Docstoc

Lathe Accessories

Document Sample
Lathe Accessories Powered By Docstoc
					Lathe Accessories
Session 7




                    1
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
                                              2
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 shank
  60º centers, steel with carbide tips
• Care to adjust and lubricate occasionally
                                              3
Lathe Centers




                4
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
                                                 5
Revolving Tailstock Centers




                          6
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


                                          7
Microset Adjustable Center




                             8
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


                                                          9
Self-Driving Live Center




                           10
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


                                          11
Three-jaw Universal Chuck

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




                            13
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

                                            14
Four-Jaw Independent
Chucks




                       15
Headstock Spindle Types
1. Threaded spindle nose
  •   Screws on in a clockwise direction
2. Tapered spindle nose
  •   Held by lock nut that tightens on chuck
3. Cam-lock spindle nose
  •   Held by tightening cam-locks using T-
      wrench
  •   Chuck aligned by taper on spindle nose

                                                16
Threaded Spindle Nose




                        17
Tapered Spindle Nose




                       18
Cam Lock Spindle Nose




                        19
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
                                            20
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




                                                21
Spring Collet Chucks




|




                       22
Spring Collet Chucks




                       23
Jacobs Collet Chuck
• Jacobs collet chuck
  • Utilizes impact-tightening handwheel to
    close collets
  • Wider range than spring-collet chuck




                                              24
Jacobs Collet Chuck




                      25
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


                                              26
Magnetic Chucks




                  27
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
                                                 28
Faceplates




             29
Faceplates




             30
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
                                            31
Steadyrest




             32
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

                                             33
Follower Rest




                34
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

                                         35
Plain Mandrel




                36
Expanding Mandrel




                    37
Gang Mandrel




               38
Stub Mandrel




               39
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
                                             40
Standard bent-tail lathe
dog
• Most commonly used for
  round workpieces
• Available with square-head
  setscrews of headless
  setscrews




                               41
Standard bent-tail lathe
dog
• Bent tail engages in slot on
  drive plate




                                 42
Straight-tail lathe dog
• Driven by stud in driveplate
• Used in precision turning




                                 43
Safety clamp lathe dog
• Used to hold variety of work
• Wide range of adjustment




                                 44
Heavy Duty Lathe Dog
• Wider range than others
• Used on all shapes




                            45
Super Quick-Change
Toolpost
• Provides fast, accurate, and reliable
  method of quickly changing and setting
  various toolholders for different
  operations
• Locking system has two sliding gibs
  forced out against toolholder
  • Handle pulled into lock position
  • Provides rigid, positive lock with zero
    backlash
                                              46
Super Quick-Change
Toolpost




                     47

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:300
posted:2/8/2010
language:English
pages:47