Mini Lathe Tooling

Turning

Turning is the simplest operation on a lathe. It is reducing the outside diameter of a work piece. It's probably the first thing you will do with a lathe.

There are two basic types of turning tools: high-speed steel tool bits, and carbide turning tools.

High-speed steel tool bits start as rectangles of high-speed steel that you sharpen with a bench grinder. A 5/16" high-speed steel tool bit starts as a piece of high-speed steel that is 5/16" square and 2-1/2" long. Before you can use it to cut metal, you use a bench grinder to shape and sharpen the end. There are several standard shapes for tool bits, which depend on the intended use. Here is information on rake and relief angles for high-speed steel lathe tool bits.

Carbide turning tools come in two flavors. There are tool bits with brazed-on carbide tips, and indexable carbide turning tools.

Tool bits with brazed-on carbide tips are relatively economical, but once the carbide tip is worn out, the entire tool bit is discarded.

Indexable carbide turning tools consist of a shank of hardened steel with a small triangle of sintered carbide (called an insert) attached to the end. The carbide insert is factory sharpened with three cutting edges, one at each point of the triangle. When one point becomes dull, you rotate the next point into the cutting position. When all are dull you replace the insert. These turning tools are called indexable because you can change the insert without affecting the position of the cutting edge relative to the work piece.

Cutting Tool Options