Metallics JCN168SS Nuts 12-24 Cap Nut SS (Jar 100)

It threads onto 12-24 machine screw thread, right hand, 24 threads per inch, UNC form. That is the same thread used on most electrical box and device screws, so it mates with standard 12-24 threaded rod, bolts, or screws without an adapter.

Metallics flags the JCN168SS as both Buy American compliant and ARRA compliant, which is what a government, school, or transit procurement package usually asks for. Country of origin is listed as multiple, so if your spec requires a single named origin, that is the point to verify with the submittal.

12-24 is the common thread on electrical device screws, box screws, and ground screws, and this nut is cut to that thread in UNC form to American Standard dimensions. So it caps 12-24 studs and screw ends in panel, box, and support work. It will not fit 1/4-20 or 10-32 thread, which are the two sizes most often mistaken for it.

Across the flats the nut measures 0.423 to 0.4375 inch, and Metallics notes that the width figure is the wrench size, so a 7/16 inch wrench or socket is what you want. The overall body width runs 0.482 to 0.505 inch across the corners, which is what matters if you are working in a tight box or between studs.

They are 18-8 stainless steel, the standard austenitic grade used for general corrosion resistance. That makes them suitable for damp and exterior work such as covering exposed strut or rod ends, and it avoids the rust bleed you get from plated carbon steel. For chloride-heavy coastal or pool chemical environments, 18-8 is still the base grade, not a 316 alloy.

The JCN168SS ships as a jar of 100 pieces, and 100 count is the order minimum, so a jar is the smallest buy. Metallics lists other sizes and quantities as available by request if you need a different thread or pack.

A plain hex nut is what you use where the bolt end is hidden or where you need to run a nut down a long stud. An acorn nut like the JCN168SS is closed at the top, so it hides the thread and removes the sharp bolt end, which is what you want on exposed rod in occupied spaces, on handrail and equipment anchors, and anywhere a snag or cut hazard matters. The tradeoff is thread engagement: at 0.318 to 0.338 inch tall it only accepts a short projection.

The packed jar is listed at 0.79 lbs, with the container at 3 in by 3 in by 2.15 in. It is a small-parcel item, easy to stock on a service van or in an MRO crib without a shelf rework.