i^^^ 
 
^ 1 
 
 LIBRARY OF CONGRESS. 
 
 Sh.elf-..dn-- 
 
 UNITED STATES OF AMERICA. 
 
FIRST LESSONS 
 
 IN 
 
 METAL-W(3RKING 
 
 BY 
 
 ALFRED G. COMPTON, 
 
 PROFESSOR OF AP LIED MATHEMATICS IN THE COLLEGE OP THE CITY OP NEW YORK, 
 
 INSTRUCTOR IN CHARGE OF THE WORKSHOPS OF THE COLLEGE, AUTHOR 
 
 OP " A MANUAL OF LOGARITHMIC COMPUTATION," AND 
 
 OF "FIRST LESSONS IN WOOD-WORKING.''' 
 
 NEW YORK: 
 
 JOHN WILEY & SONS, 
 
 53 East Tenth Steeet. 
 
 1890. 
 
 ^^^ 
 
.g7 
 
 Copyright, 1890, 
 
 BY 
 
 JOHN WILEY & SONS. 
 
 Robert Drummont, 
 
 Electrotyper, 
 
 Ui and 440 Pearl St. 
 
 New York. 
 
 
 
 
 P'ERRis Bros., 
 
 Printers, 
 
 326 Pearl Street, 
 
 New York. 
 
PREFACE. 
 
 The first year of iustriictioii in handicraft, as 
 exj^erience in the College of the City of New 
 York has shown, may be given to wood working 
 or metal-working with about equal advantage. 
 The minute accuracy, the acquaintance with 
 geometrical construction, and the habits of neat- 
 ness and cleanliness which are essential in the 
 one are offset by the judgment, forethought, and 
 artistic freedom of the other. Both constantly 
 teach the lesson of orderly procedure, careful at- 
 tention to instructions, and, where a text-book is 
 used, of minute and thoughtful I'eading, such as 
 takes in the full significance of every pi'oposition 
 and every limitation of it. The feeling of good- 
 fellowship which results from struggling with the 
 same difficulties, and occasionally, as in wood- 
 working, and still mo]*e frequently, as in forge- 
 work, lending a helping hand to each other, is 
 a valuable part of the product of workshop 
 training in either department. It has been the 
 
 111 
 
iv PREFACE. 
 
 author's practice therefore, for some time, to let a * 
 portion of each class begin in the wood-working 
 shop, and another in the forge and vise-room. The 
 advantao;e is thus secured of having both shops 
 well filled ; while otherwise, as the second year's 
 class is always smaller than the first, one shop is 
 overcrowded at the same time that the other is 
 perhaps not more than half full. 
 
 The amount of knowledge of drawing required 
 for these lessons is about the same as that given 
 in the author's First Lessons in Wood- Working ; 
 so that if Metal- Working is taken up first, the stu- 
 dent should be taught as much of the latter book 
 as is found in Lessons VI, VII, and XXI. 
 
 Considerable thought and space have been 
 given to the description and orderly development 
 of the processes of manufacture of iron and steel, 
 and of the annealing, hardening and tempering 
 of the latter. The book being intended, not for 
 those who are merely acquiring a trade, but for 
 those who are learning to think, and to give clear 
 expression to their thought, the lessons on this 
 subject are intended to be thoroughly mastered, 
 both by study and by practice, so that the student 
 shall be able to explain, in good language, the rea- . 
 sons of the various processes he uses. 
 
TABLE OF CONTENTS. 
 
 PAGE 
 
 Preface 
 
 Lesson I. Metal-working Tools, Wrought-iron and Cast-iron, 
 
 Cutting and Breaking 1 
 
 II, Care of Fire, Drawing and Pointing 7 
 
 III. Bending, Turning an Eye. . = 13 
 
 IV. Flattening, Punching, and Bending 18 
 
 V. Pointing and Twisting 22 
 
 VI. Welding 28 
 
 VII. Upsetting and Welding 34 
 
 VIII. Blacksmith and Helper 45 
 
 IX. Welding continued : A Tongue-weld 51 
 
 X. Testing Iron, Manufacture of Cast-iron 58 
 
 XI. Foundry- work 64 
 
 XII. Manufacture and Properties of Wrought iron 71 
 
 XIII. " " " " Steel 75 
 
 XIV. Welding Steel : Low Grade 81 
 
 XV. " " High Grade 85 
 
 XVI. Hardening and Tempering Steel 88 
 
 XVII. " " " " 98 
 
 XVIII. " " " '' 105 
 
 XIX. Chipping 114 
 
 XX. Drilling and Sawing 126 
 
 XXI. Filing 132 
 
 XXII. Soldering — Bunsen Burner 148 
 
 XXIII. " The Soldering-iron 157 
 
 XXIV. " Blow-pipe 165 
 
 Alphabetical Index 169 
 
FiEST Lessojsts 
 
 IN 
 
 METAL-WORKING 
 
 LESSON I. 
 
 METAL-WORKING TOOLS. WROUGHT-IRON AND CAST- 
 IRON. CUTTING AND BREAKING. 
 
 The tools used in cutting iron, like those used 
 in wood- working, are wedges. They are thrust 
 in or driven in between the j)articles of the metal, 
 separating them from each other, making notches 
 in the piece, and, if they penetrate far enough, 
 tearing off chips or cutting the piece in two. 
 Metal being much harder than wood, it is gener- 
 ally necessaiy to drive the cutting-tool forward 
 by blows of a hammer, as is the case in wood- 
 working also when the cut is deep or across the 
 grain of the wood. When the metal and the 
 tool can be held in powerful machines, such as 
 the engine-lathe and the planing-machine, which 
 you will understand by and by, a steady push can 
 
2 FIRST LE880N8 IN METAL- WORKING. 
 
 be used, but without these, blows of a hammer 
 are generally necessary. 
 
 Again, metal being much harder than wood, a 
 different form has to be given to the cutting-tool. 
 For wood-working the wedge may be thin, and 
 therefore can be made to penetrate easily. The 
 two faces of a knife, hatchet, or chisel make 
 with each other an angle of about 25°, which is 
 increased to 35° near the edge, by the sharpening 
 of the tool on the oil-stone. Even this is some- 
 times fonnd to be too small, and the tool splinters 
 or "nicks" when cutting hard w^ood. For iron, 
 therefore, the angle must be larger than this. It 
 need not be much larger if the tool is not very 
 brittle and if it is used only for cutting straight 
 forward ; but when the metal of the tool is very 
 hard, or when the tool is strained crosswise in 
 cutting, the angle must be larger, and is, in some 
 lathe-tools, as great as 90°. 
 
 Again, metals b^ing very hard, metal-tools are 
 much heated if driven fast. It is a familiar fact 
 that rubbing, compressing, or tearing asunder 
 any material produces keat. Wood is heated by 
 repeated blows of a hammer. In boring holes, 
 the w^ood and the bit become hot. When the 
 material worked is so hard as iron, if tools are 
 pressed against it hard enough to cut it and then 
 are moved rapidly, a great deal of heat is pro- 
 duced. In this case the heat may be enough to 
 
METAL-WORKING TOOLS. 3 
 
 soften and spoil tlie tool, and it is necessary 
 therefore to work more slowly. 
 
 In metal- working there is no operation like that 
 of splitting or hewing: chipping, which comes 
 nearest to it, is considerably slower. In all metal- 
 workingj therefore, the pieces are fashioned nearly 
 to the desired shape while they are soft, and the 
 work which the cntting-tool has to perform is 
 thus lessened. There are two ways in which the 
 metal is thns prepared — casting and forging. 
 
 Casting is melting the metal and pouring it 
 into moulds of the proper shape. In this case 
 heat performs the greater part of the work. It 
 separates the particles of the metal from each 
 other so that they can flow into every corner of 
 the mould, and the workman has then only to 
 finish the surface of the casting with suitable tools. 
 
 Forging is hammering the metal while it is 
 soft. All metals melt when heated. The tem- 
 perature for melting ranges from about 450° F. 
 for tin to about 4500° F. for platinum. Before 
 reaching the melting-point, the metal becomes 
 soft, and, while in this state, if two perfectly 
 clean surfaces are brought into close contact, they 
 adhere and the two pieces become one. This 
 process is welding. While in the soft state also, 
 a metal can be hammered into almost any desired 
 shape. This process is forging. The two pro- 
 cesses of forging and welding are generally in- 
 
4 FIRST LE880N8 IN METAL-WORKING. 
 
 eluded under the term "forge-work" or ^^ forging." 
 They are applicable, as casting is, to various 
 metals ; but all three are important chiefly in 
 the case of iron and steel, because of the ease 
 with which the operations can be performed, 
 and the abundance, cheapness, and strength of 
 the metals. 
 
 The iron used for casting, or foundry-work, 
 and that used for forge- work, are called respect- 
 ively cast-iron and wrought-iron. Cast-iron is 
 iron combined with carbon ; wrought-iron is the 
 same metal after as much as possible of the car- 
 bon is removed. We will begin our exercises in 
 forge-work by studying some of the differences 
 between them. 
 
 Examine the two specimens of iron on your 
 anvil. Holding each loosely between the fingers, 
 strike it on the edge of the anvil. Observe the 
 ringing of the one and the duller sound of the 
 other. Strike them on the edge with the edge of 
 vour hammer, and observe the difference in the 
 character of the nick. Lay them on the anvil, 
 and hammer them pretty vigorously at one end. 
 One flattens, the other does not ; one is malleable, 
 the other is not. When you have learned to use 
 the fire, repeat this lasfc experiment while the 
 pieces are red-hot, and you will find the difference 
 greater still. Lay them across two supports, 
 about 3" apart on the anvil, as in Fig„ 1, and 
 
METAL-WORKINO TOOLS. 
 
 strike tliem with the liammer (being careful not 
 to stoop over them, lest they iiy up and hurt you). 
 
 Fig. 1. 
 
 One bends, the other very probably breaks.* 
 Next try to break the bent one: you find this 
 difficult. At one end of the anvil is a chisel, 
 called the "hardee" or " hardy," mean- Exercise i. 
 ing ^' hard edge," being made of steel. Cutting with 
 and hardened on the edge. Lay the *^® i^a^dee. 
 unbroken piece over this, and strike it two or 
 three times with the hammer, making a nick in 
 it. Be very careful not to strike the hardy with 
 the hammer. Turn the piece over, and nick the 
 other side, exactly opposite the first notch. When 
 you have cut it thus, you wdll find that you can 
 break it by laying it over the two supports, and 
 
 * The same experiment may be made with less risk of injury from 
 the flying fragments when the piece breaks, by holding each piece 
 in the vise while striking the blow. Let it project three or four 
 inches above the vise. Strike from you, towards the wall behind 
 your bench, so that, if the piece flies olf, it will hit no one. Or, still 
 more safely, the pieces may be bent by holding them at the ends in 
 a suitable clamp, and pressing them down at the middle by a screw. 
 
6 FIRST LESSONS IN METAL- WORKING. 
 
 strikinof it at the nick, or even, if it is notched 
 pretty deeply, by laying it over tlie edge of tlie 
 anvil, and striking it just beyond the notch, or 
 holding it in the vise, just below the notch, and 
 striking at the end. The tough piece is wrought- 
 iron ; the brittle piece is cast-iron. Make a writ- 
 ten memorandum of all the differences between 
 them that you can discover, including the differ- 
 ence between the surfaces of fracture examined 
 with a lens. 
 
CARE OF FIRE. DRAWING AND POINTING. 
 
 LESSON 11. 
 
 CARE OF FIRE. DRAWING AND POINTING. 
 
 When an object is made of wrouglit-iron, it 
 must be made as nearly as possible of the I'ight 
 shape at first, by forging, so that it may require 
 little or no finishing with cutting tools. Forging, 
 or shaping with the hammer, includes a number of 
 distinct operations, called drawing, pointing, up- 
 setting, bending, twisting, punching, and welding. 
 In nearly all of these the first step is to make the 
 metal red or white hot, and in doing this the 
 proper management of the fire is of the highest 
 importance. 
 
 Your forge has a broad "hearth," on which 
 coal can be heaped up over the mouth of a 
 pipe called the "tuyere" (pronounced twee-er). 
 Through this tuyere a current of air can be forced 
 from the bellows or blower. With a moderate 
 supply of air the fire burns slowly, and produces 
 a temperature of about 800° or 900° C, equivalent 
 to about 1500° co 1700° F. Every atom of oxy- 
 gen that unites with an atom of cai'bon in the coal 
 pi'oduces a cei'tain amount of lieat ; hence the 
 more carbon and oxygen used, the more heat pro- 
 duced. With a good supply of air you can raise 
 
8 FIRST LESSONS IN METAL-WORKINO. 
 
 your fire, and any piece of iron in it, to about 
 1500° C. or 2700° F. It is possible, however, to 
 f urnisli nlore air than tbe carbon requires for its 
 combustion. The air then only cools the carbon, 
 or tends to blow out the fire. A lighted stick 
 thrust into a bottle goes out for lack of oxygen. 
 A lighted match goes out in a strong draught 
 because of excess of air. Remember this in man- 
 aging your fire. 
 
 To start your fire, place a small heap of shav- 
 
 Exercise 2. ^^S^ ^^^^ ^^^ throat of the forge. 
 Making a Light it, and when it is blazing, scrape 
 ^®* a few pieces of coke or coal over it, 
 
 choosing such as is free from large lumps. As 
 these light, scrape on more, blowing gently with 
 the bellows. Gradually cover completely, and 
 blow hardei-. Sprinkle with water the coal round 
 the outside of the fire, which will prevent the fire 
 from spreading too far, and will also make coke 
 for the next day. When once started, the fire 
 can be kept covered and burning slowly for a long 
 time, by leaving a stick of hard wood in it, or can 
 be blown up in a few minutes to a white heat. 
 
 For your first exercise in forging, cut off a piece 
 of ^" round iron, exactly 20'' long. If you fail to 
 
 Exercise 3. ^^^ ^^ exactly right, make a memoran- 
 Heating to a dum of the length in your note-book, 
 w 1 e ea . ^^ ^^^|j| ^^^ make a square point 
 
 two inches long on the end of this. Put the end 
 
CARE OF FIRE. DRAWING AND POINTING. 9 
 
 in the fire, covering it liglitly with the coals. It 
 is best, particularly in working such thin iron as 
 this, not to bury it very deeply in the fire, but to 
 keep it near the surface, where it can be watched 
 through the spaces between the coals, and re- 
 moved as soon as it reaches the proper heat. If 
 left too long in a very hot fire, and with a plenti- 
 ful supply of air from the bellows, the iron may 
 burn and the piece be spoiled; for iron is combus- 
 tible, just as wood and coal are, only it requires 
 a higher temperature to burn it. With larger 
 pieces, such as you will have in later exercises, 
 this accident is less likely to happen. Watching 
 your iron, you w^ill see the black rod get gradually 
 red and then white, so as to be indistinguishable 
 in the midst of the glowing fuel. In this condi- 
 tion it will burn if left too long. Remove it from 
 the fire by the cool end, which will be cool enough 
 if you have not thrust it in too far, or left it too 
 long. It should be white-hot just at the end, and 
 red about two inches farther. As you carry it 
 through the air, brilliant white sparks will shoot 
 off from it, if it is at a good white heat : these 
 are particles of iron burning. Lay it, without loss 
 of time, on the anvil, so that the hot end rests on 
 the farther edge, the end in your Exercise 4. 
 hand being raised three or four inches, Drawing and 
 so that the bar is inclined to the face p°^"*^^&- 
 of the anvil. Hold the hammer with its face 
 
10 FIRST LESSONS IN METAL-WORKINO. 
 
 similarly inclined. Grasp it firmly, with the 
 fingers under the handle and the thumb ex- 
 tending along the top. Then, with quick 
 light strokes, not near the end, but at the 
 very tip, beat the iron out, turning it to and fro 
 through a quarter turn after each blow or two, so 
 as not to flatten it, but to make the end square 
 and pointed. When a little of the end is 
 pointed, you may gradually w^ork farther back, 
 till you have produced a square point two inches 
 long. Be careful not to continue hammering, 
 particularly at the point, after the iron has 
 lost its bright white heat. If you do this you 
 will probably split it. Wrought-iron, as we 
 shall see later, is fibrous in structure, and the 
 fibres, like those of wood, can be toru asunder 
 more easily than they can be broken across. This 
 splitting is especially liable to happen in inferior 
 iron, just as it does in wood that is wanting in 
 toughness, and affords one means of judging of 
 the quality of the iron. If your rod does split at 
 the end, you can generally get the parts to re- 
 unite, by raising it again to a white heat, and 
 hammering gently. This operation is assisted by 
 sprinkling the piece with white sand when you 
 take it from the fire, and putting it back in the 
 fire a few minutes before hammering it. If you 
 do not succeed in closing the split, you must cut 
 off the cracked end on your hardy and begin 
 
CARE OF FIRE. DRAWING AND POINTING. 11 
 
 again, being more careful now to keep the metal 
 at a bright red heat when hammering near the 
 end, reheating it for this purpose several times if 
 necessary. 
 
 In turning the piece to and fro while hammer- 
 ing, you must be careful to give it just a quarter 
 of a turn each time ; otherwise you will give it the 
 
 Fig. 2. 
 
 cross-section a, Fig. 2, instead of h. In this case 
 you will have considerable trouble to restore the 
 proper shape by holding it on the anvil as at <?, 
 and striking it at d. 
 
 When you have pointed the piece and cooled 
 it, measure its length, and compare it with the 
 length it had at first. The lengthening of a piece 
 by hammering is called drawing. Observe how 
 much you have drawn this, making allowance for 
 any that you may have cut off because of splitting. 
 It is important that you should learn to estimate 
 the amount of drawing in any particular case in 
 order to be able to make allowance for it in future 
 work. Of course this lengthening cannot be ac- 
 complished without reducing the diameter, either, 
 as in this case, at the point, or at some other place, 
 
12 FIRST LESSON'S IW METAL-WORKING. 
 
 or along its whole length. This last is what takes 
 place in making " bar-iron." A short thick mass 
 of iron is passed, while white-hot, between strong 
 rollers such as are shown in Fio^. 52. As the iron 
 passes through the successive grooves, it is reduced 
 in thickness and increased in length, and comes 
 out at last as bar-iron, of the same size and shape 
 as the last groove. 
 
BENDING. TURNING AN EYE. 
 
 13 
 
 LESSON III. 
 
 BENDING. TURNING AN EYE. 
 
 Having drawn and pointed the rod, form an eye 
 on it, as in Fig. 3. The eye, being 1'' in diameter, 
 will be nearly ^^" in circumference. 
 
 1 
 
 I 
 I 
 
 Fig. 3. 
 
 Heat about 3 J'' of the end of the rod to a bright 
 red heat. Lay it over the edge of the anvil, with 
 one of the flat faces of the point tui'ned U23, and 
 bend it down at right-angles with a few gentle 
 blows of the hammer. 
 
 Strike at a and h, Fig. 4, alternately, striking 
 
 Fig. 4. 
 
 from you as well as downward, so as to give a 
 kind of pushing blow, till you have a good square 
 bend. Do not hit with the edge of the hammer, 
 nor hard enough to bruise the iron. . 
 
14. FIRST LE8S0NS IN METAL-WORKINO- 
 
 Next place the part h on the '' horn," or round 
 end of the anvil, as in Fig. 5, and bend it round 
 as at c and r/, nearly closing the ring. Then, 
 laying the part ho on the edge of the anvil, the 
 
 Fm. 5. 
 
 point d being upward, and striking lightly at d, 
 close it. Be careful to make the ring as nearly 
 Exercise 5. as possible circulaiv . pei#otly closcd, 
 Bending. .^^^ Symmetrical on the stem, as at /, 
 
 Fig, 6, not one-sided, as at g. The last part of 
 the eye, near the point of closing, must be bent 
 with the tail or " pene" of the hammer. If you 
 do not succeed the first time, heat the eye again, 
 spread it out by driving it on the horn of the 
 anvil, and repeat. 
 
 If the eye closes too far dowm on the stem, as at 
 
BENDING. TURNING AN EYE. 
 
 15 
 
 a^ Fig. 7, open it on the horn, and then bend it to 
 the proper shape with light blows of the tail of 
 the hammer at h^ while resting on the horn at c. 
 If it closes too far up, as at d, strike at /, while 
 resting on the horn at e. If the iron gets too 
 much burned, you must cut it off on the hardy 
 
 Fig. 6. 
 
 Fig. 7. 
 
 and begin again ; but this ought not to occur, as 
 it spoils the proportions of the piece. 
 
 Use the eye already formed, if it is a good one, cut- 
 ting off the square point on the hardy. Exercise 6. 
 If it is not good, cut off another piece of a forge- 
 bar-iron of the proper length, and form a P° 
 new eye. Flatten the rod for about 4'' from the 
 end, to a width of about %", which will give a thick- 
 ness of about ^". In flattening, or in any operation 
 in wdiicli much hammering is to be done on one piece, 
 do not move the hammer about on the anvil, l^ut 
 let it fall constantly on the same point, about the 
 middle of the face of the anvil, and move the iron 
 
16 FIRST LESSONS IN MET AL- WORKING. 
 
 instead of tlie hammer. This principle is even more 
 important when two persons work on the same 
 piece, as in some later exercises. Hold the rod so 
 that the plane of the flattened portion shall be 
 perpendicular to the plane of the eye. In this, 
 as in Exercise 4, page 10, begin hammering at the 
 tip, and with a good bright w^hite heat, so as not 
 to split the rod. Having flattened it to the 
 proper amount, hammer it cold, to smooth it. 
 Heat it again, lay it over the edge of the anvil and 
 bend it at right angles at a, Fig. 8, as in Exercise 
 
 Fig. 8. 
 
 5, Fig. 4. Lay it across the horn and bend the 
 curved part ha. Again lay it on the edge of the 
 anvil as at c?. Fig. 9, and form the straight end as 
 at d. The plane of the bend should be the same 
 as the plane of the eye. Look along the rod and 
 test this. See also whether the rod is straight, 
 and whether the plane of the shoi't flattened piece 
 at the end is perpendicular to the plane of the 
 bend and the eye. Correct any crookedness by 
 
BENDING. TURNING AN EYE. 
 
 17 
 
 gentle blows while the iron is cooling. If the 
 plane of the flattened portion is not perpendicular 
 to the plane of the ring and of the curve ah^ heat 
 the straight part near ab to redness, place it on 
 
 Fig. 9. 
 
 the anvil so that the eye is perpendicular to the 
 face of the anvil, and strike a light blow or two at 
 h. Or hold the ring in the vise, and, taking hold 
 with the tongs at Z>, twist the I'od to the proper 
 position. 
 
18 FIB8T LESSONS IN METAL-WOEKING. 
 
 LESSON IV. 
 
 FLATTElS^INa, PUNCHIl^G, AIN^D BENDIIS^G. 
 
 While iron is soft it is easy to maka holes in it 
 of any desired shape, with a steel punch. 
 
 We will make an '^ angle-iron " or " bracket," 
 Fig. 10, from a piece off round iron 8'' long. 
 
