Collets are normally used in automated tool machines for holding work stocks, usually bar or rod stocks, for machining. A two-piece collet typically comprises a collet head having a plurality of work gripping segments and a collet body secured to the collet head for axially moving the collet head relative to the axis of the machine spindle. The spindle typically has a conical surface which cooperates with the conical surface on the collet head gripping segments. When the collet head is moved relative to the spindle, the work gripping segments will either close to grip or open to release the work stock. Spring means for spreading the work gripping segments when pressure is released is usually provided in the collet head.
A collet is typically more accurate and has greater gripping characteristic than a typical jaw chuck used in a typical lathe machine. A jaw chuck typically loses a substantial portion of its gripping pressure at relatively high rate of rotation due to centrifugal force. Therefore, where loss of gripping power cannot be tolerated, use of a collet on such a machine is usually advantageous, because a collet inherently retains its holding power even at relatively high rotational speed.
However, the jaw chuck cannot simply be replaced with a collet, since a lathe machine utilizing a jaw chuck is typically not designed to use a collet.
Therefore, there is a need to provide a collet assembly that will enable a jaw chuck machine to use a collet thereby to take advantage of the benefits of a collet.