Metallics JDSP180 10 x 1/2 in. 5/16 Hex Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

The Metallics JDSP180 is a Type A tapping screw with a gimlet (sharp) point. It cuts its own thread as it drives into thin sheet metal, sheet metal boxes, straps and light-gauge framing, usually into a pilot or knockout hole. It does not drill its own hole, so on heavier steel you want a self-drilling (TEK style) screw instead. Thread count is 12 threads per inch, matching ASME B18.6.4 for Type A thread form.

With a 1/2 inch overall length, the JDSP180 is a short fastener meant for thin stock. Figure on the sheet plus a strap or clip, not thick assemblies. The integral washer under the head is 0.384 to 0.414 inch outside diameter and 0.019 to 0.031 inch thick, which spreads the load over a punched or knockout hole rather than pulling through it. Head height runs 0.105 to 0.12 inch, so it sits low and clears cover plates.

Zinc plating on carbon steel, which is a dry-location and interior finish. It handles normal indoor humidity and temporary exposure fine, but for exterior, wet, or corrosive locations you want stainless or a hot dip galvanized fastener instead. Base material is carbon steel to AISI 1016-1024.

Case hardness is Rockwell C28-38 and minimum torsional strength is 48 lb-in, which is what lets the point form a thread in sheet metal without shearing the head off. That said, a 48 lb-in minimum is not much margin on an impact driver run wide open. Set the clutch or ease off once the washer seats.

Head dimensions are built to ASME B18.6.3-2013 and the thread form to ASME B18.6.4. One caveat worth knowing if you are spec'ing across sizes: dimensions for the #9 diameter in the JDSP range are independent of ASME B18.6.4. The screws are flagged ARRA compliant and Buy American compliant, with country of origin China.

That is the normal use for a #10 sharp point hex head tapping screw. The gimlet point starts in a punched hole in sheet steel box, raceway, strut clip or light-gauge stud, and the hex washer head gives a positive 5/16 nut setter grip overhead. For threaded 10-32 machine screw holes already tapped in a box, you need a 10-32 machine screw, not a tapping screw, since this one forms its own thread at 12 threads per inch.

They ship in a jar of 100, and 100 count is the order minimum. The packed jar weighs 0.55 lbs. Other sizes and quantities in the JDSP range are available by request if you need a different diameter or length for the same job.