./-8 TS225 .L8 Copy ^ THE FORGING OF EYE-BARS AND THE FLOW OF METAL IN CLOSED DIES. '^ /A-^ 1^ Bv H. V. LOSS, M.E., M, Am. Soc. C. E. V^ COPYRIGHT, 1893. iyvry ^^v The Forging of Eye-Bars AND THE FLOW OF METAL IN CLOSED DIES. BY H. V. LOSS, M. E , M. AM, SOC. M. E. The modern requirements of heavy bridge-building; have given rise to special manufactures involving peculiar processes for many of the main features em- bodied in the structures of to-day. Chords, posts, eye- bars, and even the larger nuts, clevises and other less important details, are made to-day at our leading bridge establishments by methods that vpere never thought of years ago, that is, befo^^e the introduction of the present long spanned and heavy structures. The most typical detail of an American bridge is the eye-bar, and it is therefore to be supposed that the manufacture of this article has been the subject of considerable study, thought and experiment. And such is verily the case, which fact can be vouched for by any engineer who vFiU take the trouble to examine the American patent records on this subject. Following the gradual steps of the designs of machinery for this purpose you will find an evolution that represents vast experiments and great outlay of capital, and which also in itself exhibits a true picture of that patient pace which always has to be set if successful results shall ever be obtained. Eye-bars were originally made exclusively in iron. As steel gradually became introduced on the market, this material found its way, little by little, into bridges and structural work, until now, with the present perfected methods of steel making, it has taken the place of iron to the extent that only one large railroad exists in the United States at the present time which does not permit the use of steel in its bridges. Under these conditions, the vast majority of eye-bars are now made in steel, and this paper will, therefore, unless otherwise noted, refer to bars made from this material. It may be, however to advantage, before proceeding any further, to refer to the methods that have been used, or are at present in vogue, for the manufacture of iron bars, especially since bars of this material were the first ones made, and the processes, as used then, to a certain extent, gave rise to the constructions adopted in later years in the manufac- ture of steel bars. ^M 3 IRON EYE-BARS. Iron bars* were originally made by "piling," that is, by placing a piece or a number of pieces of the same material on the end of the bar, inserting this end in a furnace and there heating It; to a good welding heat. The bar was then transferred to a die, having the fin- ished :;ontour of the eye, and there subjected fo the blows of a hammer, which finished it to the correct shape and thickness. A partial " upsetting " of t he solid bar was, however, tried at a very early date, and the methods in vogue today represent both of these two systems with such additions or details as many years experience has proved to be profitable. There are sev- eral ways in which " piling" is accomplished. The necessary pieces may all be added on one side — the top— or they may be subdiv^ided between top and bottom. Again, a third method may be adopted of fold- ing the piece over the end of the bar, with or without additional pieces on top or bottom, as indicated by fig. 1. The bar while under the hammer is subjected to an occasional turn to insure sharper edges and smoother surfaces. At times, with large eyes, it has been found troublesome to fill the extreme corners, and in such events a bottom die, with a punch attached to it, will force the material, which is displaced from the center, out toward the periphery. The top of the punch must be slightly below the top surface of the fin- ished eye to prevent ccrt'ctwitb the top die. See fig. 2. T^/c/^ness •- Fig 1, / " A // v J 1; ■^ / F;g. 2. This very same arrangement is also at times used in the manufacture of steel bars, where such are finished under a hammer. As previously mentioned, a pnrtial upsetting froin the solid bar has been used in connection with the final ac- * A very old way of making iron eye-bars was to manufac- ture the eye separately ann afterward weld ii to the main bony of the b .r. The uncertainty as to strength of a bar made by this method is very obvious. H U h-l ■< > u < > K H >^ O n Hi Bi » n Ed U o S '/5 g H r/1 W H P »3 < E« S f/J ■«l « FU O P W Q (a >', (M <) U 03 « 03 03 b ^- •Ul 35I0Ja ^ Pr, (Si 03 CO a. O O 35 o o -JH CO c> CO 5 c tc oo' t-T CM 'S •o •c D'" mS . o o oo CM ^ = 5 «3 ^ ^ W o*-3 -m CO CO CM CO CM "" , m"^ V T. ts. 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Loop piling. p 1/ ' !' :i 3.Q Addition to I'gth from c. to c. of 9 ^ j^ o ik; ^,^y . — ' £n ^4 0% 14^ "% ib Vi^! 10 1.50 1.07 3 m 4 4 1 3K2 5 7>ts 1 2 4 5K2 5 7}/a 44 3J^ 5 24 4 11^ X 14 s b 14 3S 6 ■m 13)^ 7/5 '.6 6A 8% 1.50 0.69 2 UH 3 3?4 11% 4 3% 1 1 3 2% 4 3% 4 3 4 Ilk 4 11^ X 12H !£ 4 994 4 « 4% 13% 7il '/ft tifS 9% 1.50 0.81 3 294 3 9 1 m. 4 lOH 1 m 3 9 4 104 24 31/1 5 2)4 4 114 X 13 .s 5 4 £2 6 aj 6 9 3 4 5 6k 4 12 X 14 g 3B 6 0% 16.% 8,"„ % '- ■,', 10% 1.50 1.06 3 994 4 8% 1 4% 6 m 1 31^ 4 9^ t> m 3 4 5 8 4 13 X 144 i^ 37 7 i><^ lb% l-rn 7 i in% 1.50 0.73 3 6U 4 0^ I 2M. 5 3 1 3)^ 3 im 5 3 44 3^ 5 10 4 [3 X 154 <£ 9 5 7 0%. 10^ li'o 8V 1(1% 1.50 0.80 3 9% 4 m 1 394 5 8 1 4 4 4 5 8 34 4 6 1 4 13 X 1.54 OJ 10 7 6% 10% "7% 9V6 li'd S/n 11% 1.50 0.91 4 m 4 9% 1 5% 31/4 I 4^ 4 10J4 6 3k 0V6 4 6 3 4 i X 17k b 11 13 7 •i% 95-4 '.■■(i «r^ l2^ 1.50 0.98 4 3 5 m 1 fiM> 6 8 1 5 5 3* 6 8 41^ 4>^ 6 54 4 .4k X 164 ' 25 8 6 IS in'4 '^^ 9 12 1.50 0.75 4 194 4 8% 1 5!^ 6 2 1 5 4 9 6 2 6 4 6 2 4 .514 X 18i4l b 594 21* 8 5^ 14^(i 7iS 7 A 9% 1.13 0.64 2 2 2 7 9M 3 i'4 1 0!4 2 3M 3 4}^ 41^ 2^ 5 3 4 ,2 X 14 J 9k 3S» 8 5^ 15% 8V, « 7/" lfl^ 1.13 0.70 2 3% 2 9% 10!4 3 8 1 IH 2 6!4 3 8 i 2^^ 5 6 4 .2 X 14 1 1194 39» 8 ti% !>% iS 7U 10% 1.13 80 2 6 3 i 114> 4 1>^ I 2Vb 2 11 4 m 4 3 6 094 4 13 X 143^ 4 7 Floor beam bankers. tlon of the haminer, and such a process is in extensive use to-day, holh for steel and iron. One thing is very certain, however, that with iron bars the hammer must do the main part of the wori<,as, if otherwise is the case, the bar, when placed in a testing machine, is very sure to break in the eye unless the relation between diameter of head and w idth of bar is exceedingly large. This re- lation is, nevertheless, in all instances very much in ex- cess of what it needs to be in steel— the pins being of the same size— regardless of the method by which the iron bar has been made. I have had personal and continued experience in the direction of finishing or almost finish- ing iron eyes on the upsetting machine. At the Pencoyd Iron Works a number of bars (5) were upset to a finish, except allowing them to thicken about )^ in. to % in. Two of them were subsequently reduced by a hammer, the other three by a pair of rolls. The results in the testing machine are shown by table No. 1. By excess in head is understood the percentage of extra material in the head around the pin, as compared with the body of the bar; or, using the letters in the above table, the excess becomes _ 2ExD — l^xC 1% X C All rolled bars broke disastrously, and the feature that certainly saved the hammered ones was the very large excess, an amount which is far ahead of what is considered good practice. No well proportioned eye-bar of ordinary dimensions ought to require over 50 per cent, in excess, regardless of material, and the subsequent tables show the standard nractice as used by the lead- ing makers to be inside of this limit. The most important manufacturers at the present time of iron bars, who adhere to the " piling method," are the Keystone Bridure Co., of Pittsburgh, Pa., and the Philadelphia Bridge Works, of Pottstown, Pa. The standard shapes, as adopted by the former works, are shown on table No. 2, which table also gives the size of "piling" pieces necessary to form the eye. STEEL EYE BARS. A steel bar is at the present time upset in closed dies. In fact, such has, by the natiye of the requirements of the problem, always been the case, only that the action and principle of these dies have gradually undergone an evolution. There are what might be called two gen- eral methods that at the present time represent the total output of steel eye-bars in the United States; these are: . Method No. 1.