 prevents the knife from leaving it when rounding 
 sharp corners. 
 
 The channeling of the soles (see Figure 181) is 
 done on machines similar to those used for heavy 
 skivmg; the work is fed between rolls against a sta- 
 tionary knife, which is adjusted to cut a slit in the 
 leather instead of shaving off its surface. For Good- 
 year welt insoles two channels are cut simultaneously, 
 one m the outer edge extending toward the center, 
 and the other in the lower surface. 
 ^ The manufacture of heels has developed into an 
 independent industry. After the lifts, or separate 
 layers have been cut out the heels are assembled in 
 a heel-building machine, consisting of a horizontal 
 bed on which are set three adjustable guides or jaws, 
 a clamp for holding the lifts together, and a nailing 
 device for driving the required number of nails 
 through them There is also a cement reservoir and 
 a row of small bins on each side of the bed, for hold- 
 ing sizes of lifts. The operator first places nails in a 
 plunger plate under the bed; he then selects the 
 proper lifts from the bins, dips them into the cement 
 ^ervoir, and ays them on the bed between the jaws. 
 When a treadle is pressed the jaws are moved to- 
 gether and the lifts are lined up; the power is applied, 
 clmnpmg the lifts together and driving the nails 
 
 Bottoming-Room Machinery.-The machines of this 
 department fall into three classes: lasting machines 
 
 BOOT AND SHOE MACHINERY 
 
 475 
 
 stitching machines, and moulding and leveling ma- 
 chines. Lasting consists of three operations: assem- 
 bling the upper and the insole upon the last; *' pulling 
 over," or drawing the toe part of the upper down 
 over the front end of the insole; and lasting proper, 
 which is a continuation of the pulling-over process all 
 around the sole. Tacking machines first nail the in- 
 sole to the last and fasten the upper to the last at 
 the heel by two tacks driven part way in. The next 
 operation takes place on the pulling-over machine 
 
 (Figure 187). 
 
 The principal parts of this machine are as follows: 
 adjustable rests for the last and the heel; pincers, 
 one at the toe and the others on each side near the 
 toe; levers for shifting the positions of the pincers 
 by hand after they have gripped the upper, in order 
 that the toe may be exactly centered; devices for 
 drawing the upper over the edge of the last, and for 
 moving the pincers toward each other, thus laying 
 the upper against the bottom of the last; and auto- 
 matic magazine-fed hammers for driving temporary 
 nails through the upper and the insole. The great 
 advantage of the work of this machine as compared 
 with hand lasting, aside from the saving of time, is 
 that the tension is applied evenly all around the toe 
 rather than at one point at a time, and the workman 
 can see without effort whether the upper is straight 
 and tight before he drives the tacks. 
 
 The final lasting is done on a **bed type" machine, 
 the essential feature of which is a pair of wipers at 
 the toe and heel. The shoe is held bottom side up 
 in an adjustable rest; two pairs of plates are then 
 
476 
 
 THE MECHANICAL EQUIPMENT 
 
 BOOT AND SHOE MACHINERY 
 
 477 
 
 moved forward, drawing or ** wiping'' the upper 
 closely around the edge of the sole at the heel and 
 toe. The operator then nails down the upper all 
 around the sole except at the heel, with a rapid-fire 
 tacker, holding the upper with pincers in his left 
 hand while he hammers with his right. The nails 
 are temporary for Goodyear welt and turn soles, but 
 are driven clear in and clinched against an iron 
 plate on the sole of the last in making McKay, stan- 
 dard-screw, and pegged shoes. The wipers are then 
 shd back, and the lasting is complete. 
 
 The stitching is done on a McKay, a Goodyear 
 welt, or a Goodyear outsole machine, according to the 
 location of seam and kind of shoe. Figure 188 shows 
 a McKay machine which consists of a head, a, con- 
 taining the feeding and stitching mechanism, and a 
 turntable, b, which supports the horn, c, and the 
 thread-waxing device, both of which are heated by 
 steam or gas. In operation a shoe, after the last has 
 been removed, is placed upside down on the horn, 
 where it is held by a presser foot, and the stitching 
 mechanism, shown in Figure 189, forms a chain 
 stitch. The thread comes up through the horn, a, 
 Figure 189, and is laid in the barb, c, of the needle 
 by the whorl, b; then the needle rises with a loop of 
 thread while the moving guard, d, is in the dotted 
 position, but when it starts to descend the guard 
 moves to the left and holds the loop in place, so as 
 to enchain the loop that is drawn through from be- 
 low on the next rise of the needle. 
 I The Goodyear welt machine makes a chain stitch 
 ■ by the same general method, modified in details so 
 
 FIG. 189. M 'kay chain stitch mechanism 
 
 that a surface stitch (see Goodyear welt inseam, Fig- 
 ure 181, b), instead of a through stitch — is made. 
 Thus the needle is curved instead of straight, and, 
 instead of supporting the shoe on a horn, the opera- 
 tor holds it between a back rest and a guide which 
 enters the surface channel and bears the thrust of the 
 needle. There is also a guide for feeding the welt 
 into position, which can be removed when turn §oles 
 are being stitched. 
 
 The Goodyear outsole machine makes a lock stitch 
 by a method differing materially from that of the 
 plain sewing machine. Instead of the needle thread's 
 
 I 
 
478 THE MECHANICAL EQUIPMENT 
 
 being fed from above and the shuttle thread from 
 Delow, their positions are reversed. The needle itself 
 remains on the upper side, being barbed so as to pull 
 the needle thread through from the under side. A 
 reciprocating awl makes the holes, and a take-up 
 
 Zl Tl "?• *^' '^^'^ ^ *^« th^««ds after each 
 stitch, duplicating m a clever and very rapid way 
 
 the work of the old time shoemaker. Other essential 
 parts of the machine, also found on the McKay and 
 Goodyear welt machines, are: (1) steam heating sys- 
 tem for the waxed thread, (2) thread-waxer, (3) 
 thread-tension regulator. 
 
 Moulding and leveling machines are of two kinds: 
 those which roll the sole, and those which shape it 
 by direct pressure between dies. They are built with 
 two umts in tandem, so that the operator can set up 
 one shoe while another.is under pressure. The Good- 
 year sole-leveling machine, of the first type, holds the 
 shoe upside down on a jack, while a concave brass 
 roller is passed back and forth and from side to side 
 over the sole, the pressure being applied by a treadle. 
 Ihe Goodyear sole-laying machine belongs to the 
 direct pressure type; it consists of a lower head sur- 
 mounted by a rubber die block, and an upper head to 
 which the shoe is attached, the two heads being 
 drawn together by power. The Hercules type com- 
 bines direct pressure and rolling, by having the shoe- 
 holding jack and the die that shapes the sole swing 
 cu pivoted arms, instead of sliding in guides 
 
 Rmshing-Room Machinery.-Most of this is typical 
 bufling and polishing equipment: high-speed spindles 
 on which are mounted milling cutters, emery wheels 
 
 I 
 
 II' 
 
 FIG. 190. NAUMKEAG BUFFING MACHINE 
 
 United Shoe Machinery Co. 
 
 479 
 
478 
 
 THE MECflAMCAL EQUIPMENT 
 
 being fed from above and the shuttle thread fron. 
 Delow, their positions are reversed. The needle itself 
 remains on the npper side, being l.arl.ed so as to pull 
 the needle thread through from the under side. \ 
 reciprocating awl makes the holes, and a take-up 
 lev-er draws up the slack in the threads after each 
 stitch, duplicating in a clever and verv rapid wav 
 the woi-k ot the old time shoemaker. Other essential 
 parts of the machine, also found on the McKay and 
 Goodyear welt machines, are: (I) steam heating sys- 
 tem tor the waxed thread, (2) thread-waxer, (3) 
 thread-tension regulator. 
 
 Moul.ling and leveling machines are of two kinds- 
 those which roll the sole, and those which shape i1 
 by direct pressure between dies. Thev are built with 
 two units m tandem, so that the operator can set up 
 one shoe while another is under pressure. The Good- 
 year sole-leveling machine, of the tirst tvpe, holds the 
 shoe upside down on a jack, while a Concave brass 
 roller is passed back and forth and from side to side 
 ov'er the sole, the pressure being applied by a treadle, 
 llie Goodyear sole-laying machine belongs to the 
 direct pressure type; it consists of a lower head sur- 
 mounted by a rubber die block, and an upper hea.l to 
 which the shoe is attached, the two heads bein- 
 drawn together by power. The Hercules tvpe com- 
 bines direct pressure and rolling, by having the shoe- 
 liolding jack ami the die that shapes the sole swin- 
 en pivoted arms, instead of sliding in guides 
 
 Finishing-Room Machinery.-ilost of this is typical 
 bufling and polishing equipment: high-speed spindles 
 on which are mounted milling cutters, emerv wheels 
 
 FIG. 190. NAUMKEAG BUFFING MACHINE 
 
 United SIkip Mucliincry (^'o. 
 
 4711 
 
7 
 
 480 
 
 THE MECHANICAL EQUIPMENT 
 
 sandpaper wheels, brushes and buffing wheels. The 
 ironing machine is fitted with small blocks or disks 
 of iron, heated by a gas flame, and vibrated or rotated 
 rapidly so as to burnish the surface of the leather. 
 The Naumkeag buffing machine, Figure 190, is in a 
 class by itself. This machine has two vertical spin- 
 dles, a and b, for rough and fine polishing respec- 
 tively, at whose lower ends are the emery-covered 
 rubber pads, c, d. These pads are distended by com- 
 pressed air; thus a delicate, yielding pressure is 
 obtained, and a smooth, velvet surface is given to 
 the work. 
 
