| 摘要 |
Drill guide bushing supported on legs with inner surfaces defining angle bisected by longitudinal axis of bushing and with flat coplanar bottoms in plane perpendicular to longitudinal axis of bushing. Scribe line on apparatus bisecting sand angle permits visual alignment of bushing with one of two mutually perpendicular center lines on surface to be drilled. Selected edges of legs lie in same plane as longitudinal axis of bushing and permit visual alignment of bushing with other center line. When drilling in flat surface, flat bottoms of legs contact surface. When drilling in curved surface, inner surfaces of legs tangentially contact surface.
|
