Metallics TEKDHH6B 10 x 3/4 in. 5/16 High Hat Hex Head Self-Drilling & Tapping Screws with Washer - #3 Drill Point - Steel Zinc - Each

At 3/4 inch under the head with a #10 diameter, the TEKDHH6B is sized to drill and tap steel in the 0.110 to 0.175 inch range and still leave thread engagement past the back of the panel. It will not reach through thick stacked material or spacers, so measure your total fastened thickness plus about three threads of point run-out before you commit to this length.

It's case hardened to Rockwell C32-40 with a minimum torsional strength of 61 lb-in, which is what lets the #3 point cut its own hole rather than needing a pilot. Run it with a screw gun with depth control, not an impact driver, since over-torquing past that rating snaps the point off in the hole.

Metallics lists the TEKDHH6B as both Buy American compliant and ARRA compliant, with country of origin recorded as multiple. On federally funded work, bring that compliance flag and the SAE J78 - 2013 thread standard to your submittal.

A 5/16 inch hex driver or socket. The head measures 0.305 to 0.312 inch across the flats with a hex drive, and the taller high hat profile gives the driver more engagement so the socket doesn't cam off when you lean on it.

The washer is integral to the head. The TEKDHH6B uses a hex "High Hat" washer head with a washer outside diameter of 0.364 to 0.414 inch, so you get the bearing surface without stocking separate washers. That OD is what spreads load on sheet metal and covers a slightly oversized pilot hole.

16 threads per inch, built to SAE J78 - 2013 as a Type BSD self-drilling and tapping screw from AISI 1016-1024 steel. If your drawing calls out SAE J78 drill screws in a #10 diameter, this matches the spec.

The TEKDHH6B is carbon steel with a zinc finish, which is a dry-interior and protected-location coating. For exterior exposure, coastal air, or anywhere that stays wet, specify a stainless or coated exterior-rated drill screw instead, since plain zinc will red-rust in those conditions.

These ship in box pack with an order minimum of 10,000 pieces, so it is a bulk fastener line meant for production or fleet work rather than a one-job handful. Metallics does make other sizes and quantities available by request.

The taller high hat crown gives the socket deeper purchase, which is the point of it: Metallics markets this profile for maximum drilling engagement so the driver doesn't slip off while the #3 point is cutting. On overhead strut, channel, or box work where you are driving one-handed into 0.110 to 0.175 inch steel, that matters more than on a flat bench.

Head height runs 0.125 to 0.130 inch on the TEKDHH6B. That is the clearance to allow for if the fastener sits under a trim piece, a channel flange, or anything that has to lie flat over the top of it.