— To upset in a closed die, lettmg the bar thicken considerably, while the upsetting process takes place. No special attention is made or care taken to make a perfect contour, as the exact shape and thick- ness are afterward secured by subjecting theeye — general- ly after reheating — to the action of a steam hammer, or, in isolated cases, a hydraulic press, either or both of which finish the bar in dies of proper shapes. Methid No. 2.— To upset in a closed die, forcing the metal to exact contour, and allowing it to thicken just enough, that a subsequent application to a pair of slow- running planishing rolls will at one return-pass, in and back again, reduce it to the desired thickness, the purpose of the rolling being twofold, namely, of giv- ing some extra work to the metal and also to cause smooth surfaces to insure close packing of the bars on their pins. As a proposed third method, patented in several forms, but which, however, has never yet seen a practi- cal application, it might be well to mention the scheme of upsetting a bar in a die with closed bottom and sides, the top being covered by a set of fast running rollers, with a reciprocating movement. The upsetting and rolling actions are both simultaneous, the purpose of the rollers being to spread the metal and keep the bar down to thickness. I shall abstain from any criticism on this construc- tion, as it has never been practically tried, and does not appear— to my knowledge— to have any present chance of introduction. I might, however, be pardoned for saying that I entertain suspicions as to its satis- factory effect upon the edges of the eye. In saying that steel eye-bars have always been made by upset- ting, an exception must be made when referring to the method used and invented years ago by Mr. Kloman, of Pittsburgh, who originally made bars— iron at first —by the process of first rolling the body of the bar down to its proper dimensions, leaving a thicker mass of material at each end for a subsequent manipulation in hammer or press. Such a method gives, no doubt, a very perfect eye, but the difficulties in the manufacture were so many that it has been given up entirely by all makers in the United States. In finishing the present chapter, I shall only add that while different schemes are now and then proposed, thoy have hitherto failed to find favor with the eye-bar manufacturers, partly due to the want of sound practi- cal elements in their construction, and partly to the natural hesitancy, which any one would entertain, when a question arose that would imply the throwing aside of machinery, bought or built at great cost. a.— First Method. In the effort to perform any certain amount of work or to accomplish any one end, the question of first cost of the appliances involved is — as a matter of course — of paramount importance. When such a reasoning is applied to the art of the manufacture of steel eye-bars, tlie inevitable result is a resort to the first method, viz., a partial upset and a finish by hammer or press. No' doubt the inherited application of the hammer from the manufacture of iron bars has also been greatly instrumental in preserving this machine as an element in the making of steel bars. There is, nevertheless, also a third reason: the original investors in this line of manufacture wanted to adapt their plant to suit eye- bars of either iron or steel. The dies used with this method are always rough; that is, when compared to the ones as used in method No. 2. Sometimes the neck dies —see explanation under chapter "Die Construction"— are planed top and bottom, but as a general thing the entire outfit and details are of a simpler and cheaper character than is necessary when the eye is brought to complete contour in the upsetting machine. How^ ever, as to the detailed form and different principles involved in the construction of the diebox, I shall defer this to the following chapter, which will contain a more exhaustive treatment on that subject. With dies as used in machines, built to work on this method, it has been found that only very few bars- only those with thicknesses very great, as compared to their width, and only then for comparatively small eyes— will sustain the upsetting pressure without buckling sideways inside the diebox. To prevent this Mr. Wm. Webster has patented the adoption of a longitudinal ridge or groove intended to keep the bar central and to make the material flow symmetrically on both sides of this central line. Mr. Webster uses either two grooves or two ridges or a groove and a ridge; generally, however, two ridges is the construc- tion adopted, and this form of die is at present in vogue at both the Union Bridge Co. and the Phoenix Iron Co. See fig. 3. With method No. 2, however, when the machine '^^S- ^- is fitted up with great exactness, and ail dies planed, thus insuring a more central and uniform thrust of the upsetting plunger, and with the bar practically clamped verti- cally throughout the entire length of the diebox and over its entire width, such a precaution, as introduced by Mr. Webster, has in practice been found to be un- necessary. As a matter of course, when not necessary it is rather a disadvantage, as whatever marks are left by the ridge or groove will all have to be obliterated by the finishing machinery, be it hammer or press. If finished dies are used, plain dies are also easier ma- chined than were they otherwise. In speaking about the finishing machinery, mention has been made of a hydraulic press. It is used, but Tery rarely, and for several reasons: First, the press- ure necessary to reduce a large eye down to proper thickness is extraordinarily great. The surface is very large and the metal is naturally dense after having been compressed in a closed die. Secondly, the press forces the scale into the body of the bar, causing a rough exterior. A hammer will pi'O- duce a better ^nd a smoother surface, as by proper manipulation and turning most of the scale can be separated. If steam is used for the cylinders on the upsetting machine, which is often the case, the press would require a separate hydraulic plant for its opera- tion. A comparatively small hammer has been found adequate, where a press with its dead pressure would require large dimensions to produce the same effect. Unless the bar has been reheated it will re- quire about 10,000 lbs. per square inch of horizontal area of eye to produce the desired effect, and even this will not always insure sharp corners. It is customary in riveting machinery to allow 18,000 to 20,000 lbs. per square inch of area of rivet head as a minimum press- ure — this must not be confounded with the pressure necessary to upset a rivet, as