Metallics JTSF42 10 x 2-1/2 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

The Metallics JTSF42 is a Type A tapping screw with a gimlet point, which is the coarse-thread, sharp-point style intended for thin sheet metal, resilient plastics and similar soft substrates where the screw forms its own thread as it goes. At 12 threads per inch it is a coarse thread, not a machine-screw thread, so it does not go into a tapped hole. For structural steel or thicker gauges you want a self-drilling or Type AB/B style instead.

The JTSF42 tapping screws are flagged compliant for both Buy American and ARRA. Country of origin is listed as multiple, so if your submittal package needs a single named country of manufacture you will want the mill documentation for the specific lot.

Yes. The JTSF42 is built to ASME B18.6.4 for thread form and to ASME B18.6.4-1998 dimensionally, with a gaging diameter of 0.313 and protrusion gaging of 0.025 to 0.042 above. Note that Metallics states dimensions for #9 diameter screws are independent of ASME B18.6.4, which does not affect this #10 size.

A #2 Phillips bit. The recess is a Phillips drive measuring 0.198 in. in diameter, 0.124 in. deep, with a 0.032 in. recess width, which is the standard #2 pairing for a #10 screw. Using a #1 will cam out and chew the recess.

Yes, that is what the flat head is for. The JTSF42 head measures 0.333 to 0.362 in. across with a head height of 0.098 to 0.116 in., so a standard 82 degree countersink sized for a #10 flat head takes it flush with the surface. In sheet metal you would dimple or countersink the hole; driven into an uncountersunk flat surface the head will stand proud by roughly its head height.

The JTSF42 is case hardened to Rockwell C28-38 from AISI 1016-1024 steel, with a minimum torsional strength of 48 lb-in. That is the standard tapping-screw spec, and 48 lb-in is easy to exceed with a full-power impact driver on a #10, so back the clutch off and finish the last turns at low speed rather than hammering it home.

The JTSF42 is zinc plated carbon steel, which is an indoor and dry-location finish. It handles incidental moisture during construction, but for sustained exterior exposure, wet locations or treated lumber contact you want stainless or a hot dip galvanized fastener instead, since zinc plating will bloom and then rust through.

They come in a jar, 100 count, and 100 is the order minimum. The packed jar weighs 1.35 lbs.