Abstract: High speed machining of parts is greatly enhanced when the axial alignment between the machining tool, its tool holder assembly, and a tool driver assembly can be precisely maintained, preferably within about one ten thousandths of an inch, in order to achieve the utmost in machining precision in the parts being machined. In order to maintain this desired degree of alignment, the machining tool is mounted in an angularly adjustable holder assembly which mates with a complementary socket that forms a part of the tool driver assembly. The tool holder assembly can also be used to move the tool radially sideways in a rectilinear fashion relative to the tool driver assembly, if desired. The tool holder assembly, besides being able to adjust the alignment of the tool relative to the tool driver assembly, is also operative to securely clamp the tool to the tool driver assembly.

Abstract: An adjustable drillhead suitable for mounting on a dual bit drill gun or press is disclosed. The invention allows for variation of the spacing between two drill bits and is especially suited for use in drilling dual holes through a workpiece required for nutplates. Also disclosed are means to locate the drillhead relative to a specific location on a workpiece prior to drilling the dual holes.