US2205148A - Electric die threader - Google Patents

Electric die threader Download PDF

Info

Publication number
US2205148A
US2205148A US273788A US27378839A US2205148A US 2205148 A US2205148 A US 2205148A US 273788 A US273788 A US 273788A US 27378839 A US27378839 A US 27378839A US 2205148 A US2205148 A US 2205148A
Authority
US
United States
Prior art keywords
frame
die holder
die
gear
shaft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US273788A
Inventor
Frank E Mayotte
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US273788A priority Critical patent/US2205148A/en
Application granted granted Critical
Publication of US2205148A publication Critical patent/US2205148A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23GTHREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
    • B23G1/00Thread cutting; Automatic machines specially designed therefor
    • B23G1/02Thread cutting; Automatic machines specially designed therefor on an external or internal cylindrical or conical surface, e.g. on recesses
    • B23G1/04Machines with one working-spindle
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T408/00Cutting by use of rotating axially moving tool
    • Y10T408/65Means to drive tool

Definitions

  • the present invention relates to thread cutting tools and the primary object of the invention is to provide a portable power driven threading tool primarily designed for cutting threads on bolts, rods, small pipe, etc.
  • a further object of the invention is to provide a portable self-contained electrically operated T thread cutting tool of improved construction permitting use of the tool in very restricted areas.
  • a further object of the invention is to provide anelectric die threader embodying a readily in-' Other objects and advantages of the invention.
  • Figure 1 is a view in side elevation of the electric die threading tool.
  • Figure 2 is a side view of the tool with one of the side cover plates removed.
  • Figure 3 is a longitudinal section substantially on line 3-3 of Figure 2.
  • Figure 4 is a transverse section substantially online 4-4 of Figure 2.
  • Figure 5 is an enlarged fragmentary section substantially on line 5-5 of Figure 2.
  • Figure 6 is a fragmentary top plan view showing the gear shifting lever arrangement.
  • Figure 7 is an enlarged longitudinal section thru the drive member for imparting rotation to the die holder or shell.
  • Figure 8 is a side view on a reduced scale of the die holder shown in Figures 1 and 2 for holding a solid round die.
  • Figure 9 is a side view of a die holder for holding a solid square die.
  • the electric die threader comprises a relatively fiat casing A upon one end of which is mounted an electric motor B for imparting rotation to a combined worm wheel and die holder or shell C thru speed reduction gear mechanism D.
  • the casing A comprises a relatively flat open sided metal "frame If) which preferably tapers slightly at its sides towards one end of the frame as best shown in Figures 3 and 6.
  • the frame I 0 has a circular portion II with which is integrally formed a hand grip l2 lying in the plane of the frame.
  • the wider end of the frame N forms an end wall l3 which is connected at its upper end with the circular portion H by atop wall l4.
  • Formed-on the outer side of the end wall I3 is a flange ii to which a flange of the electric motor..B is attached as by bolts or the like 6.
  • Secured as by bolts or the like l6 to a flange at the outer end of the electric motor B is a hand grip l1 lying in'the plane of the frame Hi.
  • Closing opposite sides of the open frame i0 is a pair of removable cover plates I8 and I9 which in addition to forming a cover for the gearing D, also provide bearings for the combined worm wheel and die holder C.
  • These removable cover plates l8 and I9 conform in outline to the shape of the open frame Ill and are secured to the frame by means of bolts or screws 20 suitably spaced about the marginal edge of the cover plates and threaded into tapped openings 2
  • the cover plates l8 and I9 are each annularly concaved as at 22 and are provided in these concaved portions with round openings 23 which are slightly spaced apart and axially align when the cover plates are secured in place on the frame l0.
  • These axially aligning openings 23 form radial bearings for the die holder C, while the confronting annular inner surfaces 24 of the cover plates about these openings 23 form axial thrust bearings for the die holder, as will be later described.
  • the combined worm wheel and die holder C is preferably of onepiece construction and includes a tubular sleeve portion 25 provided at one end with an internal stop flange or shoulder 26.
  • a tubular sleeve portion 25 Provided on the exterior of and intermediate the ends of the sleeve portion 25'is a worm wheel 21 having parallel opposite side surfaces which have bearing contact with the annular bearing surfaces 24 as shown in Figure 4.
  • the external diameter of the sleeve portion 25 is of a size to have a bearing fit in the openings 23 as will also be apparent from Figure 4.
  • the sleeve portion 25 is adapted to removably receive in one end thereof, a solid round die 28 which may be held in place as by a set screw 29.
