Metallics JG8HC36 Bolts 1/2-13 x 3-1/2 G8 HXBT St-zn (Jar 25)

The Metallics JG8HC36 is a 1/2 inch diameter bolt with 13 threads per inch, which is standard UNC coarse thread. It takes any 1/2-13 nut or a 1/2-13 tapped hole. For a Grade 8 bolt loaded near its capacity, pair it with a hardened nut of matching strength class so the nut is not the weak point.

Grade 8 buys you tensile capacity. This bolt is rated 150,000 psi minimum tensile and 130,000 psi minimum yield, with a hardness of Rockwell C33-39, which is the reason it gets specified in automotive and fleet work where a Grade 5 does not have enough tensile strength. It is a medium carbon steel cap screw, heat treated. Where the joint is lightly loaded or where some ductility is preferred, a Grade 5 is the usual choice.

These 1/2-13 x 3-1/2 Grade 8 bolts ship in a jar of 25. The stated order minimum is 50 each, so plan on two jars as the base buy. Other sizes and quantities are available by request.

The finish is zinc on steel, which is a general purpose plating. It handles indoor, equipment, and sheltered exterior service, but it is not a hot dip galvanized or stainless part, so in constant wet, coastal, or chemical exposure it will eventually corrode. For permanently exposed structural work, pick a hot dip galvanized or stainless fastener instead.

The record carries both ARRA and Buy American compliance flags on this Grade 8 hex bolt, with country of origin listed as multiple. On a federally funded job, submit the specific lot documentation with your submittal package since origin varies by production run.

The JG8HC36 is a 1/2-13 bolt with a 3-1/2 inch shank length, measured from under the hex head. Add up your material thicknesses plus any washers and the nut height, and leave a thread or two of stick-through. If you need a longer or shorter length in the same Grade 8 zinc hex bolt, other sizes can be requested.

Medium carbon steel in the AISI 1021 to 1045 range, heat treated, finished in zinc. That heat treatment is what puts it at Rockwell C33-39 and 150,000 psi minimum tensile. Because it is a hardened fastener, do not weld it or heat it in the field, and avoid re-tapping or modifying the threads.

Hex head. The JG8HC36 has a six point external hex head, so it drives with a standard wrench or socket, no hex key needed. It is a hex cap screw style Grade 8 fastener in zinc plated steel.