 CHAPTER XXVI 
 TEXTILE MACHINERY 
 
 The Fibres and the Processes.— Since the manufac- 
 ture of woven fabrics is one of the oldest industries, 
 it is natural that man's ingenuity should have devised 
 and perfected an almost endless variety of machinery 
 for making this product. Within the confines of a 
 single chapter, however, it is possible to describe only 
 typical machines, and merely to give the reader a 
 broad survey of the subject which may serve as an 
 introduction to a more detailed study. The four prin- 
 cipal fibres used, in the order of their importance, 
 are cotton, wool, silk, and linen. The processes in- 
 volved are spinning, which includes cleaning and 
 straightening the fibres, drawing them out and twist- 
 ing them into yarn; weaving and knitting; and finish- 
 ing, which comprises a number of processes for im- 
 proving the appearance of the rough web of cloth. 
 In the manufacture of reeled silk, a process known 
 as throwing replaces the operations of spinning. 
 
 Cotton-Spinning Machinery. — The opening and 
 cleaning of the fibres is done in openers and pickers. 
 The essential part of both machines is a beater, or 
 set of rapidly revolving, blunt steel blades, which 
 clean the cotton over a grid. In the opener, the cot- 
 ton taken from the bale is dumped into a hopper, 
 
 481 
 
482 
 
 If 
 
 THE MECHANICAL EQUIPMENT 
 
 PIG. 191. BREAKER PICKER 
 
 .rom which It IS carried on conveying aprons to a 
 doffer, or four-bladed drum, for a preliminary 
 cleamng before it goes to the beater. From this point 
 it IS blown through an air duct, or ** trunk,'' to the 
 pickers, which are generally arranged in series of 
 three— breaker, intermediate, and finisher. 
 
 Figure 191 illustrates the working parts of a 
 breaker picker; a, is a screen drum connected at both 
 ends with the intake of fan, b, and revolving around 
 the semi-cylindrical shield, c. The cotton enters 
 through trunk, d, adheres to the drum while dust 
 passes through, is stripped off by roll, e, at a point 
 where the shield, c, prevents further adhesion, and 
 drops into the gauge box, f. This box acts as a reser- 
 
 TEXTILE MACHINERY 
 
 483 
 
 voir to compensate for irregularities in the supply 
 and discharge of cotton; any surplus overflows into 
 the space, g, from which it can be removed through a 
 door. The material in the gauge box is carried for- 
 ward on the apron, h, and between the feed rolls, i, 
 to the beater, j, which pulls it off in tufts and throws 
 it against the grid, k, through which dirt falls, while 
 the cotton is blown over the dust-catching grate, 1, to 
 the screen drums, m, m, which act very much like the 
 screen, a. It is then stripped off in an even sheet, or 
 **lap," by rolls, n, passed between weighted calenders, 
 0, and reeled on the roll, p. The intermediate and 
 finisher pickers have not the gauge box or the screen, 
 a, but have racks for holding four laps, which are 
 unwound on the apron corresponding to h. 
 
 The lap (f, Figure 192), coming from the finisher 
 picker is practically free from dirt, and the fibres are 
 ready to be straightened out. This is done by means 
 of a card. Figure 192, which combs them between two 
 surfaces covered with fine pins. The picker lap, f, is 
 
 /Vv//////////wW > y////vw^^^ 
 
 PIG. 192. COTTON CARDING MACHINE 
 
 ii 
 
484 
 
 THE MECHANICAL EQUIPMENT 
 
 TEXTILE MACHINERY 
 
 485 
 
 unrol ed by rolls, g and h, and presented to the 
 rapidly revolving leader, a, which carries it over the 
 knife, I, and grate, j, where any remaining dirt is 
 rennoved, to the cylinder, b. Since the surface speed 
 ot the cylinder is more than twice that of the leader, 
 the cotton IS picked up by the forward-pointing card 
 teeth, b', and carried under the slowly moving flats c 
 which ar6 also faced with carding teeth. Here the 
 pulling action on the fibres commences, and continues 
 until the head end of the chain of flats, c', is reached, 
 ihe cotton may travel around the cylinder a num- 
 ber of times, but it is eventually pulled off by the 
 pins of the slowly revolving doffer, d; and since it 
 rests lightly on the surface it is easily removed by 
 the vibrating comb, e, and is fed in a lap to the 
 calender, k, which thins it and narrows it down to 
 what IS termed a "sliver." It then passes through 
 an automatic coiler into the can, 1. One might think 
 that If the doffer removes fibres from the card cylin- 
 der, the flats would do the same thing; this, however, 
 IS prevented by the stripping knife, m. In order to 
 keep a card in working condition, it is necessary to 
 grind the cylinder, doffer, and flats frequently, and 
 to strip the doffer and the cylinder three or four 
 times a day. For this purpose special bearings are 
 provided on the frame, in which grinding wheels and 
 stripping brushes may be placed when they are 
 needed. 
 
 The Comb.— In the manufacture of long staple yarn, 
 the cotton is passed through an additional machine, 
 called a comb, the purpose of which is to remove all 
 short fibres. The card slivers are first "drawn " or 
 
 I 
 
 stretched out, and combined into a lap about 12 
 inches wide, which is wound on a roll. The laps are 
 fed to the comb cylinders, which are covered half-way 
 around with fine needles. These pick off tufts, re- 
 move the short fibres, and pass the long ones out 
 between detaching rolls and through a trumpet, which 
 contracts them to a new sliver. The long fibre slivers 
 are then fed through a calender, combined by draw- 
 ing rolls, and coiled in a can. The short fibres are 
 removed from the cylinder needles by a revolving 
 brush, and collected in a thin lap by a doffer comb 
 similar to that on a carding machine. 
 
 Drawing Frame; Ply Frame; Spinning Machine.— 
 The last steps in spinning are carried out on three 
 kinds of machines: the drawing frame, which com- 
 bines the slivers from six or eight cans and draws 
 them out by means of rollers; the fly frame, which 
 continues the drawing process and gives the sliver a 
 slight twist, converting it into a loose yarn, called 
 ** roving"; and the spinning machine, which twists 
 the roving sufficiently to make it into a fairly hard 
 yarn, at the same time drawing it slightly. Fly 
 frames are generally arranged three in a series: the 
 first, or ** slubber," the intermediate, and the fine. 
 Figure 193 shows a section of a fine fly frame. The 
 course of the roving is from the bobbins, a, held ij;i 
 a rack called a ** creel," thence through the drawing 
 rolls, b, where the ends from each pair of bobbins 
 are united, thence to the flyers, c, and down one arm 
 of each flyer and on to the bobbins, d. 
 
 The flyers are mounted on spindles, e, which are 
 driven at constant speed, while the bobbins are on 
 
 
 I 
 
186 
 
 THE MECHANICAL EQUIPMENT 
 
 TEXTILE MACHINERY 
 
 487 
 
 1FT 
 
 PIG. 193. PLY PRAME 
 
 eoncentric but independently driven spindles, f The 
 rotation of the flyers imparts a twist to the roving 
 and the excess of speed of the bobbins, d, over that 
 of the flyers serves to wind this roving on the bob- 
 bins In order that they may wind the bobbins 
 evenly, the spindles, f, are carried on a rail, which is 
 moved np and down by a builder mechanism, and the 
 
 spindle speed is decreased by an automatic tension 
 gear as the bobbins fill up. A standard fly frame 
 contains a row of thirty or more pairs of these flyers, 
 set side by side as close as possible. 
 
 The spinning machine is one of three types: ring 
 frame, cap frame, or mule. The first two are most 
 widely used, owing to their greater simplicity and 
 cheapness of operation. Like the fly frame, they 
 twist and wind simultaneously, whereas the mule 
 performs these operations successively on a definite 
 length of yarn, and then passes on to the next length. 
 In the ring frame the bobbin is positively driven, 
 while a wire loop sliding on a stationary ring encir- 
 cling the bobbin is moved solely by the pull of the 
 yarn passing to the bobbin. At the same time, the 
 friction between ring and loop is sufficient to hold the 
 loop back and give the difference in speeds necessary 
 for winding. All the rings of one frame are mounted 
 on a rail, which rises and falls automatically so as to 
 wind the bobbins evenly. In the cap frame, the bob- 
 bin and its spindle are the only moving parts of the 
 spinning mechanism; a close-fitting stationary cap 
 fits down over the bobbin, and the yarn, in order to 
 reach it, has to pass under the lower edge of this 
 cap. The resulting friction retards the yarn suffi- 
 ciently to cause winding. 
 
 The mule is an extremely complicated machine and 
 requires skill to operate and keep in repair. Its 
 essential parts are the creel, a. Figure 194, holding 
 the roving; a carriage, b, supporting a row of 
 spindles, c; and a head (not shown) containing the 
 driving mechanism. The roving passes from the 
 
 n 
 
 v\ 
 
488 
 
 THE MECHANICAL EQUIPMENT 
 
 *^ ^^^^^^^im„„5„^ 
 
 ^mmm//m 
 
 FIG. 194. SPINNING MULE 
 
 faller h Tho f^ii • ''^"^"^ ^^^^^r, g, and counter- 
 of opin^ '""^"^"^ ^^« *^« «t«P« - one cycle 
 
 from'?L*drarZ' 71" .''°"* '"^ ^^^^^^ ^-^^ 
 om ine dratt rolls, while the roving is naid n„f 
 
 lakeTfew ria^j' TT ^*°^^' ^'^^ ^^^^'^ 
 ,il«ri„ ^ J backward turns to unwind the irres 
 
 fnZl2 -^ *^' ^^™ ^'^^^ accumulated on tol, 
 during this spinning, and the fallers take the J,7 
 tions shown bv the dnttaA r x, P^^^' 
 
 actinff as a JI I • ''"^'' *^ counterfaller 
 
 DODDin. Third, the carriage runs back to its oris 
 anal position, and the spindles rotate slowly Z 
 
 TEXTILE MACHINERY 
 
 489 
 
 wind up the yarn that has just been spun, the fallers 
 moving up and down in such a way as to wind the 
 yarn evenly and under uniform tension. Fourth, the 
 carriage stops, and the fallers return to their position. 
 
