Abstract: An adjustable jig for hole formation including a base on which a swingable arm is mounted and carries a bushing for guiding a cutting tool through the bushing and onto a workpiece clamped onto the base. The base clamp portion positions the workpiece in a position relative to the operative position for the cutting tool bushing, and there are adjustments for controlling the positioning of the bushing in the operative position and for controlling the positioning of the workpiece relative to the base. The entire arrangement is such that accurate holes or openings can be formed in the workpiece.

Abstract: A multiple collet work-piece holder having a block with a plurality of openings and a collet retainer disposed within the openings. The retainer has pistons which are subjected to hydraulic pressure for moving the collet to a clamping position. The opposite ends of the collet are completely free from any obstructions, so the work-piece can be inserted from either end, and the collet is securely held against rotation so that the work-piece can be machined as desired. Also, an automatic release of the collet is provided, so that the work-piece can be released when fluid pressure is relieved.