Metallics TP529SFC Screws 12 x 1 FH Hx Pin TR SMS 18-8 (100 pcs)

It's a #12 x 1 inch sheet metal screw with a flat head and a hex pin tamper resistant drive, made of 18-8 stainless steel, sold 100 pieces to the box. The flat head seats flush in a countersunk hole, and the sheet metal thread is meant for thin metal such as enclosure covers, plates and panels.

A hex pin (also called pin-in-hex or hex socket with center pin) bit. A standard hex key or allen wrench will not go in, because the recess has a post in the middle that only a hollow pin-hex bit clears. If you're standardizing on the TP529SFC for public-facing covers or plates, order the matching pin-hex driver bits at the same time, since they aren't included with the screws.

They're 18-8 stainless steel, the common austenitic grade used for general corrosion resistance, so they hold up in exterior and damp interior work far better than plated steel screws. For chloride-heavy environments, coastal or pool chemistry, 316 stainless is the usual step up.

A #12 sheet metal screw is intended for sheet goods, thin-gauge metal, covers and panels, where the thread forms its own grip in a pilot hole. The 1 inch length gives you enough reach for a cover plus a backing flange. It is not a machine screw, so it will not thread into tapped 10-32 or 1/4-20 enclosure holes, and it is not a concrete or masonry anchor.

Yes, if you want it flush. The flat head is designed to sit in a countersunk or dimpled hole; drive it into a flat-drilled hole and the head will stand proud and can rock the part. Factory-punched cover plates and panels usually already have the countersink. For a straight unprepped hole, use a pan or truss head instead.

Part number TP529SFC from Metallics, packed 100 pieces per box. For MRO stockrooms that keep tamper-resistant fasteners on the shelf for restrooms, transit areas and schools, a 100-count box of one size is the usual standardizing unit.