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Oct. :22, _ Q ' D. E. WELL-s > ' 2,409,649 BALL FORMING MILL Filed June 6, 1944 5 ‘Sheets-Sheet 2 V// i Y. , : & Ii QLQ Q. ii j i WWI» m Q "1' a w 2 V w; i U ' B‘E ' ' Ia‘ _ _' _ __ SD. B.’ '__ 3g”‘ > @ > :3 o INVEN'II‘OR. _ DAVID E.WEL_\_S BY ' o . “Q ATTORNEYE - . ’ v Oct. 22, 1946. D. ‘E. WELLS , ' 2,469,649 BALL FORMING MILL Filed June 6, ‘1944 f s Sheets-Sheet s ‘N ‘1. ‘ INVENTOR. DAVID E. WELLS. \lj ' N, " Bm,mma7 " A YTORNE Y3 Oct» 22, 1946: D. E. WELLS‘ ‘ 2,409,649 BALL FORMING MILL Filed June 6, 1944 5 sheeisfsheet 4 ATTORNE Y5. 7 Oct. 22, 1946. D. E. WELLS - 2,409,649 BALL FORMING MILL Filed June a, 1944 ‘ 5 Sheets-Sheet 5 .__LL ,P" l; ‘T " pf; 7/! AIRY . I I ,' " I flaw“ H770? zyzs' 2,469,649 Patented Oct. '22, 1946 UNITED STATES PATENT ‘OFFICE 2,409,649 BALL FORMING MILL David E. Wells, San Leandro, Calif. Application June 6, 1944, Serial No; 538,985 4 Claims. (01. 80-23)’ 1 . . 2 . 1 reference should be had to the accompanying The present invention rela es to improvements in a ball forming mill, and it consists of the com drawings, forming part of this application, in binations, constructions and arrangements here~ which: ‘ Figure 1 is a longitudinal sectional View through inafter described and claimed. the ball forming portion of the mill, commencing . An object of my invention is toprovidea ball with the feeding and rod reducing end and ex forming mill, that is adapted for transforming . tending as far into the driving unit as indicated by the broken lines a—-b; 1 heated rods into metal balls, the latter being completely shaped when delivered from the mill. It is further proposed to‘provide a mill‘ in which Figure 2 is a longitudinal section through the the process of forming the metal balls may be 10 remaining part of the mill, starting with the same broken lines a—b and continuing through the carried out in a continuous manner and prefer driving'unit, parts being shown in elevation; ably at a relative high speed, whereby the pro~ , , Figure 3 is a transversevertical section taken along the line III-III of Figure 1; ,; Figure 4 is a front elevation of the millas see ployed for forming the balls. This application 15 irom'the left-hand end of Figure 1; ‘‘ is a continuation-in-part of my co-pending appli Figure 5 is a vertical transverse section taken cation on a Ball forming mill, Serial No. 360,347, along the line V-—V‘ of Figure l; , ?led October 9, 1940. Figure 6 is a plan View of the ‘feed tube cooling A still further object is to provide a novel rod feeding apparatus, which is adjustable for ad 20 box and top carrier, both of which will be better understood as the speci?cation continues‘; vancing the heated rods atthe desired speed into ' Figure '7 is a section‘ taken along ' the line the ball forming section of the mill and for resize VII—VII of Figure 6; ing the rod if necessary so that the correct amount Figure 8 is a plan view of the feed tube support, of material will be fed into the ball forming ‘sec duction of the metal balls may be speeded up as compared with the method which is now em tion. This rod-feeding apparatus rotates ‘the 25 rods as they are advanced, and I provide a pair of coasting rollers or dies that are arranged for taken along ‘the line VIII-IVIII of ‘Figure 1; Figure 9 is a vertical section taken along the line IX-IX of Figure 1; and then for. forming the latter into spherical and rest bar; 1 ‘ s Figure 11 is a partial sectional view taken along metal balls. Therod-feeding apparatusrotates the line XI——)H of Figure-1; the rod at the same peripheral speed as the pe ‘ Figure 12 ‘is a diagrammatic View of av circume ripheral speed of the dies prior tothe rod entering the dies. . v Figure 10 is a perspecive view of the ball guide cutting the advancing rod into equal segments ferential travel cutting cycle; ‘ ‘ - Figure 13 illustrates graphically the relative sizes of the cylindrical rod segment and th Another object of my ‘invention residesin the provision of a pair of rod-cutting and ball-form- . ing rollers or dies, the peripheries of which near ly contact with each other and whose axes spherical ball formed therefrom; and 1 Figure 1a illustrates diagrammatically the steps practically parallel the axis or the advancing of resizing the rod and forming the ball from a rod. rod segment. These die rollers are fashionedwith spiral grooves therein, which cut the desired amount of material from the‘rodv and, simultaneously 40 changes or modi?cations may be made within form the cylindricalmaterial into a spherical ball while it is being cut. 1 While I have shown only theipreierred form of my invention, it should be understood that various the scope of the appended claims without spart ' ing from the spirit or the invention. ' ‘ ' It is further proposed to provide a rod-feeding The entire mill is illustrated in Figures 1 and 2. apparatus that will cause the rod not only to 45 The rod resizing, feeding, cutting and ball form rotate at the same peripheral speed as that of the ing portions of the mill are shown in Figure 1, rollers, but will advance the rod longitudinally at a speed which will obviate slippage between the while the drive and adjusting mechanism is dis rod and the roller helices. ‘It is essential that closed in Figure 2'.