Metallics SD631612 Drill Bit Spiral Flute Step 6 Step 3/16"-1/2" (1pc)

The SD631612 is a 6-step bit covering 3/16 inch through 1/2 inch, so one bit handles the common small-conduit and knockout-size holes in that range without swapping tools. Step up slowly and stop at the shoulder for the size you want.

No. The SD631612 tops out at a 1/2 inch hole, which is the conductor-size reference, not the knockout size. A 1/2 inch trade size connector needs roughly a 7/8 inch hole, so you need a larger step bit or a knockout punch for that. Use this one for pilot holes, screw clearance, cable clamps and small grommet or bushing holes up to 1/2 inch.

Spiral flute, which is what the SD631612 uses, clears chips up and out of the hole as it cuts, so it bites more aggressively in sheet metal, panel boxes and enclosures and leaves less swarf packed in the step. Straight flute step bits are slower cutting but can be steadier on very thin or soft material where a spiral tends to grab. For steel panels and device boxes the spiral is the one most electricians reach for.

For sheet goods, yes within its range. A step bit self-starts, deburrs as it steps up and cuts clean round holes in thin steel and aluminum where a twist drill walks and triangulates. The SD631612 covers 3/16 to 1/2 inch in six steps. What it will not do is drill deep holes in thick stock, since the cutting depth at each step is limited to the height of that step.

It ships as a single bit, one piece, supplied in a pouch rather than a case or index. If you are stocking a van or a shop crib you will want more than one on the shelf, since there is no second size in the pack.