Metallics G8HC583 Bolts 5/8-11 X 3 G8 Hxbt St-zn (Box 25)

It's a 5/8-11 coarse thread, 11 threads per inch, so any standard 5/8-11 UNC nut or tapped hole mates with it. Shank outside diameter runs 0.6170 to 0.6250 inch. Overall length is 3 inches.

Grade 8 is the step up when Grade 5 won't carry the load. The G8HC583 is a Grade 8 medium carbon steel cap screw, heat treated, with 150,000 psi minimum tensile and 130,000 psi minimum yield, hardness Rockwell C33-39. It's the common choice in automotive and fleet work where tensile demand exceeds Grade 5. For general bracket and strut mounting with no high clamp load, Grade 5 is usually sufficient.

No on both counts. The G8HC583 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If you're on a federally funded job with domestic sourcing requirements, this part will not satisfy them.

The finish is zinc plating over steel, which handles indoor and sheltered damp conditions. It is not a hot dip galvanized or stainless fastener, so for direct weather exposure, roof work, or chemical washdown areas you want a hot dip galvanized or stainless bolt instead. Note also that zinc plating on a Grade 8 bolt means you should be mindful of hydrogen embrittlement practice in high-stress joints.

These ship as a box of 25. The order minimum is 50 each, so plan on two boxes as the smallest buy. Other sizes and quantities can be had by request.

Medium carbon steel to AISI 1021-1045, heat treated, with the resulting hardness at Rockwell C33-39. That's the material basis for the 150,000 psi minimum tensile rating.

Both. The stated field application covers electrical, plumbing, heating and air conditioning work, and the same bolt is used in automotive and fleet service where Grade 5 tensile isn't enough. In MRO terms it's a general purpose high strength cap screw for equipment mounting, hangers, and heavy bracketry.