Metallics JRM143SLT 1/2-13 x 2 in. Round Head Slotted Machine Screws - Steel Zinc - Each

They're 1/2-13, meaning a 1/2 inch nominal diameter with 13 threads per inch, which is the standard UNC coarse pitch for that diameter. Shank length is 2 inches. Any 1/2-13 nut, coupling nut, or tapped hole will take them.

The JRM143SLT is low carbon steel with a zinc finish, which is a dry-location plating. It handles indoor electrical rooms, panel and enclosure work, and general interior MRO fine. For exterior, wet, or washdown areas, zinc plated carbon steel will corrode at the slots and threads first, so specify stainless instead.

Tensile strength is 60,000 psi minimum with a Rockwell B70-B100 hardness, made from AISI 1006-1022 steel. That's a standard commercial-grade machine screw, equivalent to ordinary low carbon fastener stock, not a graded structural bolt. Use it for mounting equipment, enclosures, strut fittings and panel work. For rated overhead support or anything carrying a calculated structural load, step up to a Grade 5 or Grade 8 hex bolt.

They ship in a jar of 100, and 100 count is the order minimum, so this isn't a loose-piece purchase. The jar runs 12.2 lbs, which is worth knowing if you're carrying it up a ladder or into a crawlspace rather than leaving it on the truck.

The JRM143SLT is a single slot drive. Slotted is the right pick when the screw gets driven and backed out by hand with a flat blade, which is still standard practice in device and panel work, and it won't cam out and chew a recess. The tradeoff is that a blade walks out of the slot under a power driver, so if you're running these in volume with a drill, a combo or Phillips head version is the easier drive. Metallics offers combo drive machine screws across its line.

Round head means the screw crown sits proud on the surface, with a domed bearing face that spreads load over the hole. It will not sit flush. If your part is countersunk or the screw has to be flush with the surface, you need a flat head machine screw in 1/2-13 x 2 instead.

The record flags the JRM143SLT as both ARRA compliant and Buy American compliant, with China as the country of origin. If your contract is a strict domestic-melt-and-manufacture spec rather than an ARRA-style provision, verify against the exact clause in your contract documents before submitting.

No, the JRM143SLT jar is screws only, 100 of them. A machine screw has a fully threaded machine-cut shank and needs a mating 1/2-13 nut or a tapped hole, so order nuts and any flat or lock washers separately to complete the assembly.