Metallics JCB34 Bolts 1/2-13 X 2-1/2 Carriage Blt St (Jar 25)

Thread is 1/2-13 right hand, so any standard 1/2-13 UNC hex nut threads on. Use a flat washer under the nut on the back side; the mushroom head is designed to sit flush against the work with no washer on the head side. The bolt ships as bolts only, in a jar of 25, so nuts and washers are a separate line on the order.

Rated at 60,000 psi minimum tensile and 36,000 psi minimum yield, with a hardness of Rockwell B70 to B100. That is low carbon, general purpose strength, equivalent to common commercial carriage bolt stock, and it is sized for electrical, plumbing, heating and air conditioning work such as hanging strut, boxes, panels and brackets. For structural connections or a job drawing calling out a specific SAE or ASTM grade, specify a graded bolt instead.

No. The JCB34 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. On a federally funded job with domestic sourcing requirements you need a domestically produced carriage bolt instead.

The JCB34 is steel with a zinc finish, which is a general purpose indoor and protected-exterior coating. It handles damp mechanical rooms and covered exterior work, but direct weather exposure, coastal air, or treated lumber will eventually corrode zinc plating. For those conditions go to a stainless carriage bolt rather than zinc plated steel.

Yes, it is made to ASME B18.5-1990, the round head square neck bolt standard. Head width runs 1.032 to 1.094 inches and head height 0.250 to 0.270 inch, so it drops into the same counterbores and clearances as any other B18.5 carriage bolt of that size.

A carriage bolt like the JCB34 has a smooth mushroom head with a square shoulder underneath, so once it is seated you tighten from the nut side only, with no wrench needed on the head. That matters where you cannot reach both sides, and the low domed head leaves nothing sharp protruding in a walkway or pull space. Use a hex bolt instead when you are bolting into steel or an oversized hole, where the square shoulder has nothing to bite into.