Metallics HSDAC20 HD 135d SplPt Aircraft HiSpd Drill Bit#20 6" (1pc)

A #20 wire gauge bit, like the Metallics HSDAC20, cuts a 0.161 inch hole, which is the standard tap size for an 8-32 machine screw. Gauge-numbered bits like this are sized by wire gauge rather than fractional inches, so a #20 falls between a 5/32 and an 11/64 fractional bit.

The extra length is the whole point. At 6 inches overall the Metallics HSDAC20 reaches through studs, into panel interiors, behind junction boxes, and into bays a short jobber-length bit cannot physically get to without pulling finish material. If you have clear access to the work and only need shallow depth, a standard jobber bit is stiffer and will wander less. Use the aircraft length when access, not depth of cut, is the problem.

That is the common use. A #20 is the tap drill for 8-32, which is the thread used on most device screws, enclosure ground screws and panel mounting holes, so the HSDAC20 lets you drill and tap a new mounting or bonding point in sheet steel. Run it with a tap and a thread-cutting lubricant.

High speed steel handles mild steel, aluminum, brass and plastics, which covers strut channel, sheet metal enclosures, EMT and device boxes. Keep the speed down and use cutting oil on anything thicker than sheet. HSS is not the tool for hardened steel, stainless at high speed, or masonry, those need cobalt or a carbide-tipped bit.

One bit per pouch. The HSDAC20 is sold as a single piece in a pouch, not as a set, so if you are stocking a van or a crew you need to order the quantity you want and pick up other wire gauge sizes separately.