‘ The brokenv line web‘ of the helices of the forming rollers be‘ perfectly 50 Figure 1, if superimposed on the broken lined-b aligned with respect to one another, and I-pro~ of Figure 2, will bring the two portions of the vide novel means for accomplishing this result. mill together and give ‘a complete showing of ‘It ‘is also proposed to provide a mill of the the entire mill from end to end. In describing the construction and operation of the mill, the rod resizing and feeding end will be mentioned ?rst; then the rod cutting and ball forming portion of the mill; and, finally, the op erating mechanism which actuates the entire character described, which is adjustable for forming metal balls of various sizes. -. Other objects and advantages will appear as the speci?cation proceeds, and the novel features of my invention will beparticulariy set forth, in the claims hereunto annexed. - = i I, For a better understandingr ‘of, the; invention, 60 mill. 7 2,409,649 3 4 Rod resizing and feeding assembly frame E only will be given and the corresponding parts in the frame E’ will be primed. The frame Referring now to Figures 1 and 4, it will be noted that I make use of a base A for supporting the rod resizing and feeding assembly, and this base is secured to a bed plate B by bolts I. Two guide posts 2-2 extend upwardly from the base A E rests on the bed plate B and is adjustably se ured thereto by bolts 21. The frame has a verti cally extending guide 22 closed at its upper end by a header 23. The latter is secured to the frame by cap bolts 24, and the bolts in turn are and slidably carry lower and upper rod resizing ' removably secured to the frame by cap bolt keys and feed roller carriers 3 and 3', respectively. 25. The lower portions of the guide posts 2—2 are 10 A bottom carrier 26 (see Figure 9) is adjustably threaded and receive adjustable nuts 4 that bear mounted within the guide 22 and also a feed tube against the lower carrier 3 and prevent vertical cooling box 2'!’ and a top rider 28, are mounted movement below a predetermined point. In a above the carrier and within the guide. The like manner, the upper portions of the guide posts bottom carrier 28 is supported by a pressure 2-2 are threaded and receive adjustable nuts 4’ screw 29, which is threaded into a pressure nut that prevent upward movement of the upper car 30 that rests in the frame E. A cast iron breaker rier 3' above a predetermined point. The pur 3|, or one of any other fragile material, is inter~ pose of these positive limits which will prevent posed between the bottom carrier 25 and the movement of the carriers away from each other screw 29. This breaker will give way when the will be explained later. 20 pressure on the carrier 26 exceeds a predeterThe upper carrier 3' is similar in construction mined point. The bottom carrier has a slotted to the lower carrier and, therefore, a description ?ange at each side for receiving cap screws 32 of the lower one will suffice for both. Like ref for adjustably holding the carrier in place. A erence numerals will be applied to corresponding saddle groove 33 is formed in the top center of parts of the two carriers, except the numerals 25 the carrier and receives a brass half bushing 34%. will be primed for the parts associated with the The bushing may be made of any other anti~ upper carrier 3'. The carrier 3 has a central de friction material and is held in place by a pro pression 5, which is‘circular, with an axially dis jection 35 that enters a recess 36 in the bottom posed recess 6 (see Figure 1). of the groove indicated at 33. A rod_resizing feed roller housing‘, indicated 30 The feed cooling box 21 is also adjust-ably generally at C, has a disc-shaped platform 1 that mounted in the guide 22 and has slotted ?anges isv rotatably received in the depression 5 and a 31 (see Figures 6 and 7) for receiving cap screws concentric circular extension 8 rotatably receiv 38, which adjustably hold the box in place. The able in the recess 6. A bolt 9 secures the plat form 1 in place, while permitting angular adjust- ‘.1 ment with respect to the carrier 3. It should be noted at this time that the upper bolt 9' (see Fig ure 4) is longer than the bolt 9 and passes box receives an end feeding tube 39, which is ?anged for receiving the central feed tube IT. A water jacket 40 surrounds the tube 39 and has a cold water inlet 4! and a hot water outlet 42. On each side of the tube, the water jacket through a central opening in a top tie plate Ill that extends between the two guide posts 2_2. 