 This is to be first ham- 
 
 @ ® I mered out flat to a width 
 
 ^" of h"\ secondly, bent at 
 
 ^ ' right angles ; and, third- 
 
 ly, punched with four 
 holes for screws. Take 
 a piece of ii'on 16 long. 
 For the first operation, 
 heat one end of the 
 piece to whiteness, and, 
 beginning as in Exercise 
 ^i«- 10- 4, page 10, at the end, 
 
 and with the same care to prevent splitting, hammer 
 it down to the thickness of about \". Then, work- 
 ing from the end towards the middle, flatten about 
 ^" of the piece, w^orking always on the centre of 
 
FLATTENING, PUNCHING, AND BENDING. 19 
 
 the anvil, as iu Ex. 6. Be careful not to hammer 
 more on one edge than on the other. If you do 
 you will bend the piece. If, for instance, you 
 hammer too much on the I'ight-hand edge, you 
 will make this edge not only thinner, but longer 
 than the othe]', and will thus make the piece bend 
 towards the left. If you find this happening, you 
 can correct it by hammering a little more all along 
 the left-hand edge, or w^herever you find it thicker 
 than elsewhere. Turn the piece over occasionally, 
 and hammer on the other side to prevent the end 
 from turning up. Heat about four inches more 
 of the bar, and flatten in the same Avay the rest 
 of the 8" that will be required. Do not extend 
 the flattening more than about a quarter of an 
 inch be3^ond the required distance. The remain- 
 der of the metal was only left as a handle to hold 
 the piece by, and when you have finished, is to be 
 cut off and left undefaced for future use. 
 
 The piece is now of the unifoi'm w^idth of ^" 
 straight and uniformly thick, and is ready for 
 bending and punching. Before bending, bevel 
 the edges slightly on the side where the heads of 
 the screws will be, by hammering, cold, on the 
 anvil. Mark with a centre-punch. Fig. 11, b, the 
 place at which the bend is to be made. Heat the 
 piece to a red heat at this place, lay it on the an- 
 vil with the mark exactly over the edge, and, 
 while an assistant holds a hammer on the piece 
 
20 FIBST LESSONS IN METAL- WOBKINO. 
 
 just beMnd the mark, bend it at right angles. 
 Or, hold it in the vise at the mark and bend it. 
 
 For punching, use a slightly tapering punch, 
 
 Fig. 11, A, about jY' in diameter at the point, 
 
 and not more than J'^ at one inch from the 
 
 end. Havino; marked with a centre- 
 
 Exercise 7. punch the places where the holes 
 
 Punching. ^ ^ . i , t 
 
 are to be made, lay the piece, heated 
 to a bright red, on the anvil, and drive the punch 
 half-way through. The piece, when turned over. 
 
 a 
 
 a 
 
 Fig. 11. 
 
 will show a dark spot due to the cooling effect of 
 the punch. Apply the punch here and drive it 
 through from the other side, pushing out the 
 small piece or burr by driving it into one of the 
 holes in the anvil. Be careful not to drive your 
 punch in too far, or you will spread the hole too 
 wide, and may split the piece. Drive it so far as 
 to enlarge the hole enough for the admission of 
 the screws that are to be used in putting up the 
 bracket. If these are " round-headed " screws, 
 Fig. 12, A, this is all that it is necessary, except to 
 smooth and straighten the piece where it may 
 have been bent. If they are '^Hat-headed," Fig. 
 12, B, the holes must be "counter sunk," that is, 
 
FLATTBNINO, PUNCHINO, AND BENDING. 
 
 21 
 
 enlarged at the top, as in Fig. 18, to correspond 
 with the head of the screw, and let it come even 
 or ^' flush" with the sui'face of the „ . o 
 
 Exercise 8. 
 
 iron. Wlien only a shallow counter- Countersink- 
 
 sink is required, it may be made with ^^^' 
 
 a countersink-punch. Fig. 14, a; but to cut deep 
 
 
 Fig. 12. 
 
 Fig. 13. 
 
 <f=^ 
 
 enough to let the head of a screw come even with 
 the surface of the iron, a countersink-bit, Fio;. 14 
 B, must be used, as in wood- working. 
 
 When you have made and countersunk the 
 holes, iinish the piece as straight and smooth as 
 you can, cold. Finally, cut it oif 
 at the proper point, and bevel the 
 newly cut edge like the others. 
 When finished, the bracket should 
 be true to the proposed dimensions, 
 exactly light-angled and free from 
 ^^ winding," smooth and- without 
 marks of burning, square at the 
 ends and equally bevelled all 
 round, and the centres of the 
 holes should be in a line exactly parallel to the 
 edges. 
 
 A B 
 
 Fig. 14. 
 
22 
 
 FIRST LESSON'S IN METAL- WOBKINO. 
 
 LESSON V. 
 
 BENDING, POINTING, AND TWISTING. 
 
 Eemembeeing how much the iron was di*awn in 
 Exercise 4, provide a piece of \'' round iron of the 
 proper length for the exercise shown in Fig. 15. 
 
 (FuUSize) 
 
 Fig. 15. 
 
 Keep a memorandum of the length j)rovided, and 
 test the correctness of your estimate by compari- 
 son w^ith your finished w^ork at the end of the 
 exercise. 
 
 The iron in this exercise being short, will have 
 to be held with the tongs. Point both ends of 
 
BENDING, POINTING, AND TWISTING. 
 
 23 
 
 Exercise 9. 
 A staple. 
 
 the piece, as in Exercise 4, with the precautions 
 
 there indicated. Make the flat sur- 
 
 fac( > at the two ends to match. Heat 
 
 the piece at the middle and bend it Use of the 
 
 over the horn of the anviL Attend 
 
 to the following points : 
 
 1. Hold the tongs so that the opening between 
 the jaws shall be horizontal. One of the jaws 
 will then be over the piece you are holding, which 
 will then not be so easily knocked out of the 
 tongs as if the opening were vertical. 
 - 2. Let the bend be in the plane of two of the 
 squared faces. 
 
 3. Make the bend as nearly as possible in the 
 middle. 
 
 In making the bend you will probably bring 
 the points too near together; in fact they may 
 almost meet. To separate them, drive the staple 
 
 Fig. 16. 
 
 down onthehardee, so that the latter shall spread 
 out the legs. If they are not quite ecjual, make 
 them so by striking gently on the curve while 
 holding the staple upright with the point of the 
 long leg resting on the anvil. Straighten the 
 
24 FIRST LESSONS IN METAL-WORKING 
 
 legs by thrusting tlie thin end of the anvil be- 
 tween them as in Fig. 16, and hammering lightly 
 first one and then the other. Lay the staple on 
 the anvil and see that the legs lie in the same 
 plane, both touching the face of the anvil in their 
 whole length. If they do not, hold one end in 
 the tongs and strike the other near the top or 
 circular end till you correct the winding or twist ; 
 or you may hold one end in the vise and bend the 
 other to the proper position with the tongs, or, 
 when cold, with the fingers. Examine the curve 
 carefully for any lack of symmetry, and correct it 
 by gentle blows over the horn of the anvil. 
 Finish it smooth when cold. Do not neglect to 
 compare your finished work with your estimate, 
 so as to learn how much to allow for such objects 
 in the future. 
 
 Each ring in this exercise being 1\'' in diame- 
 ter, the circumference will be 3^ times 
 Exercise 10. ^^n ^ or about 4'', and both together 
 about 8''. A portion of the iron, about 
 \", at the middle, belongs to both rings. Deduct- 
 ing this, and about \'^ to fat each end for draw- 
 ing, leaves about 6^' as the length of the piece 
 of \'' iron needed for the Job. Holding the 
 piece with the tongs, point each end, as in Ex- 
 ercise 4, but round instead of square. It will be 
 a useful exercise, and will assist you in rounding 
 the iron symmetrically, to make it first square, 
 
BENDING, POINTING, AND TWISTING. 
 
 2b 
 
 tlien octagonal, and then round. Do not make 
 
 the points too long. If the taper 
 
 extends beyond a, Fig. 17, it will 
 
 weaken the hook. Be careful not 
 
 to burn the points. Finish them 
 
 smooth, cold. Then, heating one 
 
 end to redness, lay it on the horn 
 
 at the middle of one half, or 
 
 a little nearer to the middle 
 
 of the piece, as at 6>, Fig. 18, 
 
 and turn it as in Exercise 5. Having formed one 
 
 eye, heat the other end and form the other in the 
 
 Fig. 17. 
 
 Fig. 18. 
 
 same way. The points of the hook should be 
 bent down almost to the stem, as at c, Fig. 17, 
 leaving an opening of about ^'\ 
 Both eyes should be exactly circu- 
 lar and equal, the hook appearing 
 as in Fig. 17, not as in Fig. 19, 
 where ah is too nearly straight, and 
 the eyes are too pointed at c. 
 
 You have now disco veered that 
 forge- work requires more judg- 
 ment by the eye than wood- work. 
 It is not possible to mark out your work with 
 rule and square. You must estimate without the 
 
 Fig. 19. 
 
26 FIRST LESSONS IN METAL- WORKING. 
 
 help of these tools, and must make allowance for 
 changes of size which the pieces undergo in draw- 
 ing, and in other operations to be described here- 
 after. 
 
 Estimate the quantity of iron needed for the 
 hook, Fig. 20, making allowance for the length 
 4>:ained in drawing, and cut off a suitable piece. 
 Then proceed as follows : First draw 
 Exercise 11. ^^^ round the point as in the last ex- 
 ercise. Next bend at right-angles at 
 a, as in Exercises 5 and 6. Then turn the curve h 
 over the horn of the anvil, and form the flat curve c. 
 
 -5 ■ 
 
 ^ 
 
 Thickness }A' 
 
 Fig. 20. 
 
 Lastly, form the eye as in 5 and 6, being care- 
 ful to have it in the same plane as the hook, and 
 circular, and symmetrical on the stem. In all 
 these exercises care must be taken to keep the 
 iron hot enough to w^ork easily, but without burn- 
 ing it. A bright white heat is needed for draw- 
 ing and pointing, and a good red heat for the rest 
 of the Avork. In all the operations also, care is to 
 be taken not to mar the cylindrical form of the 
 
BENDING, POINTING, AND TWISTING. 
 
 27 
 
 iron by hammering too hard ; and in all of them, 
 any parts that have been roughened by the heat 
 should be hammered cold to smooth them, but 
 not so hard as to injure the iron. Examine your 
 work critically, looking along it to test for wind- 
 ing, and not accepting it as finished so long as 
 there is any particular in which you can improve 
 it. Finally, compare its dimensions carefully 
 with those of the working-sketch, so as to learn 
 whether your allowance of metal was correctly 
 made. 
 
 The following is a variation of the last exercise, 
 involving squaring and twisting. The dimensions 
 are given in centimeters. The thickness of the 
 iron may be the same as in the last ex- Exercise 12. 
 ercise. After pointing the rod, form a twisted 
 the hook and the eye as in the last ^°°^' 
 exercise. Then square the part ah^ Fig. 21, with 
 
 < 
 
 ^l-Si'ii.-- 
 
 I 
 
 Fig. 21. 
 
 the same precautions as in Ex. 4. Finish the 
 square part cold, with good sharp edges. Then 
 heat to redness, and cool both ends in water, 
 leaving about ^^" in the middle bright red (not 
 
^8 Fimt LESSONS IN METAL-WOMKINQ. 
 
 white, which would soften the iron too much). 
 Holding it upright in the vise by the lower end, 
 take hold of the other end with the tongs, and 
 twist it round rather slowly, through exactly two 
 turns, leaving the plane of the eye coincident 
 with that of the hook. Be careful not to bend 
 the stem in twisting it, as it will be hard to 
 straighten it without defacing it. 
 
WELDING. 29 
 
 LESSON VI. 
 
 WELDING. 
 
 WELDmo is joiniDg two pieces of metal which 
 have been made soft or pasty by heat. Wrought 
 iron, if of good quality, comes to this condition at 
 the temperature of about 1500° C, or about 2700° 
 F. This temperature is called the" welding heat," 
 and may be recognized by the dazzling white 
 light that the iron gives off, and the vivid sparks 
 that fly from it as it is carried through the air to 
 the anvil. If the 'iron is not of good quality it 
 may be made brittle by heat. Such iron is 
 called "hot-short" iron. No such iron must be 
 used. Indeed, it is hardly possible to use it, but 
 valuable time may be wasted in trying to do so. 
 Iron which breaks under the hammer when cold 
 is called "cold-short." 
 
 The sparks given off by iron at the weldiug 
 heat show that it is burning, and therefore wast- 
 ing away. This high temperature therefore must 
 not be used, except when it is absolutely necessary, 
 as in welding ; all other operations of the forge are 
 performed at a "white heat," a "bright red or 
 cherry red," a " low red," or even a " black red," 
 which is only visible in a dark place. 
 
30 FIRST LESSONS IN METAL- WORKING. 
 
 When two pieces of wrouglit-iron are to be 
 welded together, they must both be brought to 
 the welding heat ; and they ought to reach that 
 heat at the same time, otherwise one may be 
 burned before the other is ready. They, should 
 therefore be heated in the same part of the fire, 
 and should be watched, and if necessary moved 
 about, to let each receive its proper amount of heat. 
 When at the welding heat, they must be put to- 
 gether as quickly as possible in the proper posi- 
 tion, and made to adhere by a few light blows of 
 the hammer, after which harder blows are given 
 till the union is complete. 
 
 To hold the two pieces in the 23roper position 
 and manao^e the hammer at the same time is often 
 difficult, and, even if the pieces are not very large, 
 generally requires the hands of two men, unless 
 
 
 
 
 
 
 
 
 ^ --'- 1 ' 
 
 
 
 
 
 
 
 II 
 
 
 
 
 
 
 
 «/* ■ — ■ - 
 
 
 
 — > 
 
 
 1 1 
 
 1 1 
 1 
 
 if 
 
 
 
 
 
 
 Fig. 22. 
 
 some device be used for fastening the two pieces 
 toscether. We will therefore beo^in our exercises 
 in welding with such as consist in joining the 
 
WELDING. 31 
 
 ends of the same piece, and so do not requii-e an 
 assistant. The forging of an old-fashioned eye 
 for a gate-hinge, Fig. 22, is such an exercise. To 
 make the piece of the dimensions indicated in the 
 figure, cut off a piece of f " round iron b" long. 
 This is to be first flattened and shaped Exercise 13 
 as shown in Fig. 23. The drawing of Flattening 
 the ends must be done at a red heat. If ^^^ drawing, 
 a white heat is used it w^ll be harder to make the 
 weld afterwards. Turn the ]3iece over frequently 
 
 -93<- - 
 
 Fig. 23. 
 
 while working it, to keep it straight. Do not 
 make it too thin at the ends. When flattened, it 
 should have in the middle the shape and size shown 
 in the section, nearly, being flattened Exercise 14 
 less than it will be in the finished job. An eye for a 
 for fear of weakening it too much, and ^^"5®- 
 increasing the risk of burning. Reheat the piece 
 as often as may be necessary, but take care not 
 to burn it. If you are pretty skilful, one or two 
 heats will be enough to bring it to the proper 
 shape. Hammer the edges square, keeping the 
 
32 FIRST LES80N8 IN METAL-WORKINO. 
 
 corners sharp and smooth : good edges are as es- 
 sential to fine workmanship in metal as in wood. 
 
 Next, heating the piece to a dull red at the mid- 
 dle, hold it at one end with the tongs, and bend it 
 round the horn of the anvil till the two parts are 
 parallel and equal, as in forming the staple. Exer- 
 cise 9. Put a piece of f ^^ round iron in the bend, 
 and hammer the two parts close together, as at a, 
 Fig. 22, laying the piece on the anvil with the eye 
 overhanging the edge, and striking lightly with 
 the tail or "pene" of the hammer. The two parts 
 must be in as close contact with each other as pos- 
 sible, otherwise dirt will get in between them, and 
 may spoil the weld. 
 
 The piece is now ready for welding. Raise it 
 to the welding heat. It is very essential for this 
 operation that you should have a good bright 
 fire, made of fresh coals, free from the burnt-out 
 cinders on the hearth. These will not burn well 
 enough to secure a good welding heat, and besides 
 will make the surface dirty. The throat of the 
 forge also must be cleared of the solid cinder 
 which forms there, and the fire must be deep 
 enough to contain a good body of coals under the 
 iron as well as over it. When the piece is at a 
 dazzling white heat and throws off brilliant sparks 
 in the air, place it, with the least possible loss of 
 time, on the anvil, and hammer it quickly with 
 moderate force and beginning at the point, till it 
 
WELDING. 33 
 
 is welded to within about \^' of the eye. Heat 
 the eye to a dull red, drive iu a round tapering 
 punch \" in diameter where thickest, and hammer 
 harder, at a dull-red heat, to flatten the metal 
 here and smooth the eye inside and outside. If 
 you have not a proper punch, make one, from a 
 piece of \" round iron by drawing and pointing it 
 slightly, as in Exercises 4 and 9. If the eye is too 
 pointed at the base, close it by hammering on the 
 edi2:e of the anvil with the tail of the hammer 
 while the punch remains in place. The eye should 
 be perfectly round and smooth. Finish the shank 
 straight, square, and smooth, and draw the tip 
 down to a sharp point. Compare your finished 
 work with the figure, observing how much you 
 have departed from the proposed dimensions. If 
 your piece has turned out too short, it is because 
 you have burned it, or not drawn it out enough, 
 or both. Ascertain the cause of your error, and 
 work closer the next time. 
 
34 FIRST LESSONS IN METAL- WOBKING. 
 
 LESSON YII. 
 
 UPSETTES^a AND WELDING. 
 
 The next exercise, the forging of a link of a 
 chain, is similar to the last, in that the two surfaces 
 of the weld belong to the saroe piece, and thus 
 again the need of a helper is avoided. The weld, 
 however, is much shorter, and so the surfaces of 
 contact are smaller. Besides, as the link of a chain 
 is subject to great stress, it is even more important 
 in this case than in the last, that the union of the 
 two parts should be perfect. This therefore will 
 be a more difficult task than the last. ' 
 
 Use the piece of i'' iron, 8'' long, left from Ex- 
 ercise 7. The joint is of the form called a scarf- 
 joint, and is shown in Figs. 25 and 28. The sur- 
 faces may be prepared either before or after bend- 
 ing the piece, but it is somewhat easier to make 
 them fit together well if prepared afterwards. 
 It will be necessary, however, to provide against 
 the waste which will occur at the joint by thick- 
 ening or " upsetting" the piece at the ends. This 
 
 is an operation which has often to be 
 Exercise 15. performed as preliminary to others. 
 
 It may be done either before or after 
 the bending. To perform it before bending, heat 
 
UPSETTING AND WELDING. 35 
 
 about one inch of the end of the bar to whiteness. 
 If much more than an inch is heated, cool it, by 
 immersing the bar, up to within about an inch of 
 the hot end, in water. Then "upset" the piece 
 eitlier by striking the hot end on the anvil while 
 holding it npright in the tongs, or by standing the 
 piece npright on the anvil, holding it with the 
 tongs w^ith the hot end up, and striking the latter 
 w^ith the hammer. In either case the blows must 
 not be too hard or the piece will bend. The same 
 will ha23pen also if too much of the length of the 
 piece is heated. If the piece does bend, it must 
 be straightened before going any farther. If the 
 hammerino^ turns the metal over too much on the 
 edge, lay the piece on the anvil and hammer it 
 gently on the sides, but only enough to smooth 
 the ragged edge, without reducing the end to its 
 original thickness. When properly upset the end 
 should appear as in Fig. 24. After upsetting one 
 
 
 Fig. 24. 
 
 end, cool it, and then heat and upset the other. 
 It is obvious that this operation, besides thicken- 
 ing the bar will shorten it. You ought to measure 
 and keep a memorandum of the amount of this 
 shortening, so as to know how much to allow for 
 
36 
 
 FIRST LESSON'S IN METAL- WORKING. 
 
 it in other cases, wlien it may be necessary that 
 the bar should have exactly a given length. In 
 the same way that a piece is upset at the end, it 
 may, when necessary, be upset at the middle, by 
 heating at the middle only, and hammering on the 
 end lengthwise. 
 
 The ends being now upset, bend the piece to a 
 U -shape. It is then ready for the formation of 
 the joint. 
 
 The scarf -joint consists, as the figure shows, of 
 an indentation in the end of each piece, into which 
 the end of the other piece fits. These indentations 
 are not made, as in wood-working, by cutting out 
 
 Fig. 35. 
 
 some of the material, but by hammering it so that 
 it spreads out sideways and endways. Neither 
 should they, as in the case of the joint in wood, 
 be cut to half the depth of the piece, but less. It 
 will thus result that when the two ends are put 
 together, the piece will be wider and thicker at 
 the joint than elsewhere. This extra thickness 
 will disappear as the weld is hammered, and if the 
 
UPSETTING AND WELDING. 
 
 37 
 
 quantity of metal Las been correctly estimated, 
 this part will be at last neither thicker nor thin- 
 ner than the rest. 
 
 To prepare the scarf, heat the open end of the 
 U-shaped piece to a white heat. Lay it on the 
 anvil and make a bevel at one end, with the face 
 of the hammer, as in Fig. 26. This will still fur- 
 
 FiG. 26. 
 
 ther upset the piece at the upper edge of the 
 bevel, as shown in the figure. Then, using the 
 pene of the hammer, as in Fig. 27, give the piece 
 the form shown, enlarged, at a. The surface need 
 not be smooth. It is indeed preferable that it 
 should be formed of small ridges or steps as shoAvn. 
 Heat the other end of the piece and treat it in the 
 same manner, but on the other side. One heat 
 Avill be sufficient for the preparation of both ends 
 if you work quickly, but there will be no harm 
 in heating several times, if you are careful not to 
 
38 
 
 FIRST LESSONS IN METAL-WOBKING. 
 
 burn the piece. The pieces Avill have Ijeen 
 widened in the process of scarfing^ and are to be 
 brought back partly to their original width, by 
 hammering: on the sides. There should be, how- 
 ever, some extra width left, to make up for the loss 
 by burning, of which there will be some in spite 
 of all the care that can be taken. When finished, 
 the scarf will present the appearance shown in 
 plan and elevation in Fig. 28. 
 
 ^ 
 
 Fig. 27. 
 
 Fig. 28. 
 
 When the scarf has been thus prepared, bend 
 the ends of the V round over the horn of the 
 anvil as in Fig. 29, till they meet and overlap, as 
 in Fig. 30, and hammer them, at a red heat, now 
 on the face of the anvil and now on the horn, till 
 they fit together closely. You are now ready for 
 the welding. 
 
 For this make sure, as in the last exercise, that 
 you ha\'e a hot fire of good coals, and get a thor- 
 
UP8ETTINQ AND WELDING. 
 
 39 
 
 ough good welding heat, without burning. There 
 is special danger of burning in exercises like this, 
 in which the piece is small, and has a thin edge. 
 
 Fig. 29. 
 
 As soon as it shows, by the vivid sparks which it 
 emits, and by its intense whiteness when viewed 
 through the chinks in the fire, that the proper 
 heat has been reached, place it as quickly as pos- 
 sible on t\\e anvil, and hammer the parts together 
 by quick light blows. AVhen they have adhered. 
 
 } — %: 
 
 Fig. 30. 
 
 the extra metal produced by the upsetting and 
 scarfing may be hammered down on the horn of 
 the anvil, and the link brought to its proper shape, 
 more at your leisure and at a lower heat, 
 
40 FIRST LESSONS IN METAL-WORKING. 
 
 In this exercise, and in general in all welding 
 operations, it is necessary that the surfaces of con- 
 tact should be quite clean, or if there is anything 
 on them, it should only be something fusible, 
 which will squeeze out under the blows of the 
 hammer. Coal-dust will generally burn off and 
 not give much trouble. Cinders, if your fire 
 should be so " dirty " as to allow any to settle on 
 the joint, which ought not to happen, can often 
 be shaken off by a sharp blow on the edge of the 
 anvil. The oxide of iron also, in the intense heat 
 of the welding fire, is generally driven off as fast as 
 it is formed. But Avhile the piece is exposed to the 
 air on the anvil, and on its way there, some oxide of 
 iron is formed which is not got rid of, but which 
 falls off under the blows of the hammer, and is 
 found on the anvil as black scales. If any of this 
 forms on the surfaces of contact, or if any cinder 
 is held between these surfaces during the weld- 
 ing, the iron will not adhere well, and the weld 
 will fail. This therefore is another reason Avhy 
 you should work quickly at this stage. 
 
