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Lathe Accessories

Lathe Accessories. Session 7. Lathe Accessories. Divided into two categories Work-holding, -supporting, and –driving devices Lathe centers, chucks, faceplates Mandrels, steady and follower rests Lathe dogs, drive plates Cutting-tool-holding devices Straight and offset toolholders

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Lathe Accessories

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  1. Lathe Accessories Session 7

  2. Lathe Accessories • Divided into two categories • Work-holding, -supporting, and –driving devices • Lathe centers, chucks, faceplates • Mandrels, steady and follower rests • Lathe dogs, drive plates • Cutting-tool-holding devices • Straight and offset toolholders • Threading toolholders, boring bars • Turret-type toolposts

  3. Lathe Centers • Work to be turned between centers must have center hole drilled in each end • Provides bearing surface • Support during cutting • Most common have solid Morse taper shank60º centers, steel with carbide tips • Care to adjust and lubricate occasionally

  4. Lathe Centers

  5. Revolving Tailstock Centers • Replaced solid dead centers for most machining operations • Used to support work held in chuck or when work is being machined between centers • Contains antifriction bearings which allow center to revolve with workpiece • No lubrication required between center and work • Types: revolving dead center, long point center, and changeable point center

  6. Revolving Tailstock Centers

  7. Microset Adjustable Center • Fits into tailstock spindle • Provides means of aligning lathe centers or producing slight tapers on work machined between centers • Eccentric slide (dovetail) allows center to be adjusted limited amount to each side of center

  8. Microset Adjustable Center

  9. Self-Driving Live Center • Mounted in headstock spindle • Used when entire length of workpiece is being machined in one operation • Chuck or lathe dog could not be used to drive work • Grooves ground around circumference of lathe center point provide drive • Work usually soft material such as aluminum

  10. Self-Driving Live Center

  11. Chucks • Used extensively for holding work for lathe machining operations • Work large or unusual shape • Most commonly used lathe chucks • Three-jaw universal • Four-jaw independent • Collet chuck

  12. Three-jaw Universal Chuck • Holds round and hexagonal work • Grasps work quickly and accurate within few thousandths/inch • Three jaws move simultaneously whenadjusted by chuck wrench • Caused by scroll plate into which all three jaws fit • Two sets of jaw: outside chucking and inside chucking

  13. Three-jaw Universal Chuck

  14. Four-Jaw Independent Chuck • Used to hold round, square, hexagonal, and irregularly shaped workpieces • Has four jaws • Each can be adjusted independently by chuck wrench • Jaws can be reversed to hold work by inside diameter

  15. Four-Jaw Independent Chucks

  16. Headstock Spindle Types • Threaded spindle nose • Screws on in a clockwise direction • Tapered spindle nose • Held by lock nut that tightens on chuck • Cam-lock spindle nose • Held by tightening cam-locks using T-wrench • Chuck aligned by taper on spindle nose

  17. Threaded Spindle Nose

  18. Tapered Spindle Nose

  19. Cam Lock Spindle Nose

  20. Collet Chucks • Most accurate chuck • Used for high-precision work • Spring collets available to hold round, square, or hexagon-shaped workpieces • Each collet has range of only few thousandths of an inch over or under size stamped on collet

  21. Spring Collet Chucks • Spring-collet chuck • One form: Handwheel draws collet into tapered adapter • Another form: Uses chuck wrench to tighten collet on workpiece • Can hold larger work than draw-in type

  22. | Spring Collet Chucks

  23. Spring Collet Chucks

  24. Jacobs Collet Chuck • Jacobs collet chuck • Utilizes impact-tightening handwheel to close collets • Wider range than spring-collet chuck

  25. Jacobs Collet Chuck

  26. Magnetic Chucks • Used to hold iron or steel parts that are too thin or may be damaged if held in conventional chuck • Fitted to an adapter mounted on headstock spindle • Used only for light cuts and for special grinding applications

  27. Magnetic Chucks

  28. Faceplates • Used to hold work too large or shaped so it cannot be held in chuck or between centers • Usually equipped with several slots to permit use of bolts to secure work • Angle plate used so axis of workpiece may be aligned with lathe centers • Counterbalance fastened to faceplate when work mounted off center • Prevent imbalance and resultant vibrations

  29. Faceplates

  30. Faceplates

  31. Steadyrest • Used to support long work held in chuck or between lathe centers • Prevent springing • Located on and aligned by ways of the lathe • Positioned at any point along lathe bed • Three jaws tipped with plastic, bronze or rollers may be adjusted to support any work diameter with steadyrest capacity

  32. Steadyrest

  33. Follower Rest • Mounted on saddle • Travels with carriage to prevent work from springing up and away from cutting tool • Cutting tool generally positioned just ahead of follower rest • Provide smooth bearing surface for two jaws of follower rest

  34. Follower Rest

  35. Mandrel • Holds internally machined workpiece between centers so further machining operations are concentric with bore • Several types, but most common • Plain mandrel • Expanding mandrel • Gang mandrel • Stub mandrel

  36. Plain Mandrel

  37. Expanding Mandrel

  38. Gang Mandrel

  39. Stub Mandrel

  40. Lathe Dogs • Drives work machined between centers • Has opening to receive work and setscrew to fasten the dog to work • Tail of dog fits into slot on driveplate and provides drive to workpiece • Made in variety of sizes and types to suit various workpieces

  41. Standard bent-tail lathe dog • Most commonly used for round workpieces • Available with square-head setscrews of headless setscrews

  42. Standard bent-tail lathe dog • Bent tail engages in slot on drive plate

  43. Straight-tail lathe dog • Driven by stud in driveplate • Used in precision turning

  44. Safety clamp lathe dog • Used to hold variety of work • Wide range of adjustment

  45. Heavy Duty Lathe Dog • Wider range than others • Used on all shapes

  46. Cutting-Tool-Holding Devices • Available in three styles • Left-hand offset • Right-hand offset • Straight • Each has square hole to accommodate square toolbit held in place by setscrew • Angle of approximately 15º to 30º to base of toolholder

  47. Left-Hand Offset Toolholder • Offset to the right • Designed for machining work close to chuck or faceplate and cutting right to left • Designated by letter L

  48. Right-Hand Offset Toolholder • Offset to the left • Designed for machining work close to the tailstock and cutting left to right • Also for facing operations • Designated by letter R

  49. Straight Toolholder • General-purpose type • Used for taking cuts in either direction and for general machining operations • Designated by letter S

  50. Carbide Toolholder • Has square hole parallel to base of toolholder to accommodate carbide-tipped toolbits • Holds toolbit with little or no back rake • Designated by letter C

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