40 is pierced by spring-receiving compartments 43. Springs 54 (see Figures 6, 7 and 9) are received A coil spring ll encircles the bolt 9’ and has its in these compartments and have their outer ends ends bearing against the tie plate l0 and a washer bearing on the bottom carrier 25. A ?oating sup I2 is mounted on the bolt. port for the box 21 is provided in this manner. The rod resizing and feed roller housing C A brass bushing 45 rests on the top of the box rotatably carries a shaft I3 on which is mounted 21 and has a one-fourth circumferential groove a feed pinch roller M. The rollers l4 and M’ therein for a purpose hereinafter described. are designed to grip a heated cylindrical rod D The top rider 28 also ‘has slotted ?anges 46 therebetween and to move the rod longitudinally with cap screws 41 for adjustably securing it in while rotating the rod. The rod is ?rst heated to the proper temperature and is then introduced 50 the guide 22. The top rider is indentical to the bottom carrier and is turned upside down. A into a feed tube I5. The latter is carried by a brass half bushing 48 is ?tted into a groove 49 feed tube support l6 (see Fig. 1) that is in turn formed in the underside of the top rider. A pres supported by the guide posts 2-2. sure screw 50 extends through a pressure nut The rod is then gripped by the rollers Ill-M’ and is rotated and moved longitudinally into a 55 5| and is spaced from the top rider by a cast central feed tube l1, also carried by the support IS. The speed of the longitudinal movement of the rod D is controlled by canting the rollers I4—-l4'. It will be noted from Figures 1 and 5 that the carriers 3 and 3’ have two spaced lugs l8 andl8’, respectively. Set screws l9 and I9’ are adjustably carried by these lugs and bear against opposite sides of ?anges 20 and 20’ that are formed integral with the rod resizing and feed iron breaker 52. The‘ screws 29 and 50 are held against accidental rotation by pins 53 and 54 that extend through openings in the screw hand wheels 55 and 56. The bottom carriers 26 and 26’ rotatably sup port a, lower rod cutting and ball forming roller die 5‘! (see Figure 1). The brass quarter bush ings 45 and 45' rotatably support an upper rod cutting and ball forming roller die 51’. The roller An adjustment of the 65 die 5'! is connected by a. universal drive shaft 58 with the shaft l3 and in a like manner the roller set screws will swing the housings angularly and die 51' is connected by a universal drive shaft 53’ cant the rollers l4 and M’ at the desired angle. roller housings C and C’. The set screws are locked against accidental movement after they have once been set. Rod cutting and ball forming mechanism The rod cutting and ball forming mechanism is supported by frames E and E’ (see Figures 1 and 9). Both frames and their associated parts are identical and, therefore, a description of the with the shaft I3’. The roller dies 5'! and 51’ are identical and are provided with “drunken” or staggered helical 70 threads 59 and 59’, respectively. The initial por tion of each thread is made narrow and sharp for the purpose of cutting into the heated rod. The space between the cutting edges of the threads at the lead end of the rollers is such as 75 to receive the rod D. The cutting edges gradu 2,409,649 5 are mounted on guide: rests 66 that'are integral ally enlarge in radii until the threads of the two roller dies abut each other after the threads have made one circumferential turn around the rollers. In other words, one complete revolution ‘ with the‘frames E'and. E’. ‘ a Bolts 61 arepassed through openings in the guide rests 56 and through slots 68 in the guide of both rollers will‘cause the cutting portions rest bars Eli. ‘Set screws 69 are received in the of the threads to sever completely a piece from frames E and E’ and bear against lugs 10 that are integral with the guide rest bars. The set screws are independently adjustable for moving the guide plates into the proper position, after the rod D. i l ' The width of the entrance of the helical groove in each roller die formed by the start of the cut ting edge and a point 360° removed therefrom is 10 which the bolts 61 are tightened for rigidly se curing the parts in place. The guide plates til about two-thirds of the diameter of the rod. cooperate with the rollers 51 and 5'5" in holding The helical groove on each roller die widens . the‘metal balls between the rollers while they are gradually until it has a width equal to that of the‘ being formed into spheres. The completed balls rod diameter and also of the ball which is simul taneously formed during the‘ cutting operation. 