Metallics JG9HC8 Bolt 1/4-20 x 2-1/4 Grade 9 Hx Cap (Jar 25)

The JG9HC8 is a 1/4-20 x 2-1/4 inch hex cap bolt. That's a 1/4 inch diameter shank with 20 threads per inch (standard UNC coarse thread for that diameter) and a 2-1/4 inch length under the head. It takes a 1/4-20 nut or tapped hole, and a 7/16 inch wrench or socket on the head.

Each jar holds 25 bolts. Metallics packages this one in a jar rather than a loose box, which is why it works well on a service truck or a shop bench where you need to pull a few at a time without them scattering.

Grade 9 is a high-strength structural fastener class, rated above Grade 8. Where Grade 5 and Grade 8 are the common commercial grades, Grade 9 is specified when the joint sees higher tensile or shear load than a Grade 8 will carry. The JG9HC8 is a Grade 9 hex cap bolt in 1/4-20 x 2-1/4. Note that higher grade also means the bolt is harder and less forgiving, so torque it to the Grade 9 value for 1/4-20, not the Grade 5 value.

The 2-1/4 inch length is measured under the head, so subtract your total stack-up (strut channel, clamp, washers, nut thickness) to see what thread you have left. On a 1/4-20, a jam of strut plus a clamp body plus a washer and nut typically leaves usable grip at 2-1/4 inches, but if your stack is thinner you'll have excess thread protruding and should step down to a shorter 1/4-20 bolt instead.

Pair it with a 1/4-20 nut. Because the bolt is Grade 9, match the nut strength to it rather than using a low-grade nut, otherwise the nut threads strip before the bolt reaches its rated load. A hardened flat washer under the nut is also normal practice with high-grade fasteners to keep the bearing face from digging into the material.