Metallics TEKD7SSM 10 x 1 in. 5/16 Indented Hex Head Self-Drilling & Tapping Screws with Washer - #3 Drill Point - 410 Stainless Steel - Each

The TEKD7SSM is rated for panel thickness of 0.110 to 0.175 in. That is the drilling capacity of its #3 drill point. Thinner sheet than 0.110 in. lets the point punch through before the threads engage properly, and anything heavier than 0.175 in. needs a larger drill point.

Metallics lists the TEKD7SSM as both ARRA compliant and Buy American compliant. Country of origin is recorded as multiple, so for a federally funded project where origin documentation is required, request the certification for the specific lot you receive.

A 5/16 in. hex driver or socket. The head measures 0.305 to 0.312 in. across the flats and 0.34 in. across the corners, with a head height of 0.105 to 0.12 in. Drive type is hex, so it runs off a standard impact or screwgun hex bit holder, no Phillips or square bit involved.

It is an integral washer under the indented hex head, so nothing separate to order or hold in place. The washer OD is 0.384 to 0.414 in. and the washer thickness is 0.019 to 0.031 in., which gives a bearing surface wide enough to seat over a slotted strut or an oversized hole in sheet metal.

410 stainless is the hardenable martensitic grade used for drill screws because it can be heat treated hard enough to cut its own hole, Rockwell C38-46 here. It gives better corrosion resistance than plain carbon steel but less than 300 series austenitic stainless, so it suits damp interiors and normal exterior sheet metal work rather than coastal or chemically aggressive exposure.

Thread count is 16 threads per inch with a 1 in. fastener length, built to SAE J78 - 2013 thread standard and ASME B18.6.3-2010 for dimensions. Note that SAE J78 does not include specifications for #7 diameter drill screws, which is why the published dimension data is given as head, washer and drill point ranges rather than a nominal diameter callout alone.

Minimum torsional strength is 61 lb-in, and Metallics notes that minimum torques are the same for stainless and steel self-drill screws. Drill time is 2.5 seconds through a 1 mm thick plate. Most breakage on 410 stainless drill screws comes from leaning on the gun after the head seats, so back off once the washer pulls tight rather than driving to impact stall.

They ship in a box with an order minimum of 1,000 pieces, sold by the thousand. Box dimensions are 7.25 in. long by 6.75 in. wide by 3.25 in. high at 7.51 lbs. Metallics states other sizes and quantities are available by request.

Metallics targets the TEKD7SSM at the electrical, plumbing, and heating and air conditioning industries. In practice that is hanger and strut attachment, duct and sheet metal joints, panel and enclosure mounting, and anywhere you need to drill and tap in one pass without pre-drilling. The combined drill point and tapping thread means one tool and one operation per hole.