Metallics TS81M 10 x 3 in. Pan Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

The Metallics TS81M is a Type A tapping screw with a gimlet (sharp) point, so it starts in thin sheet metal and soft materials without a pre-drilled pilot. The point is the giveaway: gimlet point screws are meant to pierce and form their own thread as they drive. At 12 threads per inch over a 3 inch length, it is a coarse thread meant for thin gauge metal, wood and similar substrates rather than thick structural steel. For heavy steel you want a self-drilling point instead.

The TS81M is flagged compliant for both Buy American and ARRA, which is what a government, school or healthcare procurement file typically needs to see on a fastener line item. Country of origin is listed as multiple.

A #2 Phillips bit. The recess is 0.186 to 0.199 inch in diameter and 0.124 inch deep, which is the standard #2 Phillips geometry for a #10 pan head. Stock #2 bits on the crew; a #1 will cam out and a #3 will not seat.

Dimensions follow ASME B18.6.3-2013 for the pan head and Phillips recess, and the thread follows ASME B18.6.4 for tapping screws. Steel is AISI 1016 to 1024, case hardened to Rockwell C28 to 38, with a minimum torsional strength of 48 lb-in. Note that the published #9 diameter dimensions sit outside ASME B18.6.4.

These ship as a box of 1,000, which is the order minimum. The box weighs 17.65 lbs. If you are fastening a handful of boxes or straps, that is a lot of screws; it makes sense for an MRO shelf or a crew running the same detail across a building.

The TS81M is carbon steel with a zinc finish. Zinc plating handles dry interior work and incidental moisture, which covers most indoor electrical and MRO fastening. For sustained exterior exposure, wet locations or coastal air, move to a stainless or hot dip galvanized fastener instead.

Length is about reaching solid material through what is in between. A 3 inch #10 gets through furring, drywall layers, plaster or blocking to pick up framing behind, which is what you need when mounting boxes, straps, panels or fixture backing on an existing wall. If you are only fastening sheet to sheet, a shorter screw holds the same because engagement comes from the threads in the base material, not from extra shank sitting in the void.