  • the recessing or concaving of the cover plates as at 22 not only provides axial and radial bearings for the die holder, but also permits of the sleeve portion 25 being disposed almost completely within the planes of opposite sides of the casing A and ready access being had to the set screw 29.
  • the combined worm wheel and die holder C may be readily removed and a different die holder substituted if desired, such for instance as shown in Figure 9.
  • the combined worm wheel and die holder C has its sleeve portion 25' provided with a square opening 30 for receiving a solid square die.
  • of the electric motor B extends thru the lower portion of the end wall l3 of the frame l and is journaled in a bearing sleeve 32 preferably formed integral with the frame.
  • a driving gear 33 Fixed upon the end of the motor shaft 3
  • an intermediate or reverse drive pinion 36 suitably journaled upon a stub shaft 31 mounted in a boss 38 projecting from the end wall l3.
  • a second elongated sliding or shipper pinion 40 which is slidably and rotatably mounted upon a stub shaft 4
  • the gear 43 and worm 44 are preferably formed integral with the shaft as shown in Figure '1.
  • the ends of the shaft 42 are bored as at 45 to receive bearing studs 46 and 41 mounted respectively in bosses 48 and 43 and formed integral with the frame 10.
  • the drive shaft 42 is journaled to extend longitudinally in the upper portion of the casing A above the die holder C, with the worm 44 meshing with the worm wheel 21 and the gear wheel 43 parallel to but slightly offset out of the plane of the driving gear 33.
  • the constantly but reversely driven sliding pinions 34 and 40 are adapted to be selectively meshed with the driven gear 43 by a gear shifting or shipper means whereby the die holder C may be rotated in one direction during the thread cutting operation and rotated in the opposite direction when withdrawing the die from the work without requiring use of a reversible electric motor.
  • the die is rotated in a thread cutting direction by the sliding pinion 34 and in a reverse direction by the sliding pinion 40 with its intermediate gear 36.
  • This gear shifting means embodies a rock or shipping shaft 50 suitably journaled to extend thru the top wall I4 of the casing frame In and having mounted on its outer end a spring steel lever having its free end normally spring urged against the wall l4. Secured to the inner end of the shaft 50 is a shipping bar 52 having slotted ends receiving pins on suitable yokes 53. These yokes 53 are received in annular grooves provided in the ends of the pinions 34 and 40 whereby upon shifting of the bar 52, the pinions will be slid along their respective shafts 35 and 4
  • stop lugs 55 which limit swinging movement of the lever 5 I, and arranged between these lugs is a shallow rib 56 for retaining the lever in either position of movement, as clearly shown in Figure 6.
  • the upper edge of the cover plate I8 is preferably notched out as at 51 so as to allow for ready oiling of the gearing within the casing.
  • a small notch is also made in this cover plate as at 56 to permit oiling the motor shaft 3
  • a suitable control switch 60 is preferably mounted upon the hand grip H for controlling the electric motor B from a source of current delivered thru the conductor 6
  • the casing A Owing to the novel gearing arrangement and the combination worm wheel and die holder, the casing A, as will be seen, may be made comparatively thin, thus permitting use of the tool in very restricted places.
  • a portable thread cutting tool comprising a relatively flat open sided tapering frame, removable side plates, having flat outer faces, closing opposite sides of the frame, a hand grip carried by the narrow end of the frame in the major plane of the frame, a motor mounted upon the wide end of the frame, a hand grip at the outer end of the motor in the major plane of the frame, a die holder journaled in the side plates with its axis of rotation normal to the major plane of the frame and substantially within the fiat outer faces of the side plates, drive gearing supported by the frame for imparting'rotation to the die holder from said motor, and control means for the drive gearing for controlling the direction of rotation of the die holder.
  • a relatively flat casing including removable side cover plates having recessed portions provided with aligning inwardly offset openings, a die holder journaled in the openings within the planes of opposite sides of the casing and held against axial movement by the side plates, said die holder being removable from the casing upon removal of one of the side plates, and means for securing a die entirely within the die holder.
  • a portable power driven threading tool comprising an open sided tapering frame having a circular portion at its narrow end, an end wall at its opposite broader end, and a top wall, removable cover plates closing the open sides of the frame and having aligning openings co-axial with said circular frame portion, a motor mounted upon the end wall of the frame, a die holder journaled in said openings and held against axial movement by the cover plates, drive gearing supported by the frame for imparting rotation to having a shaft extending into the casing, a drive gear on the motor shaft, a sliding pinion constantly meshing with said gear, an intermediate pinion constantly meshing with.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

