Metallics JG8HC14 Bolts 5/16-18 X 2 G8 Hxbt St-zn (Jar 100)

It's a 5/16-18 bolt, 2 inches long. 18 threads per inch is the coarse (UNC) pitch for 5/16 diameter, so it takes a standard 5/16-18 coarse nut. Measured shank diameter runs 0.3065 to 0.3125 inch, and the hex head measures 0.489 to 0.500 inch across the flats, so a 1/2 inch wrench or socket drives it.

Grade 8 here means 150,000 psi minimum tensile and 130,000 psi minimum yield, hardness Rockwell C33-39. That's the step up you take when a Grade 5 won't carry the load, which is why these get used in automotive and fleet work. The tradeoff is the heat-treated medium carbon steel is harder and less forgiving of bending or shock-loading than a Grade 5.

No. Metallics lists these as not Buy American compliant and not ARRA compliant, with country of origin shown as multiple. If your project carries a domestic-sourcing clause, this jar won't satisfy it and you need a domestically produced Grade 8 bolt.

They ship as a jar of 100, and 100 in a jar is the order minimum, so it's full-jar quantities rather than loose counts. Metallics lists other sizes and quantities as available by request.

The finish is zinc plating over steel, which handles indoor and sheltered conditions and light moisture exposure. It is not a stainless or hot-dip galvanized bolt, so for direct weather exposure, wet wells, or corrosive environments choose a hot-dip galvanized or stainless fastener instead. Zinc plating on a heat-treated Grade 8 should also not be welded or re-heated.

Yes. Metallics lists the field application as electrical, plumbing, heating and air conditioning industries, and the 5/16-18 x 2 size is a common hanger, strut and bracket fastener for those trades. A full 2 inch length with coarse thread gives you room for a channel nut or through-bolted bracket plus washer and nut.

Medium carbon steel to AISI 1021-1045, heat-treated to reach Grade 8 properties. That material standard is what a spec reviewer or QA submittal normally asks for on a Grade 8 cap screw.