| 摘要 |
PURPOSE:To restrict occurrence of burrs due to perforation of crossed holes and to remove them at the same time by using a mere simple tool. CONSTITUTION:For example, a crossed hole 4 is drilled on a mild steel work 3. An inserting bar 6 having the same quality as the work 3 is inserted into this hole 4. Then, the main hole 5 having the central ais line rectangular to the crossed hole 4 is perforated by a drill. Since the inserting bar 6 and the work 3 are cut together, few inside burrs occur on the opening edge portion of the crossed hole 4. Next, the tip of the inserting bar 6 is inserted into the main hole 5 with a slight protrusion into the main hole, the tip portion of the bar 6 is bent by the push-rod 8 and the bar is pulled to remove burrs 9. |
