Metallics TS28B 10 x 1 in. Pan Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

The TS28B is a Type A tapping screw with a gimlet (sharp) point, which is the style meant for thinner sheet metal, with the screw cutting its own thread as it drives. Thread pitch is 12 threads per inch, coarse for a #10 screw, which is what lets it grab thin stock. It is not a drill point screw, so you still need a pilot hole in heavier gauge material.

It ships as a bulk box with a 10,000 piece minimum, so this is a stocking buy for an electrical contractor or MRO storeroom rather than a handful for one panel. Metallics notes other sizes and quantities are available by request.

Both the Buy American and ARRA compliance flags on the TS28B are marked compliant, which is what a government, school, or healthcare procurement file usually needs on a fastener line item. Country of origin is listed as multiple.

A #2 Phillips bit is the correct driver. The recess is 0.186 to 0.199 inch in diameter and 0.124 inch deep, so a #1 bit will cam out and a #3 will not seat.

The pan head measures 0.357 to 0.373 inch across and stands 0.122 to 0.133 inch above the surface. That seats flat on a panel or strut without a countersink, but if you need a flush surface this is the wrong head style.

The TS28B is carbon steel with a zinc finish, which handles indoor and normally dry locations fine. Zinc plating is a light corrosion coating, not a marine or chronically wet-location finish, so for exposed exterior or corrosive service pick a stainless fastener instead.

Head and recess geometry follow ASME B18.6.3-2013, and the thread follows ASME B18.6.4. Steel is AISI 1016 to 1024, case hardened to Rockwell C28 to 38, with a minimum torsional strength of 48 lb-in. That hardness and torque figure is what keeps the screw from twisting off when it is tapping its own thread.

Overall length is 1 inch measured from under the pan head, so the usable thread engagement is whatever is left after your top panel thickness. On thin sheet work a #10 x 1 inch leaves plenty of thread in the base material; on thicker assemblies you lose grip fast and should step up in length. Metallics offers other lengths in the same series by request.

A full 10,000 piece box runs 68.55 lbs, with the carton listed at 19 x 8.25 x 8 inches. Worth knowing before you plan a storeroom shelf or a one-man lift.