Metallics JTSF35 12 x 1-1/4 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

The JTSF35 is a Type A tapping screw with a gimlet point, meaning it drills its own thread as it drives into sheet metal and similar thin stock without a tapped hole. Thread pitch is 11 threads per inch, which is the coarse spacing Type A screws use to bite thin material. Metallics lists it for the electrical, plumbing, heating and air conditioning trades, so typical use is fastening boxes, straps, hangers and enclosures to sheet metal.

Yes, provided the hole is countersunk. The flat head measures 0.38 to 0.412 in. across with a head height of 0.112 to 0.132 in., and a flat head is designed to seat below the surface in a matching countersink. On a plain punched hole in flat sheet metal it will stand proud by roughly the head height, so if you need a flush face, countersink or dimple the hole first.

No. The JTSF35 is not Buy American compliant and is not ARRA compliant, with multiple countries of origin. On federally funded or domestic preference work you will need a domestically sourced tapping screw instead.

Use a #3 Phillips bit. The recess measures 0.262 in. diameter and 0.144 in. deep, so a #2 bit will sit shallow in it and cam out under load. That matters here because the screw carries an 83 lb-in minimum torsional strength rating, and you cannot reach that torque through a bit that is not seated.

It is built to ASME B18.6.4-1998 for dimensions and to ASME B18.6.4 for the thread form, so it interchanges with any other spec-conforming #12 Type A tapping screw. One caveat worth knowing if you buy across the JTSF series: Metallics notes that dimensions for #9 diameter screws are independent of ASME B18.6.4. The #12 is not affected.

It ships in a jar of 100, and 100 is the order minimum. The jar weighs 0.95 lbs. If you need a different count or a different screw size in the JTSF series, Metallics states other sizes and quantities are available by request.

The JTSF35 is steel with a zinc finish, which is a general purpose indoor and dry location coating. For wet, exterior, or corrosive environments, specify a stainless or hot dip galvanized fastener instead. Zinc plated steel is the normal choice for interior electrical and mechanical rough-in.

They are case hardened to Rockwell C28-38 from AISI 1016-1024 steel, which is what lets the gimlet point form threads in thinner steel rather than deforming. Torsional strength is 83 lb-in minimum. If you are driving into heavy structural steel or thick plate, a self drilling (Type TEK) screw or a drilled and tapped machine screw is the better call.