15 are fed into a ball outlet tube ‘ltd (see Figure 1), after passing through the tube 39’. The sharp cutting edge of the initial portion of the thread also widens gradually so that the walls Mill operating mechanism of the ball forming groove will have su?icient The mechanism for operating the mill is illus width to withstand the necessary ' pressure trated in Figure 2. A gear box indicated gen needed to form the rod portion into a ball during erally at G has a drive shaft ‘I!’ rotatably the cutting operation. It is obvious that more mounted therein and carrying a drive pinion than one thread may be provided on each roller. 12. Any means desired may be utilized for ro_ In order to insure a complete severing of the tating the drive, shaft 1|. A driven shaft ‘it is ' rod D for each revolution of the rollers 51 and also rotatably mounted in the gear box and 51', I form a slight recess 60 in the thread ‘59 at carries a pinion 14 that meshes with the pinion a .point 360° from the start of the thread of the '12. A shaft 15 has a universal connection at one roller 51, and I form a slight cutting projection 60' in the thread 59' at a point 360° from the 7 end with the shaft 'I3’and has a second universal connection at the other end with the roller die start of the thread on the roller 51' (see Figure 51' (see Figures 1 and 2). ‘ 30 11). The two threads on the two rollers sub Novel means are provided for‘connecting the stantially contact each other at this point and roller die 51 with the shaft ‘H and rmitting an ‘the projection 60 will, therefore, extend beyond angular adjustment to be effected between the the center of the rod D. This assuresva com two roller dies 51 and 51', if necessary. \St is vita1 plete severing of the rod by the cutting threads when the rollers have completed one revolution. 35 that the threads on the two die rollers p\e<gctly coincide so that the two roller grooves will Qrm The longitudinal movement of the rod D is such a continuous ball forming passageway or guide that the cutting threads merely cut into the rod way from end to end of the rollers. The inner\ and do not necessarily aid in advancing the rod. end of the shaft ‘H is keyed to a two-part housing The springs 44 permit a slight give to the end 16 so that the housing will rotate with the shaft. 40 tube Stand will permit the tube to adjust itself A stub shaft 11 is rotatably mounted in one wall automatically as the rod is fed therethrough and of the gear box and has its other end rotatably as the rod is subjected to cutting strains from disposed in the housing 16. A worm gear 18 is both roller threads. It is sometimes advanta keyed to that portion of the stub shaft 11 that geous to incline the cutting andlforming roller is rotatably received in the housing. The housing axes slightly toward each other from the lead end also carries a worm 19 that meshes with the worm to the rear end so that the shaping of the cut por gear 18 for a purpose presently to be described. tion or segment of the rod into a ball will be A pinion 89 is keyed to the stub shaft 11 and progressively accomplished and will ?nally give meshes with a pinion 8! that is mounted on a a completed ball expelled from the rear ends of the rollers. The cutting of the rod and the simultaneous shaping of the piece into a ball during the cutting operation are completed in one revolution of the roller dies. The remaining second driven shaft 82 similar to the driven shaft ‘13. A shaft 83, similar to the shaft ‘l5, has a universal connection with the driven shaft 82 and has a second universal connection with the roller 51. In the event vthat the threads on the two thread portions de?ne a grooved channel that smoothes the exterior ball surface. roller dies 51 and 5'!’ should be out of registry, ‘the worm "i9 is rotated for ‘turning the worm gear The pressure screws 29' and 58' may, be ad» justed for bringing the rear ends of the rollers 51 and 51' closer together than the front ends. ‘ The shafts 58 and 53' with their universal joints at ‘each end permit this movement. I provide adjustable ball guides iii-ii! (see Figures 3 and 10), that extend along the sides of the rollers 51 and 51' to hold the metal balls F in the helical grooves while they are being formed. that extends Eachbetween guide itlthe hasrollers a reduced and the edge.two 60 '58 in the housing ‘#6. This‘will rotate the stub shaft ‘H with respect to the drive shaft 'H' and through the pinions 8H and SI will rotate the roller El with respect to the roller 51’. The rela tive rotation between the two rollers can be ef fected in either direction for properly bringing the thread 59 into registry with the thread 59'. ‘One easy way of determining this is to position ' the two die rollers so that the projection 60' will be received in the recess ?ll for each complete ro tation of the rollers. After the adjustment has edges are spaced apart a distance equal to the diameter of the ball. It will be noted from Fig“ ure 10 that the reduced edge 62 is formed with been made, the worm 19 is locked against any accidental movement. Thereupon, the stub shaft a Stellite surface and terminates in a blunt cor as a unit with the drive'shaft ‘H. ner portion 63. This blunt corner is disposed at the leading ends of the rollers ti and‘ii'i'.