How to Turn Metal on a Lathe

Lathe turning can be accomplished with a good setup.

The process of turning metal on a lathe involves a few steps that must be carefully observed and carried out to assure a good finish on your final product. The jaws must be placed evenly for proper turning, and the material must be held neither too loosely or too tightly, as damage could occur in either of those instances. You must also make sure you turn the metal at the correct speeds to assure an acceptable finish and maximize tool life by reducing friction and heat.

Things You'll Need

• Jaws
• Allen Wrench

Instructions

1. Choose the correct jaws for the chuck of a metal lathe. Loosen the two screws per jaw on a three jaw chuck and slide each individual jaw out of its slot. Clean the slots with compressed air and remove the retaining blocks from each jaw. The retaining blocks sit in the slot and when the screws are tightened, keep the jaw in place.

2. Attach the retaining blocks to the jaws you plan on using for turning the metal in the lathe. Put each bolt through each hole in the jaw and screw into the corresponding holes in the retaining block, leaving them loose. Estimate the distance of the jaws from the center using a piece of the material you plan to cut. The piece must fit snugly in the jaw and be neither too tight nor too loose. Slide each jaw into a slot and hand tighten trying to place each in the same position so that the jaws line up when the chuck is spinning.

3. Turn on the chuck to make sure that the jaws are spinning concentrically. If they are not, count the teeth on the slot and make sure that a each jaw is in the same position. Loosen the screws of each misplaced jaw and slide into the correct position. Turn the chuck on again to make sure they are lined up correctly and repeat the process until they are all lined up properly.

4. Place the raw material in the chuck jaws and tighten the jaws either manually on a manual lathe or using the hydraulic foot pedal on a CNC machine. Turn on the chuck and make sure that the raw material is spinning concentrically as well. Look at the far end of the piece to assure that the piece is not out of round. An out of round piece of raw material can damage tooling when cutting begins. Tap the material with a mallet if it is crooked to alleviate this problem.

5. Take the first cuts with the lathe running at the optimal RPM's for the material you are cutting. Softer material can run at a high rate while steel and titanium must be turned at a slower rate to get a good finish. Turning steel or titanium at a high speed can result in damage to the material and the cutting tools.

References

• American Machine Tools: How to Use a Lathe