Metallics JG8HC341 Bolts 1/2-20 x 2-1/2 G8 HXBT St-zn (Jar 25)

It's a fine thread bolt: 1/2-20, meaning 20 threads per inch on a 1/2 inch diameter shank. It mates with 1/2-20 UNF nuts and tapped holes only. A 1/2-13 coarse nut will not thread onto it, so if your existing hardware is coarse thread you need a different bolt.

The JG8HC341 is a Grade 8 cap screw with a minimum tensile strength of 150,000 psi and minimum yield of 130,000 psi, made from medium carbon steel and heat treated to Rockwell C33-39. Grade 5 tops out well below that, so Grade 8 is what gets specified in automotive and fleet work where the joint load exceeds what a Grade 5 will carry. For general light-duty bracket and strut work a Grade 5 is normally plenty.

They ship 25 to a jar, and 25 each is the order minimum. The jar pack keeps loose fine thread hardware sorted on a service truck or in a shop bin rather than mixed in with coarse thread of the same diameter.

The finish here is zinc over steel, which is a general purpose corrosion coating suited to dry indoor and sheltered use. It is not a marine or chemical duty finish, and Grade 8 bolts in particular should not be used where hydrogen embrittlement or heavy corrosion is a concern. For sustained wet, coastal, or wash-down exposure, specify stainless or hot dip galvanized hardware instead.

Both flags are marked compliant on the JG8HC341: Buy American compliant and ARRA compliant. Country of origin is listed as multiple, which is common on fastener lines produced across more than one plant, so if your contract requires documentation for a specific lot, request the mill paperwork with the order.

Standard hex head, and the head measures 0.428 to 0.438 inches across the head height dimension with the across-flats body figure at 0.484 to 0.505 inches. A 1/2-20 hex cap screw takes a 3/4 inch wrench or socket across the flats. No washer or nut is included, so add 1/2-20 nuts and hardened washers to the order if the joint needs them.

Material standard is AISI 1021 through 1045 carbon steel, heat treated to Rockwell C33-39. That is the medium carbon range Grade 8 is built from, and the heat treat is what gets it to the 150,000 psi tensile minimum. Worth knowing if you are welding near the joint, since heat on a hardened Grade 8 bolt will pull strength out of it.

Yes. The G8HC and JG8HC series covers other sizes and quantities by request, so the same zinc plated Grade 8 hex cap screw is available in diameters and lengths beyond the 1/2-20 x 2-1/2 inch JG8HC341. Tell us the diameter, thread pitch, and length you need and we will pull the matching part number from the series.