Metallics JSFN1024SS Nuts 10-24 Serr Flange Locknut SS (Jar 100)

No. The serrated flange takes the place of a washer. The flange measures 0.480 to 0.500 inch across its outside diameter, so it spreads load the way a small flat washer would, and the serrations bite the surface to resist loosening from vibration. Fewer loose parts in the bag on a service call, and nothing to drop into a panel.

Yes, it is rated down to 0.03 inch panel thickness, which covers typical sheet steel enclosure walls, strut fittings, and light gauge brackets. Keep in mind the serrations will mar the finish of the panel face they seat against, so put the flange on the non-cosmetic side where appearance matters.

Solid 18-8 stainless steel, not plated. That matters if you are fastening into stainless strut or stainless enclosures outdoors or in a wash-down area, where a zinc plated nut would start rusting and where mixing plated steel against stainless invites galvanic corrosion. Pair it with a stainless screw or bolt of the same family.

Across the hex flats the nut measures 0.365 to 0.375 inch, so a 3/8 inch wrench or socket is the fit. Corner to corner it runs 0.416 to 0.433 inch, and overall nut height is 0.203 to 0.219 inch with 0.13 inch of wrenching height, so a standard deep socket is not required but clearance for a short socket is.

Treat it as a one-time fastener. The locking action comes from the serrations under the flange deforming into the mating surface, so once it has been torqued down and backed off, both the serrations and the seating surface are already set. For anything that gets opened repeatedly, use a fresh nut on reassembly, which is why these ship 100 to a jar.

The JSFN1024SS is flagged compliant for both ARRA and Buy American provisions in the manufacturer data, with country of origin listed as China. On federally funded work the compliance pathway depends on the specific provision cited in your contract, so match that flag against the clause on your spec before you submit it.

They are built to ASME B18.16.4-2008, the standard for prevailing torque metric and inch lock nuts. If your submittal or drawing calls out a flange nut to B18.16.4, these meet that call-out, which is what an institutional or MRO reviewer usually wants to see before approving a substitution.