Metallics JTSP20 8 x 3/4 in. Pan Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

The JTSP20 is a Type A tapping screw with a gimlet (sharp) point, which is the type made to start in thin sheet metal and form its own thread as it drives. Coarse 15 threads per inch gives it bite in light gauge material. In heavier stock or in anything hard you still want a pilot hole, since Type A relies on the material deflecting to form the thread.

Yes. Head and recess dimensions conform to ASME B18.6.3-2013 and the thread form to ASME B18.6.4. The steel is AISI 1016 to 1024, case hardened to Rockwell C28 to 38, with a minimum torsional strength of 39 lb-in. Those four values are usually what a spec reviewer or institutional submittal package is asking for.

A #2 Phillips bit drives the JTSP20. The recess is 0.169 to 0.182 inch in diameter and 0.108 inch deep, which is standard #2 Phillips territory, so a worn #1 or an oversized #3 will cam out or ride high in the recess. Keep a fresh #2 in the driver if you are running a jar of 100 in one go.

Pan head height on the JTSP20 runs 0.105 to 0.115 inch with a head width of 0.306 to 0.322 inch. That is a low, broad crown, so it clears most device and cover plates, but it is not a flush head. If the application needs the fastener dead flush with the surface you need a flat head screw instead, not this one.

The JTSP20 is zinc plated steel. Zinc plating is a mild corrosion coating meant for dry interior work and protected locations, electrical enclosures, panels, raceway and box mounting. For wet exterior or coastal exposure, specify stainless steel or hot dip galvanized fasteners instead; plated zinc will bloom white rust and then red.

Minimum torsional strength on the JTSP20 is 39 lb-in, with a core hardness of Rockwell C28 to 38. That is a normal case hardened tapping screw, so it will shear if you keep driving after the head seats. Run a drill/driver on a clutch setting rather than an impact, especially in heavier gauge where the thread has to form.

The JTSP20 is flagged compliant for both ARRA and Buy American in Metallics' own product data, though country of origin is listed as China. On a federally funded project, hand both of those facts to the compliance reviewer, since the governing clause on your contract decides whether the compliance flag or the origin controls.

A Type A screw like the JTSP20 has a gimlet point that pierces and forms thread in thin sheet metal, but it does not cut its own hole in thicker stock. A self-drilling screw carries a drill tip and makes the hole as it goes, which is what you want in heavier gauge steel or structural studs. For light enclosure sheet, boxes, and panel work, the Type A with its coarse 15 TPI thread is the simpler, faster fastener.

They come in a jar of 100, and 100 count is the order minimum. For MRO stockrooms that is a convenient bin quantity for a common #8 x 3/4 in. pan head; the jar weighs 0.42 lbs.