Metallics TRM85M 8-32 x 3/4 in. Round Head Tri-Drive Machine Screws - Steel Zinc - Each

Tri-drive means the round head is machined with three drive recesses at once: a slot, a Phillips cross, and a square. One screw takes a flat blade, a #2 Phillips, or a square driver, so whatever bit is already in the drill or on the belt will turn it. That is the main reason electricians keep them on the truck for device and cover-plate work.

8-32 is the thread used on receptacle and switch mounting ears, device boxes, and cover plates, so the TRM85M threads straight into that hardware. The 3/4 inch length gives you extra reach for mud rings, deep plaster rings, or stacked spacers where the factory screw runs out of thread. For flush box-to-device mounting the short factory screw is usually enough, so order the 3/4 inch when you need the added length.

The TRM85M is zinc plated steel, which is a dry-interior finish. It handles normal indoor box, panel, and device work fine, but in a wet location, exterior wall, coastal site, or washdown area the plating will eventually give up and the head will rust in place. For those openings specify a stainless 8-32 machine screw instead.

Round head sits proud of the surface with a domed crown, which is what you want for device mounting, strap and clamp fastening, and anywhere there is no countersink. If the part you are fastening has a tapered countersunk hole and the head has to finish flush, a round head will stand up above the surface and you want a flat head 8-32 instead. The TRM85M is the round head version.

No. It is a machine screw with 8-32 machine threads, so it needs a tapped hole or a nut. It will not cut its own thread in sheet metal, stud, or plywood. For those use a self-tapping sheet metal screw or a wood screw of the same gauge.

Metallics part number TRM85M, an 8-32 x 3/4 inch round head tri-drive machine screw in zinc plated steel, made in the USA. TRM85M is the only model under that designation, so the part number alone pins the size, head, drive, and finish.

No, the TRM85M is the screw only. If you are fastening through an untapped hole you need to supply your own 8-32 nut, and any flat or lock washer under the round head has to be ordered separately.