Metallics JTSF34 12 x 1 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

That is what the flat head is for. On the JTSF34 the head measures 0.38 to 0.412 inch across and 0.112 to 0.132 inch high, so it seats into a standard 82 degree countersink and finishes flush with the surface. If your hole is not countersunk, the head will stand proud by roughly that head height and you want a pan or hex washer head instead.

The JTSF34 is zinc plated carbon steel, which is an indoor and dry location finish. Zinc gives you handling and light humidity protection, not weather exposure. For exterior walls, rooftop duct, wash-down areas, or anything coastal, specify stainless steel instead; zinc plating will bloom white and then rust.

No. The JTSF34 is listed as not Buy American compliant and not ARRA compliant, with multiple countries of origin. If your contract carries a domestic sourcing clause, this screw will not satisfy it and you need a domestically produced fastener.

Type A tapping screws cut their own thread as they drive, so they go into sheet metal and similar thin materials without a pre-tapped hole. The Metallics JTSF34 is a #12 x 1 inch flat head Phillips version with a gimlet point, which is the self-starting point that lets it bite in a punched or drilled pilot hole. Metallics lists it for electrical, plumbing, and heating and air conditioning work, so think enclosures, panels, duct, strut accessories, and bracket mounting.

11 threads per inch, which is the coarse Type A spacing per ASME B18.6.4. Coarse, widely spaced threads are what let a Type A grip thin stock, so this is a screw for sheet gauges and light metal, not for thick plate where a machine screw into a tapped hole is the correct choice. With a 1 inch length you have plenty of thread for stacked sheet plus a standoff.

The JTSF34 is case hardened to Rockwell C28-38 with a minimum torsional strength of 83 lb-in, made from AISI 1016-1024 carbon steel. That hardness is what lets the gimlet point form its own thread in steel sheet. Keep driver torque under that 83 lb-in figure, which in practice means clutching back an impact driver rather than running it wide open.

Yes. The JTSF34 is built to ASME B18.6.4-1998 for dimensions and ASME B18.6.4 for threads, with a gaging diameter of 0.362 and protrusion gaging of 0.027 to 0.045 above. One caveat worth knowing if you also buy the #9 diameter from the same JTSF series: Metallics notes those #9 dimensions are independent of ASME B18.6.4.