Drilling & Boring

What you need to know about reconditioning carbide drills.

Understanding the entire gundrilling system helps resolve tooling problems.

Small bores present big challenges.

Trepanning--another way to produce deep holes.

Test results show a new HSS drill can provide cost-effective performance when machining hardened plate material.

From the spindle to the cutting edge, advice on adjustable heads, boring bars and inserts.

A new drill point geometry developed by a tool and cutter grinder. The through-coolant drill is ground in such a way that a hollowed out chamber on the face of the tip retains coolant in the cutting zone while hydraulic forces that are created push fluid to the cutting edge.

Cutting forces cause the boring bar to deflect, which can lead to vibration and damaged workpieces. The author gives an overview of available boring bars and offers guidelines for selecting one for a specific application.

The author discusses the advantages and proper application of twin-cutter boring tools. They're recommended for rough-boring applications on castings, forgings and other jobs requiring a tool that can bore a cored hole. Details are provided on the three basic types of methods for rough boring with a twin cutter: balanced, stepped and full profile.

Gundrilling: going deep

Switching from a brazed-tip trepanning tool to an indexable-insert tool nreduced downtime for a manufacturer of cast iron cylinder heads by 45 nminutes. And, incredibly, the price-per-piece dropped so much that the ncompany could save $690,000 annually.

A detailed description of a combination drill that machines six different nhole diameters. Used on a dedicated drilling machine that drills cast iron ncylinder heads, it was developed over a number of years.