Metallics JHHN34SS Nuts 3/4-10 Hvy Hx Nut SS (Jar 50)

The JHHN34SS is a 3/4-10 nut, meaning 3/4 inch nominal size with 10 threads per inch, which is the standard UNC coarse thread for 3/4 inch bolts and all-thread rod. It will not thread onto 3/4-16 fine-thread fasteners.

The JHHN34SS is 18-8 stainless steel, an austenitic grade that is corrosion resistant for general outdoor and damp-location work. If you are in a marine, coastal, chloride, or elevated-temperature environment, 316 stainless is the grade with greater corrosion resistance and better strength at raised temperatures, so specify 316 rather than this one.

No. The JHHN34SS is not Buy American compliant and is not ARRA compliant, and country of origin is listed as multiple. On a federally funded job with domestic sourcing language, this nut will not satisfy it, so source a domestically produced stainless heavy hex nut instead.

Pair it with stainless steel bolts, screws, or threaded rod in 3/4-10 whose specified minimum tensile strength is equal to or less than the proof stress of the nut. Matching stainless to stainless also avoids galvanic issues you can get mixing a stainless nut onto a plain or galvanized bolt in a wet location.

Hardness on this 18-8 stainless heavy hex nut is Rockwell B80 to C32. That is a soft-to-moderate range compared with heat-treated carbon steel structural nuts, which is why the pairing rule matters: keep the bolt's minimum tensile strength at or below the nut's proof stress. For high-strength structural connections, a quenched and tempered carbon steel heavy hex nut is the right call and this stainless one is not a substitute.

A heavy hex nut is thicker and wider across the flats than a standard hex nut of the same thread. On this pattern, thickness runs 0.875 times the nominal size and width across flats 1.5 times nominal, which at 3/4-10 puts the measured width at 1.382 to 1.443 inches and height at 0.710 to 0.758 inches. The extra bearing area spreads load over a larger footprint, which matters on slotted or oversized holes and on softer base material.

These ship in a jar of 50 pieces, and 50 each is the order minimum. The jar packaging suits a service van or a shop crib where you are pulling a handful at a time rather than opening a bulk box.

The Metallics JHHN series covers other sizes and quantities by request beyond the 3/4-10 jar of 50, so if you need a different diameter or a larger bulk count for a repeat run, ask rather than piecing it together from 50 packs.