Editing Collet (section)

====5C collets====
Unlike most other machine collet systems, 5C collets were developed primarily for work holding. Superficially similar to R8 collets, 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 (5C collets often also have an internal thread for workpiece locating). Collets are also available to hold square and hex stock. 5C collets have a limited closing range, and so shank and collet diameters must be a close match. A number of other C-series collets (1C, 3C, 4C, 5C, 16C, 20C & 25C) with different holding ranges also exist.

A collet system with capabilities similar to the 5C (originally a proprietary system of [[Hardinge, Inc.|Hardinge]]) is the 2J (originally a proprietary system of Sjogren,<ref>"Show-grin"</ref> a competitor of Hardinge, and which Hardinge later assimilated).
[[File:Hardinge Collets.jpg|thumb|From left to right 5C, 2J and 3J collets. All 1" workholding size.]]