such a resistance depends upon its diametei^ length, condition of rivet hole, etc. —but it is probable that the small quantity of material contained in a rivet head will result, through a more rapid rate of radiation and conduction of its heat, in a somewhat lower final temperature. Nevertheless, accepting 10,000 lbs. as a fair estimate, an 18-in. eye would require about 3,000,000 lbs. to do the necessary work. At the Edge Moor Iron Works it was found some years ago that it was difficult to finish an 18-in. eye on a 24-in. diameter press with a water pressure of 6,000 lbs. per square inch, unless the bar had a fairly high temperature. If the bar is reheated after coming from the upsetting machine, its resistance is naturally very much lessened, but it is of importance to note that all eye-bar manu- facturers consider it a vital aim to be able to make an eye and finish it in the same heat. The steel is not improved by being returned to the furnace, and the out- put is seriously diminished. As to the size of the hammer to be used, quite a di- vergency of opinion exists amongst the different makers. It is a well established fact that a large ram exerts a greater penetrative power than a smaller one, the energies of both being equal at the time of striking the bar. Probably this feature, resulting in an in- creased shattering action, is the cause of the aversion of some eye-bar makers toward a large hammer. -I liavo heard such mannfacturprs say, Oive us 2 or a 214-ton hammer; while on the other hand, the 5-ton hammer has its advocates as well. Personally, I shall admit that I do not advise a hammer at all, of any size whatever, as I do not believe any steel bar is left unhurt after being subjected to the blows of a hammer at such temperatures as those at which the bars are generally finished. The shattering action is certainly greatly nullified by careful annealing, but many bars are not carefully annealed, and again the annealing— io iiowever good— may not restore all steel to its original structure, and, speaking generally, "all steel" is more Fig. 5. or less apt to find its way into the upsetting machine, however careful the outside inspection may be. Any engineer who has spent some years around a steel mak- 11 ing establishment will realize and admit this statement. (lomiug back to the (iiicstion of tho haminor, I am certainly in favor of a less injurious manner in which to finish the bar, and the second method permits this to be done by a pair of slow-running planishing rolls. Such a process is, however, out of the question with bars manufactured by this first method, as the use of rolls presupposes the completion of the contour of the eye in the upsetting machine. h.— Second Method. If the objections raised to the use of a hammer and press are considered vital, and if an additional first cost can be tolerated, in view of being followed by an increased output, the second method will be found to fulfill all the requirements. An upsetting plant of this character is certainly very costly, but when in good working order thfe larger output will justify the additional expense, as long as the market requires the product. The machines are in this case capable of the exertion of intense pressures, this being necessary to form satisfactory edges and to force the metal into the most remote corners of the die. The driving medium is therefore invariably water under pressures of from 3 to 4,000 lbs. per square inch. Old parts are of great strength and durability, made of the best of materials and the whole fitted up like a machine tool. The dies are planed throughout and made exceedingly strong. Such machines are at the present time running with the capacity for making 30-in. diameter eyes, which would represent about a 12 to 13 in. wide bar. The largest dimensions, as hitherto made for the market, however, have been 24 ins. in diamoter on a 10x3-in. bar. Nevertheless, machines have been planned for 36-in. eye on 16 x 4-iu. bar, but whether such an eye- bar will ever be called for js a question to be decided by the bridge engineers and outside the scope of this paper. To make bars that can be relied upon as being homogeneous in such large cross-sections, is also a problem for the steel maker. -. avorable reply to both of these queries— in connec- tion with the final disappearance of iron eye-bars — would certainly stimulate the use of this method. At this writing, however, the second method is used by only two makers, viz., the Edge Moor Bridge Wortcs and the Pencoyd Iron Works, the remaining manufac- turers of steel eye-bars all adhering to the process, rep- resented by method No. 1, as being the cheaper first outlay. As previously mentioned, the bars are finished in a pair of slow-running planishing rolls. In passing throngh these rolls the eye is naturally elongated, and the dies are therefore correspondingly shorter in the upsetting 12 inachine to compensate for this stretch, which varies from about y^ in. on an 8-in. eye to about V/^ in. on a diameter of 18 in. A bar, as manufactured by this method, is allowed to thicken about 8-16 in., which can readily be reduced by one return-pass. Figs. 4 and 5 show the finishing machine, as used by the Edge Moor Bridge Works. It is driven by a hydraulic cyl- inder, located on the top of a pair of housings. The piston is connected through racks, with a pinion on the end of each roll, thus causing a partial revolution, of sufiicient magnitude, however, to reduce the full length of the maximum eye and its neck. The rolls are made of cast iron, chilled to prevent cracking. As to the form of dies used with this method, they will be treated in the next chapter, entitled: "Die Con- struction," containing a full treatise on the different principles involved in this part of the machinery. c — Die Construction. When referring to eye-oar machinery generally, no engineer familiar with the subject can do so without referring in strong terms to the Edge Moor Iron Co. No establishment could have devoted more time, money or a more untiring energy to improve the methods of this important branch of manufacture, and the pres- ent state of perfection owes its existence greatly to the results that have been obtained at that establishment. Referring to "the die construction," it would form • quite a history to mention all the gradual steps that these parts have undergone, and the extent to which they have been experimented upon at those works. When speaking generally about upsetting an eye- bar in a closed die, three distinct systems of dies can be used, and, in fact, they either have been or are used at the present time and really represent the three great steps in the evolution of the die mechanism of an eye-bar upsetting machine. Again, speaking in a general way, any one of these systems can be considered as consisting of: A movable plunger, of header, of equal or greater thickness than the eye-bar head to be made, and two neck or side dies — generally termed cheek dies — which are always stationary and bear against offsets in the sides of the main housing, containing the diebox. These dies are always of the same thickness as the head. The plunger and the cheek dies have the internal con- tour of the head to be made. Finally we have the top and bottom dies, either movable or stationary, these forming the top and bottom surfaces of the head. The three separate systems may be classified as fol- lows: 1. To upset a bar in a stationary die, the plunger beiog the only movable part. 13 2. To upsot a bar in a die, the cheeks