 This oxide of iron, when its formation cannot 
 be prevented, is removed by the use of white sand 
 or borax as a ^^ flux," that is, a substance which 
 unites with the oxide and makes a sort of glass, 
 which is fusible and is squeezed out by the ham- 
 mer. With good wrought-iron the flux is not 
 generally necessary, provided a true welding heat 
 
UPSETTING AND WELDING. 41 
 
 is used and tlie work is done quickly. With 
 steel, as will be seen hereafter, it is indispensable. 
 When a flux is used with wrought-iron, it is to be 
 sprinkled on the joint, or the iron is to be plunged 
 in the flux, but only at the welding heat. At a 
 lower temperature the sand will not adhere and 
 melt, and will do no good. At the welding heat 
 it melts and spreads over the surface, partially 
 protecting it from the air, and allow^ing it to be 
 raised to a higher temperature without burning 
 so much. When it is put into the fire again, the 
 brilliant white s]3arks still appear, and as it is 
 carried to the anvil it will give forth a hissing 
 noise. When this happens you are pretty sure of 
 a good weld if you work quickly. 
 
 The form of the joint is important also, with 
 
 L^_SZ=A' 
 
 \ 
 
 T 
 
 Fig. 31. 
 
 reference to the escape of impurities. If the sur- 
 faces of the scarf are concave, as in Fig. 31, a, 
 
42 FIRST LESSONS IN METAL- WORKING. 
 
 the welding takes effect first at the two points of 
 contact shown, and some of the impurities may be 
 imprisoned, and prevent a good union of the pieces, 
 though in general they will escape sideways, par- 
 ticularly if the surfaces are small. If the surfaces 
 are convex, as at b, they touch at first only at 
 the middle, and there is sure to be plenty of op- 
 portunity for the impurities to escape, however 
 large the surfaces may be. The same result is 
 secured nearly as well if the surfaces at a are put 
 too-ether in the manner shown at c. 
 
 It is desirable that the weld should be accom- 
 plished at a single heat, because in reheating the 
 danger of burning is increased ; but you must not, 
 merely to avoid this risk, allow an imperfect weld 
 to pass. 
 
 Inspect your work critically when done. It 
 should show the following appearances : 
 
 1. The weld should be invisible. 
 
 2. The iron should not be burned away at the 
 thin edges of the scarf, leaving little notches ; yet 
 this is a less serious fault than if the scarf itself is 
 visible as a fine crack for the whole or a part of 
 its length. 
 
 3. The ring should not be any thicker at the 
 weld than elsewhere, nor any thinner, — which is 
 more likely to happen, and is a more serious fault. 
 
 4. The iron should be of circular cross-section 
 throughout, and without bruises, 
 
UPSETTmQ AND WELDING. 
 
 43 
 
 5. The link should be a perfect ellipse, and 
 with the 7-iiich piece of ii'on that yon have used, 
 should be of the exact size and shape of Fig. 32. 
 
 Fig. 32. (Full size.) 
 
 If the iron is too much reduced, or the weld 
 bad, cut out the imperfect part, and rej)eat. This 
 will, of course, make the link too small. After- 
 wards, take a new piece, and try again. 
 
 The scarfed surfaces in this exercise may be 
 prepared in another way, using the face of the 
 
 Fig. 
 
 hammer instead of the pene. Having upset and 
 bent the piece as before, lay it on the anvil as in 
 Fig. 33, only about half an inch of the ends rest- 
 
44 FIBST LESSONS IN METAL WORKING. 
 
 ing on the anvil. With a full red heat, strike a 
 blow or two on one end, holding the face of the 
 hammer parallel to that of the anvil. Draw the 
 piece toward you about -^-^" and strike again. 
 Kepeat this operation out to the end of the piece, 
 then turn it over and treat the other end the same 
 way. The edge of the anvil thus serves the same 
 purpose as the pene of the hammer in the pre- 
 vious method. In this ease also, as before, the 
 piece must be lightly hammered on the sides to 
 partially correct the spreading. 
 
BLACKSMITH. AND HELPER. 45 
 
 LESSON VIII. 
 
 BLACKSMITH AND HELPER. 
 
 You will now join two separate pieces by a 
 scarf-joiut. In this case, botli pieces, when pre- 
 pared and heated, will have to be held in tongs 
 to bring them together. If one workman attempts 
 to do this, he has to lay down one pair of tongs 
 and take np his hammer, and thus runs the risk 
 of having one piece fall out of its place, or both 
 pieces get chilled. The ojjeration is therefore 
 much more easily performed with the aid of a 
 "helper," who follows the lead of the other work- 
 man, called the '' blacksmith " or ''fireman," strik- 
 ing and stopping as the latter directs, and work- 
 ing the bellows while the other manages the fire. 
 A skilful workman can indeed perform this task 
 without a helper, particularly with the aid of cer- 
 tain devices to be described presently; but many 
 other operations, particularly on heavy pieces, are 
 impossible without a helper. 
 
 Cut two pieces of 1'' square iron, each b" long. 
 If you fail to do this exactly, make a memoran- 
 dum of the exact amount of your error, that you 
 may, when the work is finished, learn how much 
 has been used up in the weld, and therefoi'e be 
 
46 FIRST LE8S0N8 IN METAL- WORKING. 
 
 able to make the proper allowance for such a joint 
 in the future. 
 
 Place both pieces with one end in the fire, but 
 bring only one at a time to a white heat. Hav- 
 ing the services of a helper, we will 
 Exercise 16. ^|^-g ^-^^ prepare the scarf with the 
 
 Use of fuller. ^ -■- 
 
 tool called a " top-fuller." This is a 
 tool very much like the pene of your hammer, the 
 edge being set (as may also be the case with the 
 hammer) either parallel or perpendicular to the 
 handle. It is held in one hand by the blacksmith, 
 and struck with a heavy hammer, or " sledge," by 
 the helper, w^hile it rests on the part of the piece 
 which is to be indented. As an unskilful blow 
 may give a painful Jar to the hand of the holder, 
 the handle of this or any similar tool is sometimes 
 made of twisted wire, or even of a withe or rod 
 of hazel or other flexible wood. The rod is sev- 
 eral times wetted, heated, and twisted at the mid- 
 dle, to loosen the fibres of which it is composed. 
 It is then passed once or twice round the head of 
 the tool, twisted, and held in place by a small iron 
 ring, as in Fig. 34. With this flexible handle the 
 hand of the holder is safe from shocks. A similar 
 tool, with the edge turned upward and shaped like 
 the hardee, so as to be set in the anvil, is called a 
 "bottom-fuller." 
 
 To make the scarf-Joint with this tool, the fire- 
 man brings the end of the piece to a white heat, 
 
BLACKSMITH AND IlELPEK. 47 
 
 as before, and bevels and upsets it, as in Figs. 24 
 and 26. Then, taking the fuller in the right 
 
 Fig. 34. Fig. 35. 
 
 hand, he holds it on the bevelled surface, as in 
 Fig. 35, while the helper strikes it with the sledge. 
 It is easy to see that this tool can be guided with 
 more accuracy than the pene of the hammer. 
 With this the two pieces are brought to the form 
 shown in Fig. 31 B. They are then laid in the 
 fire, the scarfed surfaces downward, that no dirt 
 may fall on them as they are removed from the 
 fire, and as close together as they can be placed 
 without touching, in order that they may arrive at 
 the welding heat at the same time. They must not 
 touch, however, as they would adhere in the fire. 
 When they have been sprinkled with 
 
 •^ ■•■ . Exercise 17. 
 
 sand and brought to the full weldmg scarf-joint 
 heat, they are taken quickly from the ^^^'^ ^'^^ 
 fire, first one piece by the helper and 
 then the other by the blacksmith. The helper 
 
48 FIRST LE880N8 IN MEIAL- WORKING. 
 
 goes first, because his place is on the farther side 
 of the anvil, while the blacksmith stands between 
 the anvil and the fire. The helper strikes with 
 his piece a sharp blow on the edge of the anvil 
 farthest from him, to knock off any cinders that 
 may be on it, and then rests it on the near edge, as 
 in Fig. 36, the scarf surface up, but being very 
 
 Fig. 36. 
 
 careful not to let the thin edge of the iron touch 
 the anvil, which would chill it. The blacksmith 
 follows quickly with his piece, knocking off dirt 
 in the same way, and places it on the first piece, 
 as in Pig. 37. It is of the utmost importance that 
 
 Fig. 37. 
 
 the first piece be neld quite steady, and the second 
 placed on it in exactly the right position. If it 
 laps a little too much or not quite enough, the 
 scarf will turn out bad. The thin edges, which 
 
BLACKSMITH AND HELPER. 
 
 49 
 
 may have cooled a little in the air, are lieated again 
 by contact with the tliicker parts. A quick light 
 blow or two at h by the blacksmith, will make the 
 iron adhere. The blacksmith turns the piece over 
 and makes it adhere at a in the same way. It is 
 then laid flat on the anvil, as in Fig. 38, and welded, 
 
 Fig. 38. 
 
 with heavier blows, by blacksmith and helper 
 together, the former with his hammer, the latter 
 with a sledge. The blacksmith strikes wherever 
 he considers it best, and turns the piece when 
 necessary, and the helper follows him, striking at 
 the same point, and beginning and stopping when 
 the blow of the blacksmith's hammer on the piece 
 or on the anvil gives the signal. Test the weld 
 before finishing. Holding one end of the piece 
 with the tongs, strike it at the middle, while hot, 
 over the horn of the anvil, bending it, and then 
 again straightening it or bending it the opposite 
 way. The weld should not open under such treat- 
 ment. If the weld is satisfactory, the piece is fin- 
 ished smooth and square with the "flatter," Fig. 
 89, which is held on tlie bar by the blacksmith and 
 struck by the helper. With this tool, of course, 
 
50 
 
 FIRST LE880N8 IN METAL-WORKING. 
 
 a better finish is possible tlian with the hammer 
 Exercise 18. ^loue. The bar should be tested at 
 Use of the the weld with calipers and square, 
 flatter. ^^^ made perfectly straight. After 
 
 this it may be finished smooth and partially pol- 
 ished, by dipping the face of tlie flatter in water 
 
 Fig. 39. 
 
 and slightly wetting with it the face of the anvil 
 during the last part of the hammering. 
 The result of the work should be — 
 
 1°. A perfectly straight bar; 
 
 2°. Of uniform cross-section of 1" ] 
 
 3°. Perfectly square ; 
 
 4°. Without any twist ; 
 
 5°. With no visible or a scarcely visible weld ; 
 
 6°. Nowhere burnt; 
 
 7°. Quite smooth and polished; and, 
 
 8°. Exactly 11^' long. 
 
 If its length differs from that given, it is be- 
 
BLACKSMITH AND HELPER 51 
 
 cause you did not cut tlie pieces to the right 
 length, or because you have used up too much 
 material in welding. In either case note the 
 facts in your memoranda, and be forewarned for 
 the next task of the kind. 
 
52 FIRST LE8B0N8 IN METAL- WORKING. 
 
 LESSON IX. 
 
 WELDINa (continued). A TONGUE- WELD. 
 
 The scarf- weld just practised is an excellent 
 joint, and, for most purposes, as good as can be 
 desired. For many heavy pieces, such as shafts 
 of steamers, the tongue- joint, Fig. 40, is often 
 
 I 
 
 Fig. 40. 
 
 used, and even in smaller work, such as the re- 
 pairing of a broken wagon-axle, it is useful. 
 Moreover, it can be more easily managed without 
 the aid of a helper than the scarf -joint can. We 
 will exemplify it with pieces of the same size as 
 those used in the last exercise. Cut them, as be- 
 fore, to the exact length, or record the error. 
 
 Heat the pieces, and hammer one of them out 
 on the edge of the anvil, to the wedge-form. Fig. 
 41, A. The hammering will " spread " or widen 
 the piece on the edge, as shown in the plan b. 
 This widening is to be, for the present, only very 
 slightly reduced, by hammering on the sides. 
 
 Upset the other piece as in the last exercise, 
 
WELDING. A TONOVE-WELD. 
 
 53 
 
 o-iving it the appearance shown in Fig. 42, a. 
 This piece is now to be split and opened, as 
 
 > 
 
 ■I 
 
 Fig. 41. 
 
 Fig. 42. 
 
 shown in Fig. 42, b, to a depth equal to the 
 len^Hh of the wedsire. It is important that the 
 opening should be of this depth, otherwise a 
 
 Fig. 43. Fig. 44. 
 
 portion of the reduced thickness of the wedge 
 will be left exposed, and the piece, when finished, 
 
54 
 
 FIRST LES80N6 IN METAL- WORKING. 
 
 will be too small at this point. If, on the other 
 hand, the cut is too deep, the wedge will go in too 
 far, and the piece will be shortened, besides being 
 thickened at the joint. The slit is made with a 
 "hot chisel," Fig. 43, that is, a chisel adapted to 
 the cutting of hot iron. While the piece is at a 
 bright red or white heat, the blacksmith holds it 
 on the edge of the anvil, as in Fig. 44, and holds 
 the chisel on the line of the proposed cut, and the 
 helper drives the chisel in with blows of the 
 sledge. The workman does not try to make the 
 whole length of the cut at once, but begins at the 
 end, and works gradually inward. When the cut 
 is about half-way through, he turns the piece over 
 
 Fig, 45. 
 
 and w^orks from the other side. The cut being 
 Exercise 19 made, it may be widened by setting 
 A split or the piece on end, with the cleft up, 
 v-weid. .^^^1 driving the chisel into it, or by 
 
 setting it up with the cleft down, and driving it 
 
WELDING. A TONGUE-WELD. 
 
 m 
 
 on the hardee, or on a bottom-fuller. When the 
 piece has been split, hammer out the edges of the 
 Jaws a little, as in Fig. 45, thinning them only a 
 little, and then close the jaws again, partly, as in 
 Fig. 46. If you have no helper, the whole opera- 
 
 FiG. 46. 
 
 tion may be performed, though not quite so easily, 
 on the hardee and a bottom-fuller, or even by 
 holding the piece in the vise, and splitting it with 
 a chisel. 
 
 The split piece, or V-piece, being now again 
 heated to whiteness, the blacksmith holds it up- 
 right on the anvil with one pair of tongs, and the 
 cold wedge-piece with another pair, while the 
 helper drives it in gently. The wedge must enter 
 to its full depth, and, if necessary, the cut must 
 be extended for this purpose, for the reason al- 
 ready given. It must also go cpiite to the bottom 
 of the cut, otherwise a hole will be left in the 
 finished piece at that j^oint. 
 
 The wedge being quickly di'iven in to its proper 
 
56 
 
 FIRST LES80N8 IN METAL-WORKING. 
 
 de]3tn, tlie pieces are turned over on their side, 
 and the jaws of the slit hammered down closely 
 on the wedge, the blacksmith and helper push- 
 ing the pieces firmly together all the time, to pre- 
 vent the wedge from slipping out. The ears a 
 and h, Fig. 47, b, which project beyond the edges 
 
 i- 
 
 Fig. 47. 
 
 of the wedge-piece, are to be turned down round 
 it, thus holding the two pieces together while the 
 weld is being finished. The two pieces thus 
 joined together are laid in the lire and brought 
 to a welding heat. Two or three blows struck 
 lengthways will make the w^eld secure at the 
 middle. Then reheat, and, blacksmith and helper 
 together pushing strongly towards each other, fin- 
 ish the weld while the piece lies on its side and is 
 turned to and fro by the former. 
 
 The finishing is effected in the same way as in 
 the last exercise, and the same tests are applied to 
 the work. 
 
WELDING. A TONOUE-WELD. 57 
 
 This joint can be made by one workman alone, 
 if lie is skilful and tlie pieces are not too large. 
 He will cut the slit on the hardee, or in the vise 
 with a chisel. To diive the cold wedge into the 
 V , he will hold the V -piece, red-hot, upright in 
 the vise, and holding the cold wedge-piece in the 
 hand, drive it in with the hammer. He will then 
 squeeze the jaws of the V together with the 
 tongs, and turn the ears over the wedge by light 
 blows of the hammer on the anvil. The two 
 pieces should then hold together iirmly enough to 
 allow of handling them (with care) in the fire, 
 while being heated for the weld. 
 
 The V-weld, or split-weld, is especially valua- 
 ble for very large pieces. With such pieces, after 
 the joint has been formed and the two pieces have 
 been fitted together, and while they are at a ^veld- 
 ing heat in the fire, they are partly welded, with- 
 out removing them from the fire, by blows of a 
 heavy sledge on the end. Only the finishing of 
 the weld has then to be done on the anvil. 
 
58 FIRST LES80N8 IN METAL-WORKING. 
 
 LESSON X. 
 
 TESTIIN'G IPvON. MAIN^UFACTUKE OF CAST-IRON. 
 
 Baes welded by any of these methods should be 
 almost as strong as bars without welds. They can 
 be readily tested in a machine such as that used 
 in the Lessons on Wood-working, only larger and 
 stronger. Such machines are made of sufficient 
 power to break a bar of wrought-iron five inches 
 in diameter. The small machine wnll serve for 
 testing wires, and such pieces as were used in 
 your first exercises ; and you should now make a 
 few welds with such iron and test them, compar- 
 ing their strength with that of the solid bar. 
 
 Put one of these pieces, \" square, into the ma- 
 chine, and apjDly a gradually increasing force till 
 the piece breaks. The cross-section being yig of a 
 Exercise 20. square iuch, the '' tensile strength" 
 Testing bars or " tenacity" of the iron per square 
 and welds. -^^^-j^ -^ gj^teeu timcs the amount that 
 
 the testing-machine indicates. If the bar were 
 round and \" in diameter its cross-section would 
 be about -^-^" (-eVoVO? ^^^^ ^^^ tenacity about 20 
 times that of the specimen. This strength varies, 
 
TESTING IRON. MANUFACTURE OF CAST-IRON 59 
 
 for different kinds of wrougLt-iron, from 35,000 
 to 55,000 lbs. It is usually higher for iron wire 
 than for bar-iron, because none but the best qual- 
 ity of iron can be used for making wire, and be- 
 sides, the " drawing" of the wire lengthens and 
 compresses the fibres, thus giving additional 
 strength. Test two or three specimens of wire, 
 and calculate their tensile strength. 
 
 The tensile strength of wa'ought-iron is not 
 the only important quality that can be tried and 
 measured in the testing-machine. Good wrought- 
 iron should have great ductility, that is, it should 
 suffer considerable stretching, and consequently 
 considerable reduction of cross-section, before 
 breaking. If it does not, it is not fit for use in 
 such a structure, for instance, as an iron bridge, 
 because when a great stress is put upon it, in- 
 stead of stretching, and so giving warning, it will 
 break suddenly. It is usual, therefore, with en- 
 gineers to require that the iron to be used in 
 bridges, shall suffer an elongation of 12 to 20 per 
 cent and a reduction of cross-section Exercise 21 
 of 30 per cent before breaking. Mea- Test of 
 sure the diameter of the section of the '^"^^^^^^y- 
 broken rod at the point of rupture, compute its 
 area, and the percentage of reduction. 
 
 Besides tenacity and ductility, good wrought- 
 iron has great hardness and stiffness, that is, it re- 
 quires great force to crush it or to bend it. Test 
 
60 FIRST LESSONS IN METAL-WORKINO. 
 
 a specimen of \'' wi'ouglit-iron in tliese respects in 
 the macliiue, and record the results for compari- 
 son hereafter with cast-iron and with steel. You 
 will find that w^hile different kinds of wroiight- 
 iron differ from each other, they are, on the aver- 
 age, superior in all these respects to cast-iron. 
 
 The differences between cast-iron, wrought-iroD, 
 and steel, and between different specimens of 
 each, result from their composition and mode of 
 manufacture. Cast-iron is a mixture of iron with 
 about 4 to 7 per cent of carbon, which makes it 
 fusible at about 1100° C. or about 2500° F. It 
 generally contains also, small quantities of othei* 
 substances, as sulphur, silicon, and phosphorus, 
 which have various effects on its fusibility, its 
 ductility, and its hardness. As more and more 
 of the carbon is removed, the iron becomes first 
 steel and then wrought-iron, endless varieties of 
 each resulting from the kind and quantity of the 
 impurities. The way in which these substances 
 find their way into the product, and the means by 
 which they are removed, will be understood from 
 a brief description of the methods of manufactur- 
 ing cast-iron, wrought-iron, and steel. 
 
 The broken-up ore is placed in a structure forty 
 to eighty feet high, called a ^'blast-furnace," shown 
 in Fig. 48, in layers alternating with layers of 
 coal or charcoal and of broken limestone. The 
 coal beino; is^nited and a strong; blast of air driven 
 
TESTING IRON. MANUFACTURE OF CAST-IRON. 61 
 
 through the iron pipes or " tuyeres" which enter 
 the furnace near the bot- 
 tom, the heat melts the 
 material above, which 
 flows off below through 
 the opening shown in the 
 iigure. Fresh layei's are 
 added above, and thus the 
 furnace is kept in con- 
 stant action, for months 
 or years, till it becomes 
 necessary to let the fire 
 out in order to make re- 
 pairs. 
 
 The use of the coal in 
 this operation is evident. 
 That of the limestone is 
 to form an easily fusible 
 mixture with the silica or 
 sand and the earthy mat- 
 ter of the ore, and cause it 
 to flow off. At the same 
 lime some of the carbon of 
 the fuel joins with the iron 
 and makes another fusible 
 mixture, cast-iron. There 
 are thus two fluids con- 
 stantly accumulating in 
 the bottom of the furnace. The heavier one settles 
 
 Fig. 48 
 
62 
 
 FIRST LESSONS IN METAL- WORKING. 
 
 to the bottom, and is drawn off from time to 
 time, tlirough an opening made for the purpose, as 
 cast-iron. The lighter one floats above this, and 
 is drawn off through another opening, as "slag" or 
 " cinder." When cold, it is usually, though not 
 always, broken up and thrown away as a waste 
 product. 
 
 The iron thus obtained from the furnace flows 
 down a trough ^4^ in a bed of sand on the floor 
 to the troughs i>^, and thence into the moulds 
 
 CO. One of the groups composed of ^ and O is 
 called a " sow and pigs," and the pieces O, each 
 of which is about three feet loni>; and contains 
 about 100 lbs. of iron, is called a "pig." 
 
 The " pig-iron" thus produced contains various 
 impurities, according to the hinds of ore, lime, and 
 fuel used. The study of the various grades of 
 pig-iron would lead us farther than we can go at 
 present. They are designated, in part, by tlie 
 name of the country or district in which they are 
 
TESTING lEON. MANUFACTURE OF CAST-IRON 63 
 
 produced, or the furnace producing tliem — Norway, 
 Cumberland, Lownioor, Warwick, Salisbury. Be- 
 sides this, they are also divided into three princi- 
 pal grades used for different purposes. These 
 are : 
 
 ^^ No. 1," which is coarsegrained and very dark 
 and soft, and is used for foundry-work ; 
 
 " No. 2," which is less coarse, but still dark and 
 soft, and is also used for foundry- work ; 
 
 " No. 3," or Gray Forge, also sometimes called 
 No. 1 Mill ; 
 
 '' Mottled j'' \n\\\q\i is light gray with specks of 
 white ; and, 
 
 '• White j^ which is white all over. 
 
 The last three are used for reheating and manu- 
 facturing into refined iron, as explained in Lesson 
 NIL 
 
64 
 
 FIBST LESSONS IN METAL- WOBKINO. 
 
