Metallics JG8HC43 Bolts 5/16-18 X 1 G8 Hxbt St-zn (Jar 100)

It's a 5/16-18 bolt, 1 inch long under the head. The 18 is threads per inch, which is the UNC coarse pitch for 5/16 diameter, so it mates with standard 5/16-18 nuts and tapped holes. Shank outside diameter runs 0.3065 to 0.3125 inch.

Grade 8 buys you tensile strength. These are medium carbon steel, heat treated, rated 150,000 psi minimum tensile and 130,000 psi minimum yield, with a Rockwell C33-39 hardness. The description calls out automotive and fleet work where Grade 5 doesn't carry enough. For general electrical strut, hanger, and bracket work a Grade 5 is usually plenty; go Grade 8 when the connection is loaded in tension or vibration and the engineer called the grade out.

No. The JG8HC43 is not Buy American compliant and is not ARRA compliant, and country of origin is listed as multiple. If your project has domestic-content requirements on fasteners, you need a documented domestic-source bolt instead.

Head width across flats measures 0.489 to 0.500 inch, so a 1/2 inch socket or wrench is the fit. Standard hex head, nothing unusual about the drive.

Finish is zinc plating over steel. That handles indoor and protected exterior conditions, mechanical rooms, and general MRO use. For sustained wet exposure, coastal air, or direct ground contact, zinc-plated carbon steel will corrode, and hot-dip galvanized or stainless is the better call. Note also that Grade 8 steel is not available in stainless, so if the job needs both the strength and the corrosion resistance you're into a different fastener spec entirely.

They ship 100 bolts to a jar, and the jar is the minimum order unit, so 100 is the smallest quantity. A full jar weighs about 1302 g. Other sizes and quantities are available by request.

AISI 1021 through 1045 medium carbon steel, heat treated to Rockwell C33-39. That's the standard chemistry range for a Grade 8 cap screw and it's what gets you the 150,000 psi tensile floor.

Both. The stated field application is electrical, plumbing, heating and air conditioning work, and the same bolt is used in automotive and fleet service where Grade 5 strength isn't enough. For a contractor it's a general-purpose high-strength hex cap screw for hangers, brackets, and equipment mounting.