and bottom of which are stationary, tlie top and phinger of which are movable. Of course this order may be reversed, • let- ting the top and cheeks be stationary, while the bottom and plunger move. 3. To upset a bar in a die, the only stationary parts of which are the cheek dies, the top, bottom and plunger all being movable. Each of the above three systems represents a well defined and distinct result in its effect upon the bar, and will be treated separately hereafter. With any and all of these systems it is an accepted construction to provide a separate gripping mechanism, located in front of the dies. The bar itself is there- fore always stationary, the plunger being always mov- able. This "grip" will thus have to sustain the entire upsetting pressure, whatever it may be, until the neck of the eye has been formed sufficiently to throw the reaction upon the cheek dies, which then transmit it into the housing through "the offsets" on the sides. This being done, the grip is of course relieved through- out the remaining stroke. We will now proceed to the First System. When speaking in a general way of the forging of metals, when using closed dies a system of this kind is always in vogue. It is used in the manufacture of rivets, in the upsetting of rounds and squares and for many other purposes. It is therefore natural that it was also applied to the art of eye-bar making, in which line of manufacture it really represents the first and original step in "Die Construction." Referring to the previous general description of all three systems, it is seen that they all contain separate top and bottom dies. Such a construction is adopted to facilitate the removal of the bar after upsetting, as also to permit the insertion of the bar into the dies with ease and comfort. It serves, besides, an additional third pur- pose, namely, to allow a gradual thickening up as the upsetting takes place, which fact tends to lessen the necessary upsetting pressure and to allow the necessary stock for "finishing" the eye by whatever means that are adopted, viz., the hammer, press or rolls. Coming back to the first system especially, it would require too voluminous an article to treat separately the different arrangements that have been tried and dis- carded in the effort to secure the best results. I will only mention the "double-decked" system, if such a term is permissible, at once tried and for quite a time used at the Edge Moor Iron Works. Dies were here arranged in series, one set above and on the top of the other, each set intended to do a part of the work and having in- Fig. 6. 14 ternal contours more and more approaching the finished form of the eye. Phmgers were, of course, introduced to match each die. The construction of dies, working under this system is of the very simplest kind, and needs no elaborate illustration. Take a stationary box, fig. 6, containing a hollow of the form of the finished eye to be made, introduce a plunger of a thickness equal to the thick- ness of the eye, and divide this box itself into four parts, two sides and top and bottom. This constitutes it all, while the minor details may vary to suit the form of the main housing, in which the diebox operates. In the above fig. 6, D equals diameter of eye, and W denote* the width of bar. As to the effect upon the metal o'f this system of work- ing, it is a very distinct one, viz., the bar wiU upset im- mediately at the plunger end . , ^„ , leaving the neck as the last part to he filled. The plan, fig. 7, shows the appearance of a partly upset bar. This action is invariably so with all classes of forgings. where this system is introduced m upsetting rounds and squares it is again experienced. Two great ob- jections exist, how- f- / ^■^''^ ■ '•''^'''■( ^^z^izz.^z^^ ever, with this sys- tem: -T-;--'-^:;- 1. The gripping [/''-^ mechanism in front ' will have to be of extraordi nary strength, as it will have to sustain nearly the entire upsetting pressure. The neck is the last part to be formed, and the grip is therefore not relieved, until all the work is practically done. For heavy sections this fact would mean a gripping ma- chinery of huge dimensions and capacity. 2. As the bar is gradually being upset, the material which already fills the die to a certain extent, at least vertically, will have to slide backward, being pushed by the plunger in front of it. The great friction thus overcome means a vast waste of power Wherever this method has been changed into one having dies with more or less movable parts, a very great decrease in the power necessary to do the work has invariably been the result. A great waste in fric- tion means also a short life for the dies, a fact the importance of which no manufacturer q^n afford to fTenookv 15 Altogether, the stationary diebox can be considered aa abandoned in this branch of the arts, and has gen- erally been replaced by one or the other of the following two systems: Second System. The natural consequence of any effort toward les- sening the upsetting pressure in making an eye will be a deviation in the line of movable dies. Such a result is, indeed, represented by the second system, with which either the top or the bottom die can slide. Gen- erally a sliding top die is preferred, as the stationary bottom makes an easier construction and forms a con- venient table or platen for the manipulation of the bars. A very good arrangement of dies, designed to work under this system, is shown in cross-section by fig. 8. The bar A is located between the cast iron dies B and C. The former is attached to a movable steel block or die D, while die C is fastened to the stationary platen E— also made of steel and extending forward like a table. H is the side grip and I the plunger, made of hard forged steel, while K is an attachment to the piston of the pushing cylinder, which is operated by hydraulic pressure. F is a stationary steel block, at- tached to the underside of a piston, working in a verti- cal hydraulic cylinder, which cylinder 'performes the function of a die-closer. The drawing shows the posi- tion of dies after a completed stroke, the ram L com- ing to a stop against the backward projection of the stationary platen E. The above construction of dies was used in connec- tion with the "Second Method," thus forming a com- plete eye in the upsetting machine, followed by a sub- sequent rolling process. With this system is experienced another and equally distinct effect upon the material, as shown by fig. 9, which represents a partly upset bar. As will be seen, the upsetting action occurs about simultaneously at both ends, the middle part of the eye being the last portion ■filled. This peculiar result is due, first, to r, '/pZ:22Z^iii2Z^^^^;^^ the plain action of the ^^^ T^ plunger — similar to the effect, in stationary dies, in upsetting the portion in immediate contact with it — and secondly, to the drag- ging effect of the slid- Fig. 9. ing die on top or bot- tom, which has a tendency to force the metal against the cheek dies, The practical results of this construe- 16 tion are beneficial in many ways. The grip is more quickly relieved, thus requiring only a smaller machine to attend to this function; and the final upsetting press- ure needed to complete the eye is very much less, as compared to what is required with the stationary die- box. The final effect of the plunger is to eject between it and the side dies the surplus of material, which has to exist in order to insure a perfect eye, this part of the bar being, therefore, the one last