Metallics BBH38 Bolts 1/2-13 x 4-1/2 HXBT Sbr (Jar 25)

The BBH38 is a 1/2-13 x 4-1/2 inch hex bolt, so it's a 1/2 inch diameter shank with 13 threads per inch (standard UNC coarse) and 4-1/2 inches of length under the head. Threads are cut to ANSI/ASME B1.1, so they mate with any standard 1/2-13 nut or tapped hole.

Silicon bronze is the material you reach for on grounding and bonding connections and in wet or corrosive locations where dissimilar-metal corrosion is a problem. The BBH38 is silicon bronze to ASTM F468, which is the spec for nonferrous bolts, so it pairs with bronze and copper hardware without setting up a galvanic couple the way a steel or galvanized bolt would. It is sold for electrical, plumbing, heating and air conditioning work.

No. The BBH38 is bolts only, 25 to the jar. Silicon bronze nuts and washers have to be ordered separately, and for a grounding or wet-location joint you want matching silicon bronze or bronze hardware rather than steel, otherwise the corrosion resistance of the bolt is wasted at the nut.

These ship 25 pieces per container, and 25 count is the order minimum, so that jar is the smallest unit. Metallics does make other sizes and quantities in the BBH and JBBH series available by request if 1/2-13 x 4-1/2 is not the length you need.

The BBH38 is flagged compliant for both Buy American and ARRA, though country of origin is listed as China. On a federal or federally funded project, submit the manufacturer's compliance documentation with your submittal package and let the specifying authority confirm it against the clause in your contract.

At 4-1/2 inches of length with a 1/2 inch shank, the BBH38 suits thick stacked connections, timber-to-bronze joints, and clamp bodies where a shorter bolt would bottom out before it reaches the nut. For a thin plate or lug connection it leaves a long run of exposed thread, and a shorter length out of the same BBH/JBBH range is the better call. Those other lengths are available on request.

Finish is bronze, and that is the bare material rather than a coating, since the bolt is solid silicon bronze. It will weather naturally to a darker patina outdoors, which is normal and does not affect holding strength. Visually it reads as bronze alongside copper grounding lugs and bronze pipe fittings, not as plated steel.

A jar of 25 comes in at 6.68 lbs, with the packed carton listed at 7.25 by 6.75 by 3.25 inches. Worth knowing if you are planning a multi-jar order for a large grounding scope, since bronze is heavier per piece than the steel equivalent.