Metallics JG8HC58334 Bolts 5/8-11 X 3-3/4 G8 Hxbt St-zn (Jar 25)

Grade 8, with a minimum tensile strength of 150,000 psi and minimum yield of 130,000 psi. Grade 5 cap screws top out around 120,000 psi tensile, so this is the step up you take when the joint load exceeds what a Grade 5 will carry. It's medium carbon steel, heat treated, hardness Rockwell C33-39.

Coarse. It's 5/8-11, meaning 11 threads per inch, which is the UNC pitch for 5/8 inch diameter. If your nut or tapped hole is 5/8-18 fine thread, this bolt will not thread into it.

The finish is zinc over steel, which handles indoor, enclosed, and sheltered equipment work and gives short-term protection in the weather. For permanent exterior or wet exposure, zinc plating will eventually corrode through; a hot dip galvanized or stainless fastener is the better call there. Note that galvanizing is normally not applied to Grade 8, so for truly corrosive outdoor service most buyers move to a different grade or material rather than hunting for a coated Grade 8.

It is flagged both ARRA compliant and Buy American compliant in the product record, which is what procurement for federally funded work normally asks for. Country of origin is listed as multiple, so if your specification requires a single named origin on the certification paperwork, confirm the origin on the lot you receive.

Match the nut to the bolt: with a 150,000 psi minimum tensile Grade 8 cap screw, use a Grade 8 (or Grade C) hardened nut. A Grade 2 or Grade 5 nut will strip before the bolt reaches its rated clamp load, which wastes the strength you paid for. A hardened washer under the head is also standard practice on Grade 8 joints to keep the head from embedding in softer material.

AISI 1021 through 1045 medium carbon steel, quenched and tempered to Grade 8 hardness of Rockwell C33-39. That heat treatment is why these are not a fastener to weld, bend, or re-heat in the field; doing so destroys the temper and drops the strength below what the joint was designed for.

Yes. The G8HC and JG8HC series runs other diameters, lengths, and pack quantities beyond the 5/8-11 x 3-3/4 jar of 25, available by request. Give the diameter, thread, and length you need and the quantity per pack.

It's a hex cap screw, not a fully threaded machine bolt, so expect an unthreaded shoulder under the head on a 3-3/4 inch length in 5/8 diameter. That matters if you're relying on the shank to take shear in the joint, which is the usual reason to pick a cap screw over an all-thread bolt. If your grip length needs thread the whole way, specify a fully threaded tap bolt instead.