Metallics TSP80M 12 x 1/2 in. Pan Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

A #3 Phillips bit. The TSP80M has a Phillips drive with a #3 recess, so a #2 bit will cam out and chew the recess on a #12 screw. Recess diameter runs 0.246 to 0.259 inch with a 0.141 inch depth, which is why the larger bit seats properly.

The TSP80M is a Type A tapping screw with a gimlet (sharp) point, so it is made to start in thin sheet metal and form its own thread at 11 threads per inch. It is intended for thin-gauge sheet metal and similar soft materials, not for thick steel plate, where a self-drilling or machine screw into a tapped hole is the right call. The point type is what distinguishes it from a blunt Type B screw.

Yes. The TSP80M is built to ASME B18.6.3-2013 for head dimensions and ASME B18.6.4 for the tapping thread, with steel per AISI 1016 to 1024 and a case hardness of Rockwell C28 to 38. Torsional strength is 83 lb-in minimum. Note that #9 diameter dimensions in this family fall outside ASME B18.6.4, though that does not affect the #12 size.

No. The TSP80M is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. On a federally funded project with domestic sourcing requirements you will need a domestically produced fastener instead.

The TSP80M is steel with a zinc finish, which is a plating for indoor and dry-location corrosion resistance. For exterior, wet, or coastal work, zinc-plated steel will rust out; specify stainless or a hot-dip galvanized fastener instead.

The TSP80M carries a minimum torsional strength of 83 lb-in, which is the point where the screw twists off. An impact driver will exceed that on a #12 screw if you let it run to stall, so set a clutch or drive with a screwgun and stop at seat. Case hardness is Rockwell C28 to 38, hard enough to tap sheet metal but not immune to over-torque.

A Type A screw forms its own thread, so the pilot has to be smaller than the major diameter of the screw, not a clearance hole. The TSP80M threads at 11 TPI on a #12 body; follow the ASME B18.6.4 hole sizing for the gauge of metal you are fastening, going slightly larger as sheet thickness increases to avoid twisting the head off at the 83 lb-in limit.

They ship in a jar of 1,000, and 1,000 is the order minimum, so this is a bulk-count buy rather than a small blister pack. Good for a shop or truck stock item on repetitive sheet metal and enclosure work.