Metallics JSFN1213SS Nuts 1/2-13 Serr Flange Locknut SS (Jar 50)

No. The flange does the washer's job: it spreads load across a bearing face of 1.000 to 1.031 inches outside diameter, and the serrations on the underside bite the work surface to resist loosening. That saves a part and a step on strut, channel, and panel connections.

The JSFN1213SS is 18-8 stainless steel, so it resists corrosion in damp, outdoor, and washdown conditions where a zinc-plated steel nut would rust at the threads. Pair it with stainless rod or bolts where you can, since mixing stainless hardware onto plain steel fasteners leaves the steel part as the weak link.

That is what they are built for. Metallics lists the JSFN1213SS for high vibration areas along with electrical, plumbing, and HVAC work. The serrations under the flange dig into the mating surface as the nut is torqued, which is what resists back-off from vibration, rather than a nylon insert. Note that the serrations mar the surface they bite, so they are not the choice for finished or soft-coated panels you need to keep cosmetically clean.

No. Metallics lists the JSFN1213SS as not Buy American compliant and not ARRA compliant, with country of origin reported as multiple. For a job with domestic sourcing requirements you need a domestically produced 1/2-13 stainless flange nut instead.

The hex measures 0.736 to 0.750 inches across the flats, so a 3/4 inch wrench or socket is the right size. Across the corners it runs 0.840 to 0.866 inches, and overall height is 0.437 to 0.458 inches with 0.31 inches of wrenching height, so use a socket with a deep enough chamfer to clear the flange and still grab the flats.

Metallics rates the JSFN1213SS against a panel thickness of 0.05 inch. On thinner or softer sheet than that, the serrations and flange load can dimple or deform the material, so back it with a larger load-spreading washer or a thicker plate.

They ship 50 to a jar, and 50 each is the order minimum, so the jar is the smallest unit. Filled weight is 2.29 lbs. Metallics does offer other sizes and quantities by request if 1/2-13 or a 50-count jar is not what the job needs.

Yes. The JSFN1213SS is made to ASME B18.16.4-2008, the dimensional standard for prevailing-torque and flange lock nuts, so the hex, flange diameter, and height fall inside published tolerances rather than a house pattern. That is the figure to cite on a submittal.

Pick by surface and reuse. A serrated flange nut like the JSFN1213SS locks mechanically against the mating surface and handles high vibration, and it needs no separate washer because its flange bears across a 1.000 to 1.031 inch face. A nylon insert nut locks on the threads instead, so it does not scar the work surface and is friendlier to repeated removal, but it is temperature limited and still wants a washer. On strut, enclosures, and vibrating equipment, the serrated flange is the usual call.