formed. As an experimental verification of the pressures and resistances encountered in forming an eye with this system, the indicator card, fig. 10, shows clearly the 17 work done at the different periods throughout the stroke. The card is taken from an ordinary steam indicator, actuated by water, however, and which is connected to the main pushing cylinder through a pressure-reduc- ing mechanism of a latitude of about 40 to 1. The bar was a small one — 3 in. wide by % in. thick with a dy^- in. eye — the "Second Method" being used of completing the contour in one operation, followed by rolling. The diameter of water cylinder was 24 in., and the water pressures per square inch of piston are marked on the card at different intervals, so as to readily show the power needed. The grip was in the above case arranged to engage the bar on its edges, and was located very close up to the cheek-dies, thus being underneath the projecting part of the movable top die, when this die is in the position of a completed stroke. See fig. 8. It is essential always to have the grip located as- Perfect Eye - Accvrm. Load' ISOOlbs. "iaoo lbs. Pr. =355 lbs 3 X ?^ X 6^ in. eye, steel. 154 I'l. tot. stroke. % in before strik. bar. 5V6 in. high-pres water. Water run constantly on dies, plunger and forging slab^ Plumbago grease used on dies- Hor. ram worked freely. Fig. 10 close up to the cheek-dies as possible to prevent the bar from buckling vertically, and the more so with the first and second systems, as the gripping mechanism- is in these cases generally made to attack the bar on its- edges. Tlie exposed part of the bar — ^between plunger and grip — represents a column, which, if too long and with an edge grip, would sway vertically at its very point of support, viz., the grip. A top and bottom en- gagement would certainly hold the bar firmer and the comparative value of the two constructions — as meas- ured by their effect — would be about as- two columns, the grip ends of which are fixed in one case and sup- ported in the other. The top and bottom engagement offiers also a very largely increased bearing sur- face for the same gripping pressure, which again results in a decreased cutting action on the material and a very much less defaced appearance generally. While such a grip could be U(sed foir small bars with IS the first system, its application to the second system is rather doubtful, as it is possible that the neck is not formed quickly enough to relieve the grip before any serious resistance is encountered, and the additional distance away from the diebox, at which such a grip would have to be located — to clear the moving top die — would result in a column too long and too heavily loaded. With the third system, however, the above suggested arrangement can be used to advantage, as will be mentioned in the following. The second system is applicable to both methods— first and second— and is Fig. 11. Fig, -2. used by the majority of steel eye-bar makers at the present time. The writer has always considered it suc- cessful and only inferior in its actions and principles to the final and Third System. While the system just described is a great improve- ment upon the stationary die, it nevertheless requires very large efforts for heavy sections, and it was while trying to decrease the amount of this effort that the third system was developed. The movable diebox, as patented by the writer, and used with this construc- tion, is shown very plainly by figs. 11, 12 and IB. H\ H^ F and P are here movable cast iron dies, while H and I are steel plattons, also movable. B is a sta- tionary slab, resting in the main housing A, while D is connected to the vertically moving holding-dowa ram, which is actuated by water, tj is the plunger, -J — J are the cheek-dies, and F is attached to the up- setting ram. To diminish the friction when moving the diebox, friction rollers a — held together by the frames b — are inserted between the stationary and movable parts. The above die construction is in successful use at the Peacoyd Iron Works with a smaller machine, de- signed originally for G in. wide bars with about 13^/^ to 14% in. diameter of head. It was found after trial, liowever, that the power as provided could finish an 18-in. eye on an S-in. bar — the housing being wide enough to accommodate this diameter — with simply one reheating. The larger machine mentioned at an earlier stage of this paper as being designed for 3l3-in. head on a 16-in. bar, was planned by the writer for the same works. The "Second Method" is used in connec- tion with this system at the above-mentioned works, the bars being finished by rolling. As to the effect of the upsetting action upon the material, this is shown by fig. 14, which represents a partly finished eye. The neck is foryned imTnediate- '//////////// ////////A fig. 14. carried forward so rapidly ly thus relieving the grip almost at the start, the last part to fill being near' ly always at the back of the rye at th€ points Tnarked c. This result is due to the intense dragging action of the dies, in this case both, at top and bot- tom, the material being that no upsetting action 2U ean occnr at tbe plunger end, until near the compretioni of the stroke. It must be remembered in this connec- tion that the holding-down cylinder or die-closer bears- on the top of the upset portion of the bar with an- immense pressure, running up to from 1,000,000 to 5,000,000 lbs., depending on the size of the machine. It is plain that this peculiar action facilitates the- rapid filling of the head with a minimum amount of pressure, and it also permits the use of a top and bot- tom grip, as the length of the column can well be tolerated, barring possiblie for very small and thin bars, because the longitudinal force acting upon it ts not suflr- cient to buckle it vertically. For such small dimensions where danger does exist, it IS a common custom with both of the latter two die systems, to "double up"; that is, to upset two bars in- one operation. Such a procedure practically doubles the resistance to buckling, as it takes very little more force to form a neck on a bar of twice the thickness, the main resis-tance being, always concemtratedl at the endp ■^ &or, ty/th /Qiyx H-, 15. of the stro>ke. By this act of "doubling up," the procJi- uct is also largely increased, and the difficulties in. separating the bars after upsetting are generally not serious. The beneficial effect of a top and bottom grip can thus be secured by an application of this system, and such grips are used in connection with the pres- ent machine and also with the larger one planned for the Pencoyd Iron WoEks. As in the previous systems, the plunger and cheek- dies come together at the center of the eye, ejecting at this point the surplus material, the plunger being also somewhat less than a semd-circle to allow for the stretch, caused by the subsequent rolling. As to the resistances encountered throughout the stroke, a reference to the indicator card, fig. 15, will reveal one fact, which, ho-wever, might have been sus- pected from what has been said previously, namely, the large amount of work done in the earlier part of the stroke. This is emphasized by comparing it to the card, fig. 10, representing the second system, 8ucb 21 being the case, it is, therefore, natural that as so much work has been done during the commencement, that much less remains to be done during the final part of the stroke; which means, thai the satne eye can be upset with less pressure by this system