Description

' June 18, 1940. F. s. MAYOTTE ELECTRIC DIE THREADER Filed lay 15, 1939 2 Sheets-Stunt 1 INVENTOR.
Frank ElTgyuTIe.
wgg
Filed lay 15, 1939 2 Sheets-Sheet 2 .fi n .1. N m n R v 0 A w k n m y F r fM v Y B 5 4 \AN N\ IJ. Q m I mm 1 3 mm kw 3+ i V 66E X7 \1 Patented June 18, 1940 UNITED STATES PATENT OFFICE 4 Claims.
The present invention relates to thread cutting tools and the primary object of the invention is to provide a portable power driven threading tool primarily designed for cutting threads on bolts, rods, small pipe, etc.
A further object of the invention is to provide a portable self-contained electrically operated T thread cutting tool of improved construction permitting use of the tool in very restricted areas.
A further object of the invention is to provide anelectric die threader embodying a readily in-' Other objects and advantages of the invention.
will be apparent from the following detailed description taken in connection with the accompanying drawings forming a part of this specification and in which drawings:
Figure 1 is a view in side elevation of the electric die threading tool.
Figure 2 is a side view of the tool with one of the side cover plates removed.
Figure 3 is a longitudinal section substantially on line 3-3 of Figure 2.
Figure 4 is a transverse section substantially online 4-4 of Figure 2.
Figure 5 is an enlarged fragmentary section substantially on line 5-5 of Figure 2.
Figure 6 is a fragmentary top plan view showing the gear shifting lever arrangement.
Figure 7 is an enlarged longitudinal section thru the drive member for imparting rotation to the die holder or shell.
Figure 8 is a side view on a reduced scale of the die holder shown in Figures 1 and 2 for holding a solid round die.
Figure 9 is a side view of a die holder for holding a solid square die.
Referring to the drawings in detail and wherein like reference characters designate corresponding parts thruout the several views, the electric die threader comprises a relatively fiat casing A upon one end of which is mounted an electric motor B for imparting rotation to a combined worm wheel and die holder or shell C thru speed reduction gear mechanism D.
The casing A comprises a relatively flat open sided metal "frame If) which preferably tapers slightly at its sides towards one end of the frame as best shown in Figures 3 and 6. At its narrow end, the frame I 0 has a circular portion II with which is integrally formed a hand grip l2 lying in the plane of the frame. The wider end of the frame N forms an end wall l3 which is connected at its upper end with the circular portion H by atop wall l4. Formed-on the outer side of the end wall I3 is a flange ii to which a flange of the electric motor..B is attached as by bolts or the like 6. Secured as by bolts or the like l6 to a flange at the outer end of the electric motor B is a hand grip l1 lying in'the plane of the frame Hi.
Closing opposite sides of the open frame i0 is a pair of removable cover plates I8 and I9 which in addition to forming a cover for the gearing D, also provide bearings for the combined worm wheel and die holder C. These removable cover plates l8 and I9 conform in outline to the shape of the open frame Ill and are secured to the frame by means of bolts or screws 20 suitably spaced about the marginal edge of the cover plates and threaded into tapped openings 2| in the frame. The cover plates l8 and I9 are each annularly concaved as at 22 and are provided in these concaved portions with round openings 23 which are slightly spaced apart and axially align when the cover plates are secured in place on the frame l0. These axially aligning openings 23 form radial bearings for the die holder C, while the confronting annular inner surfaces 24 of the cover plates about these openings 23 form axial thrust bearings for the die holder, as will be later described.
