Tip-Angle

Why Post-Regrind Inspection Matters I measure every reground gun drill before it goes back into production. Incorrect regrind geometry is one of the most common causes of poor hole quality that I see. The regrind operator might be having a bad day, the grinding wheel might have dulled mid-cycle, or the fixture might have moved. The measurement catches these errors before the tool goes into a part. A gun drill with incorrect geometry cuts poorly from the first revolution. It will produce rough surface finish, oversized bores, or excessive burrs. In some cases, it will break within the first few millimeters of cut. The inspection takes 2-3 minutes and saves hours of troubleshooting time. ...

If there is one thing I have learned across years of running gun drills in production, it is this: tip geometry is everything. You can have the best coolant system, the tightest bushing alignment, and the most rigid machine on the floor, but if the tip geometry is wrong the drill will chatter, wear prematurely, or produce scrap. This article is the practical breakdown I wish someone had handed me when I started — what each angle does, why it matters, and how to set it for the material in the spindle. ...