 Wool-Spinning Machinery.— All raw wool contains 
 a quantity of grease and dirt, which must be re- 
 moved in dusters and scourers. The dusters are 
 horizontal skeleton con^s with inwardly projecting 
 pins, rotating in an air-tight chest, which acts like a 
 tumbling barrel; the wool enters at the small end of 
 the cone and leaves at the large end, while dust is 
 drawn out through a fine screen above the cone and 
 larger particles of dirt drop through a coarse screen 
 below it. The scourers are shallow troughs, or, 
 ** bowls," about 3 feet wide and 16 to 40 feet long, 
 fiilled with a warm solution of soft soap, into which 
 the wool is fed and paddled along by a series of 
 . rakes, which enter the liquor vertically, advance 
 about twelve inches, rise from the bowl, and return 
 to their first position. This motion is necessitated 
 by the nature of the wool fibres, which are very 
 easily felted or matted under the action of heat and 
 agitation, on account of the scales that cover their 
 surface. On reaching the end of the bowl, the wool 
 passes between squeezing rolls to the next scouring 
 bowl or to a rinsing bowl filled with running water 
 instead of washing liquor. After washing, the wool 
 is carried on a perforated apron through the drier, 
 a closed chamber about 20 feet long, where it is dried 
 by a forced circulation of warm air. 
 
 The rest of the preparation of the fibres for the 
 spinning frames depends upon whether they are to 
 
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 ^^I^H 
 
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 ^^^^H, 
 
 ^^m 
 
 ^^^^m 
 
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 H 
 
 
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 490 
 
 THE MECHANICAL EQUIPMENT 
 
 cQTv,^ 4? ..• "i^dKer, and taisher, performs thp 
 
 flaS ther^ ."^ ''' ''""" ^^'•^«' ^-^^ -«t^a<i « 
 'Wkers» "^^"^ ^'"^"^ t^^t'^^d rolls called 
 
 inder wLh . ?. ''"'" *° ^'^^ ^^^^^^^ °f the cyl- 
 inder, which straighten out and even the fibres jL 
 
 ratesMe'fir"' ^\^ '^^^^' « toothed "fancy roll'' 
 the case of K'''r ^'^^^ '^'^ ^^« ^^^^'^ ^^d- In 
 he doffer .^'k !,' '^'^'' ^^'^ ^'' then collected by 
 o layth /r ' ^'■^"".^"to a sliver from the side! 
 Sie finisher .r^ "-regularly, and wound into balls 
 ste«d of ? "^ ^^' ^^'^ ^"ff^'-^' e««h of which in- 
 
 nating rings of teeth and leather about an inch wide 
 
 r^ '' anTr T"" 'T '""^'^ ™^^ ^^^ ^ ' "^Pe 
 sTstin/nf / *^™"^^ "" ^Pr°" condenser, con- 
 on aft witT T"l '"'^ ^ '''"^^ ^Pr^'^ traveling in • 
 contact with the slivers and oscillating at the time 
 
 aTh Hv"rttV°-f ^' *'^ ^^^^* '' -'"^^ - to rub 
 eacn sliver into a loose round roving The rnvir,<r« 
 
 for w . f ^'""""^ Machinerjr._Carding machines 
 yarn, but the teeth are so spaced and the rolls «,o 
 
 known !s <S. "^ f ^ '*^P'^ ^°°^«' the process 
 
 qir a serirof'""^ ''''^^''' ^^^^'"S" ™« >•«- 
 quires a series of nine or ten gill boxes, which are 
 
 Xf rth:?r?'*^""^ ^"^ '^^^"^ t''^ fibres par! 
 aliel, by the following simple method: The loose wool 
 
 straightened as much as possible by hand, tfed Te-' 
 
 TEXTILE MACHINERY 
 
 491 
 
 IF///"/////////////////////////^^ 
 SECTION 2-Z 
 
 ^:^ 
 
 I' 
 
 ! 
 
 Ill 
 
 
 
 « ! 
 
 no. 195. NOBLE COMB 
 
492 
 
 THE MECHANICAL EQUIPMENT 
 
 tween two fluted rolls and caught on pins projecting 
 from a series of bars called fallers, which travel con- 
 siderably faster than the rolls. These pull out the 
 fibres. On reaching the end of the faller travel, the 
 lap passes between a second pair of rolls, revolving 
 at still higher speed, which pull it out still further. 
 In each passage of the wool through a gill box, the 
 lap is pulled out from ten to forty times its original 
 length. 
 
 At this stage the short fibres (or **noil") which 
 are unsuited for worsted yarn, are separated from 
 the long ones in a comb, one form of which is shown 
 in Figure 195. A ring, about five feet in diameter, 
 carries several rows of pins, a, a circular creel hold- 
 ing balls of wool, b, and a set of conductors, c, 
 through which the slivers, d, pass on their way from 
 the creel to the pins. Inside this ring, and revolving 
 in the same direction and with approximately the 
 same peripheral speed, are the rings, e, e, also pro- 
 vided with pins. As seen in the sectional views, the 
 conductors are hinged at their outer ends, and the 
 inner ends are narrowed to keep the slivers from 
 slipping back. At x-x, the ends of the slivers rest 
 in the pins, as shown; at y-y, an additional length 
 is fed out by tilting the conductors while keeping 
 the sliver ends in the pins by means of the bar, f; 
 at z-z, knives, g, lift the slivers off the pins; and at 
 the point of tangency of the rings, dabbing brushes 
 push the slivers down into the pins of both the large 
 ring and the pair of small ones, e, e. 
 
 The further rotation of the rings causes the sets 
 of pins to separate from each other, and the short 
 
 TEXTILE MACHINERY 
 
 493 
 
 fibres are pulled out and stick to the pins on the 
 rings, e, e, while the long fibres remain on the large 
 ring, projecting inwardly in a long fringe, which is 
 pulled off by the fluted rolls, h, and delivered in 
 sliver form to a can. Some of the long fibres adhere 
 to the rings, e,e; these are removed by the rolls, i, 
 while the noil is stripped by knives (not shown) set 
 between the rows of pins. This machine makes an 
 extremely well-blended product, as it combines sev- 
 enty-two slivers into one. 
 
 The remaining treatment in the preparation of the 
 yarn consists of additional drawing, followed by 
 twisting, for which gill boxes and fly, ring and cap 
 frames are employed. Soft yarns are spun on the 
 
 mule. . . J i. 
 
 Linen and Silk Preparation.— Flax is received at 
 
 the spinning mills in bunches of long filaments of 
 **line," from which the short pieces or **tow" must 
 be removed by *' hackling." This is still done largely 
 by hand, in spite of the existence of machines 
 for the purpose. The process consists of grasping 
 one end of a bunch of flax in the hand or holder, 
 and pulling it through combs set with progressively 
 finer and finer teeth. The bunches then pass through 
 a *'spreadboard," where they are combed and made 
 into a continuous sliver, a number of which are 
 combined and drawn repeatedly, after which they are 
 spun on ring, cap, or fly frames. 
 
 Keeled silk, consisting of strands of six to twelve 
 or more elementary filaments, is wound onto bobbins 
 and ** thrown," i. e., twisted and doubled with other 
 strands. The twisting is generally done on a fly 
 
494 
 
 THE MECHANICAL EQUIPMENT 
 
 frame, and the doubling is done on a machine that 
 winds the threads from a number of bobbins onto a 
 smgle bobbin. After each doubling, a twist is given 
 to the thread in the direction opposite to that in 
 which the original strands were twisted. Spun silk 
 manufactured from silk waste, is beaten, combed or 
 hackled, drawn, and spun on machines that are in the 
 mam similar to those which perform these operations 
 on other textile materials. 
 
 Weaving Machinery.-Filling thread is ready for 
 
 the loom shuttle as soon as it has been wound on 
 
 cops or bobbins, but warp threads require additional 
 
 preparation in spoolers, warping machines, and 
 
 slashers. The purpose of the spooler is to wind the 
 
 warp thread from the spinning-frame bobbins onto 
 
 large spools, each of which holds sufficient thread to 
 
 extend the length of a warp without piecing. The 
 
 spools are mounted loosely on vertical spindles ar- 
 
 ranged m a double row of sixty or more in a long 
 
 machine resembling a fly frame; they are driven by 
 
 friction and receive the thread from bobbins resting 
 
 horizontally in wire cages. The warper combines 
 
 the threads from three hundred to one thousand 
 
 spools. 
 
 It consists of the following parts: a creel, or 
 set of upright racks standing side by side, which hold 
 the spools; a *^reed," or series of vertical wires set 
 m a rectangular frame, through which the threads 
 are passed; a measuring roll, which is rotated by the 
 threads as they pass over it, and is geared to a 
 pointer indicating the length of warp that has been 
 wound off; a comb, similar to the reed, which lays 
 
 TEXTILE MACHINERY 
 
 495 
 
 the threads in a sheet of the same width as the beam; 
 and the beam, on which this sheet is wound. 
 