Referring now to the combined worm wheel and die holder C, the same is preferably of onepiece construction and includes a tubular sleeve portion 25 provided at one end with an internal stop flange or shoulder 26. Provided on the exterior of and intermediate the ends of the sleeve portion 25'is a worm wheel 21 having parallel opposite side surfaces which have bearing contact with the annular bearing surfaces 24 as shown in Figure 4. The external diameter of the sleeve portion 25 is of a size to have a bearing fit in the openings 23 as will also be apparent from Figure 4. The sleeve portion 25 is adapted to removably receive in one end thereof, a solid round die 28 which may be held in place as by a set screw 29. As will be observed in Figures 3 and 4, the recessing or concaving of the cover plates as at 22 not only provides axial and radial bearings for the die holder, but also permits of the sleeve portion 25 being disposed almost completely within the planes of opposite sides of the casing A and ready access being had to the set screw 29.
By removing the cover plate IS, the combined worm wheel and die holder C may be readily removed and a different die holder substituted if desired, such for instance as shown in Figure 9. In Figure 9, the combined worm wheel and die holder C has its sleeve portion 25' provided with a square opening 30 for receiving a solid square die.
With reference now to the transmission gearing D for imparting rotation in either direction to the die holder C, the shaft 3| of the electric motor B extends thru the lower portion of the end wall l3 of the frame l and is journaled in a bearing sleeve 32 preferably formed integral with the frame. Fixed upon the end of the motor shaft 3| at the inner end of the sleeve 32 is a driving gear 33 with which is adapted to constantly mesh, an elongated sliding or shipper pinion 34 slidably and rotatably mounted upon a stub shaft 35 secured at one end in the end wall l3 and extending parallel to the motor shaft 3|. Also in constant mesh with the driving gear 33 is an intermediate or reverse drive pinion 36 suitably journaled upon a stub shaft 31 mounted in a boss 38 projecting from the end wall l3. In constant mesh with the intermediate drive pinion 36 is a second elongated sliding or shipper pinion 40 which is slidably and rotatably mounted upon a stub shaft 4| secured at one end in the endwall I3 and extending parallel to the motor Journaled in the frame l0 just beneath the top wall l4 thereof, on an axis parallel to the motor shaft 3|, is a drive shaft 42 having at one end a gear wheel 43 and at its opposite end a worm 44. The gear 43 and worm 44 are preferably formed integral with the shaft as shown in Figure '1. The ends of the shaft 42 are bored as at 45 to receive bearing studs 46 and 41 mounted respectively in bosses 48 and 43 and formed integral with the frame 10. The drive shaft 42 is journaled to extend longitudinally in the upper portion of the casing A above the die holder C, with the worm 44 meshing with the worm wheel 21 and the gear wheel 43 parallel to but slightly offset out of the plane of the driving gear 33.
The constantly but reversely driven sliding pinions 34 and 40 are adapted to be selectively meshed with the driven gear 43 by a gear shifting or shipper means whereby the die holder C may be rotated in one direction during the thread cutting operation and rotated in the opposite direction when withdrawing the die from the work without requiring use of a reversible electric motor. In the example illustrated, the die is rotated in a thread cutting direction by the sliding pinion 34 and in a reverse direction by the sliding pinion 40 with its intermediate gear 36.
This gear shifting means embodies a rock or shipping shaft 50 suitably journaled to extend thru the top wall I4 of the casing frame In and having mounted on its outer end a spring steel lever having its free end normally spring urged against the wall l4. Secured to the inner end of the shaft 50 is a shipping bar 52 having slotted ends receiving pins on suitable yokes 53. These yokes 53 are received in annular grooves provided in the ends of the pinions 34 and 40 whereby upon shifting of the bar 52, the pinions will be slid along their respective shafts 35 and 4| into and out of mesh with the gear wheel 43 on the drive shaft 42. Thus, when the shipping bar 52 is shifted in one position as in Figure 3, the constantly driven pinion 34 is meshed with the gear 43 for rotating the die holder in one direction, and when the shipping bar is shifted into the other position, the constantly driven pinion 40 is meshed with the gear 43 for rotating the die holder in the opposite direction.