 LESSON XL 
 
 ^OUI^^DRY-WORK. 
 
 Cast-iro]^ is readily fusible, and a great many 
 articles are made directly from it in the ^4i*on-foiin- 
 dry," different kinds of pig being mixed together 
 to obtain the desired quality. To illustrate the 
 method of casting or founding in metal, which is 
 Exercise 22 ^^^^ Same in its essentials, whether the 
 Making a metal be iron, steel, brass, or zinc, we 
 pattern. ^^^l cast a Small object in brass, which 
 
 can be melted in your forge-iire or in that of a 
 small portable furnace, while iron would require 
 a much higher temperature. We will take for 
 the object the square prism shown in isometric 
 projection in the sketch, Fig. 50, to 
 be used in a later exercise. The rough 
 casting must be a little larger than it 
 is shown in the sketch, to allow for 
 waste in finishing. The amount of 
 the difference depends on the fine- 
 FiG. 50. ness of the casting. If the casting 
 is very rough, ^'^ may be lost on each face; 
 
FO UNDR Y- WORK. (55 
 
 if very smootli, less than yig^' maybe euough. As 
 we shall perform several operations on tlie casting 
 before iinisliing it, we will make the casting 2J'' 
 square and 2^^' long. If, however, we make a 
 mould of this size, the metal when poured into it 
 will shrink in cooling, and make the piece too 
 small. It is usual, as the result of experience, to 
 allow about 1 per cent or about ^" to a foot for 
 shrinkage ; but this allowance, which is important 
 in large pieces, may be neglected in so small a 
 work as the present. 
 
 If the pattern were made of the size and shape 
 thus far determined on, 3^ou would find, on trying; 
 to perform the next operation, that you w^ould 
 fail. After packing the sand round your pattern 
 in the mould, you would find that the pattern 
 would not •' draw," that is, it could not be lifted 
 from the sand without breaking^ down the mould 
 It must be a little thinner on that side which is 
 set deepest in the sand. The least taper that will 
 suffice for this purpose is about ^^ in a foot, or 
 about y-^o"'' in an inch. Allowing something more 
 than this in this very small piece, you may make 
 one face of your pattern about ^'' wider than the 
 opposite face. Finish up the pattei'n as smooth 
 as you can make it, and give it a smooth coat of 
 shellac varnish. 
 
 The process of " moulding" consists in making 
 a depression in sand, of the size and shape of the 
 
66 
 
 FIRST LE880N8 IN METAL- WORKING. 
 
 pattern, and that of ^' casting" consists in filling 
 this depression with the melted metal. The sand 
 must be very firm, and jnst moist enough to 
 " pack," or stick together slightly when squeezed 
 in the hand. If it is moister than this, it may 
 cause accidents by the sudden generation of steam 
 when the melted metal is poured into the mould. 
 The sand is held in place while it is being packed 
 round the pattern, by a moulding-box or " flask," 
 of wood or iron, formed in two parts, which can be 
 separated and put together again in exactly the 
 same position, being guided by two pins in one 
 part, which pass through two holes in correspond- 
 
 3 c 
 
 3c 
 
 Fig. 51. 
 
 
 3 C 
 
 ing ^'lugs" on the other. Each part is accom- 
 panied by a flat " moulding-board " about two 
 inches longer and wider than the flask, with 
 " tongue-and-grooved " strips across the ends to 
 
FO UNDR Y- WORK, 67 
 
 prevent it from warping. The two parts A and B^ 
 with the moulding-boards C\ are shown in front 
 elevation and side elevation in Fig. 51, wdiere P 
 and Q are the upper and lower lugs. 
 
 Set one half of the flask on its monlding-board, 
 with the lugs downward. Sprinkle 
 some fine sand on the lower part of the fL^®^"?.^^ ^^' 
 
 ^ Moulding. 
 
 flask, through a sieve, and fill up the 
 remainder of the box without sifting, bnt press 
 and ram the sand firmly into the corners of the 
 box till it is quite full. Scrape off the excess with 
 a straight-edge, sprinkle a little loose sand on the 
 surface, and cover it w4th another board, rubbing 
 this to and fro till it fits closely on the edges of 
 the box. Now, grasping the edges of both boards 
 in the hands, turn the box over without disturb- 
 ing the sand, and remove the upper board. 
 Sprinkle the moist surface of the sand with fine 
 red brick-dust obtained by crushing bricks. Put 
 the dust into a linen bag, and sift it out by sha- 
 king the bag while holding one corner of the open 
 end in one hand and a corner of the bottom in the 
 other. Blow off any excess of dust, and lay the 
 pattern on the sand with the wider face dowai. 
 Sprinkle the surface of the pattern with dust, then 
 set the upper part of the flask in place, and fill it, 
 and cov.er it with a board in the same way as the 
 first. 
 
 The upper half is now to be removed, so tliat 
 
68 FIRST LESSONS IN METAL- WORKING. 
 
 the pattern may be taken out. Tap tTie top board 
 gently all over with a light mallet. This will 
 loosen the sand a little from the pattern, and the 
 brick-dust will prevent the two surfaces of the 
 sand f]'om sticking together. Taking hold of the 
 upper box and moulding-board with both hands 
 and lifting carefully straight upwards, you can 
 remove this box and turn it over on its moulding- 
 board. In lifting, you must be careful to keep 
 the box quite level and not to move it horizontal- 
 ly, or you will break the mould. 
 
 If the sand has not broken away to any consid- 
 erable extent, you may remove the pattern ; but 
 if it has, the breaks must first be repaired. 
 Moisten a little the hollows from which the sand 
 has been torn out, and replace the other box. 
 The pieces torn out will adhere and remain in 
 their proper places, where they can afterwards be 
 smoothed off, if necessary, with a small trowel. 
 If the pattern should happen to come oif with the 
 upper flask, it can be removed by sticking into it, 
 obliquely, two sharp-pointed steel wires, tapping 
 them gently sideways and endways to loosen the 
 pattern, and then lifting it out by the wires as 
 handles. 
 
 In one end of the flask there is a hole through 
 which the melted metal is to be poured in. Con- 
 nect this with the end of the mould by a small 
 channel cut with the trowel, and smoothed and 
 
FOUNDRY-WORK. 69 
 
 liardeiied at the entrance by the pressure ot the 
 finger. Repair any small breaks, \Ao\y out any 
 loose sand, dust both surfaces of the mould lightly 
 with flour or with finely ]>owdered charcoal in the 
 same way that you applied the brick-dust, put the 
 two halves of the flask together and clamp them 
 in place, and everything is then ready for the 
 pouring of the metal. 
 
 Brass is best melted in a brass-founder's furnace, 
 which, however, it is not necessary to describe 
 here, as the small quantity required at present can 
 be melted in a crucible in your forge. Make a 
 Are of good hard coke, in pieces about t^vo or 
 three inches in diameter. Set the crucible on this, 
 mouth downwards, urging the fire gently till it is 
 thoroughly heated, because, if heated first on the 
 outside, or too suddenly, it is apt to crack. When 
 it is red hot all over, turn it over, build up the 
 fire round it to the edge, put in the charge of 
 metal, and cover it with large pieces of coke. 
 The amount of metal required can be determined 
 approximately f]-om the fact that the density of 
 the metal is 14 or 15 times that of the wooden 
 pattern. To allow for waste, however, and to be 
 quite sure of having enough to fill the mould, let 
 the weight of the charge be from 20 to 25 times 
 that of the pattern. Keep up a strong draught 
 with the bellows, till the whole of the charge is 
 melted. 
 
70 FIRST LES80N8 IN METAL-WOBKING. 
 
 Brass is an alloy or mixture of copper and zinc, 
 usually in the ratio of 90 to 10. When it is ex- 
 exposed to the air at a very high temperature, the 
 zinc burns, giving off a light blue flame and a 
 cloud of white smoke. For thin castings, which 
 chill quickly, and which therefore require a high 
 temperature, the metal should be poured in this 
 condition. For such a piece as the one in this 
 exercise, a somewhat lower temperature will be 
 best^ such as is unattended by the flame and smoke. 
 When the metal has cooled to this point, skim off 
 the dross, and it is then ready to be poured. 
 
 For this purpose, after having turned the flask 
 downward to let any loose sand that might pos- 
 sibly have falleD into the mould fall 
 Exercise 24. ^^x ^^^ j^ upri2:ht, with the mouth 
 
 Casting brass. ^ ^ 
 
 Up, and m such a way that the point 
 of the mould at which the inlet enters shall be the 
 highest point, otherwise the air will collect at any 
 point that may be higher, and prevent the metal 
 from entering. Pour the metal carefully into the 
 mould, in a steady stream of such size as to leave 
 room in the channel or " ingate" for the escape of 
 the air without forming bubbles, which might 
 scatter the metal. The mould must be filled quite 
 up to the ingate, to insure soundness of the cast- 
 ing at the top. When the casting is " set," the 
 mould is opened, the piece cooled, the ingate-piece 
 sawn oft*, and the ridge along the line of meeting 
 of the halves of the flask filed away. 
 
MANUFACTURE OF WROUOHT-IKOK. 71 
 
 LESSON XII. 
 
 MANUFACTUEE AND PEOPERTIES OF WROUGHT-IRON. 
 
 We have seen that the two kinds of iron, 
 called No. 1 and No. 2 foundry pig, are used 
 singly or mixed in various proportions for cast- 
 iron, and No. 3, or forge-pig, is manufactured into 
 wrouo-ht-iron. The manufacture consists in ex- 
 pelling the other substances, mainly carbon, sili- 
 con, phosphorus, and sulphur, with which it is 
 mixed, leaving pure iron. 
 
 For this purpose, the iron is again melted in a 
 furnace without blast, called a " puddling-furnace," 
 where it is stirred up with wrought-iron rods till 
 nearly all the carbon has been burned out of it 
 by contact with the air, and the other impurities 
 have been carried away in a "slag," made by 
 throwing limestone, oxide of iron, salt, and other 
 fusible substances into the furnace. It thus be- 
 comes first pasty and then granular, and requires 
 a very intense heat to keep it from solidifying. 
 In this state it is taken out of the furnace in 
 lumps of about 40 lbs., on the ends of the iron 
 rods, and hammered by heavy hammers driven 
 l^y machinery, or compressed between powerful 
 '' squeezers," the remaining silicon and other im- 
 
T2 
 
 FIRST LESSONS IN METAL WORKING. 
 
 purities being thus pressed out. The lump of 
 pure iron thus obtained is passed between strong 
 cylindrical rollers, which have grooves turned in 
 
 Fig. 52, A. 
 
 both, opposite each other as in Fig. 52, and thus 
 drawn out into bars from 3 to 5 inches wide, and 
 
 Fig. 52, B. 
 
 from ^" to ^" thick. These are called "muck- 
 bars," or '^ puddled bars," and are coarse WTought- 
 iron. These bars are cut into short pieces, which 
 are fastened together, reheated, and again rolled 
 out to such sizes and shapes as may be required. 
 
MANUFACTURE OF WROUGHT- IRON. 73 
 
 The irou thus produced is called " refined " iron. 
 This iron is sometimes again "piled" and reheated 
 and rolled, producing what is called "double re- 
 fined" iron. After these operations the iron will 
 be found to have an entirely different structure 
 from that of cast-iron. The latter is composed of 
 granules or crystals. Wrought-iron, if good, has 
 lost its granular or crystalline structure, each of 
 the granules having been drawn out into a long 
 fibre, so that the bar itself is a bundle of such 
 fibres stuck tosrether at their sides. Wrouo-ht- 
 iron thus resembles a piece of tough wood, while 
 cast-iron is more like unstratified stone, such as 
 granite. Cast-iron has the same structure and 
 strength in all directions, while wrought-iron is 
 tougher or harder to tear asunder by a force ap- 
 plied in the direction of the length of the fibres 
 than by one applied perpendicular to this direc- 
 tion, — in which respect again it is analogous to 
 wood. (Wood- working, p. 17.) 
 
 This fibrous structure is possessed in very differ- 
 ent degrees by different kinds of wrought-iron. An 
 iron of poor quality can be readily broken across 
 by bending. Take a piece of \" bar-iron of the 
 cheaper (and therefore poorer) quality. 
 Nick it on one side on the hardee. Testing 
 Lay it across two pieces of ^" flat wrought-iron 
 
 ,1 _e • 1 J i 1 on the anvil. 
 
 n-on tnree or tour inches apart on the 
 
 anvil, the nick being between the supports, but 
 
74 FIRST LESSON'S IN METAL- WORKING. 
 
 near one of tliem, and strike it a heavy blow or 
 two with the pene of a hammer. If the specimen 
 is of very poor quality, or " cold short," it will 
 break at the nick. A piece of better quality 
 will stand bending cold at right angles without 
 breaking; and a very tough piece may be bent 
 
 ^ double without breaking:, or 
 
 will split at the nick, as m 
 
 Fig. 53. The best bar-iron 
 
 \ can be tied in a knot cold, 
 
 ^ though not after it has been 
 
 ^^^- ^^' nicked. 
 
 Break in this way two or three pieces of iron 
 of different qualities. Examine the surfaces of 
 the fractures with a lens. You find that the bet- 
 ter or tougher the iron, the more distinctly fibrous 
 it is; and you can soon learn to judge of the 
 quality of wrought-iron, as of cast-iron, by the 
 appearance of a freshly-broken surface. 
 
MANUFACTURE AND PROPERTIES OF STEEL. 75 
 
 LESSON XIII. 
 
 MA^UFACTUEE AND PROPERTIES OF STEEL. 
 
 You have learned that wroiigbt-iron is Dearly 
 or quite pure iron, while cast-iron contains from 
 3 to 5, or, in some cases, even 7 or 8 per cent of 
 carbon. Steel is intermediate in composition be- 
 tween these two, and contains from 1 per cent to 
 0.15 of one per cent of carbon. It might be sup- 
 posed, therefore, that steel could be made in the 
 puddling-furnace by stopping the operation be- 
 fore the carbon is all removed ; and this process is 
 sometimes actually used. It is difficult, however, 
 to obtain in this way a product containing exactly 
 any desired proportion of carbon, and besides, the 
 distribution of the carbon throughout the mass is 
 apt to be irregular, or, in other words, the steel is 
 not homogeneous. 
 
 For a long while, therefore, steel was made al- 
 most exclusively from the best qualities of 
 wrought-iron l:>y a process called ^'cementation," 
 a process which is still in use for the manufacture 
 of fine steel. The bars of wrought-iron are em- 
 
76 FIRST LESSONS IN METAL- WORKING. 
 
 bedded in powdered charcoal, and baked in a 
 furnace for from seven to fourteen days continu- 
 ously. Tlie iron is then found to have increased 
 in weight about 1^ per cent by the absorption of 
 carbon, and has become what is called "blistered" 
 steel, from the blisters which appear on its sur- 
 face, and which are probably caused by the escape 
 of bubbles of air. 
 
 From the blistered steel two other kinds are 
 made called "shear" steel, and "cast" or "cruci- 
 ble" steel. The former is made by fastening to- 
 gether a number of bars of blistered steel, and 
 hammering them at a welding heat with a trip- 
 hammer. The process is like that of refining 
 wrought-iron, and has a similar eifect — the pro- 
 duction of a more or less fibrous structure. The 
 steel thus made is especially adapted for welding 
 to wrought-iron, and is commonly used in making 
 the cutting edges of those tools of which the 
 other parts are made of iron. The other kind of 
 steel is made by melting in crucibles bars of blis- 
 tered steel, broken for the purpose into conven- 
 ient fragments. This is harder to weld than 
 shear-steel, and is used principally for objects 
 which are entirely of steel, and which are cast in 
 the shape required, although it can also be 
 welded, with proper precautions. 
 
 As long as steel was manufactured only by the 
 methods just described, only a small cpantity 
 
MANUFACTURE AND PROPERTIES OF STEEL. 11 
 
 could be produced at once, and it was therefore 
 very expensive. When large works are to be 
 made of crucible steel, it is necessary to have 
 great numbers of crucibles ready at the same time 
 for pouring, and very great care is necessary to 
 make sure that the charo-es of all the crucibles 
 shall have exactly the same qualities. With such 
 precautions, however, very large works, such even 
 as cannons weighing 139 tons, are satisfactorily 
 cast at the great Krupp foundry in Germany. 
 
 In recent times much less expensive processes 
 have been devised for making steel in very large 
 quantities. These are known as the Bessemer 
 process and the Siemens-Martin process. They 
 need not be described at present. They are used 
 mainly in the production of very large pieces, such 
 as are used in the construction of heavy machinery, 
 bridges, railroad tracks, steel ships and cannon, 
 and the armor-plating of war-vessels. For small 
 tools, shear-steel and crucible-steel are still gener- 
 ally employed. 
 
 To the mechanic who is working in steel, the 
 properties of the metal are generally more impor- 
 tant than the way in which it may have been 
 manufactured ; and in wdiatever way his steel may 
 have been made, he distins^uishes what he calls 
 "high-grade" or '^tool" steel from "low-grade," 
 " mild," or " machinery" steel. The former con- 
 
78 FIR8T LESSONS IN METAL- WORKING. 
 
 tains about 1 per cent of carbon, tlie latter from 
 J- to -^ as much. 
 
 On your anvil are two specimens of \'' square 
 steel, each 18^^ long. One is of high grade, the 
 other of mild steel. Study the properties of each. 
 First, heating them to redness, nick them both on 
 the hardee, 8[^_ from the end; and then, after cool- 
 ing them slowly, try to break them as you did 
 
 Exercise 26 ^^^ ^^'^^^ ^^ Excrcise 26. Or better. 
 Testing steel lay the piecc across the hole in your 
 on the anvil. 2inN'A, hold a uarrow fuller on the nick, 
 and let a helper strike with a sledge till the piece 
 breaks. Compare the effort necessary to break 
 each of these with that required to break a piece 
 of bar-iron similarly treated. Examine the frac- 
 tures and compare them with each other, and with 
 that of good wrought-iron. Make memoranda of 
 the results of all your observations. 
 
 Next, wedge the short pieces one after the 
 other in the hole of the anvil, making, if neces- 
 sary, a wrought-iron wedge to hold the piece 
 tightly in position, about 2" of the piece being in 
 the hole. Strike the piece sideways near the upper 
 end, till it is bent aside at an angle of 50° or 60°. 
 Strike it on the other side and bend it back to an 
 equal extent in the other direction. Try to break 
 it by repeated bendings, and note how much of 
 such treatment each piece will stand. Cut a si mi- 
 
MANUFACTURE AND PROPERTIES OF STEEL. 79 
 
 lar inacQ of bar-iroD, and compare' this with the 
 two kinds of steel. 
 
 Next, heat one end of each piece to a cherry-red, 
 plunge it quickly into water, and hold it there till 
 cold. With an old file try the hard- Exercise 27. 
 ness of the end thus treated, and com- Experiments 
 pare with that of the opposite ends, i^ i^^^^ening. 
 You find that sudden cooling from a red heat 
 hardens tool-steel. You have long ago found that 
 no such effect is produced on wrought-iron ; and 
 you find that mild steel is in this respect much 
 like wrouo!:ht-irou. 
 
 Again, test the piece thus hai'dened for tough- 
 ness, as you did before hardening it: you find it 
 has become not only hard, but brittle. 
 
 Lastly, heat about 2'^ of one end of the tool- 
 steel to whiteness, and treat it as you did 
 wrought-iron, in previous exercises for drawing 
 and pointing. You find it brittle, like hot-short 
 iron, and it is evident that it cannot be worked 
 at such a heat. Try successively low^r tempera- 
 tures, till you find one at which it can be forged. 
 Do the same with the low steel. You will find 
 hereafter that though the steel is not made brittle 
 at this temperature, it has probably suffered an- 
 other injury, which you will understand when you 
 come to consider the subject of "hardening" and 
 " tempering " steel, that it is necessary to work it 
 at a still lower temperature, and that each kind 
 of steel has a temperature of its own at which it 
 
80 FIRST LE880N8 IN METAL-WORKING. 
 
 can be worked, and which, generally, can be as- 
 certained only by trial. 
 
 Collect, now, all the points of resemblance and 
 of diiferetice that you have discovered between 
 wrought-iron, cast-iron, mild steel, and high-grade 
 steel, and write them out in a clear and orderly 
 manner in your memorandum-book. 
 
WELDING STEEL: LOW GRADE. 81 
 
 LESSON XIV. 
 
 WELDIIS^G STEEL : LOW GRADE. 
 
 We will make our iirst attempt at a steel weld 
 witli a low-grade steel containing about ^ of 1 per 
 cent of carbon. This may be eitlier a mild shear- 
 steel, or a Bessemer steel of about the quality now 
 used for carriao:e-tires. It will differ but little 
 from wrought-iron, except that it will be tougher. 
 It will be easier to Aveld than tool-steel, but will 
 require more care than wrought-iron. We will 
 take the tough ^" piece of the last exercise, and 
 join it again to the piece from which it was cut. 
 
 First, straighten the pieces at a dull-red heat. 
 Upset and scarf one end of each piece, with the 
 aid of a helper, using a fuller, and proceeding as 
 in Exercise 19. Be careful to use a coke fire in- 
 stead of one of green coal, and to work at a low 
 heat, never exceeding a cherry-red. Unless you 
 work very expeditiously, therefore, sticking always 
 at exactly the right place, and without loss of 
 time, you will not be able to prepare the scarf - 
 piece in one heat. Beheat cautiously, 
 moving and turning the piece occasion- weiding steel 
 ally in the hre, and watching the color on steel: low 
 closely. Keep the other piece in the 
 e.dge of the lire, so that it sliall be nearly ready 
 
82 FIRST LESSON'S IN METAL- WORKING. 
 
 for use when wanted, but in no danger of burning. 
 Make the scarf in as few heats as possible. When 
 the two surfaces are prepared, put the pieces in the 
 fire side by side, as in Exercise 19, and raise them 
 slowly to a cherry-red. Sprinkle the scarf -surf aces 
 with powdered borax and allow it to melt, and 
 spread over the surface before you put the pieces 
 into the fire again. Heat them slowly, and as 
 soon as the borax smokes, which will be an indi- 
 cation that they have reached a cherry-red, with- 
 draw them from the fire, and finish the weld as in 
 Exercise 19, observing all the precautions there 
 described, but remembering that, after the first 
 adhesion of the two surfaces, there is not the same 
 necessity for rapid work in this case as in the 
 iron weld, because the steel, being worked at a 
 lower temperature, does not quite so quickly fall 
 below the required heat. Remember that, in this 
 case as in the previous ones, it is essential to a 
 good weld that you should have a bright, clean, 
 and deep fire; but you should not have a broad 
 one, as that will heat too much of the length of 
 the pieces. Finish square, straight, and smooth, 
 as in similar work with wrought-iron, and test in 
 the same way. If the result is not satisfactory, 
 cut out the weld on the hardee at a red heat, and 
 repeat. 
 
