US3076359A

US3076359A - Machine for producing thin walled tubing

Info

Publication number: US3076359A
Application number: US794769A
Authority: US
Inventors: Edward L Mayo
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1959-02-20
Filing date: 1959-02-20
Publication date: 1963-02-05
Anticipated expiration: 1980-02-05

Description

Feb. 5, 1963 E. L. MAYO MACHINE FOR PRODUCING THIN WALLED TUBING Original Filed Jan. 3, 1956 Sheets-Sheet l r .1. i I) lw e- 1 2a H 14 8 L za 9 J 3 Z7 u -11 Z2 Z6 Z5 za 5 3536 I 34 Z5 s. I 29 -57 J" 33 l v r I 19 I I F a; I 6 D INVENTOR.

Feb. 5, 1963 E. L. MAYO 3,076,359

MACHINE FOR PRODUCING THIN WALLED TUBING Original Filed Jan. 3, 1956 3 Sheets-Sheet 2 INVENTOR. 93 [guy/add Wig 0 Feb. 5, 1963 E. L. MAYQ 3,076,359

MACHINE FOR PRODUCING THIN WALLED TUBING Original Filed Jan. 3, 1956 3 Sheets-Sheet 3 IN V EN TOR.

[aQuzwQ Z. Wgyo United States Patent Ofiice 3,d7,359 Patented Feb. 5, 1963 3,076,359 MACHINE non PRODUCING THIN WALLED TUBING Edward L. Mayo, Cleveiand, Ohio, assignor, by mesne This invention relates to machines for producing thin walled metal tubing, and has to do with a machine for producing elongated thin walled metal tubing from relatively short thick walled blanks.

The machine of my invention is intended for accomplishing comparatively great--60% or more-- reduction in the wall thickness of the blank'by subjecting it to pressure between exterior rollers and an interior mandrel while advancing the areas of the applied pressures lengthwise of the blank thereby thinning and elongating the wall thereof to produce an elongated thin walled tube. It is important that the rate of advance of the applied pressures lengthwise of the blank and the speed of rotation of such areas around the blank be properly related in order to guard against twisting or tearing of the resultant tube. In the machine of my invention the blank is mounted upon a mandrel fitting closely the interior thereof and is moved axially through a roller assembly which is fixed in position and comprises a plurality of pressure applying rollers mounted for free rotation, the mandrel and the blank thereon being rotated at comparatively high speed. The mandrel is disposed vertically and the rollers of the assembly define a passage coaxial with the mandrel and underlying the latter, such passage having a downwardly tapering upper portion and a cylindrical lower portion the radius of which exceeds the radius of the mandrel by the desired wall thickness of the tube to be produced from the blank. I provide power means for rotating the mandrel at comparatively high speed and for moving the mandrel downward at a uniform rate and for returning it to raised position. The means for'moving the mandrel vertically is adjustable so that the rate of downward movement of the mandrel, during the op eration of reducing the wall thickness of the blank to form the tube, may be adjusted accurately relative to the speed of rotation of the blank so as to guard against tearing or other injury to the tube while accomplishing the desired reduction of the wall thickness thereof at the maximum permissible rate. The means for moving the mandrel vertically also includes means for reversing movement thereof and means for disconnecting the mandrel, i.e., the spindle which carries the mandrel, from the power means, supplementary means being provided whereby the mandrel may be abruptly moved downward manually, for a purpose to be later disclosed. Further objects and advantages of my invention will appear from the detail description.

