Metallics JTSS25 10 x 1/2 in. Pan Head Square Drive Tapping Screws - Steel Zinc - Each

A #2 square (Robertson) bit. The recess is specified at driver size 2R, with 0.112 inch across the flats and a gaging depth of 0.060 to 0.075 inch, so a worn or undersized bit will cam out. Keep a fresh #2 square bit in the driver and these seat clean.

Yes, that is exactly what a Type A tapping screw is for. The JTSS25 has a gimlet point, so it starts in a pilot hole in thin sheet metal and forms its own thread as it drives. It is a thread-forming screw, not a machine screw, so no tapping operation is needed. At 1/2 inch long with 12 threads per inch it is sized for sheet metal, not for thick stock.

No. The JTSS25 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your job carries a domestic sourcing clause, this screw will not satisfy it.

Yes. The JTSS25 is specified for the electrical, plumbing, heating and air conditioning trades, which is where #10 pan head sheet metal screws typically go: enclosure covers, mounting straps, duct flanges, device plates on metal boxes. The pan head bears flat against sheet without needing a countersink.

The head measures 0.357 to 0.373 inch across and stands 0.122 to 0.133 inch high. That matters when the screw lands next to a conductor, a gasket edge, or a cover lip, and when you are checking the head will not foul a slot or a bracket. Head geometry follows ASME B18.6.3-2013.

They are case hardened to Rockwell C28-38 with a minimum torsional strength of 48 lb-in, made from AISI 1016-1024 steel. That is enough to form threads in sheet metal without shearing, but 48 lb-in is a modest ceiling for a #10, so drive them with a clutch or a drill on low rather than leaning on an impact gun.

Zinc plating on steel is a mild corrosion coating, fine for dry interior enclosures, conditioned spaces, and duct work. For wet locations, washdown areas, coastal exposure, or anywhere the fastener sees standing moisture, specify a stainless screw instead. The JTSS25 is steel with a zinc finish.

Threads are to ASME B18.6.4 and the head dimensions to ASME B18.6.3-2013, so a #10 JTSS25 interchanges with any other standards-conforming #10 Type A sheet metal screw. The square recess has a tapered side wall and conical bottom, which is what keeps a #2 square bit from slipping out under torque.

They ship in a jar of 100, and 100 is the order minimum. The packed jar weighs 0.49 lbs. If you need a different count or a different size in the same pan head square drive Type A pattern, Metallics builds the JTSS series in other sizes.