than by any of the preceding ones. With machines, as designed exclusively for very- small bars, it matters not which of the latter two sys- tems is used, as the saving in power is here of minor importance. In fact, for very thin bars the second system offers the advantage of a grip close up to the cheek-dies, but for any ordinary machine, proportioned to take the heavier bars of the market, say, from 5 in. and up, the writer is absolutely convinced from ac- tual experience of the superiority of this third system. The power is less and top and bottom grips can be used, which two facts in themselves are sufficient to place this construction in advance of any of the two preceding ones. With the latter two systems friction rollers have sometimes been introduced between the stationary and the sliding parts, and such a construction has proved to be of a decided advantage.. They will have to be close together and to be backed by good steel surfaces, the rollers themselves being made of hard steel, to stand the intense pressure under which they work. Of course, when the pressure is at its maximum, the speed of motion is at its minimum, which fact helps consider- ably to save them. Such rollers are applied to the con- struction, shown in figs. 11 and 12, and may be any- where from 11^ to 2 in. in diameter, depending on their load, I have not hesitated to burden them with a maxi- mum pressure of 3,000 lbs. per running inch. d.— Forms and Sizes of Eyes. Up to a few years ago there existed quite a con- troversy as to the correct form of eye back of the pin. Two distinct types exist to-day, viz., the circular eye and the one having an elongated form. These two shapes are both illustrated by fig. 17, which shows the most accepted standard eye of the circular form, while several modifications exist, when the elongation shape is used. Table No. 2t, giving the Keystone standards for iron bars, shows a more rounded back, the underlying principle being always the same, however, when a deviation from the circular form is accepted. If a beam is loaded in the middle and supported at each end its greatest depth needs to be in the center, the width being uniform. If, therefore, the back of the eye conld be considered as such a beam— better illustrated if assumed hinged on each side of the pin, as shown on fig. 16— the elongated form would undoubtedly be 22 correct. Such, however, is not the case. It is not a beam loaded in the middle, nor supported at each end. If a bar was fixed at each end and loaded at its center, it would require the same depth — the width still being uniform — at three points, viz., at the center and at f^'g- 16' both ends, while a load uniformly distributed would require the greatest depth to be equal at both ends. In reality the beam is more fixed than supported, while the load is possibly more central than distributed, as the pin is generally from 1-50 to 1-100 in. less in diameter than the hole in the eye. Taken as a whole, the requirements— if not favoring a heaviest dimension at the sides— certainly do not demand the greatest depth at the center. A uniform dimension around the back of the pin will, therefore, come nearer the desired results than any irregular shape. Professor Burr has written a lengthy and a very thorough paper on this very question; it was published in the proceed- ings of the American Society of Civil Engineers for 1875. He assumes here, however, that the pin, when under stress, exerts a normal pressure against the eye on its circumference. Such an assumption is too deli- cate, and as it is a well known fact in all analysis A Fig 17. of this kind that a rather small deviation from the as- sumed elastic conditions of a bar will greatly change the results, I should, for practical purposes, attach a great deal more weight to the experimental data, which happily is at hand in sufficient quantity to establish the desired facts. While several more or less isolated ex- periments have been conducted from time to time, as, for instance, by Messrs. Charles Macdonald and Charles D. Fox, of London, England, and others, the most com- plete results in this direction have been acquired by the late Mr. O. Shaler Smith, of St. Louis, who published in the proceedings of the American Society of Civil Engineers for 1877 the conclusions derived by 114 ex- periments, 57 of which were made of iron-hammered bars — the eyes having been made separately and after- ward welded to the body of the bars— manufactured 23 for the St. Charles bridge, the experiments being made at St. Charles. The type of eye was the one shown by A, fig. 17. The remaining 54 bars were made of steel by the Edge Moor Iron Co., the tests also being conducted at that place. The type of eye used was the one shown by B, fig. 17. The latter bars were made for the Kentucky River bridge. The bars in both tests were of rather small dimensions, from 3 to 4 in. in width, the other relative dimensions being given by fig. 17. The tests were made by hydraulic power, the bars being pulled to destruction. Mr. Smith's conclusions were so distinct and well de- fined, that I can do no better than simply quote his own words, which were: "1. As the relative proportion of diameter of pin to width of bar increases, more metal is required in the section across the eye. "2. In hydraulic forged eyes, this— across the eye- is the weak point and governs the rest of the eye, which is consequently a true -circle. "3. In hammered eyes two points must be fixed, the section back of the pin and the section across the eye. "4. A pin of a diameter equal to 6G per cent, of the width of bar is the smallest which will invariably break the bar or develop its full strength." It seems thus fair to assume that the elongated eye is proper for iron bars, especially if hammered. This fact is possibly due to the weakness of this material across its fibers, it is remembered that considering the back of the eye as a beam, the tension and compression on the center line are here across the fibers, hence the greater depth. The amount of material on each side of pin has con- tinuously been decreased, as the modes of manufac- ture have been improved. Starting originally for steel bars with the same excess in eye as is at present used for iron, viz., 50 per cent., this figure has gradually been lowered down to 30 per cent., and in many in- stances 25 per cent., or even less, has broken the body of the bar. Different makers have slightly different standards, and referring r,o Table No. 2t, as representing "piled" and hammered iron eyes, the following tables, 3, 4, 5 and 6 give the standard dimensions for steel eye-bars, as made by the leading manufacturers of United States. These tables give also the largest diam- eter of pins that can properly be used in connection with given dimensions of eyes and widths of bar. As showing a successful application of a very small excess for eye, see the experiments made with Edge Moor bars, as published by Mr. Joseph M. Wilson in the proceedings of the American Society of Civil Engineers in 18S6. On 4 and 5-in. bars of about 1 in. thickness —steel— an excess varying from 21 to 26 per cent, sue 24 -&q' k-a-*) •pBaqguooiJOj 5 p a J inbaj 9^3 JO jjjaa.3 paoiaq jeq jo qSa,i 1 uoijippv O — lO to t~ 'O — «o o {M(Mn o o 1 t; O S£ o D. «2 •pBaqaaoiuioj o 1 pa a inbai ajCa JO J3JIIS0 paOitaq juq jo qguji'Baoiuppy O •jBq JO Apoq aqj ui i^qj JO ssjoxa UI o s outi am ob^^aq aqi jo corococococococo eococciocoeotoco .5 o cas Q q;i q; TO ■«Om50«DCX)a50 •j'Bq JO ssau -Jjoiq^ uj,uiiaii\[ a o o :s:g (MiM(N<>i-( '&?fl q o o o S 2 *^ -p: a'^ -^ |i2So»s-S2 T,j: «£ S-a ya's t*!