In the drawings:

FIGURE 1 is a front view of a machine embodying my invention;

FIGURE 2 is a side view of the machine of FIGURE 1;

FIGURE 3 is a detail, on an enlarged scale, partly in section and partly broken away, of the inner end portion of the quill drive shaft and associated parts; i

FIGURE 4 is a sectional view, on an enlarged scale, taken substantially on line 4-4 of FIGURE 1;

. FIGURES is a sectional view, on an enlarged scale, taken substantially on line 55 of FIGURE 1 showing a blank on the mandrel about to enter the roller assembly; FIGURE 6 is a view like FIGURE 5 but showing the tube on the mandrel produced by movement of the blank through the roller assembly;

FiGURE 7 is a plan view of the roller assembly;

FIGURE 8 is a sectional view, on an enlarged scale, taken substantially on line 8-8 of FIGURE 7;

FiGURE'9 is a plan view of the lower roller assembly clamp plate; and

FIGURE 10 is an underneath view of the upper roller assembly clamp plate.

This applicationis a continuation of my copending application, Serial No. 556,948, filed January 3, 1956, now abandoned.

The machine of my invention is, in certain of its aspects, similar to a drill press and a brief description of such features will suifice. The machine comprises a base 10 secured to a suitable stand 11 and receiving a column 12 to which is secured a brace frame 13 also secured to stand 11. Suitably spaced

arms

14, 15, 16 and 17 are secured upon column 12 in a known manner and project forwardly therefrom. The

arms

14, 15 and 16 are provided at their forward ends with heads or

sleeves

18, 19 and 20, respectively. Aquill 21 is slidably mounted in

heads

19 and 29 of

arms

15 and 16 for vertical movement, in a suitable known manner, and is restrained against turning movement. A spindle 22 is slidably and rotatably mounted, at its upper portion, in a bushing 23 carried by head 18 of arm 14, and is mounted in quill 21 for relative rotation and for movement therewith, in a known manner.

A multiple V pulley 26 is splined on spindle 22 at the upper end of head 19 of arm 15 and has driving connection, by means of a belt 27, to the lower element of a multiple V pulley 28 mounted on an arm 29 secured to arm 15. The upper element of pulley 28 has driving connection, by means of a belt 30, to a multiple V pulley 31 secured on the upper end of shaft 32 of an electricmotor 33 secured on a mounting plate 34 which is suitably secured to the arm 15. The pulley 26 also has driving connection, by means of a belt 35, to a speed indicator unit 36, of, suitable known type, mounted on a plate 37 suitably mounted on head 19. The motor 33 drives the spindle 22 at a constant comparatively high speed approximately 2500 r.p.m., for example, and also drives the speed indicator unit 36 which shows the speed of rotation of spindle 22. l

The rearward or back portion of quill 21 is cut to provide a lengthwise rack bar 40 which meshes with the reduced inner end portion 41 of a quill drive shaft 42. The inner end portion 41 of shaft 42 is formed to provide a spur pinion of substantial length which is rotatably mounted in a transverse bearing sleeve 43 at the back of the lower end portion of head 20 of arm 16. Collars 44 and 45 are secured on the reduced inner end portion 41 of shaft 42 at the ends of sleeve 43 and restrain the shaft 42 against endwise movement. The sleeve 43 is of sub stantial length and, in conjunction with the end portion 41 of shaft 42, also of substantial length, effectively holds shaft 42 against any objectionable transverse movement. As will be understood from what has been said, the quill 21, and with it the spindle 22, may be either raised or lowered by turning shaft 42 in proper direction.

