Metallics JSRM90 1/4-20 x 1-1/2 in. Round Head Slotted Machine Screws - 18-8 Stainless - Each

The Metallics JSRM90 is a 1/4-20 thread, 20 threads per inch, so it mates with any 1/4-20 tapped hole or nut. Note that most outlet boxes, device yokes, and cover plates are tapped 6-32, 8-32, or 10-32, so a 1/4-20 is the larger size used for strut, channel nuts, box hangers, and equipment mounting rather than device screws. Check the tap in your hole before ordering.

They're 18-8 stainless, the austenitic grade used where plated carbon steel would rust, so wet locations, exterior boxes, and damp mechanical rooms are fine. 18-8 is not the choice for chloride-heavy coastal or pool chemical exposure, where 316 stainless is the step up.

No. The JSRM90 is listed as not Buy American compliant and not ARRA compliant, with country of origin shown as multiple. On a federally funded or domestic-content-restricted project you'll need a domestically sourced fastener instead.

At 1-1/2 inches of overall length under the round head, the JSRM90 gives you usable grip after the nut and washer stack. Round head machine screws measure length from under the head, so plan the full 1-1/2 inches as clamp plus thread engagement. For blind tapped holes you want at least one diameter (1/4 inch) of engagement left at the bottom.

Metallics lists 80,000 psi minimum tensile and a hardness of Rockwell B85-B95 for these 18-8 stainless screws. Stainless also galls when driven dry into a stainless nut, so use anti-seize on stainless-to-stainless joints. Tensile values for stainless screws are approximations, since there is no single performance standard for stainless machine screws.

The JSRM90 ships in a jar with a 100 piece minimum, so you're buying a full jar rather than counting out singles. The packed jar weighs 2.07 lbs. Other sizes and quantities are available by request.

Screws only. The jar contains 1/4-20 x 1-1/2 in. round head slotted stainless screws and nothing else, so order 1/4-20 nuts, flat washers, and lock washers separately. Match them in 18-8 stainless to avoid a dissimilar metal pairing at the joint.

A machine screw like the JSRM90 has a uniform straight thread with no point, so it needs either a tapped hole or a nut on the back side. If you're fastening into sheet metal with only an undersized pilot and no access behind it, a self-tapping or sheet metal screw is the correct part instead. The upside of the machine screw is a removable, re-usable joint that holds thread after repeated service access.

Metallics lists the SRM series as being for the electrical, plumbing, heating and air conditioning industries. In practice that is panel and enclosure hardware, strut and channel nut work, equipment and bracket mounting, and duct or hanger assemblies where a through-bolted machine screw and nut is wanted rather than a tapping screw.