Metallics JCB30G Bolts 3/8-16 x 8 Carriage Blt Galv (Jar 25)

The JCB30G is a 3/8-16 x 8 inch galvanized carriage bolt, packed 25 to a jar. The 3/8 refers to the nominal shank diameter (measured shank is 0.360 to 0.388 inch), the 16 is threads per inch, and 8 inches is the overall bolt length under the head. Order minimum is 25 count.

Anything cut 3/8-16 UNC. The bolt is 3/8 inch nominal diameter with 16 threads per inch, so standard 3/8-16 hex nuts, lock nuts, channel nuts and strut fittings thread straight on. Use galvanized or hot dip nuts and washers to match the galvanized finish, otherwise you set up dissimilar-metal corrosion in an outdoor or damp run.

Yield strength is 36,000 psi minimum with a hardness of Rockwell B70 to B100, which puts them in the low carbon, general purpose class used for wood framing, strut, signage and fence work. They are not a high strength structural bolt, so do not substitute them where a drawing calls out a higher strength grade for a steel-to-steel structural connection.

The mushroom head spans 0.782 to 0.844 inch, so it covers well over twice the hole diameter and spreads load on the head side without a washer in most timber and strut work. The nut side is a different story: a flat washer there protects softwood and gives the nut a clean seat. No nuts or washers are included with the bolts.

Yes. It is steel with a galvanized finish, which is the standard choice for exterior timber framing, fence and gate hardware, pole line work and damp mechanical rooms. For fully submerged or chemical exposure you would step up to stainless instead.

The JCB30G is flagged compliant for both Buy American and ARRA in the manufacturer data, which is what procurement on federally funded work usually asks for. Country of origin is listed as multiple, so if your contract requires a single named origin on the submittal, that is the detail to pin down at order time.

The carriage bolt's domed head and square neck give you a smooth, tamper-resistant outside face and let you tighten from the nut side with one wrench, which is why they are standard on gates, fences, playground and strut assemblies. A hex bolt needs a wrench on both ends and leaves a grippable head; a lag screw threads into one member only and cannot clamp a through connection like this 8 inch bolt can.

Yes. The CB and JCB series covers other sizes and pack quantities by request; the JCB30G is specifically the 3/8-16 x 8 inch galvanized bolt in a 25 count jar. If you are running a volume job, ask for the bulk pack rather than buying multiple jars.