An inner sprocket wheel 48 is mounted on midportion 49 of shaft 42 for free turning movement thereon adjacent collar 44, midportion 49 of shaft 42 being of increased diameter. The sprocket wheel 48 is provided at its outer end with a clutch element and the outer portion of shaft 42 is of reduced diameter relative to the midportion 49 thereof. An outer sprocket wheel 50, of much less diameter than the sprocket wheel 48, is mounted on the reduced outer portion of shaft 42 for free turning movement thereon. The sprocket wheel Sit is provided at its inner end with a clutch element and is confined therewith between midportion 49 of shaft 42 and a collar 51 secured on shaft 42. Sprocket wheel 48 has driving connection, by means of a chain 52, to a sprocket wheel 53, of relatively small diameter, secured on the inner end of the output shaft 54 of a speed reducer unit 55 of suitable known type secured to the rearward end of the arm 16. A spur gear 57, secured on the outer end of shaft 54 meshes with a spur gear 57a secured on the outer end of a second counter shaft 58 disposed in front of and parallel with shaft 54 which, like the quill drive shaft 42, is disposed horizontally. Shaft 58 is rotatably mounted in bearing brackets 59 mounted on the front of plate 56 for vertical adjustment. Plate 56 is suitably supported on column 12 and is notched out at its outer end to accommodate the rearwardly extending portion of the spur gear 57. A stop collar 60 is secured on shaft 58 at the inner side of the outer bearing bracket 59 and, in cooperation therewith and with the spur gear 57a, restrains shaft 58 against endwise movement. A sprocket wheel 61 is keyed on shaft 58 and has driving connection, by means of a chain 62, to the sprocket wheel 50 on the quill drive shaft 42. As will be understood from what has been said, the Shafts 54 and 58 are driven in opposite directions so that by clutching one or the other of the sprockets 43 or 50 to the quill drive shaft 42 the direction of rotation of the latter may be reversed for raising or lowering the quill 21 and the spindle 22, as desired.

A clutch member 65 is splined on the midportion 49 of shaft 42 between the clutch elements of the sprocket wheels 48 and 50. Clutch member 65 is provided at the opposite sides thereof with clutch elements which cooperate with theclutch elements carried by the sprocket wheels '48 and 50 at their opposed ends. A forwardly extending clutch shift lever 66 is pivoted at its rearward end on an angle bracket 67 secured to and extending forwardly from the mounting plate 56. Shift lever 66 is provided with a substantially circular enlargement or strap portion 68 extending about clutch member 65 and carrying pins 69 extending into a circumferential groove in member 65 for shifting the latter in either direction desired lengthwise of the quill drive shaft 42. The clutch member 65 and the clutch elements of the sprocket wheels 48 and 50 are of conventional type and require no detailed description. When clutch member 65 is in its neutral position shown in FIGURE 1, midway between the clutch elements of the sprocket wheels 48 and 50, both of the sprocket wheels are free from shaft 42 and the latter may then be turned manually in either direction by means of a bar 70 secured through the outer end of shaft 42 diametrically thereof by a set screw 71. A speed selector V pulley or sheave 72 is keyed on the upper end of input shaft 73 of the speed reducer unit 55. Sheave 72 has driving connection, by means of a belt 74, to an adjustable or speed selector V pulley or sheave 75 keyed on the lower end of the motor shaft 32. The effective diameter of sheave 72 may be adjusted by an adjusting screw 76 threaded through a bracket 77 secured to a plate 78 which is secured to and extends upward from the back of the unit 55. Increasing the effective diameter of sheave 72 results in corresponding decrease in the effective diameter of sheave 75 and vice versa, so that by adjusting the sheave 72, by means of screw 76, the speed of rotation of the shafts 54 and 58 may be accurately controlled thereby giving accurate control of the speed of rotation of the quill drive shaft 42, when the latter is power driven, with resultant accuracy in control of the speed of travel of the quill 21 and the spindle 22 either upward or downward. That is particularly important in respect to the rate of downward travel of the quill 21, which should be at relatively low speed, as will appear more fully later. Assuming that the sheave 72 has been properly adjusted for the desired rate of downward travel of quill 21, the clutch member 65 is shifted toward the'left, as viewed in FIGURE 1, thereby clutching sprocket wheel 48 to the quill drive shaft 42. Referring to FIGURE 2, shaft 54 is driven in counterclockwise direction, as indicated by the arrow and shaft 58, consequently, is driven in clockwise direction. With the motor 33 in operation, when sprocket wheel 48 is clutched to shaft 42, the latter shaft is driven in counter-clockwise direction effective for moving the quill 21, and with it the spindle 22, downward at a uniform predetermined rate properly correlated to the speed of rotation of spindle 22 so as to avoid damage to the tubing being formed from the blank, as previously explained. After completion of the forming operation and removal from the mandrel of the formed tube, the quill 21 and the spindle 22 may be raised at relatively high speed by shifting clutch member 65 to the right into engagement with the sprocket wheel 50.

