Metallics JRMB61 6-32 x 1/2 in. Round Head Slotted Machine Screws - Brass - Each

6-32 is the standard thread used for switch, receptacle and cover plate mounting in US electrical boxes, and the Metallics JRMB61 is cut to that thread at 32 threads per inch to ANSI/ASME B1.1. The 1/2 inch length gives enough engagement for a device yoke into a box ear without bottoming out in most standard boxes.

Round head, which means it sits on top of the surface with a domed profile, not flush. Head height runs 0.091 to 0.103 in. and head width 0.24 to 0.26 in., so it stands about a tenth of an inch proud. For a countersunk hole in a cover plate or a surface that has to be flush, specify a flat head machine screw in the same 6-32 x 1/2 size instead.

Head, slot and thread dimensions are built to ASME B18.6.3, the standard for inch-series machine screws, and the thread conforms to ANSI/ASME B1.1. That is what a spec reviewer wants to see on a machine screw callout. Note that the JRMB61 is marked not Buy American compliant and not ARRA compliant, with multiple countries of origin, so it will not satisfy a domestic-content requirement on a federally funded job.

Brass is the material on the JRMB61, and that is why electricians reach for it in damp locations, outdoor boxes, and marine or coastal work where plated steel starts rusting in the threads. Brass is also non-sparking and far easier to back out years later. If you need higher tensile strength for a structural or bracket attachment, use a steel or stainless screw instead.

They ship in a jar of 100, and 100 is the order minimum. Jar weight is 0.29 lbs. Handy for a van stock item rather than a loose count off a bin.

The JRMB61 is listed for electrical, plumbing, heating and air conditioning work. Common uses are device and plate mounting, grounding screw replacement, securing nameplates and small brackets, and holding covers on control enclosures where a corrosion-resistant screw is wanted.