Metallics RM89-1M 8-32 x 2 in. Round Head Combo Machine Screws - Steel Zinc - Each

The RM89-1M is cut 8-32, meaning a #8 diameter at 32 threads per inch, which is the standard machine screw thread used on device yokes, box ears and fixture straps in North American electrical work. The 2 inch length is the long end of the range, meant for pulling a device or fixture through deep mud rings, thick plaster or stacked spacers. For a flush box with a device sitting tight to the ring, a shorter 8-32 is the one to reach for.

No. The RM89-1M is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If the contract carries a domestic sourcing clause, these will not satisfy it.

Either a flat blade or a #2 Phillips. The RM89-1M has a combo head, slotted and Phillips in the same recess, so a crew can grab whatever driver is already on the belt. The Phillips recess runs 0.165 to 0.178 inch across and 0.075 to 0.101 inch deep; the slot is 0.045 to 0.054 inch wide and 0.058 to 0.077 inch deep.

Head height on the RM89-1M runs 0.107 to 0.12 inch, with a head width of 0.287 to 0.309 inch. That domed round head sits proud rather than sinking flush, so it needs a clean flat bearing surface, not a countersunk hole. If the head has to finish flush with the plate or panel, a flat head 8-32 is the correct choice instead.

They ship boxed at 1,000 pieces, and 1,000 is the minimum order quantity on the RM89-1M. This is a bulk MRO pack, not a hardware card, so it suits a shop or truck stock program rather than a one-off repair.

The RM89-1M is a low carbon steel screw made from AISI 1006 to 1022 stock, hardness Rockwell B70 to B100, with a 60,000 psi minimum tensile strength. That is standard commercial machine screw territory, fine for mounting devices, plates, straps and enclosures. It is not a graded structural fastener, so anything calling out a bolt grade on the drawing needs a different part.

Zinc plating on these steel screws is a mild corrosion coating meant for dry indoor service, junction boxes, panels and interior fixtures. In wet, coastal or washdown areas the plating will eventually give up and the steel rusts. For those openings, specify a stainless 8-32 machine screw instead.

A combo head carries both a slot and a Phillips recess machined into the same head, so it drives with either tool. Metallics has built the RM series that way since 1985, when it became the first US fastener house to offer a full combo line. Practical upshot for a service van: one bin of 8-32 x 2 covers both drivers, and a chewed Phillips recess can still be backed out with a flat blade.