Session 5 & 6 - Lathe

1. Always wear safety glasses.
2. Work piece must be clamped securely in a vice or to the mill table.
3. Make sure you are using the proper speeds and feeds for the material and cutter size.
4. Make sure you understand how to switch from high to low range and how to change the v belt on step pulleys.
5. Do not use dull or burned cutting tools.
6. Once tool is clamped into the collet remove drawbar wrench immediately. Do not leave wrench on drawbar nut.
7. Make sure spindle is running in the proper direction. Cutters are right hand. Spindle must rotate clockwise when viewed form the top of machine.
8. Make sure cutter is clear of part, vice, and your hands before starting spindle.
9. Always stay at the machine when it is running.
10. Make sure cutter is a safe distance away from part when using power feed.
11. Make sure machine has fully stopped before making any measurements, adjustments, or removing part. After spindle is turned off use the brake to stop the spindle.
12. When removing a tool from the spindle fold up a rag and put it on the table under the tool. Hold the brake and loosen the drawbar nut with the wrench 1/2 to 1 turn. Hold the tool with one hand and hit the nut with the brass part of the wrench.

13. Once machine is off and tool is removed clean machine with a brush, compressed air, then wipe off with a rag.

• Chucks
  1. 3 jaw - limited holding power, not adjustable
  2. 4 jaw - irregular shaped parts, fully adjustable, slow to setup
  3. 6 jaw - good holding power, adjustable, fast
  4. Mounting and removing chucks
     • Place a board under chuck when removing or mounting it.
     • Make sure chuck is tight on spindle before turning lathe on.
     • Disengage power feed when cutting close to chuck.
  5. Collets - 1/64“ to 1 1/8”, run out of ~.001“
  6. Faceplate
  7. Turning between centers- use live center to support long work
• Lathe cutting tools
  1. HSS, carbide
  2. Grinding proper clearances and rake- wood examples
  3. Honing
• Tool holders
  1. Setting tool on center
  2. Short extension for rigid setup
• Operations
  1. Facing
  2. Center drilling/drilling/reaming/tapping (using Tail stock and center to guide tap)
  3. Straight Turning
  4. Taper Turning - angle compound
  5. Boring
  6. Knurling
  7. Cutoff/parting
  8. Single point threading - internal & external
  9. Filing & polishing- file left handed to keep hand away from chuck jaws
• Speeds and Feeds
  1. Cutting speed formula
     • RPM = (4 x cutting speed) / Work diameter
     • Aluminum 150 SFM
     • Brass 150 SFM
     • Copper 100 SFM
     • Stainless Stl 30 SFM
     • Steel 50 SFM
     • Example: Calculate the approximate rpm the spindle should turn when machining a 2” OD piece of stainless steel in the lathe.
       • (4 x 30 SFM) / 2 = 60 RPM
  2. Finish Feed = .002“ advance per revolution
  3. Roughing Feed = .008” advance per revolution
  4. Changing feeds and speeds on various lathes