 In the case of yarns which must be dyed before 
 weaving, the threads are condensed into a narrow 
 chain and wound into a ball; and after dyeing, the 
 chain is spread out into a sheet. To keep the threads 
 from tangling in the chain, and to simplify the piec- 
 ing of loose ends if a break occurs, the comb is re- 
 placed by a ** lease reed,'* in which each wire is per- 
 forated. Alternate threads pass through these per- 
 forations, while the others pass between the wires. 
 At intervals of five hundred to one thousand yards, 
 the operator raises the lease reed, lifting up half of 
 the threads, and passes a cord between the two sheets 
 of warp threads from one side to the other, then de- 
 presses the reed, passes the cord back again, and ties 
 the loose ends together. By this method the warp 
 threads are maintained in their correct places 
 through all the rough handling involved in chaining, 
 linking or balling, and dyeing. 
 
 The slasher. Figure 196, receives the thread from 
 a number of warper or '*back'' beams, sizes it to 
 increase its strength and smoothness, and winds it 
 onto the warp beam of a loom. The figure shows 
 the creel, a, holding the back beams; the size box, b, 
 through which the warp passes; the squeeze rolls, 
 c, c, which remove the excess of size; the steam- 
 heated drying drums, d, d^ about seven and five feet 
 in diameter, respectively; a fan, e, to assist in drying; 
 dividing rods, f , f , for separating the threads which 
 tend to stick together from the sizing; a tension roll, 
 g; and the warp beam, h, which is removed and 
 
496 
 
 THE MECHANICAL EQUIPMENT 
 
 FIG. 196. SLASHER 
 
 mounted in a loom as soon as it contains the requisite 
 length of yarn. 
 
 Mechanism of the Loom.— The loom makes a rec- 
 tangular web of cloth by interlacing two sets of par- 
 allel threads— the warp, running lengthwise, and the 
 weft or filling, running crosswise. The mechanism 
 for a plain loom is shown in Figure 197. The a\ arp 
 threads, a, pass from the warp beam, b, to the cloth 
 beam, c; alternate threads, as for example the odd- 
 numbered ones, are drawn through the eyes, d, while 
 the even-numbered ones are drawn through the eyes, e. 
 A shuttle, f, carrying a bobbin of filling thread,' is 
 thrown back and forth from one side of the loom to 
 the other, and after each traverse the position of 
 the even- and the odd-numbered warp threads is inter- 
 changed, so that the filling is woven between the 
 threads of the warp. Five motions are required, all 
 derived from the shaft, g: the *^ shedding'' motion, 
 which separates the even- and the odd-numbered warp 
 threads by alternately raising and lowering the eyes 
 d and e; the ^* picking'' motion, which throws the 
 shuttle from side to side, each traverse being called a 
 pick; the ** beating up", occurring after each pick. 
 
 TEXTILE MACHINERY 
 
 497 
 
 which drives the filling firmly into place by a quick 
 motion of reed h towards the right; the *' let-off", 
 which unwinds the warp from the beam, b; and the 
 ** take-up", which winds the cloth on the beam, c, at 
 the right of the drawing. 
 
 The figure shows the cams and the gearing for 
 shedding and beating up, as well as one of the pick- 
 motion cams, i. The rest of the pick motion can be 
 seen in Figure 198, which is a front view of the 
 **lay," the name applied to the swinging frame sup- 
 porting the reed and the shuttle. The shuttle, f, is 
 just entering the shuttle box, k, having b^en thrown 
 across from the box, 1, by the picking stick, j, actuated 
 by the cam, i. 
 
 If a simple design is to be repeated, the eyes d and 
 e are carried in three to ten or more sets, instead of 
 two, each set being operated by its own *' harness/' 
 For more complicated patterns, the harnesses are 
 raised by levers actuated by buttons, or *' risers," 
 inserted in sin endless chain which is moved forward 
 at the rate of one link per pick. This device, called 
 a *'dobby," is fastened to the upper part of the loom 
 and controls the design. If the same harness arrange- 
 ment is to be repeated for a number of picks, as in 
 the weaving of checks, a multiplier chain is used. 
 This chain is started by the arrival at the working 
 point of a button on the harness chain. The harness 
 chain then stops until a button on the multiplier 
 chain arrives at the working point when the multi- 
 plier stops and the harness chain starts on again. 
 When more than one color of filling is required, a 
 *'box loom" is used, having several shuttles carried 
 
498 
 
 THE MECHANICAL EQUIPMENT 
 
 TEXTILE MACHINERY 
 
 499 
 
 BACK 
 
 FRONT 
 
 V///////7//////////y/y/y////^^^^^ 
 
 PIG. 197. PLAIN I/)OM, LONGITUDINAL SECTION 
 
 
 FIG. 198. PLAIN LOOM, SHOWING LAY AND PICK MOTION 
 
 on the lay in a tier of boxes, which is elevated or 
 depressed to bring the proper shuttle into action by 
 a mechanism similar to the dobby. 
 
 Weaving Intricate Patterns.— The most intricate 
 patterns afe woven on a loom whose ** shedding'* is 
 operated by a Jacquard machine, Figure 199, which 
 controls each warp thread by perforations in a chain 
 of cards, just as each key of a piano is controlled by 
 perforations in a paper roll on the piano player. The 
 elements of the machine are a set of needles, a, equal 
 in number to the warp threads in the pattern; hooks, 
 b, normally resting on the grating, c; a rectangular 
 block, d, called the cylinder, supported on trunnions, 
 d', and provided with holes into which the needles, a, 
 fit; and a ** griff e,'* or set of bars, e, for raising the 
 hooks. 
 
 The several hooks are connected by strings, g, 
 with the eyes, f, through which the warp is threaded. 
 Three cards of the chain appear at h. Preceding each 
 pick the cylinder, d, moves away from the needles, 
 makes a quarter turn, bringing a new card into 
 action, and returns to the position shown. This mo- 
 tion will force to the right all those needles for which 
 there are no perforations in the card; and the loops 
 in these needles will press the corresponding hooks 
 off the griff e, so that when the griff e is raised by the 
 shed motion, a certain number of the warp needles 
 will be drawn up by the strings or ** harness,'' g, 
 while the rest will remain in place. As may be 
 imagined, the cost of Jacquard weaving is principally 
 due to the labor involved in preparing the cards and 
 rigging the harness. 
 
 
500 
 
 THE MECHANICAL EQUIPMENT 
 
 TEXTILE MACHINERY 
 
 501 
 
 Knitting Machines.— Knitting is done on two types 
 of machine: spring needle, for plain work; and latch 
 needle, for plain, tuck, ribbed, and other varieties of 
 fabrics. Both types produce a tubular cloth, forming 
 the stitches in spirals around the fabric, like the 
 threads of a multiple screw. The stitching devices 
 vary with different manufacturers and are compli- 
 cated by adjustments for changing the kind of stitch, 
 but the essential features of all knitting machines 
 are these: a single or a double row of hooked needles, 
 arranged in a circle, each of which engages one loop 
 of the working edge of the fabric; cams or wheeFs 
 for moving the needles and fabric relatively to each 
 other in such a way as to form new stitches; and a 
 take-up for winding the knitted fabric on rolls or 
 folding it in cans as fast as it is made. 
 
 Figure 200 shows how this is done on a spring needle 
 machine. The various wheels used to direct the 
 thread are termed a feed; four of these feeds are 
 usually attached at equal intervals around the ring, a, 
 on which the circular row of needles, b, is mounted. 
 The needles move past the feed from left to right', 
 as indicated, passing in turn the holding wheel, c, 
 which pushes the work below the barbs of the needles, 
 sinker burr, d, which feeds the new thread under the 
 barbs, presser wheel, e, which closes the barbs, landing 
 burr, f , and cast-off burr, g, which casts off the old 
 stitches and raises the new ones into the hooks of the 
 needles. By noting each stitch in the figure, starting 
 at the left and ending at the right, the reader can 
 see than an additional course of stitches has been 
 laid during the passage of the needles through the 
 
 I 
 
502 
 
 THE MECHANICAl/ EQUIPMENT 
 
 i 
 
 TEXTILE MACHINERY 
 
 503 
 
 feed. The latch needle machine uses two rows of 
 needles, one set vertically and the other horizontally, 
 which are moved in and out at each feed point by 
 means of cams. 
 
 Finishing Machinery. — Woven fabrics are passed 
 through a number of machines; the purpose is to im- 
 prove their strength, durability and appearance. The 
 fulling mill, used for partially felting woolen goods, 
 is a chest containing two rolls behind which is a 
 compartment with a constricted opening. A piece 
 of goods, saturated with soapy vater, is fed between 
 the rolls, and the ends are stitched together. The 
 rolls are then run continuously for some time; the 
 cloth passes between them, folds up in the compart- 
 ment, is squeezed out through the narrow opening, 
 drops to the bottom of the mill, and then repeats 
 this cycle Under the influence of pressure, moisture, 
 and the heat developed by friction, the cloth shrinks, 
 at the same time becoming firmer and stronger. 
 
 The short threads adhering to the surface of cloth 
 are removed by a singeing machine, which consists of 
 a frame carrying rollers over which the goods are 
 passed from one folded pile to another; at certain 
 points gas flames impinge on the cloth, or heated 
 copper plates come in contact with it, and by proper 
 legulation of cloth speed and intensity of flame all 
 the short fibres are removed. In other cases, when a 
 nap on the surface of the goods is desired, it is ob- 
 tained by a **gig," a machine whose principal part 
 is a cylinder covered with special thistles or 
 ** teazles'' grown for the purpose, which rotates close 
 to the surface of the goods to be napped. After 
 
604 
 
 THE MECHANICAL EQUIPMENT 
 
 napping, the surface is made uniform in a shearing 
 machine, which brushes up the nap and then trims it 
 to the correct length by means of a rotary cutter act- 
 ing against a stationary blade. 
 
