1. Facing Between Centers
Unit 51

2. Objectives Set up workpiece for machining between centers
Set up workpiece to face the ends
Face workpiece to exact length

3. To Set Up Cutting Tool for Machining
Move toolpost to left-hand side of T-slot in compound rest
Mount toolholder in toolpost so setscrew in toolholder approximately 1in. beyond toolpost
Insert the proper cutting tool into toolholder
Have toolbit extend .500 in beyond toolholder
Never more than twice its thickness

4. Set cutting-tool point to center height
Tighten toolholder setscrew with only two-finger pressure on wrench to hold toolbit in toolholder
Careful tightening setscrew – too tight, break toolbit
Set cutting-tool point to center height
Tighten toolpost securely to prevent it from moving during cut

5. To Mount Work Between Centers: Using Revolving Tailstock Center
Check live center by holding piece of chalk close it it while revolving
Not true – chalk will mark only high spot
If not true, remove live center from headstock and clean tapers on center and headstock spindle
Replace center and check for trueness

6. Adjust tailstock spindle until extends about 2. 50 to 3 in
Adjust tailstock spindle until extends about 2.50 to 3 in. beyond tailstock
Mount revolving center into tailstock spindle
Loosen tailstock clamp nut or lever
Place lathe dog on end of work with tail pointing to the left
Place end of work with lathe dog on live center and slide tailstock toward headstock until dead center supports other end of work

7. Tighten tailstock clamp nut or lever
Adjust tail of dog in slot of driveplate and tighten lathe dog screw
Tighten tailstock handwheel using thumb and finger pressure only to snug up work between centers
Tighten tailstock spindle clamp
Move carriage to farthest position (left-hand end) of cut and revolve lathe spindle by hand

8. To Mount Work Between Centers: Using a Dead Center
Follow steps 1-4 of revolving center method
Mount dead center in tailstock spindle and then check center alignment
Place dog on end of work and lubricate the dead center hole
Mount work between centers and tighten tailstock lamp nut or lever

9. Adjust tail of dog in driveplate and tighten setscrew
Turn driveplate until slot is in horizontal position
Hold tail of dog up in slot and tighten tailstock handwheel
Turn handwheel backward until tail of dog just drops and tighten tailstock spindle clamp
Check center tension of work. There should be no end play

10. Facing Between Centers
Facing – operation of machining ends of workpiece square with its axis
Lathe centers must be in line
Purposes of facing
Provide true, flat surface, square with axis of work
Provide accurate surface from which to take measurements
To cut work to required length

11. To Face Work Between Centers
Move toolpost to left-hand side of compound rest and set right-hand facing toolbit to height of lathe center point
Clean lathe and work center and mount work between centers
Use half-center in tailstock if available
Set facing toolbit pointing left
Point must be closest to work and space must be left along the side

12. Set lathe to correct speed for diameter and type of material being cut
Start lathe and bring toolbit close to center of work
Move carriage to left until small cut started
Using apron handwheel
Feed cutting tool out by turning crossfeed handle and cut from center outward
Repeat 5-7 until work cut to correct length

13. Facing the Workpiece to an Accurate Length
Compound rest graduated micrometer collars may be used
Compound rest set to 30º (to the cross-slide)
Side movement of cutting tool always half the amount of the compound feed