These inserts are made with a black alumina ceramic on the cutting edges. Compared to carbide inserts, ceramic lasts longer in hardened-steel tooling applications because it is chemically inert and has better heat resistance. Ceramic inserts have comparable wear resistance to cubic boron nitride, but ceramic is best for continuous and light cutting while cubic boron nitride can also be used in heavy interruption. These inserts have multiple cutting edges, so when a cutting edge becomes dull, rotate the insert in the holder to use a sharp edge. Larger nose angles and larger tip radii provide a stronger cutting edge but result in increased vibration and a rougher finish.

Positive-rake inserts have an edge that is less than 90° to sit flat in the holder for improved cutting clearance and a better finish than negative-rake inserts. They have cutting edges on one side of the inserts.

Negative-rake inserts have a 90° edge and sit at an angle in the holder to provide a strong cutting force for heavy duty applications. They have cutting edges on both sides of the inserts for twice the life of comparable positive-rake inserts.

For technical drawings and 3-D models, click on a part number.