 Numerous other machines, of course, are used in 
 textile making, for instance in the processes of 
 bleaching and dyeing— but as these are in the nature 
 of special equipment, detailed information should be 
 sought in works devoted entirely to the subject. 
 
 INDEX 
 
 Advantages of Grinding, 377 
 Air Furnace, Section of, 70 
 Allowances, Pattern, 37 
 Alloys, 44 
 
 Amazeen Machine, 465 
 Annealing, 150 
 Armor Plate Planer, 295 
 Arrangement of a Shoe Factory, 462 
 Automatic Bevel-Gear Milling Machine, 
 355 
 
 — Bevel-Gear Planer, 356 
 
 — Robbing Machine, 352 
 
 — Milling Machine, 315 
 
 — Screw Machine, 234 
 Automatic Lathe, Cleveland, 236 
 
 —Fay, 240, 241 
 
 — Gridley, 236, 237 
 
 — Multi-Spindle, 238, 239 
 
 — Principle of, 232 
 
 Band Saw, 418, 419 
 Beaters and Refiners, 447 
 Belt-Driven Open-Back Press, 411 
 Bench, Saw, Universal, 419-420 
 Bending, Pipe, 100 
 Bevel-Gear Milling Machine, 355 
 
 — Planer, Automatic, 356 
 Bevel Gears, 337 
 
 — Cutting of, 354 
 Binders, Core, 55 
 Blanchard Lathe, 244, 432-433 
 Blast, Sand, 79 
 Blocks, Die, 110 
 
 Blue-Printing Machine, Electric, 28 
 Blue Prints, Issuance of, 25 
 Board Drop Hammer, 105 
 Bolt Threading Machines, 365, 367 
 Boot and Shoe Machinery, 459 
 Boring Machine, Horizontal, 258, 2C1, 
 264 
 
 — Portable, 263 
 
 — Wilkinson's, 245 
 Boring Mill, Table, Drive and Tool for, 
 255 
 
 ^versus Vertical Planer, 249 
 
 —Vertical, Construction of, 251 
 
 — (Vertical) versus Lathe, 247 
 Boring Mills Classified, 246 
 Bottoming Boom Machinery, 474 
 Box, Change Gear, 210 
 
 — Tool, Multiple, 225 
 Brazing and Soldering, 135 
 
 — Process, 136 
 Breaker Picker, 482 
 Briggs' Type of Milling Machine, 314, 
 
 315 
 Broach and Dies, 404 
 Broaches and Samples of Broaching 
 
 Work, 402 
 Broaching Machine, 400, 401 
 
 — Process, 398 
 
 — ^Tools, 401 
 Bryant Chucking Grinder, 394 
 Buffing and Polishing, 397 
 
 — Machine, Naumkeag, 479 
 Building Method, 2 
 
 — Tools used in, 4 
 
 — Type, for Special Work, 4 
 
 ^Type used in Manufacturing 
 Work, 7 
 Buildings, Foundry, 45 
 Bullard Mult-au-matic Vertical Lathe, 
 
 256. 257 
 Butt Welding Machine, 124 
 
 Carbonizing, 153 
 Carbon Steel, 171 
 
 — Heating of, 144 
 Car-Wheel Lathe, 216 
 Cast Steel, 43 
 Castings, Cleaning of, 78 
 
 — Defective, 76 
 
 — Pickling of, 79 
 
 — Tumbling of, 78 
 Chain Stitch Mechanism, 469 
 
 —McKay, 477 
 Change-Gear Box, 210 
 Changes in Drawings, 26 
 
 505 
 
506 
 
 INDEX 
 
 INDEX 
 
 507 
 
 Checking Designs, 24 
 
 ChiUed Iron, 42 
 
 Chuck, Lathe, 213 
 
 Chucking Grinder, 394 
 — Machine, 465 
 
 Circular Saw, 418 
 
 Classes of Welding, 118 
 
 Classification of Boring Mills, 246 
 
 Cleaning of Castings, 78 
 
 Cleveland Automatic Lathe, Top View, 
 
 Cold Trimming of Forgings, 115 
 Collapsing Die Head, 368 
 
 — Tap, 368 
 Collection of Milling Cutters. 310 
 color and Temperature Scale for Tool 
 
 Hardening, 152 
 Column and Knee Type of Milling 
 
 Machine, 318 
 Comb, 484 
 — Noble, 491 
 
 S!"i*°!2"° Production Methods, 11 
 Construction of Shaper, 299 
 
 — Vertical Boring Mill 251 
 Continuous Rotary Feeding, 828 
 Contour Gauge, 169 
 Cope, Description of, 56 
 Copying Lathe, 432-433 
 Core Binders. 55 
 
 — Prints, Pattern, 38 
 Cores, 55 
 
 Correct Mounting For Grinding Wheel, 
 
 384 
 Cotton Carding Machine, 483 
 — Spinning Machinery, 481 
 Crank Planer, 289 
 Cross-Section^of Head Stock. 208 
 Crucible Furnace for Melting Brass 74 
 
 —Gas-Fired Heating Furnace. 146 
 Cupola, Method of Melting in, 65 
 
 — Section of, 67 
 Cupolas, Dimensions of, 69 
 Curve, Heat-Temperature. 142 
 Cutlery, Milling, 310 
 Cutter, Rag, 440 
 Cutters and Dusters, 439 
 — Heavy-Gauge Milling, 186 
 — Milling, 180 
 
 —Standard Types of, 181, 185 
 Cutting Areas. Effective, 250 
 — Bevel Gears. 354 
 — Gear Teeth. 335 
 — Helical Gears, 353 
 — Lubricants, 198 
 — r.crew Threads, 364 
 Cutting Gear, Formed-Tooth Principle, 
 
 — Generating Principle of, 343 
 
 — Template Principle of, 341 
 Cutting Boom Machinery, 464 
 S"*!?"*'™^'***' **" Lathes, 371 
 rl^A^ ^^**^^' Material used in. 171 
 Cylinder Paper Machine, 455 
 
 Defective Castings, 76 
 
 Department. Drafting, Functions of. 
 
 — Personnel of, 18 
 Description of Cope, 56 
 — Drag, 56 
 — Ladles, 75 
 Desi^ Of Plant Equipment, 14 
 
 — Product. 14 
 Designs, Checking, 24 
 Development of Grinding Process. 377 
 — Lincoln Miller, 316 
 — the Lathe. 200 
 Die Blocks, 110, 118 
 
 — Head, Collapsing, 368 
 — Sinking Machine, 320 
 — Working, 109 
 Dies, 404, 405 
 
 — and Their Action, 408 
 — Drop Hammer. 107 
 — Threading. 195 
 — Use of, 195 
 Digesters and Washers 441 
 Dimensions of Cupolas,' 69 
 Distinction between "Building" and 
 
 Manufacturing, 1 
 Drafting Lists, 15 
 
 Drafting Department, Functions of the, 
 
 — Personnel of, 18 
 Drafting Boom Equipment, 26 
 — Location of, 27 
 — Policies of. 19 
 — Practice, 23 
 
 —Supplementary Functions of 17 
 Drag, Description of, 56 
 Drawing Frame, 485 
 
 — Process, 99 
 Drawings, 15 
 
 — Changes in, 26 
 — Piling ot, 25 
 Drill Column, Section of, 275 
 — Multiple-Spindle, 277, 278 
 — Radial, Pull Universal', 277 278 
 — Sensitive, 266, 267 
 Drilling Jigg, 279 
 
 ^"^ ^eT' ^^"'''^''''^ ^P"'«»>t. 267. 
 — Work, 281 
 
 Drills. Radial. 273, 275 
 ^Types Of, 188 
 
 — Use of, 187 
 Drive. Rack-and-Pinion, 286 
 Driving Pulley, Single. 212 
 Drop Hammer, 103 
 
 — Hammer Dies, 107 
 
 — Table Moulder, 431 
 Drop Forging Operation. 114 
 
 — Section of, 110 
 
 — Stages of a, 112 
 
 — Utility of, 102 
 Drop Forgings, Pickling. 115 
 Duster, Taylor, 440 
 Dusters and Cutters, 439 
 
 Early Methods of Cutting Screws, 360 
 
 — Types of Planers, 284 
 Effective Cutting Areas on Planer and 
 
 Boring Mill. 250 
 Electric Blue-Printing Machine, 28 
 
 — Furnace, 75 
 
 — Resistance Welding, 122 
 Elements of Spring Needle Knitting 
 
 Machine, 502 
 Elevation of Fourdrinier Machine, 449 
 Engine Lathe, The, 204. 206 
 
 — versus Turret Lathe, 220 
 Equipment, Drafting Room, 26 
 
 — Foundry, 45 
 
 — Machine, for Tool Room, 159 
 
 — Plant, Design of, 14 
 Estimating, 17 
 
 Example oi Profiling Work, 323 
 Extrusion Process, 100 
 
 Facing, Mould, 54 
 
 Factory, Shoe, Arrangement of. 462 
 
 Fastenings, Sole, Types of, 463 
 
 Fay Automatic Lathe, 240, 241 
 
 Feed Motions. 290 
 
 Feeding, Continuous-Rotary, 328 
 
 Fellows Gear Shaper, 348, 349 
 
 Fibres and Processes. 481 
 
 Filing of Drawings, 25 
 
 Fillets, Pattern, 38 
 
 Finishing Machinery, 456, 503 
 
 — Room Machinery, 478 
 First Screw Cutting Lathe, 202 
 Fixtures and Jigs, 160 
 Flame Welding, Gas, 130 
 Flat Turret Lathe, Hartness. 229 
 Fly Frame, 485, 486 
 Forge, The, Description of, 81 
 Forging Machine, 96 
 
