Metallics HSSC7E Drill Bit HD Cobalt St 135d SplPt 5/32"" 3-1/8" YLW (1pc)

The HSSC7E is a 5/32 inch diameter bit with a 3-1/8 inch overall length. That diameter is the common pilot size for self-tapping screws and small anchors in metal, and it suits drilling struts, channel, and enclosure walls where a full-size conduit hole is not wanted.

Cobalt is the right choice for stainless, hardened steel, cast iron, and tool steel because the cobalt is alloyed through the whole bit rather than coated on, so it keeps its edge at the heat those materials generate. The HSSC7E is a heavy duty cobalt straight shank bit. Carbide only becomes necessary for masonry, tile, or abrasive composites, which this bit is not intended for.

A 135 degree split point starts on its own without a center punch and resists walking on round or sloped metal surfaces. The flatter 135 degree angle also spreads cutting load over a wider edge, which is why it is standard for metal, versus the sharper 118 degree point used mostly for soft materials. On the HSSC7E that means you can drill sheet metal, strut, and panel faces without pre-dimpling.

It ships as one bit, packed in a pouch. If an electrician is standardizing on 5/32 inch for self-drilling screw pilots across a crew, order the quantity you need rather than expecting a graduated index in the pack.

The yellow on the HSSC7E is the finish on a cobalt bit, used in the trade mainly so the metal bits are easy to pick out of a pouch from black oxide or bright HSS. Because cobalt is alloyed into the steel rather than applied as a surface layer, the cutting performance does not depend on that color staying put, and the bit can be resharpened.