 Try next a split weld, of steel on iron, taking 
 one end of the piece just finished, and an 8^' piece 
 
WELDING STEEL: LOW -OR AD E. 83 
 
 of V square bar-iron. Make this weld without a 
 helper. Upset and split the iron, and Exercise 29 
 lay it in the edge of the fire to keep it Welding mild 
 at a red heat while you are preparing ^*®®^ °" *^°"" 
 the steel wedge-piece. This is because the steel 
 must be worked at a lower temperature than the 
 iron, and therefore, when they are presently put 
 into the fire together, the iron should be hot and 
 the steel cold, so that they may reach their proper 
 heats at the same time. Hammer the steel to the 
 wedge-shape, and fit the hot V-piece to it as in 
 Exercise 19. Then, without letting the V-piece 
 cool, place both together in a good welding fire 
 and raise the steel to a bright cherry-heat, when 
 the iron will probably be at a welding heat. 
 During this operation keep them on the top of 
 the fire, so that they can be easily watched, and 
 move them about so that they shall not get too 
 hot beyond the joint. In doing this, take hold of 
 both pieces, and keep the wedge pressed well up 
 into the split. When the joint is at the proper 
 heat, take up some poAvdered borax on a bit of 
 hoop-iron or small flattened bar-iron as a sort of 
 spoon, and sprinkle it abundantly on the joint. 
 Watch the melting of this, while you keep up the 
 heat by means of the blast. When it has thor- 
 oughly run into and around the joint, and the 
 steel is at a bright cherry-red, take hold of the 
 joint with a pair of tongs while it lies in the ^re^ 
 
84 FIRST LESSONS IN METAL- WORKING. 
 
 and without removing it, squeeze it vigorously. 
 This will partially weld the Joint, and enable you 
 to handle the pieces with less risk of separating 
 them. Remove them to the anvil, strike a few 
 quick blows to make good the weld, and you can 
 then finish more at your leisure, reheating the 
 pieces as often as may be necessary. The finish- 
 ing and testing should be exactly as in Ex. 19. 
 
WELDING STEEL: HIOH-QRADE. 85 
 
 LESSON XV. 
 
 WELDIIS^G STEEL : HIGH-GEADE. 
 
 We will now try a weld of liigh-grade or tool 
 steel, which will be somewhat more difficult to 
 manae'e. Take the piece of A^' tool 
 
 ^ ^ ^ Exercise 30. 
 
 steel of Ex. 26. Be careful to per- weiding high- 
 form all operations on it at a tempera- s^^^de steel on 
 ture lower than that at which you have 
 found that it becomes brittle. Upset it as in the last 
 exercise, holding the piece this time in the vise for 
 the purpose,. In upsetting in the vise it is easier 
 to prevent bending, if you are careful not to strike 
 too hard. On the other hand, if you set the 
 piece too low in the vise you will limit the upset- 
 ting to the extreme end, and the work will turn 
 out too thin when the weld is finished. While 
 upsetting, keep the piece square and straight by 
 occasional hammering on the anvil. With this 
 kind of steel you will probably have to reheat 
 each piece several times for each operation, which 
 will do no harm unless you make it too hot. 
 When it is properly upset, split it, again at a red 
 
86 FIRST LE8S0JVS IN METAL- WORKING. 
 
 heat, holding it upright in the vise and using a 
 thin hot-chisel. When the cut has been made to 
 the proper depth, widen it a little with a duller 
 chisel, spread the lips, form the wedge-piece, and 
 drive it in till it reaches quite to the bottom of 
 the cut, all as in previous exercises of the same 
 kind. Put the pieces together and fit them as 
 closely as you can, at a red heat. They are now 
 to be heated together in the fire, with even more 
 caution than in the last exercise as to the charac- 
 ter of the fire, the mo vino;; about in the fire to heat 
 all parts of the Joint but without parting the 
 pieces, and the keeping within proper limits of 
 temperature. Sprinkle abundantly with borax 
 without removing from the fire, pinch together in 
 the fire, and weld and finish, all as in the last ex- 
 ercise. 
 
 This will probably be found to be a rather dif- 
 ficult task, and you may have to try several times 
 before succeeding. Some of the causes of failure 
 are the following : 
 
 1°. Overheating at any stage of the operation, 
 which will cause the steel to break or crumble 
 under the hammer. 
 
 2°. Underheating at the time of welding, 
 which will prevent the pieces from uniting. 
 
 3°. Dirty fire, letting cinders get into the Joint. 
 
 4°. Too much thinning of the lips of the V- 
 piece, which will make the Joint so weak that it 
 
WELDING STEEL: HIGH-GRADE. 87 
 
 may be impossible to keep the two pieces together 
 iu the fire, or while removing them to the anvil. 
 
 5°. Too short a notch, leaving part of the 
 thinned wedge exposed. 
 
 6°. Loss of time in striking, after removing the 
 work from the fire. 
 
 7°. Imperfect contact of the edge of the wedge 
 v^dth the bottom of the notch, leaving a hole, or, 
 if this is closed by hammering, leaving the piece 
 too thin. 
 
 8°. Imperfect union of the edges of the lips of 
 the V-piece with the sides of the wedge, owing 
 to burning of the edges, which often happens if 
 they are too thin. 
 
88 FIBST LESS0N8 IN METAL- WORKING. 
 
 LESSON XVI. 
 
 HARDENING AND TEMPERING STEEL. 
 
 You have learned (Lesson XIII., p. 79) that 
 high-grade steel, when cooled from a red heat by 
 plunging into water, becomes very hard. The 
 same effect, with some differences in degree which 
 need not be considered yet, results when the steel 
 is cooled suddenly from the same temperature in 
 any other way, as by plunging into oil or tallow, 
 or even, if it is a thin piece, by contact with a 
 large mass of cold metal, such as the anvil. Again, 
 you have found that the piece which has been 
 thus hardened has also been made brittle. In 
 some tools, as in those intended for cutting metals 
 and stone, this property of hardness is of great 
 value ; but on the other hand, the brittleness which 
 accompanies it may very much lessen this value. 
 The sharp corner of a scrap of glass, for instance, 
 is hard enough to scratch iron or steel; but the 
 brittleness of glass makes it worthless as a mate- 
 rial for cutting-tools, as its sharp edge is quickly 
 broken off*. The same is true of very hard steel. 
 It is important, therefore, to understand exactly 
 
HARDENINO AND TEMPERING STEEL. 89 
 
 the means by which this hardness is produced, and 
 the means by which the brittleness can be dimin- 
 ished without sacrificing too much of the hardness. 
 In the first place, the amount of hardness pro- 
 (1 need by sudden cooling depends on the tempera- 
 ture from which the cooling takes place. Perform 
 the following experiment to satisfy yourself of 
 this. Take four pieces of high-grade octagon or 
 round tool-steel, \" or f^'in diameter and 2" long. 
 Mark them, near one end, with file-scratches, so 
 that you can identify them. Let them lie for fiYO; 
 minutes, one in boilinc^ water, one in boilinof lin- 
 seed-oil, one in red-hot melted lead, and one in the 
 fire till it is as hot as it can be made without burn- 
 ing. (The oil may be boiled in a small iron ladle 
 on a dull forge-fire with a very gentle blast, takiug 
 care not to let it boil over, and, if it takes fire, 
 raising it from the fire and letting it cool a little, 
 so that you can blow it out, but without removing 
 it from the forge, for fear of accident. The lead 
 may be melted in a similar ladle, or in the same 
 one after the oil has been poured off and the rem- 
 nant of it burned out. The lead must be red- 
 hot.) The first of the four pieces will then be at 
 a temperature of 212° F., the second at about 580°, 
 the third at about 1500°, and the fourth at about 
 2500°. Picking up each piece with a small pair 
 of tongs which have been standing in the fiuid or 
 the fire so that their jaws are at the same temper- 
 
90 
 
 FIBST LESSONS IN METAL- WORKING. 
 
 ature as tlie j)iece of steel and will not cliill it, 
 drop each into cold water. 
 
 Test them, as to hardness, in the following way: 
 Clamp the piece in a hand-vise, as in Fig. 54, let- 
 Exercise 31. ^ng it project about \" at the side of 
 Experiment the vise. Fasten the hand-vise to a 
 T 1^ ^"^"^ piece of wood four or five feet long 
 
 and 3^' wide, with a 
 screw and washer, as in 
 the same figure. Sup- 
 porting one end of the 
 Fig. 54. strip on a bench or 
 
 table, and preventing it from shifting by means 
 of a nail passing through an auger-hole, let the 
 
 Fig. 55. 
 
 end of the piece of steel rest on the grindstone 
 Hang a weight of 8 or 10 lbs. on the strip, to pro- 
 duce a suitable pressure on the stone, making a 
 notch for the cord so that it shall be attached at 
 the same place in all the experiments. Let the 
 
HARDENING AND TEMPERING STEEL. 91 
 
 piece bear on the stone, keeping it well watered, 
 and grind the end square, moving it to and fro 
 sideways, so as not to wear the stone in one place. 
 When all the ends ai'e square, weigh the pieces, 
 and record the weight of each. Then grind off 
 from each as much as the stone will remove in 
 1000 or 1500 revolutions, and weigh the pieces 
 again. The percentage of loss of weight w^ill in- 
 dicate the softness of the pieces, since all have 
 been treated alike. You can therefore arrange 
 the pieces in the order of hardness, and can learn 
 the effect of sudden cooling from these tempera- 
 tures. 
 
 Next, holding the pieces in succession on the 
 anvil, and striking them at the end with the ham- 
 mer, first gently, and then more forcibly, you can 
 learn, in a general way, which are the most brit- 
 tle, though this experiment is only a rough one, 
 and its results cannot be expressed in figures. 
 Make a record of these results, and remember 
 them. 
 
 The hardness produced by sudden cooling from 
 a red heat can be entirely removed by cooling the 
 metal slowly from a red heat ; and the more 
 slowlv it is cooled, the softer and touo^her will the 
 steel be. The brittleness and the hardness are 
 reduced together„ Experiment on this in the 
 following way: Heat three pieces of steel, such as 
 you used in the last experiment, to a bi'ight red 
 
92 FIRST LESSONS IN MB TAL- WORKING. 
 
 heat in melted lead, having, as before, marked 
 them for identification. Harden them 
 Experiment" all alike, by plunging them suddenly 
 on annealing ^j^to cold Water. Then, heating them 
 to a bright red again, cool them in the 
 following ways : 
 
 No. 1, by holding it in the tongs (previously 
 heated to a ^' black red") and letting it cool in 
 the air till the redness is invisible in the light, 
 but just visible in a dark corner, and then plung- 
 ing it into water. 
 
 No. 2, by laying it on the loose cinders in the 
 forge, and letting it cool slowly in the air ; and, 
 
 No. 3, by leaving it, red-hot (but not white-hot), 
 in the fire, well covered with the coals and cin- 
 ders, letting the fire go out, and leaving it there 
 till quite cold. 
 
 Test these pieces for hardness and brittleness, 
 as in the last experiment. You will find that the 
 steel has recovered more or less of its toughness, 
 and also of its softness, by this gradual cooling. 
 This process is called annealing; and the three 
 methods you have just tried are called water, air, 
 and fire annealing. Make a record of the effects 
 of each, and remember them. 
 
 It is usually said that while cooling suddenly 
 from a red-heat hardens steel, cooling from a 
 lower heat, whether slowly (as in the air) or 
 quickly (as in No. 1 of your last experiments), 
 
HARDENINO AND TEMPERING STEEL. 93 
 
 softens it. Try to ascertain from your experi- 
 ments whether these statements are correct. 
 
 Glass is very much like steel in the effects of 
 heat on it, while some metals and alloys, as cop- 
 per and brass, behave, as you can now easily 
 prove by experiment, in exactly the opposite way, 
 being hardened by slow cooling and softened by 
 rapid cooling. 
 
 You have found now that, in general, the harder 
 steel is, the more brittle it is, and the tougher the 
 softer. It is therefore impossible to retain the 
 highest degree of hardness with great tough- 
 ness; and for each particular use to which steel 
 is to be put we have to try to secure the particu- 
 lar degree of hardness and toughness most nearly 
 suited to that use. 
 
 As your experiments show that the hardness 
 and toughness of steel depend on the temperature 
 from which the metal is cooled, and as small dif- 
 ferences in toughness may suffice to make a tool 
 very valuable or altogether useless for a given pur- 
 pose, it is important to know how to select the 
 right temperature for each case. The red which 
 is Just visible in the dark (or black-red, as it is 
 called) is a very good indication of one tempera- 
 ture—about 500° to 525° C, or 932° to 977° F. ; 
 but sudden cooling from this point gives a hard- 
 ness which, though it serves very well for files, is 
 too great for most other tools. If a tool which 
 
94 FIRST LESSONS IN METAL- WORKING. 
 
 has been thus hardened too much be raised again 
 to some lower temperature, and then cooled from 
 that temperature, it will be softer than before ; 
 and by selecting the proper temperature it will be 
 possible to give it any lower degree of hardness 
 that may be required. This process is called 
 '' letting down" or "tempering." Success in tem- 
 pering depends — 
 
 First, on the selection of the proper tempera- 
 ture; 
 
 Second, on the method of applying the heat; 
 and. 
 
 Third, on the method of cooling. 
 
 We will consider these three subjects sepa- 
 rately : 
 
 1. The temperature used, when it is lower than 
 the black-red heat, is indicated by the color which 
 is assumed by a brightened portion of the surface 
 of the steel. Ii'on or steel when heated in the 
 air oxidizes on the surface. Grind two or three 
 inches of the surface of an old flat file, making it 
 bright on one side. Heat a piece of 1" bar-iron, 
 « . «^ 15'' or 20'^ long:, to a bris^ht red at one 
 
 Exercise 33. ^/ . (, . . . 
 
 Experiment end, and lay the piece of brightened 
 on colors of gtccl ou it, in a good light, with the 
 bright part projecting about an inch or 
 two beyond the end of the hot bar. The project- 
 ing part will be cooler than the rest, and the heat 
 will travel along to it gradually. Fix your atten- 
 
HAUDENINO AND TEMPERING STEEL. 95 
 
 tioii on the end, and watch and record the several 
 colors as they appear there, one after the other. 
 These colors are produced in the same way as the 
 colors of the soap-bubble, and, like them, they 
 change with the thickness of the very thin film 
 which causes them. As the temperature of the 
 steel rises the thickness of the film of oxide of iron 
 increases, and the color changes. The color is 
 therefore an indication of the thickness of the 
 film, and that in its turn shows the temperature 
 of the metal. It has been found that the tem- 
 peratures corresponding to the several colors are 
 as follows : ^ 
 
 1. Very pale yellow, . . . 221° C. or 430° F. 
 
 2. Pale straw, 232 " 450 
 
 3. Full yellow, 243 " 470 
 
 4. Brown, 254 " 490 
 
 5. Brown, with pur23le spots, 265 " 510 
 
 6. Purple, 277 " 530 
 
 7. Bright blue, 288 " 550 
 
 8. Full blue, 293 " 560 
 
 9. Dark blue, 316 " 600 
 
 If a piece of steel whicli has been hardened be 
 heated to one of these colors and then cooled, it 
 will be softened, and the higher the temperature 
 to which it has been raised the softer it will be. 
 Try this in the following way : Take three pieces 
 
 * Percy's Metallurgy. 
 
96 FIB8T LESSONS IN METAL- WORKING. 
 
 of octagon steel, as in your last experiments, and 
 
 harden them by plunging them in water at a red 
 
 heat. Rub them on a piece of srrind- 
 
 Exercise 34. i i • i x 
 
 Experiment stouc or othcr saudstoue to brighten 
 on tempering them. Lay them on a red-hot bar of 
 
 steel. . , -\ ^ £. J. 
 
 iron supported over a vessel oi water. 
 When any one of the pieces shows a pale-straw 
 color, push it off into the water. Do the same 
 with the others when they reach a light purple 
 and a dark blue respectively. Now, using an old 
 file, try how much of each piece you can remove 
 by a given number, say fifty, of similar strokes of 
 the file, and thus compare the results obtained by 
 tempering from these various temperatures. You 
 might measure the hardness on the grindstone, 
 but it is well also to get accustomed to judging 
 the hardness approximately by the way the metal 
 feels under the file. 
 
 It is generally stated that the colors in the pre- 
 ceding table indicate the proper temperatures for 
 the following objects, respectively :^ 
 
 No. 1. Lancets. 
 
 2. Razors and surgical instruments. 
 
 3. Penknives. 
 
 4. Small shears, chisels for cold iron. 
 
 5. Axes, planes, pocket-knives. 
 
 6. Table-knives, large shears. 
 
 * Percy's Metallurgy. 
 
HARDENING AND TEMPERINO STEEL. 97 
 
 7. Swords, springs. 
 
 8. Fine saws, daggers, augers. 
 
 9. Saws. 
 
 As your future exercises give you opportunity, 
 you ought to compare tliese results with those of 
 your own experience, remembering the agree- 
 ments, and the differences if you iind any, and 
 noticing any peculiarities in the behavior of differ- 
 ent kinds of steel, so as to know how to treat dif- 
 ferent kinds when particular results are sought. 
 
 The three pieces tempered in the last experi- 
 ment may be tested also as to toughness, by hold- 
 ing them one after the other in exactly the same 
 way in a vise, and striking them on one side in- 
 creasingly heavy blows with the hammer till you 
 break them. No very exact result will be reached 
 in this way, because you cannot measure the 
 energy of your blows ; but you can form an ap. 
 proximate estimate of the toughness of the pieces. 
 
98 FIRST LESSONS IN METAL- WORKING. 
 
 LESSON XVII. 
 
 HAEDEIS^ING AND TEMPERINa ^TYIEL.— Continued. 
 
 We come now to consider — 
 
 2. The metliod of apply log heat. 
 
 When a piece is to be hardened all over alike, 
 it is important that it should have the same tem- 
 perature throughout. It may, if not too small, 
 be heated in the forge-fire ; but it must be moved 
 about, so that all parts may be exposed to the 
 heat, and must be heated slowly, so that all may 
 have time to arrive at the same temperature. 
 
 The hollow fire is useful for this purpose, as it 
 allows the piece to be watched closely, and in- 
 sures the heating of the top as well as the bottom. 
 If the piece is small, an excellent plan is to im- 
 merse it for some minutes in red-hot melted lead. 
 The piece quickly takes the temperature of the 
 lead, and care must therefore be taken not to 
 allow the latter to rise to the point at which 
 it would injure the steel. The lead must be 
 watched, and if it is found to be getting too hot, 
 it must be cooled by putting the end of a bar of 
 
HARDENTNO AND TEMPERING STEEL. 99 
 
 cold iron into it. The pieces slionld be rubbed 
 with soft soap before immersiDg them, to prevent 
 the lead from sticking; or a paste made of black- 
 lead and water may be used ; but in this case 
 care must be taken to let the paste dry before im- 
 mersing the piece, as otherwise the steam produced 
 may scatter the lead in a dangerous way. 
 
 If small objects be removed from the lead with 
 cold tongs, they ^vill be irregulai'ly cooled. It 
 will be well therefore to let the ends of the tougs 
 lie iu the lead for some time ; or they may be 
 first heated iu the fire, and then stood in the 
 lead till wanted; or the piece may be held by 
 means of a piece of soft wire twisted rouud it as a 
 handle. 
 
 The heat for auuealing may be applied iu the 
 same way as that for hardeniug. The heat for 
 tempering would be more difiicult to manage if it 
 were always necessary that all 23arts of the piece 
 should have the same tem23erature, because all 
 will not reach this temperature, or show the cor- 
 responding color at the same time. Fortunately, 
 however, this is seldom required. It is always, 
 for instance, the edge of a cutting-tool that is to be 
 tempered ; the exact condition of the rest of the 
 tool is not so important. It is the face of a ham- 
 mer, the 2^oint of a drill, the iipper surface of an 
 anvil, that is to be tempered, and it is on these 
 that the attention is to be fixed while the piece is 
 
100 
 
 FIRST LES80NS IN MBTAL-WORKINO. 
 
 being heated. Small objects, therefore, such as 
 drills and knife-blades, may be heated on a hot 
 bar and pushed off at the right time; or small 
 drills may be heated in the blue part of the flame 
 of a candle, applied just behind the point, so that 
 the color of the point may be watched. Larger 
 objects, such as chisels, cold-chisels, hatchets, and 
 rock-drills, may be still more conveniently tem- 
 pered at the edge by means of the heat left in the 
 rest of the tool after the edge is cooled. The 
 making and tempering of a cold-chisel will afford 
 a good illustration of this very useful method. 
 
 Take a bar of f ^' octagon tool steel. Cut off a 
 piece ^" long by nicking it all round on the 
 Exercise 35. l^^rdee at a red heat, cooling it quickly 
 Making a in watcr, and then breaking it off as 
 cold-chisel. .^ Exercise 26. Be careful not to hit 
 so hard as to make the piece fly, and not to place 
 it in such a position that, if it does fly, it can hurt 
 
 anybody. Working at a red 
 heat and avoiding overheat- 
 ins:, draw one end down to a 
 bevel extending back about 
 To do this, hold the 
 
 piece on the anvil, resting 
 obliquely on it at the farther 
 edge, as in Fig. 5 6, and strike 
 Fig. 56. it with the hammer inclined 
 
 at a little larger angle. Both the opposite faces 
 
 Ql^^ 
 
HAKDENING AND TEMPERINO STEEL. 
 
 101 
 
 will thus be flattened at once. The angle of the 
 faces should be about 16°, which it will be if 
 the thickness of the steel is ^" and the length 
 of the bevel ^\". If the angle is much larger 
 than this it will not allow the workman to have 
 a good view of the edge of the tool in using it ; if 
 much smaller, the tool will be too thin and will 
 spring too much. In flattening the bar you will, 
 of course, spread it sideways also, as in previous 
 
 Fig. 57. 
 
 scarfing exercises. Reduce the bar again nearly to 
 its former width at the edge, by hammering on 
 the sides. Cut off the ragged edge at a red heat, 
 on the hardee, being very careful not to strike the 
 edge of the hardee with the hard face of the ham- 
 mer. It Avill be safer to do this with a hot-chisel 
 and the assistance of a helper. Hold the bar on 
 the anvil with the left hand, the edge projecting 
 
102 FIRST LESSONS IN METAL-WORKING. 
 
 about \" over tlie edge of the anvil. Set tlie hot- 
 chisel over it, as in Fig. 57, and hold it with the 
 right hand while the helper strikes it with the 
 sledge. Take care that the chisel as it cuts 
 through shall pass just clear of the edge of the 
 anvil, shearing the piece off without injury to the 
 chisel. 
 
 You need not be afraid of injuring the steel by 
 too much hammering, or by hammering after it 
 has fallen below the red heat. Unlike iron, it is 
 improved by hard work on the anvil, having no 
 fibres which can be separated by hammering. 
 Finish the faces with the flatter, as in Exercise 18. 
 
 You are now ready for the annealing, harden- 
 ing, and teniperiug. Heat the whole chisel to a 
 cherry-red, slowly and uniformly, as explained in 
 Exercises 28-30. Hold it in the tongs by the 
 upper end till it has reached a black-red heat, and 
 then plunge it endways, edge first, into cold 
 water, immersing it completely, and leaving it 
 there till cold. The tool is now annealed. All 
 the inequalities of hardness which may have re- 
 sulted from the diffei'ent treatment that different 
 parts of the tool have received during the forging 
 are removed, and the whole tool is soft enough to 
 be sharpened with a file. 
 
 To harden and temper the edge, raise about 2" 
 at the cutting edge to a red heat. Holding it in 
 the tongs with the edge downward, lower it into 
 
HARDENING AND TEMPERING STEEL. 103 
 
 the water to the depth of about 1". Then grad- 
 ually raise it till about half an inch is immersed, 
 and hold it there, either still or moving gently to 
 and fro sideways, till the edge is cold. The object 
 of this movement upward is to prevent a too ab- 
 rupt change from the cold to the warm part. If 
 the chisel is immersed to a given depth and held 
 steadily there, the boundary between the hard and 
 the soft part is too distinct, and the chisel is al- 
 most sure to break at that place. 
 
