Metallics JTSF31 10 x 2 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

It's a Type A tapping screw, which is a sheet metal screw. The gimlet point and 12 threads per inch let it tap its own thread in sheet metal, and Type A is the coarse-thread version meant for thinner gauge material rather than the fine-pitch Type AB or B. It will bite in wood, but the thread form is specified for sheet metal work, not for structural wood fastening.

Yes, if the countersink is sized for a #10 flat head. The head measures 0.333 to 0.362 in. across with a head height of 0.098 to 0.116 in., so the countersink needs to be at least 0.362 in. at the surface to pull the head fully below flush. In a punched or drilled hole with no countersink the head will stand proud by about the head height.

No. The JTSF31 is not Buy American compliant and not ARRA compliant, with country of origin listed as multiple. If your project has domestic-sourcing requirements, this screw won't satisfy them.

A Type A screw is self-tapping, not self-drilling. The gimlet point starts the thread but there is no drill flute on it, so you need a pilot hole in anything but the thinnest stock. There's no point driving it through a stud or a knockout box without one.

A #2 Phillips. The recess is 0.198 in. diameter, 0.124 in. deep and 0.032 in. wide, which is standard #2 geometry. Running a #1 or #3 bit in it is how you strip the head on a long 2 in. screw that takes some torque to seat.

The JTSF31 is AISI 1016-1024 carbon steel with a zinc finish. Zinc plating is a dry-location corrosion coating, so it's fine for interior electrical, plumbing and HVAC work but will rust in sustained outdoor exposure or damp locations. For wet or exterior use, go to a stainless sheet metal screw instead.

Torsional strength is 48 lb-in minimum with a case hardness of Rockwell C28-38, which is the ASME B18.6.4 requirement for a #10 tapping screw. That's enough for hand driving or a clutched drill-driver into sheet metal. An impact driver set high will exceed 48 lb-in on a 2 in. screw that binds, so dial the torque back.

Yes. The JTSF31 is made to ASME B18.6.4-1998 for dimensions and ASME B18.6.4 for the thread, with a gaging diameter of 0.313 in. and protrusion 0.025 to 0.042 in. above the gage. That matters if you're buying to a submittal that calls out B18.6.4 fasteners.

They're packed in a jar with an order minimum of 100 pieces. Pack weight runs 1.15 lbs.

Metallics lists the field application as electrical, plumbing, heating and air conditioning. The 2 in. length suits mounting boxes, straps, hangers and plates where you need to reach through finish material into metal, and the flat head lets it sit flush where a pan or hex washer head would interfere.