Metallics JG8HC765 Bolts 7/16-14 x 2-3/4 G8 HXBT St-zn (Jar 25)

It's a Grade 8 hex cap screw with a 150,000 psi minimum tensile strength and 130,000 psi minimum yield. Grade 5 tops out around 120,000 psi tensile, so this is the step up you take when the joint needs more clamp load than a Grade 5 can carry. Hardness runs Rockwell C33-39, from medium carbon steel in the AISI 1021-1045 range, heat treated.

7/16-14, which is 14 threads per inch, the coarse (UNC) pitch in 7/16. Pair it with a 7/16-14 UNC nut, and for a Grade 8 bolt use a Grade 8 (or Grade C) nut so the nut isn't the weak link. Measured shank diameter is 0.4305 to 0.4375 in.

The hex head measures 0.612 to 0.625 in across the flats, so a 5/8 in socket or wrench fits. Head height is 19/64 in., which matters if you're torquing in a tight pocket or under a bracket.

25 pieces per jar, and 25 is the order minimum, so a jar is the smallest buy. Jar packaging is the reason for the J prefix on the part number (JG8HC765); the same bolt in the plain G8HC series is the bulk form.

The finish here is zinc over steel, which handles indoor, under-hood, and sheltered outdoor duty. It is a sacrificial plating, not stainless, so in constant wet, coastal, or chemical exposure it will eventually rust at the threads. For permanent exterior structural work, hot dip galvanized or stainless is the better call, though neither matches Grade 8 strength in stainless.

Both the ARRA and Buy American compliance flags on the JG8HC765 read compliant. Country of origin is China, so if your specification demands domestic melt and manufacture rather than the program flag, confirm which standard your contract is written to before you submit it.

At 2-3/4 in. overall, measure your combined material plus washers and nut and leave the threads fully engaged through the nut. A Grade 8 hex cap screw this length typically has a partially threaded shank, so if your joint is thin you may end up with unthreaded shank inside the nut. Other lengths in the G8HC and JG8HC series are available by request if 2-3/4 in. doesn't land right.

Fleet and automotive joints, suspension, drivetrain brackets, towing hardware, see cyclic load and vibration, and need clamp load a Grade 5 can't hold. This cap screw is medium carbon steel, heat treated, 150,000 psi minimum tensile, which is why it's specified in those applications. One caution: Grade 8 is strong but not ductile, so don't reuse it after it's been torqued to yield, and never heat or weld it.