The motor 33 is controlled by a main switch 80 and two limit switches 81 and 82 secured on a mounting plate 83 carried by a collar 84 which is secured on the upper end of head 20 of arm 16. A rod 85 is secured adjacent its lower end to a collar 86 secured about the lower end of quill 21 and extends therefrom upwardly alongside quill 21 parallel therewith. A lower stop 87, pieferably spring mounted in a suitable known manner, is adjustably mounted on the lower end of rod 85 and an upper resilient stop 88 is adjustably mounted on rod 85. The stop 87 is disposed to actuate limit switch 82 when the quill 21 has been moved upward to the desired extent, thereby stopping the motor 33 and the upward travel of quill 21. Similarly, the stop 88 actuates the limit switch 81 and stops downward travel of quill 21 when the latter has been moved downward to a desired predetermined extent, as will be explained more fully later. A floating chuck assembly 89, of suitable known type, is secured on the lower end of spindle 22 and receives an elongated cylindrical mandrel 90 secured therein in a known manner.

A table 93 is secured to the forward end of arm 17 above a drip pan 94 and in underlying relation to the mandrel 90, in the raised position thereof. A lower roller assembly clamp plate 95, circular in plan, is bolted to table 93 at the upper face thereof. Clamp plate 95 is provided with a reduced upwardly extending neck 96 and is positioned over opening in table 93, as shown more clearly in FIGURES 5 and 6. Clamp plate 93 is provided with a concentric cylindrical recess 97 extending from the upper end of neck 96 and coaxial with a bore 98 of reduced diameter extending through the neck 96. An upper clamp plate 99, also circular in plan but of substantially less diameter than the lower plate 95, is disposed above the latter plate and is provided with a concentric recess 100 extending from its underface and of the same diameter as recess 97 of plate 95, the

recesses

97 and 100 being coaxial when the two

clamp plates

95 and 99 are secured together in proper relation. Clamp plate 99 is also provided with a bore 101 of reduced diameter extending from recess 100 to the upper face of plate 99. Plate 99 is further provided at its underface with equally spaced downwardly extending spacing bosses 102 the radially inner ends of which are coincident with the surrounding wall of the recess 100. Plate 99 is further provided with a plurality of equally spaced recesses 103 of relatively small diameter extending upward from the top wall of recess 100 and disposed equidistant from the center of plate 99. The lower plate 95 is also provided with a plurality of recesses 104 extending downward from the main recess 97 and equidistant from the center thereof, the recesses 104 being of the same diameter as the recesses 103 of plate 99, as shown more clearly in FIGURES 9 and 10, so that when

plates

95 and 99 are disposed in proper cooperating relation the small recesses 103 of plate 99 will be respectively aligned vertically with the recesses 104 of the lower plate 95.

The roller assembly 107, previously referred to, is shown more clearly in FIGURES 5 to 8, inclusive. It is similar to the roller assembly disclosed in Patent No. 2,522,257 issued September 12, 1950, to Walter A. Curtis.