 — Methods, 80 
 
 — Press, 1100-Ton Hydraulic. 96 
 
 — Rolls, 96 
 
 — Tools. Hand. 83. 85 
 Forging, Drop, Section of, 110 
 
 — Stages of a, 112 
 
 — Utility of, 102 
 Forging, Hand, 80 
 
 — Operations of, 86 
 Forgings, Cold Trimming of, 115 
 
 — Drop, Pickling of, 115 
 Formed-Tooth Principle of Gear^Cut* 
 
 ting, 338 
 Forming Tools, Single-Edged, 179 
 Foot Press, 4ir 
 Foundry Buildings and Equipment, 45 
 
 — Cores for Moulding in, 55 
 
 — Loam used in, 54 
 
 — Melting, Pouring and Cle.' ning in, 
 65 
 
 — Metals, 41 
 
 — Moulding Materials used in, 52 
 
 — Moulding Sands used in, 53 
 
 — Mould-Making in, 58, 60 
 
 — Transportation in, 49 
 Fourdrinier Machine, Plan of, 450 
 
 — Paper Machine, 449 
 Frame, Drawing. 485 
 
 — Ply, 485, 486 
 FuU Universal Radial Drill, 277 
 Function of Pattern Shop, 30 
 Functions of Drafting Department, 13 
 
 — Drafting Room, 17 
 
 — Tool Room, 156 
 Furnace, Air, 70 
 
 — Air, Section of, 70 
 
 — Crucible, for Melting Brass, 73 
 
 — Crucible Gas Fired Heating, 146 
 
 — Electric. 75 
 
 — Gas. 71 
 
 — Oil, 71 
 
 — Oil, Tilting Type. 73 
 
 — Open Hearth. 71 
 
 — View of Open Hearth, 72 
 
 Gang Milling Cutters, Heavy, 186 
 
 —Mills. 185 
 
 —Saw, 423 
 Gardner Horizontal Disc and Ring 
 
 Grinder, 385 
 Oas Flame Welding. 130 
 
 — Welding, Uses of, 130 
 
 — Weldings. Advantages of, 133 
 Gated Patterns, 34 
 Gauge, Contour, 169 
 
 — Lathe, 432 
 Gauges, Types of, 165, 167 
 Gauging, 164 
 Gear Box, Change-, 210 
 
 — Planer, 349 
 
 — Teeth, Cutting, 335 
 Gear-Cutting, Formed-Tooth Principle 
 of. 338 
 
508 
 
 INDEX 
 
 — Generating Principle of, 343 
 — Template Principle of, 341 
 Gears, Bevel, 337 
 
 — Bevel, Cutting of, 354 
 — Helical, 337 
 — Helical, Cutting of, 353 
 — Spur, 336 
 — Worm, 337 
 Gear-Staaper, Fellows. 348. 349 
 — Head, Section of, ^51 
 — Slide, 128 
 Generating Principle of Gear- Cutting, 
 
 343 
 Gisholt Lathe, 226, 227 
 Grading of Grinding Wheels, 381 
 Gray Iron Foundry, Plan and Section 
 
 of 41, 47 
 Gridley Automatic Lathe, 236, 237 
 Grinder, Bryant Chucking, 394 
 — ^Horizontal, Disc and Ring, 385 
 — Surface, 388 
 — Tool, 395 
 — Wood-Pulp, 445 
 Grinding, Advantages of, 377 
 — Machine, Heald, 394 
 — Machines, 391 
 — Machines, Types of, 386 
 — Process, Development of, 377 
 — Wheel, Correct Mounting for, 384 
 — Wheel Stand, 385 
 Grinding Wheels, 380 
 — Grading of, 381 
 — Mounting of, 383 
 — Selection of, 382 
 Gun Lathe, Large, 216 
 
 Hammer, Board Drop, 105 
 
 — Drop, 103 
 
 — Power, 91, 93 
 
 — Steam, Work of, 88 
 
 — Upright Helve, 93 
 Hand p'^h Automatic Turret Lathes, 
 221 
 
 — Milling Machine, 312 
 
 — Operated Rock Over Molding Ma- 
 chine, 62 
 
 — Operated Turret Lathes, 223 
 
 — Planer, 425 
 Hand Forging, 80 
 
 — Operations, 86 
 
 — Tools, 83, 85 
 Hardening, 140 
 
 , — by Quenching, 147 
 Hartness Flat-Tarret Lathe, 230 
 Head, Surfacer, Section of. 425 
 Headers and Upsetters, 94 
 Head-Stock, 207 
 
 — Cross Section of, 208 
 
 Heald Internal Grinding Machine, 394 
 Heat Temperature Curve, 142 
 
 — Treatment Processes, 139 
 Heating of Carbon Steels, 144 
 
 — Steel, 114 
 Heavy Duty Drill Presses, 270, 271 
 
 — Gang Milling Cutters, 186 
 Helical Gears, 337 
 
 — Cutting of, 353 
 Henry Maudslay and Modern Tools, 200 
 High-Speed Steels, 172 
 History of Shoe Machinery, 459 
 Hobbing Machine, 351 
 
 — Automatic, 352 
 Holders, Tool, Multiple, 178 
 HoUow Chisel Mortiser, 435 
 Horizontal Boring Machine, 258, 261, 
 264 
 
 — Disc and Ring Grinder, 385 
 Hydraulic Forging Press, 96 
 
 — Press, 94 
 
 Indexing Heads for Milling Machines, 
 326 
 
 — Threading Tool, 373 
 Interchangeable Production System, 6 
 Interna) Grinding Machine, 394 
 Iron, Chilled. 42 
 
 — Gray, 41 
 
 — Malleable, 43 
 
 — Pig, Storage of, 49 
 Issuance of Blue Prints, 25 
 
 Jacqaard Machine, 500 
 Jigs and Fixtures, 160 
 — Drilling, 279 
 
 Key-Seating Machine, 307 
 Knitting Machines, 501 
 Knuckle- Joint Press, 411 
 
 Ladles, Description of, 75 
 
 La Grange-Hoho Process, 127 
 
 Large Double Frame Steam Hammer, 
 
 90 
 Lathe, Blanchard, 244, 432-433 
 
 — Bullard Mult-au-matic Vertical, 
 256, 257 
 
 — Car Wheel, 216 
 
 — Chuck, 213 
 
 — Cleveland Automatic, 236 
 
 — Development of the, 200 
 
 — Engine, 204, 206 
 
 — Fay Automatic, 240, 241 
 
 — Flat Turret, 229 
 
 — Gauge, 432 
 
 — Gisholt, 226, 227 
 
 — Gridley Automatic, 236, 287 
 
 INDEX 
 
 509 
 
 — Gun, Large, 216 
 
 — Lo-Swing, 241, 243 
 
 — Operations, 215 
 
 — Speed, 203 
 
 — Standard Engine, 206 
 
 — ^Turret versus Engine, 220 
 
 — versus Vertical Boring Mill, 247 
 
 — Vertical Turret, 248 
 
 — Warner and Swasey, 228 
 Lathe-Planer, The, 174 
 Lathes, Automatic, Principle of, 232 
 
 — Mounting the work on, 212 
 
 — Multi-Spindle Automatic, 222, 
 238, 239 
 
 — Special, 215 
 
 — Thread-Cutting on, 371 
 
 — Turret and Automatic. 219 
 
 — ^Turret, Hand Operated, 223 
 "Lay and Pick" Motion of Plain 
 
 Loom, 498 
 Lincoln Miller, Development of, 316 
 
 — Type of Milling Machine. 312 
 Linen and Silk Preparation, 493 
 Lists, Drawing, 15 
 Loam, 54 
 Location of Drafting Room. 27 
 
 — Pattern Shop. 30 
 Lock Stitch Mechanism, 470 
 Log-Mill, 421-422 
 Loom, Mechanism of, 496 
 
 — Plain, "Lay and Pick" Motion. 
 498 
 
 — Plain, Longitudinal Section of, 
 498 
 Lo-Swing Lathe, 241, 243 
 Lubricants, Cutting, 198 
 
