Metallics JCN163 Nuts 1/4-20 Cap Nut St-Ni-P (Jar 100)

The JCN163 acorn cap nut is a 1/4-20 nut, so it threads onto any 1/4 inch bolt or rod with 20 threads per inch (standard UNC coarse thread for that diameter). If your rod is 1/4-28 fine thread, this is not the nut.

Allow for a dome roughly 0.318 to 0.338 inch tall measured on the nut itself, with an across-flats dimension of 0.482 to 0.505 inch and a head width of 0.423 to 0.4375 inch. Remember the nut only caps the rod, it does not shorten it, so trim the rod so the dome bottoms out where you want it and no thread shows below the hex.

No. The JCN163 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic sourcing clause, this part will not satisfy it.

It covers the exposed threaded end of a bolt or hanger rod with a closed dome, so there is no sharp thread left sticking out and the finished job looks clean. Metallics lists the JCN163 for electrical, plumbing, heating and air conditioning work, which is where you most often have trapeze hangers, strut and all-thread ends in occupied or visible space.

Plated steel: the body is steel with a nickel plated finish. That gives you a bright decorative cap suited to interior finished work, not a corrosion-rated nut for wet or exterior exposure. If the location is damp or outdoors, specify a stainless acorn nut instead.

They ship in a jar of 100, and the jar is the minimum order unit, so 100 pieces is the smallest quantity. The packed jar weighs 0.75 lbs. Metallics notes other sizes and quantities are available by request.

Treat the JCN163 as a finish cap, not a structural fastener. Nothing in the Metallics data assigns it a load or torque rating, and the dome has limited thread depth. Standard practice is to run a hex nut and washer to carry the load, then thread the acorn nut on behind it to cover the remaining thread.

Across the flats it measures 0.482 to 0.505 inch, which is the 1/2 inch hex you would expect on a 1/4-20 nut, so a 1/2 inch wrench or socket seats on it. Snug it by hand where the plating is visible, since a wrench on nickel plate marks easily.