How to Cut Lathes

Users, who cannot grasp manual cutting on a lathe, can also use a computer numerical control (CNC) machine and a program to thread to certain specifications.

A lathe is a machine used to shape threads or pieces of wood and metal. It does so by spinning while the lathe's cutting edge is pressed upon the surface the material. The edge subsequently cuts and shaves the material. Cutting on a lathe is both a science and an art form. With a little practice and patience, you can quickly prepare and cut material on a lathe.

Things You'll Need

• Blank Material
• Sharp cutting tool

Instructions

1. Determine the threads per inch (TPI) for the turning project. Threading is another term for cutting.

2. Use a sharp cutting tool to round the material, also known as a blank, to a cylinder form, while matching the desired diameter.

3. Mount the blank onto the lathe using the machine's brackets. Start the lathe.

4. Align the 60-degree angle point cutter with the TPI gauge. Be sure to hold the point perpendicular to the blank mounted on the lathe. Shift the tool point slightly to line with the matching 60-degree angle mark on the gauge. Clamp the cutting tool into this position.

5. Move the cutting tool toward the cylinder until they barely touch. Crank the lathe in reverse until the tool clears the bottom of the cylinder.

6. Push the cutting point into the cylinder 1/4-inch. Repeat the process from the bottom to top once the first pass is completed. Advance the cutting point another .0025-inch. Repeat this process until the cylinder's thread reaches the desired depth.

7. Test the thread in the fitted object to confirm a smooth insertion and removal. If the thread is too snug, cut off another thousandth of an inch until a desired fit is achieved.

References

• Lathe Design, Construction, and Operation
• MIT: Lathe
• Metal Web News: Lathes
• Dave Hylands: CNC Threading