Metallics JG5HTB39 Bolts 5/16-18 x 2-3/4 G5 Hx Tap Blt (Jar 100)

It's a 5/16-18 right-hand thread, 18 threads per inch, made to ASME B18.2.1-2012 for hex bolt dimensions. So yes, it threads into any standard 5/16-18 UNC tapped hole or nut. Shank outside diameter runs 0.3065 to 0.3125 in., which is normal for a 5/16 bolt.

Grade 5, medium carbon steel, heat treated, with a minimum tensile and yield of 105,000 psi and hardness of Rockwell C19-30. That is the usual class for bolting motors to machinery bases and for automotive and truck repair work, which is exactly what Metallics lists it for. If your drawing calls for grade 8, this is not a substitute.

Metallics flags the JG5HTB39 as both ARRA compliant and Buy American compliant. Country of origin is listed as China, so if your specification requires domestically melted and manufactured fasteners rather than the broader compliance flag, verify that against your project's own clause before you submit.

The hex head measures 0.489 to 0.500 in. across the flats, so a 1/2 in. wrench or socket is the right tool. Head height is 13/64 in., with a wrenching height of 0.14 in., so you need roughly that much clear head exposure for the socket to grip.

The finish is zinc over steel, which handles indoor and sheltered conditions and incidental moisture. Zinc plating is a sacrificial coating, not stainless, so for constant wet exposure, washdown areas, or coastal work, step up to 18-8 stainless or hot dip galvanized hardware instead.

A hex tap bolt is threaded full length to the head, which is what lets it bottom into a tapped hole of any depth, and Metallics describes it as a cap screw made from medium carbon steel and heat treated. Nuts and washers are not part of the pack, which is bolts only, so order those separately if you are going through a clearance hole rather than into tapped threads.

They ship as a jar of 100, and 100 count is the order minimum, so a jar is the smallest unit. Metallics notes other sizes and quantities are available by request if 2-3/4 in. length or a 100 pack does not suit the job.

Material standard is AISI 1008 through 1026 steel, heat treated to grade 5 properties. That carbon range is why the bolt holds Rockwell C19-30 hardness rather than the softer unhardened grade 2 range.