| 摘要 |
A self-chamfering drill bit is disclosed having a shank (12) with a longitudinal groove (28) formed therein. A resilient, cantilevered insert (36) is located in the groove. The insert has a radially projecting cutting tip (44) formed thereon. The cutting tip has forward and rearward bevelled cutting edges (46, 48) formed thereon, so that as the drill advances to make a hole in a workpiece (60), the cutting tip forward bevelled cutting edge chamfers the front side of the hole. The cutting tip then retracts into the groove as it passes through the workpiece, and as the cutting tip emerges from the backside of the workpiece, the cutting tip rearward bevelled cutting edge automatically chamfers the backside of the hole being made in the workpiece. |
