Metallics JSFN1024 Nuts 10-24 Serr Flange Locknut St-zn (Jar 100)

The JSFN1024 is a 10-24 nut, so it threads onto a #10 machine screw or bolt with 24 threads per inch. That is the standard coarse thread for #10 hardware, so it mates with common 10-24 machine screws, strut hardware and ground screws. Wrong pitch (10-32) will not run on.

No. The flange on this 10-24 locknut spreads the load like a built-in washer, with a bearing diameter of 0.480 to 0.500 inch, and the serrations on its underside bite the mating surface as you wrench it down. It also spans oversized or poorly aligned holes, which is what usually sends people looking for a washer in the first place.

That is what it is built for. Metallics lists the JSFN serrated flange locknut for high vibration areas across electrical, plumbing and HVAC work. It takes more torque to loosen than it did to tighten, and the serrated flange forms a connection that resists backing off, so no thread locker or jam nut is needed.

Yes, and that is by design. The serrations displace material on the mating surface to lock the nut, so they will score paint, plating or an anodized face. Use them on raw steel, strut, enclosure sheet metal or unfinished brackets. On a finished surface you want a plain hex nut with a washer, or a nylon insert locknut, so the cosmetic face stays intact. The sheet thickness referenced for this nut is 0.03 inch.

Across the hex flats the nut measures 0.365 to 0.375 inch, so a 3/8 inch wrench or socket is the fit. Overall height is 0.203 to 0.219 inch, with 0.13 inch of wrenching height, and the flange flares out to 0.416 to 0.433 inch across, so use a socket deep enough to clear the flange rather than seating on it.

They are made to ASME B18.16.4-2008, the standard covering prevailing-torque and all-metal lock nuts, so dimensions interchange with other nuts built to that spec. Steel with a zinc finish, hardness Rockwell HR15N 78 to 90.

Zinc-plated steel is a dry-location and light-exposure finish. It handles interior electrical, plumbing and mechanical room work fine, but in persistent wet, coastal or washdown conditions zinc plating will eventually rust through. For those openings specify a stainless 18-8 serrated flange nut in the same 10-24 size instead.

No. The JSFN1024 is not Buy American compliant and is not ARRA compliant, and country of origin is listed as multiple. If you are on a federally funded job with domestic-sourcing language in the spec, this nut will not satisfy it.

No. This style does not gall screw threads, because the locking action happens at the flange face against the work surface, not inside the threads. That is the practical difference from a distorted-thread or all-metal prevailing-torque nut, and it is why the nut can be run on and off with ordinary tools, though the serrations bite fresh material each time they are reseated.

The JSFN series runs other sizes and quantities beyond the 10-24 jar of 100, available by request. If you are standardizing a shop or a stockroom on one locking nut, ask for the sizes you run alongside 10-24 so the whole bin matches on finish and standard.