‘ The ball guides iii are secured to guide rest bars -. . 64 by bolts 65. rI‘he guide rest bars 63 in turn ‘ill, the worm ‘I8 and the housing 16 will rotate The worm ‘[9 acts as a natural look worm gear, since the rotative movement the worm gearl‘to the worm when the operating. Of course, a worm gear of for the is from mill is limited \ 2,409,649 7 8 spiral angle cannot rotate a'worm. In addition rollers accomplish th'e'smoothing of the outer surface of the ball. The guides 6| hold the metal to this, I mount and key the worm on a bolt 84, The ends of the bolt extend through the two part housing 16, one end of the bolt being pro balls between the rollers during this process. The Vided with a head and the other end with a nut 91 (not shown). Both parts or halves of the two part housing ‘iii are identical in size and shape. The bolt 84 and the bolts 85 may be tightened feed roller pressure screw nuts 4 and 4' are ad justed to exert the proper pressure on the rollers i4 and M’ to feed the rod longitudinally and also rotate it. The rollers M and I4’ resize the rod if it is oversize. The feed rollers are driven after the angular adjustment has been made, at the same speed as the cutting and forming thereby clamping the two-part housing together 10 rollers and this prevents slippage between the with sufficient force to grip the worm and pre rod D and the threads on the forming rollers. vent rotation of the latter. The two-part hous The cutting portion of the threads on the forming 16 and the worm 19 now will rotate as a unit ing rollers increases in height from zero'to one and the pinions ‘l2 and 8 will revolve at the half the diameter of the ball for one complete same speed. 15 cycle of the thread. A cycle may be one fourth, The mill can accommodate rods D of different one third, one half, a complete revolution or more, diameters. In the event that the rods are smaller depending upon the number of threads on the than the feed tubes, bushings (not shown) are roller and the size and hardness of the material. placed in the tubes and different die rollers 57 and The cutting portion of the thread has a double 51’ are mounted in place of the die rollers shown. A larger feed tube could be used when the rod is larger. A change in feed and forming rollers is necessary with each change in the diameter of the rod except ‘where the pinch feed rollers re duce the diameter of the rod to the proper size as they feed the rod into the die rollers. Operation From the foregoing description of the various cove contour with constant cove radii no matter what the thread height. This will cause the cut oil‘ section to be nearly spherical when severed. The ball forming portion of the thread is made thicker to obtain suihcient strength to perform the side work of forming the cut portion of the rod ‘into a sphere during the cutting action. The eight stages of the circumferential travel cutting cycle is illustrated in Figure 12 and shows how the rod is simultaneously cut and shaped into parts of the mill, the operation thereof may be a sphere. readily understood. The operation of the mill has been partially described when setting forth the several Parts. stage. Figure compares the length of the cut rod portion with the diameter of the ball made The rOd D is heated to a forging temperature to suit the material used. Any desired metal may be used for making the metal balls, such as prckel, chrome, or any high abrasive resisting alloys. The bar or rod, when heated to forging temperature, is inserted into the feed tube l5, where it is grasped by the pinch feed rollers l4 and It’. These rollers have been previously cant ed to the desired degree for feeding the rod for wardly at the proper speed and also set at a cor rect opening in order to feed the correct amount of material for forming a proper size ball. Stage I and stage I’ are the same from the same portion. If the ball diameter is one inch, then the length of the rod section will be 0.666 of one inch or of the ball diameter. Figure 14 shows diagrammatically 'howan over sized rod D is resized by the pinch feed rollers l4 and hi’ and further discloses what portions of the rod section are forced into places to form the completed ball. The rod section is shown at D’ and the completed ball is shown at F. Referring to Figure 12, the development of the cutting thread is shown at 86 by the dot-dash line. The eight stages illustrate the step by step action » of the cutting thread in cutting the rod and Should the rod be slightly oversize, the pinch simultaneously forcing the material of each suc feed rollers would “pinch” or resize the rod to ceeding cylindrical portion of the rod into the the proper diameter. The rod is fed through the form of a ball. This action is performed in the feed tubes I1 and 39 and then reaches the rod following progressive and orderly manner; stage cutting and ball forming roller dies 51 and 51’. 