 McKay Chain Stitch Mechanism, 477 
 
 — Sewing Machine, 473 
 Machine, Automatic Hobbing, 352 
 
 Bolt-Heading, Upsetting, and Forg- 
 ing, 95 
 
 — Bolt-Threading. 365, 367 
 
 — Boring, Horizontal, 258. 261 
 
 — Boring, Wilkinson's. 245 
 
 — Broachinig. 400. 401 
 
 — Cotton-Carding, 483 
 
 — Die-Sinking, 320 
 
 — Equipment, Tool Room, 159 
 
 — Fourdrinier, Paper, 449 
 
 — Hobbing. 351 
 
 — Jacquard, 500 
 
 — Key-Seating. 307 
 
 — Milling, Planer Type of. 329 
 
 — Moulding. 62 
 
 — Operations of Shoe Manufacture, 
 461 
 
 — Pipe-Threading, 369, 370 
 
 — Profiling, 320. 322 
 
 — Spinning, 485 
 
 — Thread-Milling, 375 
 
 — Thread-Rolling, 375 
 
 — Vertical-Slotting, 306 
 Machine, Milling, Automatic, 315 
 
 — Briggs Type of, 314, 315 
 
 —Hand, 312 
 
 — Origin and Development, 309 
 
 — Planer Type of, 331 
 
 — Universal, 324, 325 
 
 — Vertical, 320 
 
 — Work of, 308 
 Machine Moulding, 60 
 Machinery, Boot and Shoe, 459 
 
 — Bottoming Room. 474 
 
 — Cotton-Spinning. 481 
 
 — Cutting-Room. 464 
 
 — Finishing. 456. 508 
 
 — Finishing-Room. 478 
 
 — of Stock Fitting Room, 472 
 
 — Paper, 438 
 
 — Pattern-Shop, 40 
 
 — Rag, 438 
 
 — Stitching-Room, 468 
 
 — Textile, 481 
 
 — Weaving, 494 
 
 — Wood-Pulp, 444 
 
 — Wool-Spinning, 489 
 
 — Worsted- Spinning. 490 
 Machines, Automatic Screw, 234 
 
 — Boring, Horizontal, 264 
 
 — Boring, Portable Type, 263 
 
 — Grinding, 391 
 
 — Grinding, Type of. 386 
 
 — Knitting, 501 
 
 — Miscellaneous, 434 
 
 — Paper, 448 
 
 — Woodworking, Types of, 416 
 Making. Mould, 58 
 Malleable Iron, 43 
 Manufacturing Method, 3 
 
 — Tools, Used in, 5 
 Marking of Patterns. 38 
 Matcher, Six-Head Planer or, 429 
 Material, Pattern, 36 
 
 — Used in Cutting Tools. 171 
 Materials, Moulding, Foundry, 52 
 Maudslay, Henry, 200 
 
 — Screw-Cutting Lathe, First, 202 
 Mechanism, Chain Stitch, 469 
 — Lock Stitch, 470 
 — of the Loom, 496 
 Melting, Cupola Method of, 65 
 
 — Pouring and Cleaning in Foundry, 
 65 
 Metal Pouring, 76 
 Metals, Foundry, 41 
 
\ 
 
 510 
 
 INDEX 
 
 INDEX 
 
 511 
 
 Method of Melting, Cupola, 65 
 
 — The Building, 2 
 
 — The Manufacturing, 3 
 Methods, Forging, 80 
 
 — of Cutting Screws, 360 
 
 — Production, Combination, 11 
 Mill, Log, 421-422 
 MiUer, Vertical, 319, 320 
 Milling of Long Spirals, 327 
 
 — Operation Speeds and Feeds, 187 
 
 — Process. Advantages of, 308 
 
 — Screw Threads, 374 
 
 — Teeth of Spur Gear, 327 
 
 — Thread, Machine, 375 
 
 — Wood, Machine, 435 
 Milling Cutters, 180 
 
 — Collection of, 310 
 
 — Types of, 185 
 Milling Machine, Automatic, 315 
 
 — Automatic Bevel Gear, 365 
 
 — Briggs Type of, 314, 315 
 
 — Hand, 312 
 
 — Lincoln Type of, 312 
 
 — Origin and Development, 309 
 
 — Plain, Column-and-Knee Type, 318 
 
 — Planer Type of, 329, 331 
 
 — Universal, 324, 325 
 
 •^Vertical, 320 
 
 — Work of the, 308 
 Milling Machines, Indexing Heads for. 
 
 326 
 Mills, Boring, Classiflcation of, 246 
 
 — Boring, Vertical, 251, 253 
 
 — Gang, 185 
 Miscellaneous Machines, 434 
 Modem Planer, The, 284 
 Modem Development of Lincoln Miller. 
 316 
 
 — Tool Room a, 155 
 Mortiser, Hollow Chisel, 435 
 Motions, Feed, 290 
 Mould, Making a, 58 
 Moulder, Drop Table, 431 
 Monlders and Shapers, 424 
 
 — Time of, 30 
 
 — Tools of, 57 
 Moulding, Machine, 60 
 
 — Sands, 53 
 Moulding Machine and Sectional View, 
 62 
 
 — Hand-Operated Rock Over, 62 
 Moulds, Facing used for, 54 
 Monnting of Grinding Wheels, 383 
 
 — for Grinding Wheel, 384 
 
 — Work on Lathes, 212 
 Mule, Spinning, 488 
 Mult-an-matic Vertical Lathe, — ^Bul- 
 lard. 257 
 
 Multiple Box Tool, 225 
 — Tool-Holders, 178 
 Multiple-Spindle Drill, 277, 278 
 Mnlti-Spindle Automatic Lathes, 222, 
 
 238, 239 
 Mnshet, or Self-Hardening Steel, 172 
 
 Naumkeag Buffing Machine. 479 
 
 Noble Comb, 491 
 
 Norton Grinding Wheel Stand. 385 
 
 Oil Furnace, Filling Type of, 73 
 
 — or Gas Furnace, 71 
 Open-Hearth Furnace, 71 
 Open-Side Planer. 293 
 Operation of Shaper, 299 
 Operations, Hand-Forging, 86 
 
 — in Shoe Manufacturing, Machine, 
 461 
 
 — Lathe, 215 
 Origin and Deyelopment of Milling 
 
 Machine, 309 
 
 Fainting of Patterns, 38 
 Paper Mact>ine. Cylinder, 455 
 
 — Machine, Fourdrinier, 449 
 
 — Machinery, 438 
 
 — Machines, 448 
 Pattern Allowances, 37 
 
 — Core Prints, 38 
 
 — Fillets for, 38 
 
 — Makers, Time of, 30 
 
 — Material, 3(J 
 
 — Records, 40 
 
 — Storage. 39 
 Pattems, Gated, 34 
 
 — Intricate, Weaving of, 499 
 
 — Marking and Painting of, 38 
 
 — Splitting and Warping of. 38 
 
 — Types of, 32, 35 
 Pattern Shop, Function and Location 
 of, 30 
 
 — Machinery. 40 
 Personnel of Drafting Department, 18 
 Picker, Breaker, 482 
 Pickling Drop Forgings, 115 
 
 — of Castings, 79 
 Pig Iron, Storage of, 49 
 PlUar Press, 411 
 Pipe-Bending, 100 
 
 — Threading Machine, 369, 370 
 Plain Loom, Lay and Pick Motion, 498 
 
 — Longitudinal Section, 498 
 Plan of Fourdrinier Machine. 450 
 Planer, Armor Plate. 295 
 
 — Automatic Bevel Gear, 356 
 
 — Crank. 289 
 
 — Gear, 349 
 
 — ^Hand. 425 
 —Open Side, 293 
 — Rotary, 332 
 — Screw-Driven, 296 
 —standard Type of, 285, 2«7 
 — The Modern, 284 
 —Thirty-Foot, 295 
 —Type of Milling Machine 329 
 —versus Vertical Boring Mill, 249 
 Planers, 331, 424 
 
 — Early Types of, 284 
 —Special Types of, 292 
 Plant Equipment, Design of, l* 
 Plate Planer, Armor, 295 
 Policies of Drafting Room. 19 
 Polishing and Buffing, 397 
 Portable Boring Machines, 263 
 Post, Tool, 214 
 Pouring, Metal, 76 
 Power Consumption of Saws, 424 
 
 — Hammers, 91, 93 
 Practice, Drafting Room, 23 
 Preparation of Silk and Linen, 493 
 Press, Belt-Driven, Open-Back, 411 
 —Drill, Upright, 267, 268 
 — Foot, 411 
 — Hydraulic, 94 
 — Knuckle-joint, 411 
 — Pillar. 411 
 
 — Trimming, 106 „„« oti 
 
 Presses, Drill, Heavy-Duty, 270 271 
 Pressure Welding by H«imniering 119 
 Principle of Automatic Lathes, 232 
 
 -Template, of Gear-Cutting. 341 
 Process, Brazing, 136 
 — Broaching, 398 
 — Drafting, 99 
 —Extrusion, 100 
 —Grinding, Development of, 377 
 —La Grange-Hoho, of Welding. 127 
 —Milling, Advantages of, 308 
 —Rolling, 97 
 Processes, Heat Treatment, 139 
 
 — Types of, 409 
 Product, Design of. 14 
 Production Methods, Combination. 11 
 
 —System. Interchangeable, 6 
 Profiling Machine, 320, 322 
 — Work, Example of, 323 
 Pulley, Single Driving, 212 
 Pulling-Over Machine, 47 d 
 Punches and Dies, 405 
 — Use of, 195 
 
 Quenching, Hardening by. 147 
 
 Rack-and-Pinion Drive 286 
 Radial Drill. Full Universal. 277 
 
 —Drills, 273, 275 
 Bag Cutter, 440 
 
 — Machinery, 438 
 Eeamers, Types of, 192 
 
 — Use of, 191 
 Records of Work Done, 16 
 
 — Pattern, 40 
 Beflners and Beaters, 447 
 Belation of Tool Room to Shop. 155 
 Resistance Welding, Electric, 122 
 Best, Slide, 210 , ^„^ 
 
 Boiling Machine, Thread, 375 
 
 — Process, 97 
 
 — Threads, 376 
 BoUs, Forging, 96 
 Botary Feeding, Continuous, a^o 
 — Planer, 332 
 
