Metallics JDSP184 10 x 1-1/2 in. 5/16 Hex Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

The JDSP184 is a Type A tapping screw, #10 diameter by 1-1/2 inches long, with a gimlet (sharp) point and 12 threads per inch. The sharp point and coarse Type A thread are made to form their own thread in thin sheet metal, as well as in wood and other soft substrates, without a tapped hole. It is not a self-drilling screw, so a pilot hole is still needed in heavier gauge steel.

Yes, it is a hex washer head. The integral washer runs 0.384 to 0.414 inch outside diameter with a thickness of 0.019 to 0.031 inch, which spreads the clamp load and keeps the head from pulling through sheet metal, strut, or a soft panel face.

These are carbon steel with a zinc plating, which is a mild indoor corrosion coating. Fine for dry interior electrical work, panel and box mounting, and general MRO. For exterior exposure, wet locations, or coastal air, step up to a stainless or hot dip galvanized fastener instead, since zinc plating on steel will eventually rust in standing moisture.

The JDSP184 is case hardened to Rockwell C28-38 with a minimum torsional strength of 48 lb-in, made from AISI 1016-1024 carbon steel. That is enough to form thread in sheet metal, but 48 lb-in is a hard ceiling. Run an impact driver on a low setting or finish by hand, because overdriving past that torque will twist the shank off in the hole.

The JDSP184 is listed as both Buy American compliant and ARRA compliant, with country of origin China. If your contract is a strict domestic-melt-and-manufacture spec rather than a Buy American trade-agreement provision, confirm which clause your project is written to before you submit it.

Head dimensions follow ASME B18.6.3-2013 and the thread form follows ASME B18.6.4, which is what a submittal or spec reviewer will ask for. One caveat from the manufacturer: dimensions for the #9 diameter in this series are independent of ASME B18.6.4. The #10 x 1-1/2 size is within the standard.

At 1-1/2 inches of overall length, the JDSP184 is sized for driving through a bracket, clamp, or box flange and well into framing or a backer. If you are fastening only to a thin steel stud or a panel face, that extra length leaves a sharp gimlet point protruding on the back side, which matters in a finished wall or inside an enclosure. Pick a shorter length from the JDSP series for sheet-to-sheet work.

The JDSP184 ships as a 100 count jar, and 100 is the order minimum. Packed weight is 1.03 lbs. Other sizes and quantities in the JDSP series are available by request if you need a different length or diameter for the same job.

Head height on the JDSP184 runs 0.105 to 0.12 inch, so the hex washer head sits low and flush enough that it will not foul a cover plate, a conduit run, or a mating bracket in most electrical mounting work.