Metallics JG8N164 Nuts 5/16-18 G8 Hx Nut St-zn (Jar 100)

The JG8N164 is a 5/16-18 hex nut, so 18 threads per inch on a 5/16 inch diameter bolt or rod. That is the standard UNC coarse pitch for 5/16, so it threads onto common 5/16 coarse-thread bolts, anchors and all-thread. It will not run on a 5/16-24 fine thread fastener.

Grade 8 is the higher strength class and these are hardened steel at Rockwell C24-32. Running a Grade 8 nut on a Grade 5 bolt is fine, the bolt simply becomes the limiting part. Where you do need Grade 8 is on Grade 8 bolting in high-torque or vibration-prone connections, seismic bracing, equipment mounts and heavy pipe hangers, because a lower grade nut will strip before the bolt reaches its rated torque.

No. The JG8N164 hex nut is not Buy American compliant and is not ARRA compliant, with multiple countries of origin. If your project carries domestic sourcing language, these will not satisfy it and you need a domestically produced nut instead.

Across the flats the nut measures 0.489 to 0.500 inches, which is a 1/2 inch wrench or socket. Across the corners it runs 0.557 to 0.577 inches, worth knowing if you are working in a tight channel or strut bay where the socket has to clear.

The finish is zinc plating over hardened steel. That handles indoor, damp mechanical rooms and covered exterior work. For direct weather exposure, wet locations, coastal or chemically aggressive areas, zinc plating will eventually corrode and a hot-dip galvanized or stainless nut is the better call.

Dimensions follow ANSI/ASME B182.2 and the steel is AISI 1021 to 1045, hardened to Rockwell C24-32. For a submittal on an electrical or mechanical package, that is the dimensional and material citation you need alongside the Grade 8 designation.

They ship 100 nuts to a jar, and the jar is the order unit with a 100-piece minimum. Total weight is 1.1 lbs per jar. The jar format keeps them off the floor of a van bin, which is the point of buying loose hardware this way rather than in a bag.

Metallics lists these for the electrical, plumbing, heating and air conditioning trades. In practice that means strut and channel assemblies, pipe and duct hanger rod, panel and transformer mounting, equipment anchoring, and any bolted connection where you want a hardened nut rather than a standard one.

Yes. The JG8N series covers other sizes and quantities by request beyond the 5/16-18 jar of 100, so if you are standardizing a facility on one hardened nut across several bolt diameters it can be sourced that way.