Deep Hole Drilling for Fasteners and Threaded Rods
Fasteners are not the first thing that comes to mind for deep hole drilling, but I have drilled plenty of bolts and threaded rods that needed a through-hole for safety wiring, weight reduction, or lubrication passages. The applications range from aerospace fasteners to oil and gas stud bolts that need center bores for hydraulic tensioning. The challenge is that fasteners are usually hardened, and they are mass-produced — so the deep hole drilling needs to be fast, consistent, and gentle on the threads. A bolt with crushed threads is scrap regardless of how good the through-hole is. ...