Metallics QTEKD5M 10 x 1/2 in. 5/16 Head Quadrive Self-Drilling & Tapping Screws - #2 Drill Point - Domestic Steel Zinc - Each

Quadrive is a square-recess (Robertson style) drive, so it takes a square bit rather than a Phillips. The QTEKD5M pairs that recess with a 5/16 inch hex washer head, which means you also have the option of running it with a 5/16 inch magnetic hex driver in a screwgun or impact. Most electricians use the hex socket for speed and keep the square recess as the backup if the socket slips.

Yes, the QTEKD5M is made in the USA and the material is called out as domestic steel with zinc plating. That domestic origin is why this part gets specified on federal, military, and other Buy American funded electrical work where imported fasteners are not accepted.

At 1/2 inch of overall length, the QTEKD5M is sized for fastening thin material directly to thin material, strap to stud, box bracket to stud, sheet metal to sheet metal. Once the drill point and the thickness of the item you are mounting are accounted for, there is very little thread left for engagement, so it is not the screw for anything with standoff or for layered assemblies. For those, step up to a longer #10 self-driller.

The QTEKD5M is domestic steel with a zinc plating, which is a dry interior finish. Zinc plating handles indoor humidity but corrodes in direct weather exposure, in treated lumber contact, and in coastal or wash down environments. For exterior raceway, rooftop work, or wet locations, specify a stainless or coated exterior self-driller instead.

They are not interchangeable. A wood screw has a sharp gimlet point and coarse thread that needs wood fiber to hold, and it will skate on steel. The QTEKD5M carries a #2 drill point and machine style tapping thread, so it cuts and threads sheet steel without a pilot. On steel framing use the self driller, on wood blocking use a wood or sheet metal screw.