Metallics SD91434 Drill Bit Spiral Flute Step 9 Step 1/4"-3/4" (1pc)

The SD91434 is a 9-step bit covering 1/4 inch through 3/4 inch. Each step gives you one hole size, so a single bit handles the common range for conduit connectors, cable glands and knockout starter holes in that span. If you need holes larger than 3/4 inch, this bit will not get you there.

One bit per pack, supplied in a pouch. If you are outfitting a crew or stocking multiple trucks, order a quantity that matches the number of kits you need to fill.

The SD91434 uses a spiral flute. The spiral pulls chips up and out of the hole as you drill, which keeps swarf from packing into the cut on sheet metal and thin-wall enclosures. Straight flute step bits cut the same hole sizes but rely more on you clearing the chips. For electricians opening panels and boxes repeatedly, the spiral is the version most reach for.

For holes up to 3/4 inch in sheet metal enclosures, the 9-step SD91434 covers the range a punch set would, without the setup of a draw stud and die. Where a punch still wins is larger trade sizes, thick-gauge material, and clean burr-free openings in a finished panel. Many crews carry both: the step bit for quick small penetrations and pilot holes, the punch for 1 inch and up.

It is catalogued by Metallics as an electrical supply item, and the 1/4 to 3/4 inch step range lines up with the holes an electrician drills most: enclosure and panel penetrations, connector openings, and pilot work ahead of a knockout punch. Nothing about the bit restricts it to electrical use, but that step range is why it sits in an electrician's pouch rather than a machinist's index.