The roller assembly comprises a race 108 at the under face of which is disposed a ring 109 of a width to extend. a substantial distance radially inward beyond race 108, the latter having at its upper face a plurality of upwardly extending bosses 110 spaced equidistant circumferentially thereof. A top ring 111 seats on the upper faces of the bosses 110 and is secured thereon by bolts 112 having at their upper ends hexagonal heads seating on ring 111, the bolts 112 passing through bosses 110 and race 108 and the bottom ring 109 and receiving, on their lower ends, hexagonal nuts conveniently of the same size as the heads of the bolts. The race 108 and the top ring 111 define between them slots 113 limited as to length by the bosses 110 and opening outward radially of the assembly 107. A cage 114 is positioned within the assembly 107 in concentric relation thereto and is provided with a plurality of circumferentially spaced slots 115 which receive rollers 116, the slots 115 being somewhat less in width than the diameter of the respective rollers 116, as will be understood. Each of the rollers 116 comprises a cylindrical body portion 117 and an upwardly tapering upper portion 118 of substantially frusto conical shape the upper end of which is hat. The diameter of the cage 114 is such asto hold the rollers 116 in contact with the inner circumferential surface of race 108, with the cage 114 centered in the assembly 107. The bottom retaining ring 109 extends radially inward beyond race 108, as shown more clearly in FIGURE 8, and provides an abutment or stop for the lower ends of the rollers 116, which are fiat at their lower ends as shown, and the top retainer ring 111 extends radially inward beyond race 108 to provide a stop for the flat upper ends of the rollers. The rollers 116 fit snugly, but not tightly,between the retainer rings 109 and 111 and the cage 114 fits snugly, but not tightly, about the body portions of the rollers. The rollers 116 may thus accommodate themselves to the surfaces being acted upon thereby while being efiectively restrained against objectionable tilting and endwise movement. The rollers 116 define a passage having an upper downwardly tapering portion and a lower cylindrical portion merging into and extending downward from such upper portion.

The roller assembly 107 seats at its lower end in recess 97 of the lower clamp plate 95 with the nuts on the lower ends of bolts 112 fitting snugly in the smaller recesses 104. The upper end of the assembly 197 seats snugly in the recess 100 of the upper clampplate 99 with the heads of the bolts fitting snugly in the small recesses 103. The upper clamp plate 99 is then bolted tightly to the lower clamp plate 95, with bosses 102 seating on lower plate 95 and the assembly 107 tightly clamped between the

plates

95 and 99, with the passage defined by the rollers disposed coaxially with the mandrel 90. A mandrel guide member 121 (FIGURES 1 and 2) is bolted to the upper face of the upper clamp plate 99 and is provided at its upper end with an inwardly extending finger 122 spaced a suitable distance above clamp plate 99 centrally thereof and provided with an opening 123 coaxial with the passage through the roller assembly and which snugly receives mandrel 90 and assures that it will be disposed in accurate coaxial alignment with the passage through the roller assembly. In order to produce an elongated thin walled metal tube a relatively short thick walled metal blank 124 is placed beneath finger 122 of guide member 121, the blank 124 being closed at its lower end by a wall 125. The mandrel 90 is then moved downward a short distance, conveniently manually by means of the bar 70, so as to extend into the blank 124 and contact the bottom wall 125 thereof, the interior diameter of blank 124 being such that mandrel 90 fits snugly therein. The blank 124 is then disposed upon the lower end of the mandrel adjacent the upper end or top of the roller assembly 107, as shown in FIGURE 5. When the blank has been properly positioned upon mandrel 90,

