The clamping bores in collets are made plain grooved or serrated depending on application. Normally collets are grooved or serrated from a certain diameter onwards.
Other than square and hexagonal bores, collets can be supplied with any profile.
The collet holder has a very important bearing on the concentricity of the collets. Therefore, when making inspections it is essential to see that the collet holder runs absolutely true .
Collets are carefully checked after manufacture. Special care is taken of their concentricity and measurement made at the nose of the collet. We make two different grades of collets with standard and precision accuracy (see illustration).
a) Standard concentricity which is adequate in most cases, and
b) Greater Concentricity or extra precision which would be required for collets on certain kind of machines like, precision grinding, measuring machines etc.
This comes at a higher price.