Small-Diameter Indexable Drills Handle High Feed Rates

If you're drilling holes smaller than about ½-in. diameter, you're using a solid carbide or hss drill, right?

Not necessarily, according to Mitsubishi Materials. The company has developed a series of small-diameter indexable insert drills it says can handle high feed rates and drill holes with depths up to three times diameter.

Mini TAF drills are available for hole diameters between 12 and 15.5 mm in increments of 0.5mm. Released in Japan last October, the tools are said to be the first indexable-insert drills that can be used for small-diameter holemaking.

Mitsubishi says it has found a way around restrictions in insert geometry and the strength of the drill body to produce a tool that can handle relatively high feeds. The drill uses indexable inserts with a geometry and chipbreaker designed to allow efficient and stable machining of small diameter holes.

Combined with a high-strength drill body that still allows good chip evacuation, the small-diameter indexable drills can lower cost per hole by eliminating regrinding and recoating and by providing four usable corners per insert. The tools can be used for holemaking in materials including mild and alloy steel, cast iron, and stainless steel.

Mitsubishi Materials USA Corp., 17401 Eastman Street, Irvine, California 92614. Phone (800) 621-4486.