Provided on the upper side of the frame top wall H are spaced apart stop lugs 55 which limit swinging movement of the lever 5 I, and arranged between these lugs is a shallow rib 56 for retaining the lever in either position of movement, as clearly shown in Figure 6.
Referring particularly to Figures 1 and 6, the upper edge of the cover plate I8 is preferably notched out as at 51 so as to allow for ready oiling of the gearing within the casing. A small notch is also made in this cover plate as at 56 to permit oiling the motor shaft 3| thru an oil duct 59 formed in the frame end wall l3.
A suitable control switch 60 is preferably mounted upon the hand grip H for controlling the electric motor B from a source of current delivered thru the conductor 6|.
Owing to the novel gearing arrangement and the combination worm wheel and die holder, the casing A, as will be seen, may be made comparatively thin, thus permitting use of the tool in very restricted places.
Changes in detail may be made to the form of the invention herein shown and described, without departing from the spirit of the invention or the scope of the following claims.
I claim:
1. A portable thread cutting tool comprising a relatively flat open sided tapering frame, removable side plates, having flat outer faces, closing opposite sides of the frame, a hand grip carried by the narrow end of the frame in the major plane of the frame, a motor mounted upon the wide end of the frame, a hand grip at the outer end of the motor in the major plane of the frame, a die holder journaled in the side plates with its axis of rotation normal to the major plane of the frame and substantially within the fiat outer faces of the side plates, drive gearing supported by the frame for imparting'rotation to the die holder from said motor, and control means for the drive gearing for controlling the direction of rotation of the die holder.
2. In a portable power driven threading tool, a relatively flat casing including removable side cover plates having recessed portions provided with aligning inwardly offset openings, a die holder journaled in the openings within the planes of opposite sides of the casing and held against axial movement by the side plates, said die holder being removable from the casing upon removal of one of the side plates, and means for securing a die entirely within the die holder.
3. A portable power driven threading tool comprising an open sided tapering frame having a circular portion at its narrow end, an end wall at its opposite broader end, and a top wall, removable cover plates closing the open sides of the frame and having aligning openings co-axial with said circular frame portion, a motor mounted upon the end wall of the frame, a die holder journaled in said openings and held against axial movement by the cover plates, drive gearing supported by the frame for imparting rotation to having a shaft extending into the casing, a drive gear on the motor shaft, a sliding pinion constantly meshing with said gear, an intermediate pinion constantly meshing with. said gear, a second sliding pinion constantly meshing with intermediate gear, a drive shaft journaled in the frame having a worm at one end meshing with said worm wheel and a gear at its other end with which said sliding pinions may mesh, and shipping means for the sliding pinions.
FRANK E. MAYO'I'IE.
US273788A 1939-05-15 1939-05-15 Electric die threader Expired - Lifetime US2205148A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US273788A US2205148A (en) 1939-05-15 1939-05-15 Electric die threader

