Precise angle drilling attachment

Claim 1

An angle drilling attachment for use with a portable rotary tool, such as an electric drill, comprising a base to which is orthogonally attached a sector marked with positional indicia, and two blocks which hingedly mount a one piece U-shaped ways upon which is movably mounted a sliding frame having a nest into which is fitted one of a plurality of different interchangeable contour blocks wherein a portable rotary tool is fitted against a contour block, means for adjusting the contour block relative to the nest of the sliding frame for fitting the contour block to the contour of the portable rotary tool, and which frame mounts rotary tool retaining means; and which ways mounts spring returning means for the frame; and indicating means mounted on the slidable frame relative to the sector and retaining means mounted on the sector; frame displacement indicating means including a threaded graduated length bar attached to the one piece U-shaped ways having an indicator attached to the sliding frame which indicates position on the bar and movable stop means for limiting the movement of the sliding frame in the direction of the base.