 The edge is now hai*d — too hard for use, and 
 is to be tempered. Rub one of the surfaces for 
 about \" back fi'om the edge ^vith a piece of sand- 
 stone to brighten it, and then watch carefully for 
 the appearance of the proper color at the edge, as 
 the heat comes along from the other part of the 
 chisel. What the proper color is, depends on the 
 use to which the tool is to be put. We will 
 suppose this one to be intended for cutting cast- 
 iron, in which case the proper color is a light pur- 
 ple. As the colors move along toward the edge, 
 the purple an ill be followed by the dark blue, and 
 when the latter has almost reached the edsre the 
 former will have reached it, and it is then time to 
 plunge the whole chisel into water, and move- it 
 about till it is cold. The experiments you have 
 already inade have taught you Avhat to do if you 
 require a harder or a softer temper than this. 
 
 The cutting-angle of the chisel is formed on the 
 
104 FIRST LESSONS IN METAL-WORKING. 
 
 grindstone, and extends back only about \" from 
 the edge. The size of this angle, as well as of 
 that between the two forged faces, depends on the 
 use to be made of the tool. The latter angle may 
 be 12° to 15° for brass or copper, and 16°, as in the 
 one just made, for iron. The cutting-angle should 
 be about 30° to 35° for copper, 50° for brass, 65° 
 for cast-steel, and 80° for cast-iron. 
 
HAUDENING AND TEMPERING STEEL. 105 
 
 LESSON XVIII. 
 
 HAKDElsriNa AND TEMPEEING ^T^^Jj.— Continued. 
 
 We liave next to consider — 
 
 3. The method of cooling. The piece of steel, 
 when heated, may be cooled, either for the pur- 
 pose of hai'dening or of tempering it, by plunging 
 it into any fluid which is a good conductor. The 
 better the conductor is, the more quickly will the 
 piece be cooled, and therefore the harder will it 
 be. Hence, when the highest degree of hardness 
 is required, mercury is sometimes used. Water, 
 oil, and tallo^v, which are inferior conductors, give 
 successively lower degrees of hardness. Water 
 is the material most commonly used, and, for 
 pieces which require more toughness and elas- 
 ticity, as s^D rings and small drills, oil. In temper- 
 ing also, as well as in hardening, the fluid is varied 
 according to the J'esults sought, water and oil, 
 however, being generally used, and even air when 
 the piece is very small. 
 
 To illustrate these points we will make, first, a 
 flat spring, and secondly, a small drill. 
 
106 
 
 FIRST LE880NS IN METAL WORKINO. 
 
 For the first, take a piece of |'^ round tool-steel 
 about 10'' long. Heat ?>" of the end, with proper 
 precautions against burning, and flatten it till it is 
 \" wide. Make it quite straight, and of exactly 
 
 Exercise 36. i^iiif^^i'^^ width and thickness, using 
 Making a a flatter if necessary. Finish it as 
 spring. smooth and free from scale as pos- 
 
 sible, as scales will prevent it from heating uni- 
 formly all over. With a small punch make two 
 holes \" in diameter in one end, being careful not 
 to split the piece in finishing. Bend it as in Fig. 
 58, by heating the end to a dull red, laying it 
 
 Fig. 58. 
 
 over the edge of the anvil, and hammering as in 
 Exercise 5. Be careful not to make the bend too 
 sharp, but rather curved, or you will weaken the 
 steel at that point. Bend the other end in the 
 same way. When the spring is finished, nick the 
 piece with a file at the base of the spring, and. 
 
HARDENING AND TEMPERING 81 EEL. 107 
 
 holding it in the vise, with the nick just visible 
 above the jaws, break it off by bending. 
 
 To anneal and harden the spring, provide a jar 
 of linseed-oil four or live inches deep. Tie a piece 
 of light wire 8'' or 10'' long to one end of the 
 spring as a handle. Heat the spring to redness, in 
 melted lead, and let it cool slowly on the ashes 
 beside the lire. Heat it again to redness, and 
 plunge it endways into the oil. If several students 
 are w^orking together, some may try the effect of 
 immersing it sideways. You will pi'obably find 
 that in this case the spring is bent by the unequal 
 cooling of the opposite edges, and will thus learn 
 the advantage of immersing such pieces end- 
 ways. 
 
 The spring being hardened, is now to be tem- 
 pered. This requires that it be raised to the 
 temperature indicated by a deep-blue color, or 
 about 560° F. The thinness and crookedness of 
 the piece will make it nearly impossible to do this 
 properly, either in the fire or on a I'ed-hot bar. 
 Put it into a ladel of cold oil, and heat it gradually 
 to boiling, with the precautions against accident 
 indicated on p. 89. At various stages in the 
 boiling the oil will have different temperatures, 
 which are easily recognized. When a light white 
 smoke begins to come off, the temperature is about 
 the same as that indicated by a straw-color, or 
 about 450° F. A copious dark smoke is equiva- 
 
108 FIRST LESSONS IN METAL- WORKING. 
 
 lent to a brown color, and a still more abundant 
 black smoke to a purple. At a little liiglier 
 temperature tkan this, the oil will burn if ignited, 
 but can be put out by blowing it. This tempera- 
 ture is equivalent to a blue color, and will be 
 suitable for tempering the spring, if it is made of 
 a low^-grade steel. At a still higher temperature 
 the oil sw^ells up and boils vigorously, takes fire 
 on the surface and burns continuously, igniting 
 again if blown out. This temperature is suitable 
 for the spring if it is made of high-grade steel. 
 At the proper temperature, remove the spring 
 from the oil by the wire handle, and cool it in the 
 air, in water, or in cold oil. The difference between 
 these methods wall be slight in such a small piece. 
 Set the oil aside in the forge till it cools off, after 
 which it can be put away for future use. 
 
 To test the spring, hold it in the vise by the 
 end, straighten it, and let it go two or three times. 
 It should completely regain its figure. If it 
 breaks, it is too hard, and the tempering heat Avas 
 not high enough. If it does not return, it is too 
 soft, and the heat was too great. 
 
 As a last exercise in forging and tempering 
 steel, make a small drill (y) such as is shown. 
 Exercise 37. enlarged, in Fig. 59. Take a piece of 
 Making a steel wire -f-^'' thick and ^" or 8^^ long. 
 ^"^^" On a small bench anvil, and using a 
 
 light hammer, draw it out, at a dull-red heat to 
 
HARD EN [NO AND TEMPERING STEEL. 
 
 109 
 
 c 
 
 
 
 the form shown in Fig. 59. The flame of the 
 Bunsen burner may be used 
 for this, or the forge-fire, if 
 very great care is taken. First 
 draw out the narrow part, or 
 shank of the drill, turning it 
 constantly to preserve its 
 roundness and keeping it quite 
 straight. Next flatten and 
 widen the end. Finish it 
 smooth, cut it off, and anneal 
 it at a black-red heat. Finish 
 the flat faces on the grind- 
 stone, and then form the two 
 bevelled surfaces, by holding 
 it on the grindstone or the 
 emery-wheel as in Fig. 60, 
 cutting it back to the dotted 
 line, and then turning it over 
 and cutting to the other clotted 
 line. Observe that the faces 
 that you are now forming are 
 to be, as shown at b and o, 
 not perpendicular to the flat 
 faces, but inclined to them 
 The inclination, which constitutes the cutting- 
 angle of the tool, depends, as in all other cutting 
 tools, on the hardness of the material on which it 
 is to work. If, as you hold the drill between the 
 
 Scale, % 
 
 Fig. 
 
 59. 
 
110 FIRST LE880N8 IN METAL-WORKINO. 
 
 tlmmb and finger in grinding it, you turn tlie 
 thumb a very little over toward the right, you 
 will make a drill suitable for one kind of work, 
 and if you turn it a little farther, one suitable for 
 softer material. Your drill, when finished, will 
 have, as you see on examining the figure or the 
 drill itself, not a point, but a short blunt edge, 
 running obliquely across the end, as shown in the 
 end elevation (7. 
 
 Fig. 60. 
 
 The drill is now to be hardened and tempered. 
 To harden it, hold the point in the flame, watch 
 it till it reaches a cherry-red, and then plunge it 
 into water. The butt of the drill will thus be 
 left soft. Brighten the point, and hold it again 
 in the flame, the point being this time just out- 
 side, so that the color can be seen. The color, 
 Avhich, in the case of such a small piece as this, 
 Avill appear very soon, should be brow^nish yellow 
 if the drill is intended for iron, and purple if it is 
 for wood. The moment the color appeal's, plunge 
 the drill quickly, point downwards, into cold oil. 
 
HARDENING AND TEMPERING STEED 111 
 
 The fiual finishing on the grindstone is done after 
 the tempering. 
 
 A still smaller drill may be hardened by heat- 
 ing the point in a candle-iiame, and cooling it in 
 the tallow of the candle. It is then tempered, by 
 covering the point lightly with tallow, holding 
 the stem just behind the point in the ilame till it 
 begins to give off a white smoke, and then cooling 
 it either in the tallow or in the air. 
 
 The exercises in hardening and tempering that 
 you have now gone through will give you a suffi- 
 cient comprehension of the general principles of 
 the process. A great variety of modifications of 
 the methods will be needed for ^vorks of different 
 sizes and shapes, and intended for different uses ; 
 but these will be easily nnderstood when the 
 necessity for them arises. 
 
 It might be supposed that, as cast-iron differs 
 from steel in the same way that steel differs from 
 w^rought-iron, namely, in having more carbon in 
 its composition, it might be hardened and soft- 
 ened in the same w^ay. This is to a certain extent 
 true. Cast-iron can be hardened by rapid cooling ; 
 but it requires a much higher temperatui'e for the 
 purpose than steel does. It must be cooled, not 
 merely from a red heat, but from the melting heat. 
 If cast-iron, when melted is poured into nionlds 
 of damp sand or of metal, it becomes very hard 
 on the surface. Such metal is called "chilled 
 
112 FIB8T LE8S0N8 IN METAL-WOBKINO. 
 
 iron/' and is sometimes used when great hardness 
 is required at moderate expense, and without re- 
 gard to toughness, as in ploughshares, ore-stamps, 
 rollers for pressing or crushing, and sometimes in 
 tools for turning iron and steel. Such metal, 
 however, is brittle and cannot be tempered, and is 
 not a fit substitute for steel in most of the uses to 
 which the latter is put. 
 
 Even when cast-iron is not intentionally chilled, 
 it is unavoidably hardened on the surface by the 
 chilling action of the mould, and this is one of 
 the reasons why the hard " skin" is commonly re- 
 moved with the chisel or planing-machine before 
 applying the file. 
 
 As cast-iron can be hardened by chilling, so 
 wrought-iron can be hardened on the surface by 
 baking it, at a red heat, w^hile surrounded with 
 powdered carbon. The resemblance between this 
 process and that of steel-making by cementation 
 is seen at a glance. Indeed, it is an imperfect 
 conversion of the iron into steel on the surface. 
 It is called ^' case-hardening," and is used for such 
 objects as the wearing parts of gun-locks, the ends 
 of axles, and other objects exposed to great wear 
 by rubbing. 
 
 Finally, as wrought-iron can be hardened, so, 
 by an almost exactly opposite process, cast-iron 
 can be softened. As wrought-iron is hardened 
 by absorbing carbon, so cast-iron is softened by 
 
HARDENING AND TEMPERING STEEL. 113 
 
 being made to give up carbon. For this purpose 
 it is packed in a substance containing oxygen, 
 sucli as lime (calcium oxide) or the scales from 
 the blacksmith's forge (iron oxide), and baked at 
 a red heat. A part of the carbon combines with 
 the oxygen, and escapes as carbonic oxide, leaving 
 an iron with a lower percentage of carbon, and 
 therefore I'esembling wrought-iron or mild steel. 
 Such iron is called " malleable" iron, and is much 
 used for small articles which require more tough- 
 ness than cast-iron possesses, but which are to be 
 made in large numbers, and with a cheapness ap- 
 proaching that of cast-iron. Hinges, gate-fixtures, 
 parts of harness, and a great number of small 
 household articles are made in this way. 
 
 It must be understood, however, that not every 
 kind of pig-iron can be used for the several kinds 
 of iron that have been described, but that one pig 
 or another, or a mixture of several, must be used, 
 according as high or low steel, foundry iron, 
 chilled iron, good forge iron or malleable iron is 
 required; and great skill and experience are 
 necessary to enable the iron-manufacturer to make 
 the proper selection in each case. 
 
114 FIBSl LES80NS IN METAL- WORKING. 
 
 LESSON XIX. 
 
 CHIPPING. 
 
 Objects made of iron, steel, or brass by casting 
 are frequently too rough to be used in the form 
 in which they come from the mould, and have to 
 be finished up by filing, grinding, scraping, and 
 polishing. Sometimes, also, it is necessary to take 
 off more metal than can be conveniently removed 
 by the file. On large and flat surfaces this may 
 be accomplished by means of a planing-machine ; 
 but on surfaces that are small, or of such a shape 
 that the planer cannot reach them, the part to be 
 removed is taken off by " chipping " with a cold- 
 chisel, that is, a chisel which can be used without 
 first softening by heat the substance which is to 
 be cut. 
 
 Two kinds of chisel, shown in Fig. 61, are used. 
 Tlie first. A, called a '■' cape" or cross-cut " chisel, is 
 made thin at c, but is widened, as shown at a^ 
 to f^ive it the needed sti'eiisrth. It is used in cut- 
 ting grooves. Being thinned at a little distance 
 back from its edge, it can be driven along the 
 
CHIPPING. 
 
 115 
 
 groove without catching at the sides, while the ex- 
 tra width at a prevents its ^'spiinging" under the 
 blow. The other, B^ is the " finishing " or " plan- 
 ing " chisel, and is used for cutting broader plane 
 surfaces. It is sometimes ground with a slightly 
 
 z::^ 
 
 p^^ 
 
 L^^ 
 
 rr 
 
 _.i 
 
 Fig. 61. 
 
 curved edge, in which case a very thin cut can be 
 made at the middle while the corners are not 
 cutting at all. Its action in this case is much like 
 that of the jack-plane, and leaves a series of shal- 
 low valleys on the surface that is finished with it. 
 
116 FIRST LESSONS IN METAL-WOBKING. 
 
 Tlie cMsel is tempered, as in Lesson XVI, to a 
 color which may range from yellow to purple, ac- 
 cording to the work it is to do. It will splinter 
 if it is too hard, and will turn up or become 
 rounded on the edge if too soft, and must then be 
 re-tempered. In any case, its edge must be kept 
 sharp by frequent use of the grindstone. The 
 angle also depends on the kind of work, as has 
 been explained in Lesson XVII. 
 
 As an exercise in the use of the chipping-chisel, 
 we will remove \'' from the surface of a cast-iron 
 block ^" square. We will first cut three grooves 
 
 Exercise 38. ^" ^^'^^^ ^^ ^^^ required depth, leaving 
 Chipping four surfaccs ■^-^" wide to be after- 
 cast-iron, wards cut down with the finishing- 
 chisel. It will be found that the work can be 
 done more easily in this way than by cutting the 
 whole surface at once with the finishing-chisel. 
 Lay out the face of the block for this work by 
 first rubbino; it all over with chalk, and then 
 drawing the necessary lines with a sharp-pointed 
 steel '^scriber" or marking-tool. Mark also, on 
 the edge, a line showing the depth to which the 
 work is to be cut. Put the block in one of the 
 heaviest vises on your bench. If there is a " leg- 
 vise," Fig. 62, use this, as being firmer than any 
 other. Place the block in the vise, with the lines 
 indicating the grooves perpendicular to the jaws, 
 and with the upper surface of the block only just 
 
CBIPPING. 
 
 117 
 
 above the edge of the jaws, and fasten it very 
 iirmly. Make sure that the liead of the chisel 
 and tlie face of the hammer are c[iiite free from 
 any trace of grease; by rubbing tliem on the dusty 
 
 Fig. 63. 
 
 floor. You will thus lessen the chance of the 
 hammer's glancing off and striking your hand. 
 
 In vise-w^ork hold the hammer less tightly than 
 in forge-work. Let it turn somewhat loosely be- 
 tween the forefinger and the thumb. 
 
 To begin the chipping, set the edge of the 
 
118 FIRST LESSON'S IN METAL-WORKING. 
 
 chisel at one end of the line drawn on the face, 
 and, holding it horizontally, strike it a vigorous 
 blow, cutting off a triangular chip, and making a 
 chamfer or bevel, as shown by the dotted line in 
 Fig. 63. Extend this along the whole length of 
 the end of the block, thus marking conspicuously 
 the depth to which the metal is to be removed. 
 Turn the piece in the vise, and cut a similar cham- 
 fer round each of the other pieces in succession. 
 
 ^rni 
 
 Fig. 63. 
 
 Now, using the cape-chisel, set it on the bev- 
 elled surface, at the end of one of the proposed 
 grooves, and with the edge about \" below the 
 upper surface, as in Fig. 64. Incline the handle 
 upwards, so that the lower cutting-face shall make 
 a very small angle, abd, with the intended direc- 
 tion of the cut, ahc. Hold the chisel firmly, near 
 the upper end, and keep your eye on the cutting- 
 edge, not on the handle. Using a hammer of 
 about If to 2^ lbs. weight, with a handle 13'' to 
 lA:" long, which you hold near the end, strike 
 the chisel with a vigorous swing of the hammer 
 from the elbow. Be careful to strike exactly in 
 
CHIPPING. 
 
 119 
 
 tLe direction of the leiigtli of the chisel, so that 
 it shall not receive any twist from the blow, but 
 move directly forward. It will cut off and curl 
 up a stout chip, exactly as the iron of the jack- 
 plane does, and being continually driven forward, 
 will Avork a shallow groove across the block. It 
 is important that you should hold the chisel at 
 the proper inclination. If the handle is held too 
 
 Fig. 64. 
 
 low, as in Fig. 65, the edge w411 be inclined up- 
 ward at Z*, and the tool will run up and leave the 
 cut. If it is held too high, as in Fig. ^'o, the 
 point will be driven too far into the metal, and 
 the cut will become so deep that the chip will 
 not curl up and break off, but the tool will be 
 brought to a standstill. 
 
 After the cut is started, you WiWfeel the proper 
 
120 
 
 FIRST LE880N8 IN METAL-WOHKING. 
 
 position of the chisel, by rocking it up and down 
 slightly, as you would rock a wood-chisel on the 
 oil-stone, to ascertain when the bevel - surf ace 
 touches the stone properly. 
 
 Fig. 66. 
 
 It is important, also, to strike powerful blows 
 with a free swing of the hammer from the elbow. 
 Light blows often repeated will not serve the 
 same purpose : they will not cut and shatter the 
 
CHIPPING. 121 
 
 metal. You may strike light blows at first, to 
 get your aim sure and your hand steady, but they 
 will not have much effect on the metal. Even at 
 the risk of striking your left hand occasionally, 
 you must hit hard. 
 
 In cutting the grooves, stop at about \" from 
 the end, and cut the opposite way, to avoid splin- 
 tering the metal. 
 
 In cutting wrought-iron, steel, or brass, wet the 
 edge of the chisel occasionally, by pressing it on 
 a bit of wet rag or cotton-waste kept for the pur- 
 pose. 
 
 A second and a third cut being made in the 
 same way as the first, you ^vill cut one of the 
 grooves, and afterwards all the others, down to 
 the required depth. Be careful not to go below 
 this depth at any point ; to fall short of it will 
 do less harm. 
 
 Having cut all the grooves with the cape- 
 chisel, cut down the bands between them with 
 the planing-chisel. If you have cut the grooves 
 to just the right depth, they will afford such per- 
 fect guidance to your chisel that you will cut the 
 rest of the surface with comparative ease. 
 
 If the work has been well done, the surface 
 will be uniformly marked all over with parallel 
 shallow notches, about equidistant and of equal 
 depth, indicating the successive forward steps of 
 the chisel. In perfect work, indeed, no such 
 
122 
 
 FIRST LESSON'S IN METAL-WORKING. 
 
 notches would be seen, because each forward 
 movement would be in the continuation of the 
 preceding cut. In practice such a result is not 
 to be expected ; but you should aim to come as 
 near it as possible. 
 
 The chipping of brass is similar to that of cast- 
 iron. The tool, however, may be thinner, and 
 have a smaller angle, as already explained. It 
 may also be wider (say 1''), as the same blow that 
 will drive a narrow chisel through cast-iron wdll 
 drive a wider one in brass. For an exercise in 
 brass-chipping, take the block prepared as a foun- 
 dry exercise, page 64, Fig. 50, and chip it to the 
 form of a hexagonal prism. 
 
 First, whitening the ends, lay out the bases of 
 the prism. Find the centre of each end by draw- 
 ing diagonals, and mark it 
 lightly with a centre punch. 
 With a compass, draw round 
 this the inscribed circle. 
 From a, Fig. 67, draw a line 
 on the rectangular face of 
 Fig. 67. the prism, parallel to the 
 
 edge, thus finding the corresponding point on the 
 other base, and draw the inscribed circle. Start- 
 ing from a^ lay off chords equal to the radius, find- 
 ing thus the points h, c, 4 e,f. Draw the hexagon 
 on each end of the piece. Connect the vertices 
 aa and dd of the two hexagons, by lines drawn 
 
CHIPPING. 123 
 
 on tlie faces of the block. Prolong ah, dc, af, de^ as 
 in the iigure. Connect the points gg^ 
 lili, ii^ Ilk, of the two bases by lines on Laying out a 
 the faces of the block. If now you cut hexagonal 
 oft' first the four pieces which have the P"^"^- 
 bases amg, had, doi, and alk, you will make a hex- 
 agonal prism, whose bases, however, are not regu- 
 lar. On the faces of this prism draw hh, cc, ee, and 
 ff\ and cut away the parts whose bases are hghc 
 and kfei, and tlie prism will be complete. 
 
 To cut off all these parts, first hold the block 
 endways in the vise, its edges perpendicular to the 
 jaws and the line (^/'^ parallel to them. Beginning 
 near m, cut oif a piece along the whole edge mmy 
 just as in the last exercise. As the chisel ap- 
 proaches the end of the cut, turn the piece round 
 and cut in the opposite direction, so as not to 
 splinter the base. Repeat this till you have cut 
 down to ag, being careful not to go beyond. The 
 first cuts, being narrow, may be deeper than the 
 succeeding ones. Repeat this operation at the 
 other three corners. Then, having drawn the 
 new lines bh, cc, ee^ff, cut oif the remaining por- 
 tions in the same way. If you have not cut quite 
 down to the required surfaces at first. Exercise 40. 
 you may use a thinner and sharper Chipping 
 chisel and a lii^hter liammer for the ^^^^^" 
 finish, making constant use of a straight-edge and 
 a "template" or plate of brass, Fig. 68, whose 
 
124 FIRST LESSONS IN METAL-WORKING. 
 
 angle is 120°, to make sure that you are not cut- 
 ting anywhere too deep. Having made one face 
 as straight and smooth as possible, and free from 
 winding (Wood- working, page 54), apply the tem- 
 plate repeatedly to this w^hile working the next 
 face, so as to give the next the proper inclina- 
 tion to this. When the two faces adjacent to the 
 first are finished, give the next two the proper 
 inclination to these. If this has been correctly 
 done it will be easy to give the last face the 
 proper inclination to the two preceding ones. In 
 
 Fig. 68. 
 
 applying the template, it is of the utmost impor- 
 tance that both arms of it should be exactly per- 
 pendicular to the edge of the prism which lies be- 
 tween them ; otherwise you will make the angle 
 of the prism too obtuse. Very close attention to 
 this is absolutely necessary, as is also perfect cor- 
 rectness in the angle of the template itself. Of 
 course, if the two bases have been drawn exactly 
 correct and with their corresponding sides parallel, 
 you have only to cut down to these lines and then 
 work with the straight-edge alone, the tem23late 
 
CHIPPING. 125 
 
 being uu necessary ; but your work will hardly be 
 exact enougli for this. 
 
