Center Punches - On the Lathe
Overview
The engine lathe is an excellent way to turn and shape and drill round stock accurately
⦁ Familiarize yourself with the equipment before you begin set-up procedures (ask for help if unsure)
⦁ Ensure that you have an instructors OK before beginning the knurling procedure
Equipment and Materials Needed
Remember to remove loose clothing and jewelry and tie back long hair. Equipment needed includes:
⦁ Small Centre drill
⦁ 8.5” piece of 3/8 solid steel round stock
⦁ Callipers
⦁ Accurate steel ruler
⦁ Fully equipped engine lathe
Procedure
⦁ Clamp stock in chuck with no more than 1” protruding
⦁ Set up tool but with point at centre line of stock (use sheet metal to check)
⦁ Set lathe speed and face the end of the stock
⦁ Install Jacobs chuck in tailstock and using a small centre drill drill the stock to accept the live centre
⦁ Remove Jacobs Chuck and install live centre, pull stock out with only about ½” clamped in the jaws and the other end supported by the tailstock and live centre
⦁ Move tool and trim outer diameter to remove scale. Try not to completely shrink the diameter. Go no smaller than 11/32 (be careful not to hit the chuck or tailstock)
⦁ Install knurling tool, choose desired pattern, centre and square the knurling tool to the stock (Have Mr. Holbrook check your set-up)
⦁ Knurl entire length
⦁ Remove metal stock and cut to 4” pieces
⦁ Reinstall one piece
⦁ Install cutting tool and machine off knurl on either side of stock to achieve desired knurl length as shown by the plans and turn both ends of stock to 5/16
⦁ Set compound rest to appropriate angle and machine the 5 degree taper (watch the chuck)
⦁ Use a file to add a 60-90° tip
⦁ File out any bumps or imperfections
⦁ Harden metal using OXY-Acetylene/Furnace/Kiln, etc as shown in demo. **Note this process will only work if using the correct type of metal. Otherwise this is still a good exercise in learning to use the lathe
⦁ Reinstall in lathe, file, sand, and polish.