^ D'C o " Mii.S 00 c aj -65 IS 'O r> Table No. 4. pencovd iron works— bridge and partment. table of standard steel eye bars. ^ CONSTRUCTION DE- l-'^ W t D tl Li Additional length of bar beyond center of eye required to form one head. In. 15 17!^ 18 19!^ 23k 2654 23 2m 30k 36M 269-4 30 33M Note.— To all bars up to 6 in. wide aad 1 in. thick and under add IVa in extra for each eye toi tha length of the bar. To all bars up to 7 and 8 in. wiae and 1% in. thick and under add IVz in. extra for each eye to the length of the bar. Note — Pencoyd standard eye bars are hydraulic forged and are guaianteed to develop the value of the bar, under condi- tions given lu the above table, when tested to destruction. The maximum sizes of pin holes as given in the above table allow an excess in sectional area of head on hne b3 over that of the body of the bar of 33 per cent, for diameters of pins not larger than 'he width of the bar, and 36 per cent, for pins of larger diameter than width of bar; the thickness of eye being the same as the thickness of tbe body of the bar. NOTE.-The steel manufactured by ns for the use of eye bars is op'-n hearth steel and will be furnished of such quality as to satisfy the demands of engineers. Minimum Diam. Diam. of Width thickness of largest of bar. of bar. head. pin hole. In. In. In. In. 3 % 7 3 3 H 8 3% 4 M 9!4 iVa 4 M JO^t 5t'e 5 % IIH Hi 5 M 12>4 5ii H 13 6-1% 6 % 13V^ 5}^ 6 % liV2 6t% 7 TB 16 6ii 7 V?- 17 7!4 7 II 18 iYi 8 1 17 6% 8 1 18 7% 8 1 im 7% cessfully broke the bars, when pulled to destruction. As to the stresses in eye-bar heads, Mr. Theodore Cooper published in the proceedings of the same society for 1878 a paper giving some interesting results derived from watching the scale falling off the eye- bars, when under stress in a testing machine. e. — Motors and Machines. As to the machines used in the art of eye-bar manu- facture, they naturally vary according to the methods followed. As previously mentioned, the "First Method" represents a cheaper and less exactly fitted up plant as compared to the machinery at the "Second Method;" the principles of construction, however, beiug the name in both. In a general way, an eye-bar upsetting ma- chine consists of: First, the horizontal upsetting cyl' inder; second, the vertical die-closer; third, the diebox, H a i o S O fJO ^ 2? Table No. 6. u. b. co., athk^s, pa. standard proportions for steel EYE BARS. In. 3 Diam of. head. ©: In. 6 7 9 9V^ 10 10 10^ 11 11^ 12 10 10^4 11 11}^ 12 nV£ 13 U 12 121^ 13 1314 14 15 U u% 15 16 I6I4 17 16 161^ 17 17^ 18 18!^ 19 In. 2 3 3k2 3% 5% 2H m 4M 5fi 4 4V^ 5 5% 6% 7M 61^ 7 4% S% 6% 6% 7% 7% 5% 6J^ 6% 1% Per cent, of excess in heads over that of body of bar on line A-A. Head same thickness as bar. In. S3^ oSVb SSVs 33^ 3714 37-^ 37^ sm 31 31 31 31 31 34 37i^ 3714 371^ 30 30 30 30 30 321^ 32^ 35 35 31 31 31 31 331^ 33J^ 33^ 30 30 30 30 30 30 30 29 29 29 '/9 29 29 29 Head in in. thicker than bar; bar 1 in. thick. In. 41 41 41 41 46 46 46 46 46 39 39 39 39 42 42 46 46 46 38 38 38 38 38 40 40 43 43 39 39 39 39 41 41 41 38 38 38 38 38 38 38 371/2 37^ 37;^ 37^ 37»/? 37!^ 37^2 Head is in. thicker than bar; bar 2 in. thick. In. 37i^ 31% 37^ 37}4 41 41 41 41 41 35 35 35 .35 38 38 42 42 34 34 34 34 34 36 36 39 39 35 35 35 35 37^ 3714 37^ 34 34 34 34 34 34 34 33i^ 3S]4 33^ 33k^ 331^ 3314 331^ t, fc, « ^■^ o ssa tE In. 19^ 15 '26" '2414 'si" 171^ 20 22 26^ '36" 195^ 21 23 25^ 18^ 2214 281^ 30>^ 271^ 29)^ 28 AnA, fourth, the gripping mechanism. The horizontal t-ylinder may be driven by steam or water. The die- closer may be a cylinder, the piston of which presses direct upon the diebox, in which case it is always driven by hydraulic power, or it may be a steam or water cylinder, operating through a set of wedges or toggles. The diebox has already been treated as also to a cer- tain extent the grip, which, however, will be referred to again in the following. Fig. 18 represents a ma- chine, designed by the writer for the Keystone Bridge Co., and which is intended to upset as a maximum a 22-in. diameter head on a 9-in. bar, the upsetting cyl- inder being 28 in. in diameter with water of about n k'4i T-f^-'^ Fig. 18. 2,500 to 2,700 lbs. pressure per square inch. The die- closer is a vertical hydraulic cylinder, the piston of which engages a set of very powerful toggles, thus multiplying the power manifold. The grip is of the top and bottom type, and is the only part of the ma- chine that differs from the original design made by the writer for the said company. This detail will be explained later in connection with separate drawings. The diebox and die-closer are located in the main hous- ing, to which the pushing cylinder and grip are both- one on each side— attached through horizontal tiebolts. The dies used conform with the third system, and the machine throughout is constructed to work on the "Second Method." A machine designed by the writer, and built for 29 thp Ppiicoyd Iron Works, is shown by figs. 19 and 20. The die-closer is shown as two side wedges, y, y, operated by separate hydraulic cylinders, y', y', thns greatly multiplying the downward pressure. The die- box is shown separately by tigs. 11, 12 and 13, and the grip— not shown on the drawing— is the same as illus- trated on fig. IS. This machine was designed only to make 13V{. to lli^-in. eyes on Gin. bars, and has therefore a rather small upsetting cylinder, 19 in. in diameter. The machine has proved itself fully capable, ne%-ertheless, of making IS^^-in. eyes on an 8-in. bar with only one reheating, working on the "Second Method." For very large capacities I pre- fer the direct die-closer; that is, a vertical ram acting directly on the diebox. If large pressures shall be transmitted through wedges, toggles or any other me- chanical contrivances, the result is sure to be too much wear, besides also requiring enormous dimensions to withstand the intense pressure necessary to prevent the undue thickening of the eye. Such a direct method Fig 19. Fig .0. I have, therefore, used in designing the large machine previously mentioned, for the Pencoyd Iron AVorks, The vertical cylinder is therefore 46 in. in diameter, the horizontal cylinder having a diameter of 35 in., the water pressure being in both instances from 3,000 to 3,5tX) lbs. per square inch. This construction is also used by the Edge :\Ioor Iron Co. in their large forging plant in present operation. This latter concern uses, however, a diebox on the principle of fig. 8, which em- bodies a side grip in form of two hydraulic cylinders, located one on each side of the bar. The top and bottom grip used in connection with the third system is better illustrated by figs. 21, 22, 23 and 24. It is designed and patented by the writer and is giving good results. The drawings are very plain and explain themselves. A hydraulic cylinder acting through a steel lever compresses the bar x, the grip shoe being round on top to permit an easy adjustment to suit different thicknesses of bars. The driving water enters at j), the pullback water, being constantly on, at 30 n. This construction poi-niits one important feature, viz., the grip shoe will swing entirely out of the way, thus offering no obstruction whatever in removing the bar, after the upset is finished. See fig. 22. The entire apparatus can slide longitudinally with the bar, being provided with stufttng boxes for the water connections, so as to suit any length of die used. The bar after being upset is now removed to a corn- Fig. 2'. 