5.5 REAMING

A reamer is a rotary cutting tool, either cyclindrical or conical in shape, used for enlarging drilled holes to accurate dimensions, normally on the order of 0.0001 in and closer. Reamers usually have two or more flutes which may be straight or spiral in either left-hand or right hand spiral. Reamers are made for manual or machine operation.

Reamers are made in various forms, including

• Hand reamers

• Machine reamers

• Left-hand flute

• Right-hand flute

• Expansion reamers

• Chucking reamers

• Stub screw-machine reamers

• End-cutting reamers

• Jobbers reamers

• Shell reamers

• Combined drill and reamer

Most reamers are produced from premium-grade HSS. Reamers are also produced in cobalt alloys, and these may be run at speeds 25 percent faster than HSS reamers. Reamer feeds depend on the type of reamer, the material and amount to be removed, and the final finish required. Material-removal rates depend on the size of the reamer and material, but general figures may be used on a trial basis and are summarized here:

This is an important consideration when using the expansion reamer owing to the maximum amount of expansion allowed by the adjustment on the expansion reamer.

Machine Speeds and Feeds for...