clutch member 65 is shifted toward the left, as viewed in FIGURE 1, thus clutching sprocket wheel 48 to the quill drive shaft 42. Assuming the motor 33 to be in operation, the blank 124 is moved downwardly by mandrel through the roller assembly at a predetermined uniform rate and the mandrel 90 is also rotated with the spindle 22 at a predetermined uniform speed. During such downward movement of the blank through the roller assembly, the rollers 116 exert radial and axial rolling pressures upon the exterior surface of the blank effective for displacing the metal thereof and redistributing it toward the upper end of the blank. 'The radius of the passage defined by the body portions 117 of the rollers 116 exceeds the radius of the mandrel 90 by the desired wall thickness of the tube to be produced. Accordingly, the wall of the blank is reduced in thickness to the desired wall thickness of the tube in the passage of the blank through the roller assembly. During the downward travel of the blank the displaced metal may, in certain cases, tend to pile up in advance of the rollers 116 somewhat in the manner indicated at 126 in FIG- URE 8, providing a collar or shoulder extending about the blank, it being understood that the-piling of the displaced metal is exaggerated for purposes of illustration. In some cases it maybe desirable to remove a portion of the piled up metal and, if desired, the cage 114 may be provided, at the upper ends of the slots 115, with a cutting edge or point 127. The cutting points or elemerits 127 function to trim off any objectionable excess of displaced or piled up metal in the rotation of the blank, the resultant metal chips being discharged radially through the slots 113 in the roller assembly. In many cases the provision of the cutting points 127 may not be required and they may, therefore, be omitted. When the blank has been moved downward through the roller assembly to an extent" sufficient toprovide a thin walled tube of the desired length, the stop 88 actuates limit switch 81 thereby stopping motor 33 and, consequently, stopping downward movement of mandrel 90. The thin walled tube then extends downward beyond the roller assembly with the collar 126 of piled up metal at the upper end of the tube disposed between the upper tapered portions of the rollers '116, as shown in FIGURE 6. In order to release the formed tube, clutch member 65 is shifted to neutral position, if not already in that position, and the mandrel. 90 is forced abruptly downward by turning the quill drive shaft 42 in proper direction by means of bar 70. That serves to snap off the collar 126 of piled up metal thus releasing the tube which may then readily be removed from the mandrel, the broken off collar of metal being readily removed from between the upper end portions of the rollers 116. I have found that if all of the metal in the circumferential wall of the blank 124 is rolled down to the extent required for producing the thin wall of the tube, there is a tendency for the metal at the upper end of the tube to split. That is avoided by terminating the reforming operation at such a point that a collar of metal is left at the upper end of the tube and breaking off the collar by abruptly forcing the tube downward in the manner described. In that connection it will be understood, of course, that the wall thickness and length of the original blank are such that the wastage of metal due to snapping off of the collar of piled up metal at the upper end of the tube is negligible and, in fact, is less than the wastage of metal would be if the entire circumferential wall of the blank were rolled down to the thickness of the extremely thin wall of the tube, as above mentioned, and the cracked or split upper end portion of the resultant tube were removed. The machine of my invention is particularly suitable for producing tubes of comparatively small diameters and having extremely thin walls, from various metals, it being feasible to break off the collar of piled up metal at the upper end of a tube of small diameter without risk of injury to the tube.

It is desirable that the blank and the roller assembly be adequately cooled and lubricated during the operation of rolling down the wall of the blank. To that end I provide an upright 130 adjacent one side of the lower clamp plate 95. A nozzle 131 is secured to upright 130 by a suitable clamp 132 and is connected by a flexible hose 133 to a pump or other suitable means (not shown) for supplying a suitable coolant and lubricant liquid to nozzle 131 under appropriate pressure. The nozzle 131 is so disposed as to deliver a stream of the liquid to the upper end of the roller assembly thereby effectively cooling and lubricating the parts. The liquid flows into drip pan 94 from which it may be returned to the pump or other pressure source in a known manner.

It will be understood that changes in detail may be resorted to without departing from the field and scope of my invention, and I intend to include all such variations, as fall within the scope of the appended claims, in this application in which the preferred form only of my invention has been disclosed.

I claim:

1. In a machine for forming elongated thin-walled metal tubing from a relatively short thick-walled blank, a roller assembly comprising a plurality of rollers respectively having a cylindrical body portion and a sub stantially frusto-conical end portion tapering from said body portion, said rollers being mounted for free rotation and defining a passage having a cylindrical portion of the same diameter as the outside diameter of the desired tubing and an end entrance portion tapering toward and opening into said cylindrical portion, a mandrel coaxial with said passage opposed to said entrance end portion thereof and having a radius less than the radius of said cylindrical portion of said passage by an extent equal to the wall thickness of the desired tubing, a constant speed motor, and positive driving connections irnparting relative rotation to said mandrel and said assembly at a predetermined constant speed and relative movement to said mandrel and roller assembly lengthwise of said mandrel at a predetermined constant rate relative to such predetermined constant speed of rotation, means for automatically stopping said motor to stop relative movement of said mandrel and roller assembly at a predetermined lengthwise position, and means 8. for causing relative axial motion without rotation beyond said predetermined position.

