| 摘要 |
A small cubical block has a recess defined between two plane surfaces inclined to each other (2, 3) at an angle between 100 and 135 deg. forming a broad V-groove for seating on the cylindrical part (10) of the drill behind its chuck. The block is retained in position on the cylindrical part (10) by a coil spring (4) whose ends are hooked into holes (5) in narrow flanges at either side of the block. The level indicator (8) is recessed into the top of the block. Another indicator (9) is recessed into the back of the block, performing a similar function when a vertical instead of a horizontal hole is to be drilled. ADVANTAGE - Device can be fitted easily to any tool having cylindrical mounting surface.
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