reworking bore drilled off position

Problem Description A bore drilled off position is a costly problem in deep hole drilling. I’ve had parts where the bore exit was 0.5 mm off location on a 20 mm diameter hole through 300 mm of 4140 steel. The part was otherwise perfectly machined, but the positional error made it scrap unless I could rework it. In deep hole drilling, bore position errors are especially painful because so much machining time has already been invested when the error is discovered. ...

June 16, 2026 · Engineer at the Deep Hole