Metallics JCB55SS Bolts 3/8-16 x 3/4 Carriage Blt SS (Jar 100)

The JCB55SS is a 3/8-16 x 3/4 carriage bolt with 16 threads per inch, a UNC coarse right-hand thread cut to ANSI/ASME B1.1. Measured thread diameter runs 0.368 to 0.388 inch. Pair it with a 3/8-16 UNC nut; a 3/8-24 fine-thread nut will not run on.

At 3/4 inch of shank under the head, the JCB55SS suits thin stacks, think strut fittings, sheet metal brackets, channel and box mounting where total grip is well under 3/4 inch once you allow for a washer and nut. The head itself adds 0.188 to 0.208 inch of height and sits mushroom-flat on the surface rather than adding to the grip. For thicker wood or doubled-up framing you want a longer carriage bolt in the same 3/8-16 thread.

They are 18-8 stainless steel to ASTM F593, which is the standard austenitic grade for general corrosion resistance, so they hold up outdoors, in damp mechanical rooms and in washdown areas far better than zinc-plated steel. For marine or chloride-heavy exposure, 316 stainless is the step up. One caution for electrical work: stainless against aluminum or galvanized steel in a wet location can set up galvanic corrosion, so isolate or use a compatible washer.

No. The JCB55SS is flagged Buy American non-compliant and not ARRA compliant, with multiple countries of origin. If you are on a federally funded job with domestic sourcing language in the spec, this part will not satisfy it and you need a domestically produced 3/8-16 stainless carriage bolt instead.

The JCB55SS ships as a jar of 100 pieces, and the jar is the order minimum, so 100 is the smallest quantity. Metallics notes other sizes and quantities are available by request if 100 of this length is not what the job needs.

Head and body geometry follow ASME B18.5, the round head square neck bolt standard, and threads follow ANSI/ASME B1.1. That means head diameter, head height and neck dimensions interchange with any other B18.5 3/8-16 carriage bolt, so they drop into existing prepped holes and match what a spec sheet calls out by that standard.

Metallics lists the JCB55SS for electrical, plumbing, heating and air conditioning work. In practice that is strut and channel assemblies, equipment and unit mounting, hanger and bracket fabrication, and anywhere a smooth low-profile head on the exposed side is wanted instead of a hex head. Maintenance shops keep the 100 piece jar on the shelf as a standard 3/8-16 stock item.