50 2 indicates the advancement of the rod D beyond The pinch feed rollers advance the rod at the the position of stage I and yet the rotation of the same speed as the threads 59 and 59’ advance roller dies 51 and 57’ causes the path 86 of the along the rollers while they rotate. There is, cutting edges 59 and 59’ to form a negative lead therefore, no longitudinal pulling action between of 0.110. The threads at this stage have cut into the threads and the rod. The rod is also rotated the rod diameter to reduce it from one inch to at the same peripheral speed as that of the roll seven eighths of an inch. It will be noted that ers 5'! and 5'!’ by the pinch feed rollers and this the concave portions of the groove adjacent to prevents any peripheral slippage between the the cutting edge of the thread are shaped to rod and roller dies 51 and 51’. Small balls and form the lower part of the ball F into a spherical balls of ductile material may be formed from surface. unheated rods. The pinch feed rollers start Stage 3 discloses the threads 59 and 59’ as cut moving the rod longitudinally and rotating the ting still deeper into the rod D so that they are rod before the rod reaches the roller dies. There spaced three fourths of an inch from each other. is no tearing action between the rod and dies due The rod has advanced and the dies 5?‘ and 5'!’ to lack of uniform movement therebetween. 65 have rotated so that there is still a negative lead The ?rst revolution of the threads on each of the path of the cutting edge of 0.065. At stage roller die will cause them to out through the rod. t the negative lead of the cutting edge has been In Figure 12 I show diagrammatically eight 1 reduced to 0.008 and the threads 50 and 59' are ?ve eighths of an inch apart. The concave por projection 65’ completes the severing of a rod 70 tions adjacent to the threads are forming a portion from the remainder of the rod, and is spherical surface on the portion of the ball F’ illustrated in the last stage. The cutting of the attached to the rod and are forming a spherical rod and the shaping of the rod into a ball is done surface on the rod end that will form the next stages of the circumferential cutting cycle. The simultaneously in the first revolution of the dies ball F. while the rest of the helical grooves in the two 75 Stages 5 to 8 inclusive show the path 86 of the 2,409,649 . , 9 10 cutting edge change from a negative to a positive lead of 0.0982 for stage 5; a positive lead of 0.2008 for stage 6; a positive lead of 0.3128 for stage ‘I; and a positive lead of 0.4336 for stage 8. During these four stages the threads 59 and 50’ are pro substantially abutting each other throughout the greater portions of their lengths and ball form gressively and uniformly advanced toward each ing grooves disposed between the threads, the other so that the distance between the threads is one-half an inch for stage 5; three-eighths of an‘ inch for stage 6; one-fourth of an inch for stage 1; and one eighth of an inch for stage 8. The concave portions adjacent to the cutting threads continue to form the second half of the ball F and the ?rst half of the next ball to be cut from leading thread portions having cutting edges . that gradually increase in height from points the I claim: . 1. In a ball forming mill, a pair of rod cutting and ball ‘forming rollers having helical threads same distance from the roller axes as the bot toms of’ the grooves to points where the two thread portions abut each other, concave walls disposed adjacent to the thread portions for forming the ball during the cutting operation, the remaining thread portions forming walls for the rod D. The concave ball-shaping portions create lines of force that are in a radial direction 15 smoothing the ball surface, and means for rotat ing the rollers, the opposed cutting portions of and toward the center of the ball. The displacement of the material forming the ball results in the elongation of the axis of the cut portion of the cylinder into the diameter of the ball. To accomplish this result while the die 20 rollers are rotating at a uniform speed and the rod material is being fed into the rollers at a uniform rate of two-thirds of the rod diameter per cycle of cutting operation, the cutting edges the roller threads where they abut each other being provided with a cooperating projection in one thread