| abstract |
This invention is an adjustable guide (20) for a rotary tool shaft (3) adapted to penetrate a work piece, the tool shaft (3) connected to a motor having a housing (24). The adjustable guide (20) includes a base (9) connected to the housing (24), and the base (9) having a series of threads. A stop (5) is threadingly engaged with the threads of the base (9), and axially adjustable with respect to the base (9) by rotational movement about the base (9). A guide tube (1) is slidingly connected to the base (9), and is limited in its movement by engagement with the stop (5). An indexed locking mechanism (12, 52) inter-engages the base (9) and the stop (5) to prevent locking rotation of the stop (5) about the base (9) at preset intervals, thereby axially displacing the stop (5) a preset discrete distance between each indexed interval. The stop (5) controls axial displacement of the guide tube (1), thereby controlling the depth of penetration of the rotary tool shaft into the work piece. |