DRILL JIG ASSEMBLY HAVING HYDRAULIC CHUCK AND DRILL GUIDE WITH PILOT BORE

摘要

A drill jig assembly (1) for accurately supporting a drill (10) relative to a workpiece (83) is provided that includes a drill having a cylindrical shank (9), a chuck (7) having a cylindrical exterior, and a hydraulically-operated collet (63) for detachably gripping the drill shank (9), a housing tube (21) for slidably and rotatably supporting the cylindrical exterior of the chuck (7), and a drill guide (33) mounted on the distal end of the housing tube (21). The drill guide (33) is formed from a carbide bushing (36) having a pilot bore (38) for rotatably receiving the cylindrical shank (9) of the drill (10) and maintaining a pilot concentric alignment between the bushing (36) and the shank (9) during a drilling operation. The use of hydraulic chuck (7) in combination with the pilot bore (38) of the carbide bushing (36) allows the drill (10) to accurately bore holes in a workpiece to very tight tolerances in a one-step, extend and retract drilling operation.