Metallics JG8HC75 Bolts 1/4-20 x 2-3/4 G8 HXBT St-zn (Jar 100)

The JG8HC75 is a 1/4-20 x 2-3/4 inch hex cap screw, so 20 threads per inch on a nominal 1/4 inch body. Measured shank diameter runs 0.2450 to 0.2500 inch, which is standard 1/4-20 UNC, so any 1/4-20 nut or tapped 1/4-20 hole takes it.

Grade 8 is the step up. These bolts are rated 150,000 psi minimum tensile and 130,000 psi minimum yield, with hardness at Rockwell C33-39. They're used in automotive and fleet work where a Grade 5 doesn't carry enough tensile strength. For general bracket, strut, or enclosure mounting a Grade 5 is usually plenty; reach for Grade 8 on drivetrain, suspension, towing, and high-vibration load paths.

No. The JG8HC75 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic sourcing clause, this part won't satisfy it and you'll need a domestically produced fastener.

Across-flats width on the hex head is 0.428 to 0.438 inch, which is a 7/16 inch wrench or socket. Corner-to-corner the head measures 0.484 to 0.505 inch, so plan your socket clearance around that.

These are medium carbon steel with a zinc finish, heat treated. Zinc plating handles indoor, dry, and sheltered outdoor service, but it's a sacrificial coating, not stainless. For continuous moisture, coastal exposure, or washdown areas, specify a hot-dip galvanized or stainless fastener instead. Note that stainless won't give you Grade 8 strength, so if both the load and the corrosion matter you need to look at the load path again.

They come 100 pieces to a jar, and 100 count is the order minimum. The jar is the practical part for a service truck or an MRO crib, since it keeps a single size separated instead of loose in a bin tray.

Yes. The JG8HC75 is one size out of the Metallics G8HC and JG8HC Grade 8 hex cap screw series, and other sizes and quantities are available by request. If you're standardizing a fleet shop or a maintenance crib on Grade 8, you can stay within the same series across diameters and lengths.

The head stands 0.150 to 0.163 inch above the mating surface. That matters if you're bolting into a channel, a track, or anywhere a cover plate or moving part passes close over the head.

Material standard is AISI 1021 through 1045, a medium carbon steel, then heat treated to reach Grade 8 properties. That's the normal range for a quenched and tempered Grade 8 cap screw, and it's why the hardness lands at Rockwell C33-39.