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US273788A US2205148A (en) 1939-05-15 1939-05-15 Electric die threader

Publications (1)

Publication Number Publication Date
US2205148A true US2205148A (en) 1940-06-18

Family

ID=23045398

Family Applications (1)

Application Number Title Priority Date Filing Date
US273788A Expired - Lifetime US2205148A (en) 1939-05-15 1939-05-15 Electric die threader

Country Status (1)

Country Link
US (1) US2205148A (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2549381A (en) * 1946-11-18 1951-04-17 Stephen W Matica Pipe threader and cutting device
US2567784A (en) * 1947-12-02 1951-09-11 Edward H O Boyle Pipe threading machine
US2678453A (en) * 1949-03-25 1954-05-18 George E Rudolph Supporting structure for portable power tools
US3521313A (en) * 1967-12-13 1970-07-21 Slade H Baker Powered thread cutter
US4502821A (en) * 1982-08-25 1985-03-05 REMS-WERK Christian F/o/ ll und S/o/ hne GmbH & Co. Thread cutting tool
DE4231975A1 (en) * 1991-10-02 1993-04-08 Super Ego Tools Portable electric pipe threader - is of cast monoblock construction in which widths of gear housing and rear pointing motor are less than cutter head width
US5573357A (en) * 1995-04-27 1996-11-12 Boar Tools, Inc. Portable, handheld, power tool
WO2014025497A1 (en) * 2012-08-06 2014-02-13 Emerson Electric Co. Die head retaining mechanism
US11077509B2 (en) 2018-03-16 2021-08-03 Milwaukee Electric Tool Corporation Pipe threader

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2549381A (en) * 1946-11-18 1951-04-17 Stephen W Matica Pipe threader and cutting device
US2567784A (en) * 1947-12-02 1951-09-11 Edward H O Boyle Pipe threading machine
US2678453A (en) * 1949-03-25 1954-05-18 George E Rudolph Supporting structure for portable power tools
US3521313A (en) * 1967-12-13 1970-07-21 Slade H Baker Powered thread cutter
US4502821A (en) * 1982-08-25 1985-03-05 REMS-WERK Christian F/o/ ll und S/o/ hne GmbH & Co. Thread cutting tool
DE4231975A1 (en) * 1991-10-02 1993-04-08 Super Ego Tools Portable electric pipe threader - is of cast monoblock construction in which widths of gear housing and rear pointing motor are less than cutter head width
US5573357A (en) * 1995-04-27 1996-11-12 Boar Tools, Inc. Portable, handheld, power tool
WO2014025497A1 (en) * 2012-08-06 2014-02-13 Emerson Electric Co. Die head retaining mechanism
US9095917B2 (en) 2012-08-06 2015-08-04 Emerson Electric Co. Die head retaining mechanism
US11077509B2 (en) 2018-03-16 2021-08-03 Milwaukee Electric Tool Corporation Pipe threader

Similar Documents

Publication Publication Date Title
US2445016A (en) Work manipulator
US2205148A (en) Electric die threader
US2756792A (en) Tool with speeding gear
US1852776A (en) Portable universal power tool
US2602347A (en) Thread gauge drive
US2365232A (en) Portable tool
US2198921A (en) Dual speed drive
US1785798A (en) Motor-driven tool
US1727984A (en) Spindle sleeve for drilling machines
US1579818A (en) Combination tool
US3145401A (en) Lead screw operated tapping spindle with quick acting reversing means
US2958794A (en) Variable speed cutter drive
US3521313A (en) Powered thread cutter
US1734406A (en) Motor-operated assembling tool
US2775904A (en) Portable tool
US2274448A (en) Motor driven hand tool
US2069701A (en) Auxiliary power operated device for machine tools
US884966A (en) Crank-pin-turning machine.
US1692487A (en) Motor-driven threading tool
US1296854A (en) Machine for cutting internal threads, &c.
US1686661A (en) Pipe-threading machine
US1716971A (en) Power-transmission mechanism
US1883728A (en) Portable power driven threading machine
US1517240A (en) Power-transmitting arrangement
US2578149A (en) Portable cylinder grinding tool