 Safety, 414 , ^^o 
 
 Samples of Broaching Work, 402 
 
 Sand Blast, 79 
 Sands, Moulding, 53 
 Saw, Band, 418, 419 
 
 — Circular, 418 
 
 — Gang, 423 
 
 — Swing Frame, 421-422 
 Saw Bench, Universal, 419-420 
 
 Saws, 417 
 
 — Power Consumption of, 4i!4 
 
 — Use of, 197 , „ J 
 
 Scale, Temperature, for Tool-Harden- 
 
 ing, 152 
 Screw Machines. Automatic, 234 
 Screw-Driven Planer, 296 
 Screw Threads, Cutting of. 364 
 — Milling. 374 
 — Standard, 362 
 — Standardization of, 361 
 — ^Types of, 361 
 Screws, Methods of Cutting, 360 
 Section of Cupola, 67 
 — Drop Forging, 110 
 — Gear-Shaper Head, 351 
 — Plain Loom, 498 
 
 Radial Drill Column, 275 
 
 — Shaper, 300 
 — Surfacer Head, 425 
 Sections of Standard Screw Threads, 
 
 362 
 Section of Grinding Wheels, 382 
 Self-Hardening Steel, 148, 172 
 Sensitive Drill. The, 266, 267 
 Sewing Machine, McKay, 473 
 Shaper, Construction and Operation of, 
 
 299 
 —Gear, Fellows, 348, 349 
 
 (or Slotter), Vertical, 305 
 
 — Section of, 300 
 
 fl 
 
 
512 
 
 INDEX 
 
 INDEX 
 
 513 
 
 — Standard, 298 
 — Traversing, 302, 303 
 Shapers, 424 
 Shears, Use of, 197 
 Shoe Factory, Arrangement of, 462 
 Shoe Machinery, 459 
 
 — History of, 459 
 Shoe Manufacture, Machine Operations 
 
 of, 461 
 Shoes, Types of, 462 
 Silk and Linen Preparation, 493 
 Single Driving Pulley, 212 
 Single-Edged Forming Tools, 179 
 Single-Frame Steam Hammer, 90 
 Six-Head Planer or Matcher, 429 
 Slasher, 496 
 Slide, Gear-Shaper, 128 
 
 — Rest, 210 
 Slotter, Vertical, or Shaper, 305 
 Slotting Machine, Vertical, 306 
 Soldering and Brazing, 135 
 Sole Fastenings, Types of, 463 
 
 — ^Rounding Machine, 473 
 Special Lathes, 215 
 
 — Types of Planers, 292 
 Speed, High, Steels of, 172 
 
 — Lathe, The, 203 
 Speeds, 207 
 
 — and Feeds, Milling Operation, 187 
 Spindle and Tail Stock, 209 
 Spinning Machine, 485 
 Spinning Machinery, for Cotton, 481 
 — for Wool, 489 
 — for Worsted, 490 
 Spinning Mule, 488 
 Spirals, Milling of Long, 327 
 Splitting and Warping of Patterns. 38 
 Spring Needle Knitting Machine. 502 
 Spur Gears, 336 
 Stages of a Drop Forging, 112 
 Stand, Grinding Wheel, 385 
 Standard Engine Lathe, 206 
 
 — Screw Threads, Section of, 362 
 — Shaper, 298 
 
 — Type of Planer, 285, 287 
 — Types of Milling Cutters, 181 
 — Upright Drill Press, 267, 268 
 Standardization of Screw Threads, 361 
 Standards, 15 
 Steam Hammer, 90 
 
 — Work, 88 
 Steel, Carbon, 171 
 — Cast, 43 
 — Heating, 114 
 
 — Mushet, or Self -Hardening, 172 
 — Properties, Variability of, 137 
 — Taylor-White, 149 
 Ste«l8» Carbon. Heating of, 144 
 
 — High-Speed, 172 
 
 — Self-Hardening, 148 
 Stitch, Chain, Mechanism of, 477 
 
 — Lock, Mechanism, 470 
 Stitching-Room Machinery, 468 *• 
 StocV Fitting Room Machinery 472 
 
 — Head, 207 
 
 — Head, Cross Section of, 208 
 
 — Spindle and Tail, 209 
 Storage, Pattern, 39 
 
 — Pig-iron, 49 
 Store-Boom, Tool, 158 
 Super Calender, 456 
 Surface Grinders, 388 
 Surfacer Head, Section of, 425 
 Surfacers, 424 
 Swing-Frame Saw, 421-422 
 System, Production, Interchangeable, 6 
 Systems of Tooth Forms, 334 
 
 Table, Drop, Moulder, 431 
 
 — Drive and Tools for Boring Mill 
 255 
 Tail Stock, 209 
 Tap, Collapsing, 368 
 Taps, Use of, 191, 193 
 Taylor Duster, 440 
 Taylor-White Steel, 149 
 Teeth, Gear, Cutting, 335 
 
 — Milling, for Spur Gear, 327 
 Tempering, 151 
 
 Template Principle of Gear-Cutting 
 341 * 
 
 Textile Machinery, 481 
 Thermit Welding, 133 
 Thread-Cutting on Lathes, 371 
 Threading, Bolt, Machine, 365. 367 
 — Dies, 195 
 
 — Pipe, Machine, 369, 370 
 — Tool, Indexing, 373 
 Thread-Milling Machine, 375 
 Thread-Boiling Machine, 375 
 Threads, Rolling, 376 
 Threads, Screw, Cutting of. 364 
 — Milling of, 374 
 — Standard, 362 
 — Standardization of, 361 
 — ^Types of, 361 
 Time and Power in Electric Resistance 
 
 Welding, 123 
 Time of Moulders, 30 
 
 — Pattern-Makers, 30 
 Tool, Indexing Threading, 373 
 — Multiple Box, 225 
 — Post, 214 
 Tool-Grinders, 395 
 Tool-Holders, Multiple, 178 
 
 Tool Boom, a Modern Development, 
 155 
 
 — Functions of, 156 
 
 — Its Relation to the Shop, 155 
 
 — Machine Equipment for, 159 
 Tools, Available, 24 
 
 —Boring-Mill, 255 
 
 — Broaching, 401 
 
 — Forming, Single-Edged, 179 
 
 — Hand Forging, 83, 85 
 
 — Lathe and Planer, 175 
 
 — Milling Cutters, 180 
 
 — Small, Moulders', 57 
 
 — Used in Building, 4 
 
 — Used in Manufacturing, 5 
 Tool Store Boom, The, 158 
 Tooth Forms, Two Systems of, 334 
 Transportation, Foundry, 49 
 Traversing Shaper, The, 302, 303 
 Trimming, Cold, of Forgings, 115 
 
 — Press, 106 
 Tumbling of Castings, 78 
 Turret and Automatic Lathes, 219 
 Turret Lathe versus Engine Lathe, 220 
 
 — Vertical, 248 
 Turret Lathes, Hand and Automatic, 
 221 
 
 — ^Hand-Operated. 223 
 Turret Principle, The, 219 
 Type of Planer. Standard, 285, 287 
 Type of Building for Special Work, 4 
 
 — Used in Manufacturing Work, 7 
 Types of Drills, 188 
 
 — Gauges, 165, 167 
 
 — Grinding Machines, 386 
 
 — ^Inserted Tooth Milling Cutters, 
 185 
 
 — Lathe and Planer Tools, 175 
 
 — Milling Cutters, 181 
 
 — Patterns, 32, 35 
 
 — Planers, Early, 284 
 
 — Planers, Special, 292 
 
 — Processes, 409 
 
 — Reamers, 192 
 
 — Screw Threads, 361 
 
 — Shoes, 462 
 
 — Sole Fastenings, 463 
 
 — Welds, 121 
 
 — Woodworking Machines, 416 
 
 Universal Milling Machine, 324, 325 
 Use of Tools in Building, 4 
 Upright Helve Hammer, 93 
 Upsetters, Headers and, 94 
 Variability of Steel Properties, 137 
 Vertical Boring Mills, 251, 253 
 
 — Miller, 319, 320 
 
 — Milling Machine, 320 
 
 — Shaper (or Slotter), 305 
 
 — Slotting Machine, 306 
 
 — Turret Lathe, 248 
 
 Vertical Boring Mill, Construction of, 
 251 
 
 — versus Lathe. 247 
 
 — versus Planer, 249 
 View of Open Hearth Furnace, 72 
 
 Warner and Swasey Lathe, 227 
 Warping and Splitting of Patterns, 88 
 Washer, 443 
 
 Washers and Digestors, 441 
 Weaving of Intricate Patterns, 499 
 
 — Machinery, 494 
 Welding, 87 
 
 — Butt, Machine, 124 
 
 — Classes of, 118 
 
 — Electric Resistance, 122 
 
 — Gas Flame, 130 
 
 — ^Lf Grange-Hoho Process, 127 
 
 — Pressure, 119 
 
 — Thermit, 133 
 Welds, Types of, 121 
 Wheels, Grinding, 380 
 
 — Grading of, 381 
 
 — Mounting of, 383, 384 
 
 — ^Selection of, 382 
 Whitworth Quick-Return-Motion 
 
 (Shaper), 303 
 Wilkinson's Boring Machine, 245 
 Wood-Milling Machine, 435 
 Wood-Pulp Grinder, 445 
 
 — Machinery, 444 
 Woodworking Machines, Types of, 416 
 Wool-Spinning Machinery, 489 
 Work Done on Drill Press, 281 
 
 — of the Milling Machine, 308 
 Worm Gears, 337 
 Worsted-Spinning Machinery, 490 
 
Date Due 
 
 -m-^ 
 
 iDGl3 
 
 l96f^ 
 
 Wt^ 
 
 BBSHI 
 
 i^uv 1/ 1924 
 
 U ^s^ 0^37:. 
 
 UUL 1 5 1994 
 
 COLUMBIA UNIVERSITY LIBRARIES 
 
 0041394747 
 
END OF 
 TITLE