2. In a machine for forming elongated thin-walled metal tubing from a relatively short thick-walled blank, a roller assembly comprising a plurality of rollers respectively having a cylindrical body portion and a substantially frusto-conical end portion tapering from said body portion, said rollers being mounted for free rotation and defining a passage having a cylindrical portion of the same diameter as the outside diameter of the desired tubing and an end entrance portion tapering toward and opening into said cylindrical portion, a mandrel coaxial with said passage opposed to said entrance end portion thereof and having a radius less than the radius of said cylindrical portion of said passage by an extent equal to the wall thickness of the desired tubing, drive means including first means for imparting relative rotation to said mandrel and said assembly at a predetermined constant speed and second means for imparting relative feed to said mandrel and roller assembly lengthwise of said mandrel at a predetermined constant rate, means for automatically stopping said drive means to stop relative movement of said mandrel and roller assembly at a predetermined lengthwise position short of the position at which said blank is entirely through said roller assembly, and means actuating a portion of said second means for causing relative axial motion without rotation beyond said predetermined position to separate the reduced portion of said tube from the portion thereof that has not passed through said rollers.

References Cited in the file of this patent UNITED STATES PATENTS 331,075 Miles Nov. 24, 1885 670,910 Baush Mar. 26, 1901 831,697 Barnes a Sept. 25, 1906 948,472 Barnes Feb. 8, 1910 1,703,791 Sosa et al. Feb. 26, 1929 2,365,267 Heineman Dec. 19, 1944 2,429,938 Mansfield Oct. 28, 1947 2,522,257 Curtis Sept. 12, 1950 2,619,842 Felix Dec. 2, 1952 FOREIGN PATENTS 475,313 Canada July 17, 1951

Claims

1. IN A MACHINE FOR FORMING ELONGATED THIN-WALLED METAL TUBING FROM A RELATIVELY SHORT THICK-WALLED BLANK, A ROLLER ASSEMBLY COMPRISING A PLURALITY OF ROLLERS RESPECTIVELY HAVING A CYLINDRICAL BODY PORTION AND A SUBSTANTIALLY FRUSTO-CONICAL END PORTION TAPERING FROM SAID BODY PORTION, SAID ROLLERS BEING MOUNTED FOR FREE ROTATION AND DEFINING A PASSAGE HAVING A CYLINDRICAL PORTION OF THE SAME DIAMETER AS THE OUTSIDE DIAMETER OF THE DESIRED TUBING AND AN END ENTRANCE PORTION TAPERING TOWARD AND OPENING INTO SAID CYLINDRICAL PORTION, A MANDREL COAXIAL WITH SAID PASSAGE OPPOSED TO SAID ENTRANCE END PORTION THEREOF AND HAVING A RADIUS LESS THAN THE RADIUS OF SAID CYLINDRICAL PORTION OF SAID PASSAGE BY AN EXTENT EQUAL TO THE WALL THICKNESS OF THE DESIRED TUBING, A CONSTANT SPEED MOTOR, AND POSITIVE DRIVING CONNECTIONS IMPARTING RELATIVE ROTATION TO SAID MANDREL AND SAID ASSEMBLY AT A PREDETERMINED CONSTANT SPEED AND RELATIVE MOVEMENT TO SAID MANDREL AND ROLLER ASSEMBLY LENGTHWISE OF SAID MANDREL AT A PREDETERMINED CONSTANT RATE RELATIVE TO SUCH PREDETERMINED CONSTANT SPEED OF ROTATION, MEANS FOR AUTOMATICALLY STOPPING SAID MOTOR TO STOP RELATIVE MOVEMENT OF SAID MANDREL AND ROLLER ASSEMBLY AT A PREDETERMINED LENGTHWISE POSITION, AND MEANS FOR CAUSING RELATIVE AXIAL MOTION WITHOUT ROTATION BEYOND SAID PREDETERMINED POSITION.