Multiple collet work-piece holder

A multiple collet work-piece holder, comprising a block having plurality of openings therein and having first fluid passageways separately extending to said openings at a location on each of said openings, a collet retainer disposed in each of said openings and having an axial opening therethrough, fluid seals extending between said retainer and said block on both sides of said location for fluid sealing fluid flow in said openings, each of said retainers having a fluid passageway therein forming a fluid flow passageway from said location to the interior of said retainers and presenting a plurality of cylindrical bores in said retainers, connecting means extending between each of said retainers and said block for preventing rotation of said retainers in said openings, a fluid piston movably disposed in each of said cylindrical bores in said retainers and exposed to fluid pressure in said bores and having a piston reciprocating line of movement which is parallel to said axial opening, a collet disposed in each said axial opening and having a work-piece receiving opening therein co-axial with said axial opening for receiving a work-piece to be clamped by said collet, a connector extending between said retainer and said collet for non-rotational movement therebetween while allowing axial movement of said collet relative to said retainer, a projection affixed to said collet and in contact with said pistons for clamping said collet upon axial movement of said pistons in response to fluid pressure in said fluid passageways, release means interposed between said projection and said block for releasing said collet from clamping the work-piece, and a fluid valve operative on each said first fluid passageway for separately controlling fluid pressure at said piston and thereby separately clamp each of said collets.