Tolerances

I use gun drilling alone when possible and add reaming for tight tolerances. The decision between the two processes comes down to surface finish, tolerance, cycle time, and cost per hole. Here is how I break down the comparison on my shop floor. Reaming is traditionally required after drilling to improve finish and tolerance. But gun drilling can achieve similar results in a single pass. The trade-offs are not always obvious, so I keep a systematic comparison. ...

Deep Hole Drilling Accuracy: What Tolerances Can You Actually Hold? Every customer who walks through my shop door asks the same question: “What can you actually hold?” The textbook says one thing. My CMM reports say another. Here is what I have measured across thousands of parts over the last decade. Diameter Tolerance by Process and Range I run gun drilling, BTA, and reaming every day. Each process lands in a different IT-grade band, and the diameter range changes what is realistic. ...