 The faces of the prism being finished, the bases 
 are to be cut off in the same way, perpendicular 
 to the faces, and ^^-^" apart, the work being tested 
 as it proceeds \vith straight-edge and square. The 
 result should be a true hexagonal prism Syig'^ high, 
 its opposite faces being equal and parallel rectan- 
 gles, its edges straight, and its angles all equal to 
 that of the template. There should be no marks 
 extending conspicuously below the general sur- 
 face so that they cannot be easily removed by the 
 file, as in a later lesson. 
 
126 
 
 FIRST LESSONS IN METAL-WORKING. 
 
 LESSON XX. 
 
 DEILLIJSTG ATn^D SAWING. 
 
 In the chipping exercises just finished, no large 
 amount of metal had to be removed, though the 
 quantity to be cut away was larger than it would 
 
 
 
 ^^ 
 
 
 
 J • -1^ — 
 
 S-cmr >■ 
 
 
 ^ ( 
 
 ) 
 
 f 
 
 B 
 
 
 Fig. 69. 
 
 be proper to attack with the file. In some cases 
 a larger piece has to be removed, as when a cor- 
 ner is to be cut out of a block of metal A^ or a 
 slot to be made in one, as J3. In such a case the 
 piece is cut out with a " hack-saw," Fig. 70. The 
 teeth of this saw have their front edges perpendi- 
 cular to the edge of the saw, and their back edges 
 inclined to it, as in the rip-saw (Wood- working, p. 
 
DRILLING AND SAWING. V21 
 
 88). They therefore cat under the metal, some- 
 what as a chipping-chisel does, removing the metal 
 in small chips, like the saw dust from a wood-saw. 
 Its teeth have no "set," as those of wood-saws 
 generally have, but are sometimes made a little 
 thicker than the back of the blade, by setting the 
 saw up on its back edge on a block of hard wood 
 before sharpening it, and hammering the points 
 
 Fig. 70. 
 
 of the teeth lightly. This not only spreads them 
 out sideways and gives the tool the extra thick- 
 ness on the edge which makes it run freely, but 
 at the same time brings the points of the teeth 
 into a straight line. This is very essential to the 
 proper working of a saw, whether in wood or in 
 metal. If any of the teeth stand up above the 
 rest, they catch in the work and make the saw 
 jump and " chatter." Sometimes this thickening 
 of the edge of the teeth is omitted, the " burr" or 
 roughness left by the file being sufficient to give 
 the needed " set." 
 
 The cutting of the slot B, Fig. 69, Exercise 41. 
 
 in a plate of h" brass will be a good Drilling, 
 exercise in the use of the saw and of the " ratchet- 
 
128 
 
 FIRST LESSON'S IN METAL- WORKmO. 
 
 drill." The slot is commenced by boring two holes 
 
 for its ends with the 
 hand-drilling machine, 
 Fig. 71, or the ratchet- 
 diill, Fig. 72. Mark 
 the exact positions of 
 the centres of the holes 
 with a centre-punch. 
 Provide a drill 1 cm. 
 wide, such as you made 
 in Exercise 37. If you 
 have not one of exactly 
 the ri2:ht width, alter a 
 wider one^ by reducing 
 it on the grindstone, 
 being careful to reduce 
 both sides equally. 
 
 The ratchet-drill is 
 made in various forms, 
 but the essential prin- 
 ciple of all is the same. The work to be 
 drilled rests, at A^ on blocks supported on the 
 frame-work B, which may be screwed to the 
 bench. A screw (7, which must be turned by 
 hand as the boring progresses, or else a l^ver 
 worked by the hand of an assistant, presses the 
 drill D down. A lever or handle E^ provided 
 with a spring " pawl " concealed in the box F, 
 turns on the axis or shaft of the drill. The pawl 
 
 Fig. 71. 
 
DRILLING AND SAWINO. 
 
 129 
 
 slips by the teetli of a tootbed wheel which is at- 
 tached to the axis, when the handle is turned in 
 one direction, but catches the teeth and turns the 
 drill when moved in the opposite direction. The 
 hand-drilling machine, Fig. 71, is used for the 
 same purpose, and is even more convenient. 
 
 Tgrrgr 
 
 Fig. 72. 
 
 Setting the plate on the bottom of the frame- 
 work of the drill, and supporting it on blocks, if 
 necessary, to raise it to the pi-oper height, turn the 
 screw at the top till you bring the point of the 
 
130 FIRST LES80N8 IN METAL-WORKING, 
 
 drill down into the hole made by the centre-punch. 
 Fasten the work so that it cannot turn. Turn the 
 drill by means of the handle, and keep moving it 
 down at the same time by means of the " feed "- 
 screw. Lubricate the point with oil or with soap 
 and water in cutting brass, wrought-iron, or steel ; 
 for cast-iron this is not necessary. Do not " feed " 
 or force the drill forward too fast, or you will 
 break it, or spoil its temper. Let the drill, when 
 it comes through, come out into a hole in the sup- 
 port, or else have a block of wood immediately 
 under the work. 
 
 The tw^o holes being bored, draw two parallel 
 lines tangent to them with the scriber, thus mark- 
 Exercise 42. ^^o ^^^ ^^^^ ^^^^ shape of the piece to 
 Cutting a be rcmovcd. Holding the piece in the 
 ^^°*" vise, and using a square file, cut one of 
 
 the holes to the shape shown in Fig. 73, forming 
 
 thus flat sides against which 
 the sides of the saw can rest. 
 Loosening the screw at the 
 end of the saw-frame, un- 
 hook the saw, put the blade 
 through the hole, hook it and 
 ^^^- '^'^- tighten it again, and cut down 
 
 to the other hole. Use oil to make the saw work 
 freely, except in cast-iron. Do not press too hard, 
 and be careful not to run outside of the line. 
 The first cut being made, carry the saw back 
 
 Q 
 
DRILLING AND SAWING. 131 
 
 to the first bole, and cut tlie second line in the same 
 way. The piece between the lines being removed, 
 the roughly framed slot can be finished >vith the 
 file as in the next lesson. 
 
 Such a piece is sometimes removed by boring 
 a series of holes close together along the whole 
 length of the slot, and then cutting away the metal 
 between them with a round file. 
 
132 FIRST LE8S0N8 IJST METAL- WORKING. 
 
 LESSOJST XXI. 
 FiLnsra. 
 
 After chipping and sawing, the work is ready 
 to be smoothed w4th the file. 
 
 The iile is a series of small chisels, finer or 
 coarser according to the work required of them. 
 These minute chisels are made by cutting numer- 
 ous fine grooves very close together in a bar of 
 steel shaped as in Fig. 74. If only one such set 
 of grooves is cut, the file is called a '^ single-cut " 
 file or "float," and appears as shown in the upper 
 part of Fig. 74, a. The appearance of the teeth 
 is shown, magnified, at d. The w^hole face of the 
 file is thus a series of chisels, each having a breadth 
 equal to the length of one of the lines in a, inclined 
 to the axis of the file at an angle of 35° to 55°, 
 and having their sharp edges turned towards the 
 point of the file. Files of this sort are only used 
 for soft materials, such as wood, horn, and lead. 
 When very coarse, as in the case of the files used 
 for lead, the cuts are almost 23erpendicular to the 
 length of the file. The files used for such work 
 as you will undertake, or for metal-work in gen- 
 
FILING. 
 
 133 
 
 eral, have two such sets of grooves, and are called 
 "double-cut." The first cuts are made as already- 
 described, and the second, which are not quite so 
 deep, cross these, as show^n in the lower part of 
 
 U 
 
 Fig. 74. 
 
 the figure, being inclined to the axis in a direction 
 opposite to the first, at an angle of from 75° to 85°. 
 The wide chisels of the first cut are thus divided 
 into a large number of small-pointed teeth. The 
 teeth of any one row being pushed across the 
 
134 FIR8T LESSON'S IN METAL-WORKINO. 
 
 work would make a series of fine grooves ; but the 
 teetli of the next rows following these, cut down 
 the ridges between these grooves, and so gi'adually 
 plane the work down. 
 
 Double-cut files have various names to distin- 
 guish the degrees of fineness or the closeness of 
 the grooves. These names differ somewhat in 
 the different regions in which files are .made, the 
 Lancashire names and the Sheffield names, for 
 instance, being not exactly the same. Without 
 learning both series of names it will be sufficient 
 to remember that, in both sets, the coarsest files 
 are called ^^ rough," and the very fine ones 
 '^smooth." Intermediate ones, following the rough, 
 are ^'bastard" and "second-cut," and a still finer 
 kind than the smooth are called ^' dead-smooth" or 
 "superfine." 
 
 It may be remembered also that the "rough" 
 Lancashire files have from 21 to 56 cuts to the 
 inch, the "smooth" from 56 to 112, and the "su- 
 perfine" as many as 300 in the case of the small- 
 est files. "^ 
 
 The grooves are cut with a chisel while the file 
 is soft, and it is then hardened and tempered ac- 
 cording to the kind of work it is to do, and the 
 "tang" or pointed end is softened to prevent its 
 breaking. 
 
 The description of the mode of cutting the 
 
 * Holzapfel: Turning and Mechanical Manipulation. 
 
FILING, 135 
 
 teeth of a clouble-cut file, or an inspection of the 
 teeth with a mao:nifvino^-2^1ass, will convince you 
 that files are delicate tools, and that they can be 
 easily injured by improper treatment. A few 
 precautions may be given here to enable you to 
 avoid the commonest errors, and others will 
 come to your notice afterwards, as your work pro- 
 gresses. 
 
 1. A new file must not be used on wrought-iron 
 or steel. These can be cut with a file that is 
 partly w^orn, but cast-iron and brass require new 
 and sharp files. 
 
 2. No file, unless it be one that is almost worn 
 out, should be used on chilled castings. The sur- 
 face of a casting should be carefully tried with an 
 old file, and if it is found to be very hard, the 
 skin must be removed on the grindstone. 
 
 3. No file should be used on castings, whether 
 hard or soft, in the state in which they come from 
 the foundry. The surface is covered with sand, 
 which will spoil any file. This is sometimes re- 
 moved by " pickling" in dilute sulphuric acid, 
 which eats away a portion of the iron and loosens 
 the sand so that it can be washed off. When the 
 figure of the casting is such that the surface can- 
 not be reached by the grindstone, this is the only 
 effectual method, excej^t chipping, of preparing 
 the work for the file. 
 
 4. The file should always be relieved from pres- 
 
136 
 
 FIRST LES80N8 IN METAL-WOBKINO. 
 
 sure while it is being drawn back, as lieavy pres- 
 sure on tlie backs of tke teetb breaks tkem oft*. 
 It is not necessary, however, to lift the file from 
 the work, but only to lessen the pressure. 
 
 5. The teeth of the file should be ke]3t clean. 
 They are apt to become " clogged, or " pinned " by 
 
 (T 
 
 Fig. 75. 
 
 the dust cut off, which must then be removed. 
 This can be done in several ways. The "pins" 
 may be pushed out with a pointed steel wire, Fig. 
 75, A. They may be brushed out with a wire file- 
 brush, B, of fine brass or steel wire, bound into a 
 bundle with the ends projecting; or they may be 
 raked out with the scraper, c, made of a piece of 
 sheet-brass hammered to an edge and bent at right 
 
FILING. 137 
 
 angles, into whicli the teeth of the file will cut 
 when it is drawn over them, allowing the inter- 
 mediate points to penetrate into the grooves and 
 clear them. 
 
 The file should be fitted w^th a handle of soft 
 wood. To put the handle on, hold the file in the 
 vise, protecting it from the 
 steel jaws by false jaws 
 of lead, A, Fig. 76, and 
 leaving the tang project- 
 ing forward. Then, tak- ^^^- ^^• 
 ing the handle in the hand, push the tang into it, 
 turning the handle at the same time, to let the 
 tang bore its way. Take the handle oif and 
 knock out the shavings, and repeat the operation 
 till the tang has entered about three quarters of 
 its length, or a little more, leaving the rest for 
 future use as the handle wears loose. The handle 
 is sometimes fitted by heating the tang to redness 
 and pushing it in, letting it burn its way. This 
 method is objectionable, however ; first, because 
 of the risk of overheating the file, and secondly, 
 because the charred wood wears away soon, and 
 lets the handle come loose. 
 
 Besides the differences in the teeth of files, there 
 are differences in size and shape, adapting them 
 to different kinds of work. The files that will be 
 most useful in snch work as you will do are such 
 as are shown in Fig. 74, and are called "taper- 
 
138 FIRST LESSONS IN METAL-WORKING. 
 
 flat." Their cross-section is rectangular; but they 
 are not of equal section throughout, being tapered 
 both in breadth and thickness, and swelled or 
 "bellied" in the middle. They vary in length 
 from about 4 to 24 inches, and will be most con- 
 venient for your work if about 10 to 12 inches 
 long. With such a hie you may now produce a 
 smooth, plane surface on the cast-iron block of 
 Exercise 37. Use a somewhat coarse file for the 
 first steps of the work, and afterwards, for finish- 
 ing, a finer one. Put the block in the vise with 
 Exercise 42. ^^^^ chippcd face about \" to \" above 
 Filing a the Jaws. For work such as this the 
 
 plane surface. ^^-^^ ought to be at such a height as to 
 
 bring the work about to the level of the elbow. 
 For much larger work it should be lower, to 
 enable you to throw the weight of the body on 
 the file, and for very small and fine work, higher, 
 to allow you to see it more distinctly. Spread 
 your legs apart a little, clasp the file in the right 
 hand, the fingers being below and the thumb on 
 top, hold the point of the file between the thumb 
 and fingers of the left hand to press it down, and 
 push the tool forward. The length of the file 
 should point not straight forward, but a little 
 towards the left, and the movement of the hand 
 should also be a little towards the left as well as 
 forward, but with occasionally a few strokes to- 
 wards the right to prevent the teeth from follow- 
 
FILING. 
 
 139 
 
 iug their old tracks and scratching the work too 
 deeply. 
 
 The principal difficulty in using the file is to 
 move it forward without giving it a rocking mo- 
 tion — a difficulty about the same as that encoun- 
 tered in using the jack-plane (Wood-working, p. 
 64). If you lower the point as you push it for- 
 ward and raise it as you draw it back, as you will 
 find yourself inclined to do, you w\\\ cut off the 
 front and rear edges of the work more than the 
 middle, and will produce a curved surface ; but if 
 you keep the file quite level and move it with long 
 strokes, you will cut equally across the whole 
 breadth, and produce a plane surface. Test your 
 work with respect to this point from time to time 
 as you proceed, by applying a "straight-edge." 
 Tt will not be enough to apply the straight-edge 
 in one direction, parallel, for instance, to a b, Fig. 
 77, because it is possible for the lines a b, c d 
 and E F to be all straight, 
 and yet the surface not to 
 be plane but to have two 
 oj^posite corners, as a and 
 F, higher than the others. 
 Neither is it sufficient to 
 apply the straight - edge 
 parallel to one of the 
 diagonals; but if it is applied parallel to both 
 dia2:onals and both edges, it will be impossible for 
 
 H 
 
 Fig. 77. 
 
140 FIRST LESSON 8 IN METAL-WORKING. 
 
 it to touch along all these lines if the surface is 
 warped, or "in winding." Trying the surface, 
 therefore, in all directions, and removing the high 
 parts carefully with the round or bellied part of 
 the file, and with lighter and lighter strokes as 
 the piece becomes more and more nearly true, you 
 will finish it at length to a true plane, or as nearly 
 so as it is practicable to make it with the file. 
 
 As another exercise, involving gi-eacer difficul- 
 ties than the last, you may now finish up the 
 hexagonal prism of brass made in Exercise 39. 
 
 You will make, 1st, one of the hex- 
 Exercise 43. -IT -, T T 1 , 
 
 Filing up a agonal bases plane and perpendicular to 
 hexagonal the faccs of the prism ; 2d, the other 
 prism. ^^g^ plane, parallel to the first, and at 
 
 the proper distance (2'') from it ; 3d, one of the 
 rectangular faces plane, of the proper width, and 
 perpendicular to the bases; 4th, two adjacent 
 
 faces plane, of proper width, 
 perpendicular to the bases, and 
 inclined at the proper angle 
 (120°) to the first face; 5th, the 
 last three faces plane, parallel to 
 the first three, and of the proper 
 width. 
 
 First try with a square, as in 
 Fig. 78, whether one of the bases 
 is pei'pendicular to the six faces. 
 If either of the angles is acute, the base is to be 
 
FILING. 141 
 
 filed off at this place. Holding the block in the 
 vise, file the base true as in the last exercise, iisinof 
 a coarse file first and afterwards a new and fine one 
 and trying the surface in all directions with a short 
 thin-edged straight-edge while working, and with- 
 out removing the piece from the vise for the pur- 
 pose. 
 
 When this surface will bear every test, proceed 
 to the next — the opposite base. Since this is to 
 be made parallel to the first, whether that is per. 
 pendicular to the faces or not, it is to be tested, 
 not w4th the square, but with the straight-edge 
 and the calipers, Fig. 79. They are opened to the 
 width of exactly 2'', and are 
 to be applied to the work 
 repeatedly as the second sur- 
 face approaches completion, 
 to prevent the cutting away 
 of more than the proper 
 amount of metal. Before 
 the piece is ready, however, 
 for the use of this tool, it is 
 to be first marked to the 
 proper height, and then cut 
 down close to the mai'k. The rectangular faces 
 being too rough to show a fine mark, may be first 
 filed smooth enough for this purpose. To avoid 
 injuring the finished base in this operation, use 
 the false Jaws of lead or brass. Be careful, in this 
 
142 FIRST LESSONS IN MUTAL- WORKING. 
 
 first filing of these faces, to take off no more than 
 just enough to enable them to show a fine mark. 
 Chalk the sides. Set the piece up on its finished 
 base, on a "surface-plate." This is a square plate 
 or block of hard cast-iron, which has been finished 
 as nearly as possible to a true plane surface, and 
 serves as a standard of comparison for other sur- 
 faces which are to be made plane. The prism 
 being set on this, is held firmly with one hand, 
 while the " scriber block" s. Fig. 80, is held on the 
 plate with the other hand, and the "scriber- 
 point," p, after being set to the exact height of 2'' 
 above the base by the screw v, is carried carefully 
 round all the faces of the prism, making a fine 
 mark. Then, holding the prism in the vise, cham- 
 fer the upper base down to this mark, and cut it 
 down, first Avith a coarse and afterwards wdth a 
 fine file. As you approach the mark, work more 
 and more carefully. When very near the mark 
 use the calipers frequently at all points of the two 
 bases, till the prism measures exactly Exercise 44. 
 the right height at all points. Be Use of scriber 
 careful not to force the calipers, nor ^ndcaUpers. 
 yet to make them go on too loosely. They must 
 just touch closely, and so that no rattle is possible. 
 If the joint is tight, as it ought to be, the width 
 between the points will not be altered by sliding 
 them on and off repeatedly, unless considerable 
 force is used. Furthermore, they must be held in 
 
FILING. 
 
 143 
 
 the proper 2^<^sitioii while being usea. If one 
 point is farther advanced on the surface than the 
 other, as at a, Fig. 81, you may work the piece 
 
 Fig. 80. 
 
 too short; and you will do the same if one is in- 
 clined to the right of the other, as at b. In short, 
 the line joining the two points must be exactly 
 perpendicular to the two surfaces, and when it is 
 
144 
 
 FIRST LESSONS IN METAL-WORKINO. 
 
 held thus, the two points must just touch botK 
 surfaces. Finally, the calipers must be handled 
 
 Fig. 81, a. 
 
 carefully, being laid down on the bench gently, 
 so as not to alter their adjustment, and must be 
 
 Fig. 81, b. 
 
 occasionally tested by comparison with the rule, 
 or with a block already finished to the right size. 
 When the distance between the two bases is 
 
FILING. 145 
 
 everywhere exactly 2", the second surface is parallel 
 to the first, and is plane, provided the first is so. 
 Yon should not neglect, hoAvever, to apply the 
 straiorht-edixe in all directions on the second sur- 
 face, as an additional test. This may be done 
 without removing the piece from the vise, if you 
 stoop down, so as to see under the edge. 
 
 Protecting the finished bases by false jaws, file 
 up one of the faces. The process is essentially 
 the same as before, but even more care is neces- 
 sary, to avoid filing away too much. As all the 
 lines previously drawn on the bases have been 
 filed away, it will be well to draw them again, 
 but very lightly, with sharp-pointed compasses 
 and a marking-awl, and then take care not to 
 work beyond them. When one of the rectangu- 
 lar faces has been finished, the template should be 
 used, as well as the straight-edge, in filing the 
 others, care being taken, however, to test the cor- 
 rectness of the template, and to a^^ply it properly, 
 as explained in Exercise 39. 
 
 If properly finished, the prism will stand the 
 followino; tests : 
 
 1°. All the surfaces, as tested with the straight- 
 edge, will be true planes. 
 
 2°. Each pair of opposite surfaces will be par- 
 allel, as shown by the calipers. 
 
 3°. All the faces will be perpendicular to the 
 bases, as shown by the square. 
 
146 FIR8T LESSONS IN METAL- WORKING. 
 
 4°. AH the angles will be true, as measured by 
 tbe template. 
 
 5°. All the faces will be of equal width. 
 
 6°. All the edges will be straight and sharp, 
 and all the surfaces smooth, and free from coarse 
 scratches, showing only the fine and regular marks 
 of the file. 
 
 Other methods of producing a finer finish on 
 surfaces, known as draw-filing, scraping, grinding, 
 oil-finishing and polishing, will be explained here- 
 after. 
 
 As a last exercise in filing, finish the slot that 
 you began in Exercise 41, making it 84 mm. X 12 
 mm. The surface being in this case narrow, con- 
 siderable care will be needed to avoid cutting off 
 one edge more than the other, and you must look 
 frequently at the back of the work to see that you 
 are not passing the mark. You will lessen the 
 trouble of this part of the work^ if, as in working 
 to a mark in general, you first cut, on each side, 
 a chamfer down to the mark, which will then 
 serve as a guide. The ends of the slot, which 
 were left round by the drill, are to be filed square 
 with the edge of the file. After the ends are 
 finished, if any more work is to be done on the 
 sides, for the purpose of finishing up the corners 
 sharp and clean, the ''safe edge" of the file which 
 has no teeth, should be used in the corner, so as 
 to avoid injuring the finished end. If the file hao 
 
FILING. 147 
 
 BO safe edge, you can make one by gi'indmg off 
 the teetli on one edge. This will be even better 
 than the safe edge made by the manufacturer, as 
 the teeth on the face will come up more sharply 
 to the edge, and will finish the comers better. 
 The tests of the work are obvious. The sides and 
 ends must be straight and plane, and perpendicu- 
 lar to the face of the plate and to each other, and 
 the slot must be exactly true to the proposed 
 dimensions, 84 mm. X 12 mm. 
 
148 FIRST LESSONS IN METAL- WORKING. 
 
 LESSON XXII. 
 
 SOLDEEING. BUNSEN BUENEE. 
 
 We have now learned how to give approxi- 
 mately any desired form to wroiight-iron or steel 
 by forging and welding, and to cast-iron, steel, 
 brass, zinc, and other easily fusible metals by 
 founding. When the approximate form has been 
 given, we have seen how to produce small changes 
 by chipping and filing. We have now to learn 
 another method of building up complex forms by 
 uniting simpler pieces, which partakes in part of 
 the nature of welding, and in part of that of cast- 
 
 Soldering is uniting two pieces of metal by 
 means of another metal. This other metal may 
 be, first, one which melts at a lower temperature, 
 and which adheres closely to the two pieces or 
 partially combines Avith them and thus joins them 
 together ; or, secondly, it may be the same metal 
 as that of which the two pieces are composed. In 
 the first case the operation is very much like that 
 of gluing. It is called " soft soldering" when the 
 
SOLDERING. BUNSEN BURNER. 
 
