Metallics TRM33M 10-32 x 1/2 in. Round Head Tri-Drive Machine Screws - Steel Zinc - Each

The TRM33M has a tri-drive round head, so the same screw takes a slotted driver, a Phillips bit, or a square (Robertson) bit. That is the point of the head on an electrical crew: whatever is already in the pouch or on the impact driver will seat it, and you are not stocking three different screws for panel covers, device plates, and enclosure work.

10-32 is the standard machine screw thread for grounding and device mounting in steel outlet boxes, enclosures, and panel covers, and the TRM33M is cut 10-32 with a 1/2 inch length. That length suits a tapped hole or a hole with a nut behind it; it is not a long screw, so if you are stacking a cover plus a spacer or going through a mud ring you may run out of thread.

It is steel with a zinc plating. Zinc plated steel is fine for dry interior work, inside panels, boxes, and enclosures, and it gives some corrosion resistance in occasionally damp areas. For sustained wet exposure, coastal air, or anywhere washdown chemicals hit the fastener, specify stainless instead; plated steel will eventually bloom.

The TRM33M is a round head, which means the head sits proud on the surface and bears on the face of the part. Use it where the hole is not countersunk, which covers most box ears, brackets, and enclosure covers. If the part has a tapered countersink and you need the head flush, a round head will not pull down into it and you want a flat head screw instead.

It is a machine screw, not a self-tapper. The 10-32 thread needs a mating tapped hole or a 10-32 nut, so it goes into pre-threaded box ears, tapped brackets, and enclosure holes. Drilling into untapped sheet metal and driving this in will not cut threads, order a self-drilling or sheet metal screw for that.

Yes. The 10-32 x 1/2 inch tri-drive round head machine screw is domestically made, which is the detail that matters on government, school, and other publicly funded jobs carrying a domestic sourcing requirement in the spec.