The collet is used to hold small diameter workpieces and small diameter milling cutters.
The advantages of collets are
- material can be loaded quickly
- collets are very accurate
- maximum spindle speeds can be used
Note: (A collet turning at 5000 rpm is a lot safer than a chuck at 5000 rpm)
Collets normally accept material that is .001 inches over the collet size and .004 inches under the collet size. Bar stock is usually within this tolerance.