 149 
 
 solder is an alloy of tin and lead, sometimes with 
 the addition of bismuth to make it more fusible ; 
 anc! ''hard soldering" when a less fusible material 
 is used, as gold, silver, copper, or an alloy of tin 
 lead, and zinc, called spelter solder. In tbe second 
 case, when the pieces are joined by a portion of 
 the same metal, the operation is moi'e analogous 
 to welding, and is called "burning" or ''brazing." 
 A few examples will make clear the nature of the 
 operations and the mode of proceeding. 
 
 For a first exercise, join with soft solder tw^o 
 pieces of brass in the manner shown in Fig. 82. 
 File the edo-e of the 
 piece A straight and 
 square. Scrape or file 
 the surface of b clean, 
 where a is to join it. 
 The two are now ready 
 for the solder. 
 
 As in welding, so in 
 soldering, it is necessary ^^^- ^^- ^^"^^ ^^^^'^ 
 
 that the two surfaces should be clean and free 
 from oxide. A flux is therefore used as in weld- 
 ing, to carry off the oxide that will be formed on 
 the surface when heated, as well as any dirt that 
 may be there. Various fluxes are used for differ- 
 ent kinds of work, as borax, sal ammoniac, resin 
 and muriate of zinc. For this exercise we will use 
 the last. It is prepared by dissolving scraps of 
 
 3B 
 
 A 
 
150 FIRST LESSONS IN METAL- WORKING. 
 
 ziiic in dilute liydrochloric acid. A small wide- 
 necked bottle of this solution is kept on the bench 
 ready for use. It should have a piece of iron wire 
 thrust through the cork and dipping down into 
 the fluid. With this a drop or two of the fluid can 
 Exercise 45. t>e applied to the surface of a piece of 
 Soldering metal as needed. Or, a stouter piece of 
 brass with ^'^^^ may be fltted with a wooden handle 
 soft solder. and uscd for this purpose, as well as 
 for '^ tinning" small surfaces, such as those of this 
 exercise. For the latter purpose the wire must it- 
 self be tinned at the end. To tin the wire, dip it 
 into the solution, then hold it in the flame of the 
 Bunsen burner, the outer tube of the burner being 
 turned so as to admit plenty of air, giving a blue 
 flame. If the air supply is insufficient, the flame 
 will be yellow and smoky, and not so hot. Rub 
 the end of the wire with the solder-stick, using 
 the " tin-solder" compound of 3 parts of tin to 2 
 of lead, or 2 of tin to 1 of lead. The solder will 
 adhere to the surface wherever it is clean. If 
 there is any spot where it does not adhere, it nmst 
 be cleaned with the file or a piece of sandstone, 
 and the operation repeated. With the tinned wire 
 we can now tin the surfaces of the brass. Hold 
 the piece a in the flame with pliers. Apply a 
 drop of the flux to the edge with the tinned wire, 
 and as it boils off rub the wire to and fro alonsr 
 the edo-e till the latter is covered with a brio^ht 
 
SOLDERING. BVN8EN BURNER. 
 
 151 
 
 clean layer of the solder ; or, toucli it witli the sol- 
 der stick till a drop of the solder adheres, and 
 then spread it along the edge with the wire. With- 
 
 FiG. 83. 
 
 draw it from the flame and let it cool. Tin in the 
 same way the portion of b on which a will rest. 
 The two surfaces will now unite, if held together 
 
152 FIRST LESSON'S IN METAL- WORKING. 
 
 wMle the solder is melted. They may be held 
 together in various ways. 
 
 1. The piece b may be laid on a retort-stand, 
 Fig. 83, and the piece a set up on it at the proper 
 place. The fiame being then applied below b, 
 the solder will melt, and then, the ilame being re- 
 moved, the piece will cool. As the two surfaces 
 of the solder are somewhat round, it is difficult to 
 
 make the thin piece a stand 
 
 upright. It may be held 
 
 down during the melting 
 
 with a pointed wire, or still 
 
 better by means of a wire 
 
 spring of hard brass, as in Fig. 84. In either case 
 
 it will be best to file the two round surfaces of the 
 
 solder flat before putting them together. Or, 
 
 2. The pieces may be held, one in each hand, 
 with a pair of pliers, [and pressed lightly to- 
 gether in the flame till the solder melts, and then 
 removed to cool. Or, 
 
 3. Clamped together by the spring as in case 1, 
 they may be held in the flame wdth a pair of 
 pliers, and soldered and cooled as before. 
 
 With such light pieces as these the last method 
 will probably be found the most convenient. If 
 the piece a were considerably heavier, and broader 
 at the base, its own weight would keep it in posi- 
 tion, and no special device would be needed for 
 holding it. 
 
SOLDERING. BUN SEN BURNER. 153 
 
 The two pieces of this exercise may be soldered 
 without previous tinning, if the surfaces are thor- 
 oughly clean. Hold the pieces together with a 
 spring, as before. Taking b in the pliers with 
 the left hand, put a drop or two of flux, and a few 
 small chips of solder cut off with a knife, in each 
 of the angles. Heat the pieces in the flame. First 
 the flux will flow into tlie joint and afterwards 
 the solder. If the solder does not spread along 
 the whole length of the joint, draw it along with 
 the end of the fine wire which is in the bottle. 
 Cool as before. 
 
 In whichever way the pieces are prepared and 
 heated, the principal points to be heeded are : 
 
 1. To have the surfaces quite clean. 
 
 2. Not to allow the pieces to be displaced by 
 the boiling of the flnx or the melting of the solder. 
 
 3. Not to hold the pieces in the flame longer 
 than is necessary to melt the solder, as overheat- 
 ing burns the solder and weakens the joint. 
 
 4. Not to disturb the pieces till the solder has 
 " set," or hardened. The moment of setting can 
 generally be observed by watching closely. At 
 this moment the bright surface of the solder be- 
 comes dulled by the formation of a multitude of 
 minute wrinkles as the metal contracts. The 
 cooling may be hastened, in the case of very light 
 pieces, by blowing, and in that of heavier pieces 
 by applying a few drops of water. 
 
154 
 
 FIRST LE8S0N8 IN METAL- WORKING. 
 
 5, IN^ot to use too much solder. Besides being 
 wasteful, this fills up the angle, and the excess 
 will have to be filed away to make a neat job. 
 
 Where gas cannot be used, the exercises of this 
 lesson can be performed Avitli a blow-pipe (as in 
 Lesson XXIV) or with a blast-lamp, Fig. 85. 
 This is an alcohol lamp, a, ^vhich burns under a 
 vessel of alcohol, b. The alcohol in b boilins^, 
 
 Fig. 85. 
 
 drives off first the air and then alcohol vapor 
 through the tube c, thus blowing a strong blast 
 through the fiame of the lamp, and shooting out a 
 tongue of hot flame which can be directed on the 
 work. If the lamp alone is used, and the blast is 
 produced by blow^ing with the mouth through a 
 bent tube, the instrument becomes an ordinary 
 blow-pipe. 
 
SOLDERING. BUN8EN BURNER. 155 
 
 It is obvious that such a joint as that in the 
 last exercise cannot have any very great strength. 
 It will nevertheless often be useful when, as in 
 experimental work in the physical laboratory, it 
 is desired to put two pieces together quickly, and 
 strength is not important. 
 
 Let us nov/ look a little more closely into the 
 strength of a soldei'ed joint. Join two pieces of 
 
 Fig. 86. (Full size.) 
 
 brass with a " lap-joint" as in Fig. 86, cleaning 
 and tinning the surfaces, and holding them to- 
 gether in the flame with a pair of pliers. Put the 
 jointed strip into the small testing-machine (Wood- 
 working, Fig. 8, p. 19), and pull till Exercise 46. 
 
 the joint breaks. Record the force Testing a soi- 
 used. Put one of the pieces into the d^^^^J^i^t- 
 machine and break it, and record the force used. 
 Find, 
 
 1. How^ many times stronger the brass is than 
 the soldered joint. 
 
 2. How many times stronger the brass is than 
 a soldered joint of the same area as the cross-sec- 
 tion of the brass ; and thence, 
 
156 FIRST LESSONS IN METAL- WORKING. 
 
 3. How large the joint should be to be just as 
 strong as the brass. 
 
 Then make another joint of the same kind, 
 with a lap just sufficient to make the joint as 
 strong as the metal. Test the metal and the joint 
 in the machine and record the result. You will 
 know henceforth how large a joint surface to al- 
 low, with this kind of solder and this kind of 
 brass, if you wish the joint to be as strong as the 
 metal. Stronger than the metal it is not worth- 
 while to make it. 
 
SOLDEIUNO. THE SOLDERING IRON. 157 
 
 LESSON XXIII. ] 
 
 SOLDERmG. THE SOLDERING-IEON. 
 
 Whett the pieces are large, it is convenient and 
 usual to heat only the part which is to be soldered, 
 leaving the rest cool. This is done with the" bit" 
 or "soldering-iron." 
 
 The iron is first to be tinned. Heat it to a dull 
 red on a charcoal fire, or over a large Bunsen 
 burner. File the sides bright, quickly. Exercise 47. 
 Rub it on a piece of board sprinkled Tinning a soi- 
 with powdered sal-ammoniac or resin, enng-iron. 
 and then on a plate of copper on which are some 
 chips of solder. Wipe it clean with a rag. If 
 you have allowed it to fall below the temperature 
 at which solder melts, the operation will fail, and 
 reheating will be necessary. If afterwards, in 
 using the soldering-iron, you overheat it, the tin 
 will burn off, and you will have to tin it again. 
 
 We will now make a joint somewhat like that 
 in Exercise 45, but longer and stronger, and be- 
 tween two sheets of tin (that is, tinned iron), ar- 
 ranged as in the isometric sketch. Fig. 87. Mois- 
 
158 FIBST LESSONS IN METAL- WORKING. 
 
 ten the angle c between the two pieces witli flux, 
 or sprinkle it with powdered resin. Scatter along 
 it small chips of solder. Hold the piece a down 
 firmly at one end with the end of a file, or any 
 pointed tool, and melt a drop of solder in the 
 angle. This will fasten or " tack" the piece at 
 one end. Tack it in the same way at the other 
 
 __,< 2^ > 
 
 Fm. 87. 
 
 end. This will hold it in place while yon finish 
 the job. Hold the piece level, or inclined in such 
 Exercise 48. a way that the solder shall run into 
 Soldering the joiut. Draw the bit slowly along 
 
 with the sol- .^ t ij.* ii ii n 
 
 derin«r.iron ^^^ angle, melting the solder and caus- 
 Tin on tin. ing it to run into the joint. If any part 
 is missed, go over it again in the same way. 
 
 The two sheets of metal in the last exercise are 
 in planes perpendicular to each other. In this 
 case, when the joint is at the edges of both pieces, 
 
SOLDERING. THE SOLDERING IRON. 159 
 
 it may be made as in Fig. 88, a or b. The joint 
 A would be tacked and soldered as in the exercise 
 just finished. In b the lower piece should be 
 closed tightly on the uppei' with the hammer, and 
 then soldered along both the 
 exterior and the interior an- 
 gle. The manner of bending a 
 
 the sheets for this exercise 
 
 and the last will be explained ' 
 in connection with the next. 
 
 When the two sheets are 
 to be in the same plane, there b 
 
 are several ways in which 
 they may be joined. These ' ^^^ 
 
 are shown in Fig. 89. ^ig. 88. (Full size.) 
 
 The joint a is called the lap-joint. It needs 
 but to be tacked at two or three points, as in Ex- 
 ercise 48, and soldered as there described. 
 
 B is a " cramp-joint." The edge of the left- 
 hand piece is tliinned almost to a knife-edge by 
 hammering on a small anvil. The edge of the 
 other is nicked obliquely with the shears, and the 
 pieces between the cuts are turned alternately u]^) 
 and down. The thinned piece is pushed into the 
 V-shaped space thus made, and the "cram^^s" are 
 hammered down on it. It is then tacked and 
 soldered. 
 
 The edges of the two pieces in c, as well as in 
 B, Fig. 88, and a, Figs. 87 and 88 are prepared 
 
160 
 
 FIRST LESSONS IN METAL- WORKING. 
 
 on a tool called tlie ^^hatchet-stake," Fig. 90, 
 which is set in a hole in the top of the work- 
 bench. The sheet is laid on the edge ab at a 
 proper distance from the edge of the sheet, and 
 turned over by blows of a flat mallet, the edge 
 
 Fig. 89. (Scale i.) 
 
 being either turned up at right angles to the 
 sheet, or doubled over on it, according to the 
 kind of joint proposed. 
 
 As an exercise in this kind of soldering, and 
 one in which a watei'-tight joint is required, make 
 a cubical box of tin or sheet brass, whose edges 
 
SOLDERING. THE SOLDERING IRON. 
 
 161 
 
 shall have the length of one decimeter exactly, 
 inside. Such a vessel will be a " liter" measure. 
 
 The bottom must be cut to the form and dimen- 
 sions shown in Fig. 91, a, and must be bent up- 
 ward, at right-angles, along the dotted Exercise 48. 
 lines. The sides are shown at b, and a cubical 
 are to be bent at right angles along 
 ad, dc, and ch, and doubled along ah. The notches 
 
 c 
 
 r 
 
 n 
 
 Scale, H 
 
 Fig. 90. (Scale i) 
 
 at the corners show where pieces must be cut out 
 to let the upturned edges lie flat. The dimensions 
 in the figure are those that all the pieces should 
 have if the material had no thickness. Owing 
 to the thickness of the metal these must be 
 slightly altered, and the amount of the alteration 
 will depend on the thickness. If the bottom is 
 
162 
 
 FIR8T LESSONS IN METAL- WOMKING. 
 
 put on outside of the otlier pieces, it will be necl 
 essary to make its inside dimensions larger by 
 twice the thickness of the metal. Furthermore, as 
 
 k 
 
 -10 cm 
 
 -. .-A 
 
 J 
 
 J. 
 
 -^T 
 
 JZ 
 
 h- 
 
 - -12-cm.- 
 
 -12 cm.-' 
 
 .i_ 
 
 -^• 
 
 jL 
 
 ___-_□ 
 
 ,=^- 
 
 '-^ 
 
 d 
 
 :x:.i 
 
 k— 
 
 — lOcra. 
 
 Fig. 91. 
 
 two opposite sides of the vessel are turned over the 
 other two, they also must be made wider by twice 
 the thickness, and all the sides must be higher by 
 
SOLDERING. THE SOLDERING IRON. 163 
 
 once the thickness. It ^\W\ be well to cut out the 
 pieces in card-board and put them together, to 
 assure yourself that you can cut them correctly ; 
 make the proper allowance for thickness, and put 
 them together properly. Then mark out the 
 pieces with a " scratch-awl," Fig. 92, and cut them 
 out with the shears. Bend the edges of 
 the bottom upwards, the upper edges of 
 the sides outwards, and the other edges 
 inwards, over the hatchet-stake, being care- 
 ful to keep them quite straight, and not 
 to bruise the sheets. Set the five pieces 
 together to assure yourself that they fit 
 properly. You will now discover that the 
 overturned edges of the lai'ger side-pieces, 
 overlapping the smaller side-pieces, pre- 
 vent the bottom from going on, and four 
 small square pieces have to be cut out from 
 the bottom of these. This cut is not 
 shown in the sketch, and you must deter- 
 mine for yourself its proper size and shape. Cut 
 out these pieces with small shears, being careful 
 not to make the cuts too large. 
 
 Now lay one of the larger sides on your bench, 
 and join the two narrower sides to it as in Exer- 
 cise 48, Fig. 87, being careful, in soldering, not 
 to miss any portion of the joint. Lay the other 
 large side on the bench, and repeat the same 
 operation. The four sides are now fastened to- 
 
164 FIBST LE880N8 IN METAL-WORKING. 
 
 gether, and ready for the bottom. Set the bottora 
 in place, and solder it in the same manner. 
 
 When the vessel is finished, all the angles 
 should be perfectly square, all the faces flat, and 
 all the joints perfectly water-tight and perfectly 
 smooth inside and outside, showing no places 
 without solder and no lumps of unnecessary solder, 
 and the internal dimensions should be exactly 10 
 centimeters each way. 
 
SOLDERING. BLOW- PIPE. 165 
 
 LESSON XXIV. 
 
 SOLDERING. BLOW-PIPE. 
 
 When a very small piece is to be soldered to a 
 miicli larger one, it is often convenient to use the 
 blow-pipe instead of either the Bimsen burner or 
 the soldering-iron, as with this an intense heat can 
 be applied on a very small area. As an example 
 of such a joint we will solder an elec- Exercise 49. 
 trical "binding-post," a, Fig. 93, to a Use of the 
 brass plate b. Take a piece of sheet ^^o^-pipe. 
 brass about S'^" long, 3*=" wide, and 3™" thick. Make 
 the end of the post flat, and clean with the file. 
 Scrape or file the portion of the plate at which 
 the post is to be attached. Lay the plate on any 
 convenient support, and set the post on it. 
 Moisten the angle all round with a drop or two 
 of the zinc solution, and lay a few granules of 
 solder there. Set the Bunsen burner by the side 
 of the work, with the bottom of the flame about 
 on a level with the plate. Turn the outer tube 
 of the burner so as to shut off the supply of air 
 at the bottom, giving a yellow instead of a blue 
 
166 
 
 FIRST LESSONS IN METAL- WORKING. 
 
 flame, and less heat. Holding the blow-pipe ill 
 the right hand, with the tip just outside the flame, 
 direct the current of air from the mouth through 
 the lower part of the flame. This will produce a 
 long slender jet of blue flame/in which the tem- 
 perature is very high. Direct this on the base of 
 the post and the plate adjoining. The flux Avill 
 quickly boil away, and the solder will melt and 
 
 E 
 
 2 
 
 Fig. 93. (Full size.) 
 
 run into the joint. Remove the blow-pipe, and let 
 the woT'k cool. 
 
 In making a small joint in this w^ay yoa must 
 be careful — 
 
 1°. Not to use too much solder. 
 
 2°. ]N"ot to let the flame play on parts of the 
 metal which need no heat, as it discolors them. 
 
 3°. Not to continue the heat longer than neces- 
 sary. 
 
SOLDERING. BLOW-PIPE. 167 
 
 4°. Not to let the small piece be displaced by 
 the boiling of the flux. Hold it down with a piece 
 of wire if necessary. 
 
 There is sometimes a still greater necessity than 
 in the last exercise of preventing the S23read of 
 heat to other parts than that at which the joint is 
 to be made. A good example of this is in the 
 case of the soldering of a spring a, such as you 
 made in Exercise 36, to the plate b. Fig. 94. If 
 
 Fig. 94. (Full size.) 
 
 the spring is overheated, its temper will be 
 " drawn," and the spring spoiled. This may be 
 avoided by " sweating" the spring on the plate. 
 Tin the plate, at the proper point, over Exercise 50 
 the Bunsen flame. Then hold the Sweating a 
 spring in place by means of a clamp a, '^°^^^' 
 Fig. 95, made by filing or sawing a slit in a piece 
 of brass or copper. Apply flux and bits of solder 
 along the edge of the joint. Hold the clamp, not 
 the plate, in the Bunsen flame, and watch the solder 
 closely. The heat conducted along the clamp wnll 
 reach the plate and melt the solder. As soon as 
 this happens, remove the work from the flame, 
 and cool it off before there is time for the spring 
 to be heated. 
 
168 
 
 FIRST LESSORS IN METAL- WORKING. 
 
 The exercises 45 to 50 illustrate the principal 
 methods of uniting small pieces by means of soft 
 solder, or such as melts at temperatures below 
 about 450° F. Joints with such solder are, as you 
 have found, not very strong, and when great 
 strength is important, or w^hen the joint may be 
 exposed to much heat when it is used, a hard sol- 
 der must be employed. Hard solders, instead of 
 being made of lead and tin, are commonly made 
 
 Fig. 95. (Full size.) 
 
 of copper and zinc, or of copper and silver, called 
 silver solder. They require a higher temperature 
 to fuse them, and the management of them, w^hich 
 is somewhat more difficult than that of the soft 
 solders, may be deferred to a later stage in your 
 study, along with brazing and burning. 
 
ALPHABETICAL INDEX. 
 
 Bending, 13. 
 
 Blast-lamp, 154. 
 
 Blow-pipe, i65. 
 
 Bunseu burner, 148. 
 
 Calipers, 144. 
 
 Cape-chisel, 114. 
 
 Casting, 70. 
 
 Chipping, 111. 
 
 Cold chisel, making a, 100. 
 
 Cold-chisel, angle of, 104. 
 
 Cross cut Chisel 114. 
 
 Countersinking. 21. 
 
 Cramp- joint, 159. 
 
 Diawing and Pointing, 9. 
 
 Drill, making a, 108. 
 
 Drilling, 120. 
 
 Drilling-machine, Hand. 129. 
 
 Eye, making an, Ki. 
 
 Files, care of, l:i5. 
 
 Files, varieties of, 133. 
 
 File-brush, 136. 
 
 Filing, 132. 
 
 Filing a Plane Surface, 139. 
 
 Fire, care of. 7. 
 
 Flask (moulding), G6. 
 
 Flat ten in >r, ?5. 
 
 Flatter, 50. 
 
 Fuller, 47. 
 
 Hack-saw, 127. 
 
 Hardee, 5. 
 
 Hatchet-slake, 101. 
 
 Helper, 45. 
 
 Hot Chisel. 53. 
 
 Iron, case-hardened, 112. 
 
 Iron, cast, manufacture of, Gl 
 
 Iron, cast, varieties of, 63. 
 
 Iron, cast and wrought, proper- 
 
 ties of. 4. 
 Iron, chilled, 111. 
 Iron, malleable, 113. 
 Iron, pig, 62. 
 Iron, puddling, 73. 
 Iron, refining, 73. 
 Iron, rolling, 72. 
 Iron, strength of, 58. 
 Ii'on, testing, 59. 
 Iron, wrought, manufacture of, 
 
 71. 
 Jaws of Vise, false, 137. 
 Lap-joint, 155. 
 Link, maldng a, 43. 
 Melting, temperatures of, 3. 
 Moulding, 67. 
 Oil, annealing with, 107. 
 Oil, hardening with, 107. 
 Pattern-making, 65. 
 Pointing, 9. 
 Prism, making a Hexagonal, 123, 
 
 140. 
 Punch, 20. 
 Punch, Centre, 20. 
 Punching, 18. 
 Ratchet drill, 128. 
 Scarfing, 38. 
 Scarf- weld, 39. 
 Scriber, 142. 
 Slott, cutting a, 130. 
 Soldered Joints, testing, 155. 
 Soldering with Blow-pipe, 165. 
 Soldering with Bunsen burner, 
 
 148. 
 Soldering with soft solder, 157. 
 
 169 
 
170 
 
 ALPHABETICAL INDEX. 
 
 Soldering with soldering-iron, 
 
 150. 
 Split Weld, 51. 
 Spring, making a. 106. 
 Steel, annealing, 92. 
 Steel, colors of heated, 94. 
 Steel, hardening, 88. 
 Steel, temper indicated by colors 
 
 of, 96. 
 Steel, temperature indicated by 
 
 colors of, 95. 
 Steel, testing, 79. 
 
 Steel, varieties of, 76. 
 Steel, welding high-grade, 85. 
 Steel, welding, on sieel, 81. 
 Steel, welding, on iron, low- 
 grade, 83. 
 Sweating, 167. 
 Template, 133. 
 Tongue-weld, 51 
 Twisting, 27. 
 Upsetting, 34. 
 Welding, 29. 
 
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