Abstract: The apparatus includes a body (222) that fits within the bore of a collet (228). An expandable sleeve (223) slides over the body (222). The body (222) includes a flange (240) on one end. A nut (224) is threaded over the other end of the body, with the sleeve (223) disposed between the flange (240) and the nut (224). As the nut is threaded toward the flange (240), the sleeve (223) is wedged between the flange (240) and nut (224), and forced to expand against the collet (228), thereby to fix the position of the stop apparatus body (222) relative to the collet (228). A rod (226) is slidable within the stop apparatus body (222) and may be locked in position relative to the body (222) for providing a stop face (235) for limiting penetration of a work piece (241) that is held by the collet (228).

Abstract: The stop apparatus fits into the bore of a collet and incorporates a sleeve which is expanded in diameter to lock the apparatus in place. The stop face is the end of a cylindrical rod which slides in a bore in the body of the apparatus and is held at a desired position by a set screw. The body is a body of revolution with a bore for accepting the rod and an outer surface comprising a flange at one end, a cylindrical portion, a threaded portion and a knurled portion at the other end. The flange has a conical surface facing the cylindrical portion. The cylindrical portion is surrounded by a split, resilient sleeve held in place by a nut threaded onto the threaded portion. The nut has a conical surface also facing the cylindrical portion. The conical surfaces engage chamfers at the ends of the internal surface of the sleeve so that turning the nut on the body toward and away from the flange causes the sleeve to expand or allows it to contract.