22. bined punch and shear, where the hole, allowing for finish for the boring mill, is made and the fins— the sur- plus material— sheared off on each side, all in one operation. The eye is next finished to thickness by hammer, press or rolls (see figs. 4 and 5) which being accomplished, the bar is sheared to correct length and the second eye made in a similar way. The bar 31 is uow stored on skids, until a siifficipnt niimbor has been accumulated to form a charge for the annealing furnace, where it is heated by coal, wood, oil or gas Fig 23. i. \ Ficr. 24. to about 900 to 1,000 deg. Fahr., the heat being kept upon the charge for a few hours, after which the bars are permitted to cool. This cooling ought to be aa slow as the continuous process of the upsetting plane will allow. "Water annealing has not as yet been tried 32 on rye-bars, but it would be exceedingly interesting to perform and watch any experiments made in this di- rection. The annealing being finished, the bar is straightened, bored and painted, after which it is ready for shipment. An improvement ought certainly to be made in the machinery hitherto used for straightening purposes. A power-driven gag is not to be recom- mended, and a slow-going hydraulic press is but slightly better. If the bar could be straightened in a pair of rolls — like plates at the present time — and proper allow- ance could be made originally for the elongation which this method will produce, a better bar will un- doubtedly be the result, and the effect of the annealing not so much undone. The greatest difficulty lies in the irregularities of the conditions of the eye-bars, one requiring much more straightening than another, result- ing in different elongations all along. However, it is worth calling the attention of engineers to this subject, as I know from personal observation of peculiar effects in the testing machines, which effect could often be traced back to the straightening gag. These are the genei'al machines used in the manu- facture of eye-bars, and may all be modified more or less to suit special practice. Cranes for handling the bar, pumps, accumulators, engines and many other contrivances of more or less importance will finally make up the remaining requisites of a plant, which is second to none as to the engineering skill and judg- ment necessary to build up a successful industry. /.—Pressures avd Resistances. As to the power necessary to upset an eye-bar, this will vary greatly according to the methods and con- struction used. Repeated experiments have con- clusively shown that a small eye requires relatively — and in some instances even absolutely — more power than a larger one. In a similar way a thinner bar de- mands a greater effort than a thicker one, other con- •ditions being equal. All this is solely due to the fact that a thin or a small eye generally loses its heat so rapidly that the final pressure, which would necessarily have been the greatest one any way, meets a material very much cooled and very much harder to compress. This is another and a very good reason for increasing the bulk of material inside the diebox by upsetting two thicknesses at one operation. Experiments have re- peatedly proved such a method to produce good results. The vertical pressure in an upsetting machine will have to be very much greater than the horizontal effort. This is now well established, and many were the mis- takes originally made by not realizing this fact. It ought to be anywhere from two to three times the lat- 38 ter, especially if— as with the "Second Method'* — a comparative small amount of thickening is allowed dur- ing the operation. This is very natural when consider- ing the large, horizontally exposed surface of the eye, each square inch of which is sut)jected to an intense pressure, which also pervades the entire mass of metal. Speaking in a general way about any possible analy- sis of the forces, the resistances can be divided into two distinct parts, viz., compreasiny the metal and over- coining all shdmg or rolling frictions. As to the latter,- its relative amount is extraordinarily large, so much so, that its full extent is hardly ever realized. A simple calculation will illustrate this fact. A 9-in. eye, 1% in. thick, required 652,000 lbs., as taken from experi- ments made some years ago at the Edge Moor Iron Works. Considering the cross-section of eye to be 9 X 114 in., equal to 11% sq. in., the direct pressure per square inch, allowing for no other resistance, be- 6.12JU0 comes Yi 2.5" ~ 58030 lbs. This figure is very largely in excess of what is needed, the difference being made up by frictional losses and partly, to be sure, by forc- ing the metal to flow under an angle perpendicular to the direction to the upsetting force. For larger bars the loss due to friction will be relatively smaller, but it remains, nevertheless, in all eases, too lai-ge and important a factor to be desirable. Hence the necessity of introducing the steel rollers, as shown on fig. 11. The difficulty in specifying rules and formulas, for use in this class of work, lies in the unknown temperatures existing for the different sizes of bars. It is impossible to compute with any exactness the amount of heat conducted away through the dies and through the water, which latter is generally brought to play upon the diebox, when having a continuous run. In order to throw some light upon the action of the metal during the last stages of the upsetting process in closed dies, the following analysis may act as a guide: If the eye consisted of a perfectly melted mass, then it is obvious that a certain pressure per square inch imparted to this mass in a horizontal direction would cause the same pressure per square inch to exist in any other direction, thus causing a total upward press- ure on the vertical ram, toggles or wedge, the amount of which would be larger than the total horizontal pressure from the pushing cylinder in the same pro- portion as the horizontal area of the head and neck is greater than the cross-section of the head. But as the eye is not a melted mass, especially during the Jast part of the process, the result is that the real vertical pressure is very much less, and the coefficient — a frac- 34 tion — with which the amount, corresponding to a per- fect fluid, must be multiplied in order to equal the real amount, I have called the coefficient of fluidity K, aud which equals 1 for a melted mass, gradually decreas- ing as the cohesion of the metal increases, and which becomes very small, practically zero, for a cold bur. Let further: P denote the total upsetting pressure on horizontal ram. Pi= pressure on horizontal ram nece^ssary fo ovtr- come the frictional resistances due to sliding, etc. D = diameter of eye. t = thickness of eye, as measured after thickening. (p — c^eflicicnD of trici ion for sliding ot metal on metal. Omitting the effect of the neck as being very insig- nificant and as causing very little upward reaction, the metal at this portion being very cold, we finally have: Pj = (y3 K -^ ^^ _ !L a KP i'. (1) Dt 4 ~ 4 I At the very last part of the operation the plunger presses practically against the entire back at the eye, causing a final flow and bringing the mass up to exact contour. Let the compressive action on the metal re- quire an effort Pj, and introducine a constant K, de- pending upon the resistance to compression — and flow — we have: Po=KiDb. (2) The total upsetting pressure P becomes the sum of Pj and Po, thus : 7t D P = Pi + Pa = ^-