Collets & Collet Holders

This article gives a basic overview of the function and uses of collets, how to install them in collet holders, and finally their installation in the Haas CNC mill.

Collets

 * A collet is a subtype of chuck that forms a collar around an object to be held and exerts a strong clamping force on the object when it is tightened.
 * Reliable traits of collets include:
 * Fast chucking
 * Self centering
 * Strong clamping
 * Resistance against being jarred loose
 * Precise centering

Collet Holders

 * Collet holders allow collets to be used in conjunction with machines, specifically lathes and the CNC mill. They are a larger hexagonal or square piece of metal, in which the collet is able to slide through and be fastened at the other end.

Types

 * R8 (internally threaded for use in mills)
 * R8 collets usually fit into the machine taper itself (i.e. there is no separate chuck). R8 was developed to allow rapid tool changes. R8 collets have a keyway to prevent rotation when fitting or removing.
 * 5C (externally threaded for use in lathes)
 * 5C collets were developed primarily for work holding. 5C collets have an external thread at the rear for drawing the collet closed, and so work pieces may pass right through the collet and chuck.