Metallics JTSF17 8 x 3/8 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

The Metallics JTSF17 is a Type A tapping screw, #8 x 3/8 in., with a gimlet point. Type A threads are the wide-pitch, pointed self-tapping style meant for thin sheet metal and similar light materials: the gimlet point starts in a pilot hole and the thread forms its own mating thread as it drives. At 15 threads per inch and only 3/8 in. long, it is a short fastener for thin stock, not for thick plate or structural work.

Yes. The JTSF17 is built to ASME B18.6.4-1998 for dimensions and ASME B18.6.4 for the thread, with material to AISI 1016-1024 steel. It is also flagged ARRA compliant and Buy American compliant, which is what most public-agency and institutional purchase orders are checking for. One caveat from the manufacturer: dimensions for #9 diameter screws in this family fall outside ASME B18.6.4.

No. It is a Type A tapping screw with a gimlet point, which means it needs a pilot hole or an existing punched hole. If you need a fastener that drills its own hole through sheet metal without pre-drilling, you want a self-drilling screw with a drill point, not this one.

A #2 Phillips bit. The head takes a Phillips recess 0.182 in. in diameter and 0.11 in. deep, so a #2 driver seats fully; a #1 will cam out and a #3 will not bottom in the recess.

The JTSF17 is heat treated to Rockwell C28-38 with a minimum torsional strength of 39 lb-in. That is the standard case-hardened tapping screw range, and 39 lb-in is the floor the screw will twist to before failing. It is still a #8 screw, so back off the clutch on an impact driver once the head seats; the torsional rating is a strength figure, not a license to over-drive.

They are steel with a zinc finish. Zinc plating handles indoor and dry-location work and incidental moisture, which covers most panel, box, and strap fastening. For sustained outdoor exposure, washdown areas, or coastal work, zinc-plated steel is the wrong call; specify stainless or hot-dip galvanized fasteners instead.

Size the hole off the gaging diameter, which is 0.267 in. on the JTSF17, and the thread form is ASME B18.6.4 Type A at 15 TPI. In thin sheet metal, a pilot near the screw's minor diameter lets the gimlet point start and the thread cut cleanly; too large a hole and the thread will not grip, too small and you risk twisting the head off at the 39 lb-in torsional limit.

They ship in a jar, with a minimum of 100 count per order. The jar weighs about 0.25 lbs. Metallics offers other sizes and quantities in this flat head Phillips tapping screw line by request.

Country of origin is listed as multiple, so sourcing varies by production lot. The screws are flagged as both ARRA and Buy American compliant, which is the designation that matters on federally funded and public-agency work.