receivable in a recess in the other thread for causing the projection to extend be yond the midpoint between the two rollers. A ball forming mill comprising a pair of rod feeding and rod rotating rollers, means for canting the rollers to the desired extent for con 59 and 59’ must take the form shown in Figure 25 trolling the longitudinal movement of the rod, a pair of rod cutting and ball forming the rollers 1. In stages 5 to 8 inclusive, the cutting threads widen as indicated in Figure 12. Stage I’ is the operatively connected to the feed rollers and same as stage I and here the cutting projection having spiral cutting and shaping threads, said second pair of rollers receiving the rod advanced 60’ enters the recess 60, see Figure 11, for sever ing the ball F from the rod D. The remaining 30 by the first pair of rollers, means for adjusting the axes of the second pair of rollers toward or grooves on the dies smooth the ball surface. During the rod cutting and ball forming cycle, away from each other to the desired extent to the rod is advanced two-thirds of its own diam cut theurod properly into pieces and for simul eter as indicated by the line 81 in Figure 12. taneously forming the pieces into vballs, and The cut rod portion is elongated one third of a 35 common means for simultaneously rotating the diameter. Just before the ball is severed, the Ttwo pairszof rollers, said last named means in cutting threads are made thicker from stages 5 to 'gcluding means for rotating one roller‘L of the 8 so that there is a space of ‘one sixteenth of an ‘second pairv with respect to the other r0 r or inch between the ball F and the rod except for‘ the same pair for properly aligning the threads the actual point of attachment. The shearing 40 on the two ball forming rollers so that th\\ grooves will provide a ball-forming channel. a. projection 60' operates in this space to sever the 3. A ball forming mill comprising a pair of ball. . rod feeding and rod rotating rollers, a pair of rod The forming rollers and feed rollers may be cutting and ball forming rollers axially aligned tightened or loosened, as occasion demands, to form the proper ball. If the material runs over 45 with the axes of said rod feeding rollers and. the die grooves, the feed rollers are-tightened adapted to receive a rod advanced by the feed ing rollers, ‘said second-named rollers having slightly to resize the rod. On the other hand, if ‘the ball is not perfectly formed, the feedv rollers helical rod cutting and ball forming threads, are moved away from one another to permit a means for rotating both sets of rollers at the same larger diameter rod to enter the dies. If the ball is too large, the forming rollers are brought closer together; if too small, they are separated. The amount of stock to make a perfect ball of the. correct size is governed by the pressure and the angle of cant of the feed rollers. - The device can be turned on its side if desired so that the die rollers will lie in a horizontal peripheral speed for causing the feed rollers to rotate and longitudinally advance the rod before it reaches the second pair of rollers so that the forward speed of the rod will be the same as the pitch of the threads and the rotational speed of 55 the rod periphery will be the same as the rota tional speed of the peripheries of the second pair of rollers; whereby the roller threads will sever the rod into portions and form the portions into plane. The halls can be formed and dropped ,balls, and means for canting the feed rollers at out from the dies without passing through the ball outlet tube 100,. The threads at the exit ends 60 the desired angle for regulating the movement of the rod in the direction of its‘length. of the dies would stop short of the die ends and 4. A ball forming mill comprising a pair of rod the bodies of the die rollers would be slightly re feeding and rod rotating rollers, means for cant duced in diameter at their rear ends to permit ing the rollers to the desired extent for control the balls to dropout. Where the rollers are in a vertical plane, there can be side ejection of the 65 ling the longitudinal movement of the rod, a pair of rod cutting and ball forming die rollers opera balls before the balls reach the rear of the dies. The drawings show the cutting cycle to occupy , tively connected to the feed rollers and having spiral cutting and shaping threads, said second one revolution of the dies, but it is obvious that pair of rollers receiving the rod advanced ‘by the the cycle can ‘be completed in a fraction of a revolution or one or more revolutions. Where 70 ?rst pair of rollers, and common ‘means for simultaneously rotating the two pairs of rollers. multiple cutting threads are used, the cutting and ball forming cycles of the different threads may overlap each other. a ‘ DAVID E. WELLS.