Metallics CB9G Bolts 1/2-13 x 9 Carriage Blt &NT Ga (Box 25)

The head is a mushroom (round, low-profile) type measuring 1.032 to 1.094 inch across and 0.250 to 0.270 inch high, with the square shoulder underneath that pulls into wood and keeps the bolt from spinning while you tighten the nut. Because the head seats itself in the timber, you do not use a washer under the head, only under the nut on the opposite face. On steel, the square cannot bite, so hold the head with a wrench or use a square hole.

Yield strength is 36,000 psi minimum with a hardness of Rockwell B70 to B100, which is low-carbon commercial grade steel, not a heat-treated high-strength bolt. It is sized for electrical, plumbing, and HVAC support work. If a drawing calls out a graded structural bolt, this is not the substitute.

The CB9G is steel with a galvanized finish, which is the normal choice for exterior framing, damp vaults, and unconditioned mechanical spaces. For submerged or chemically aggressive service, galvanized steel is not a stainless substitute.

These ship as a box of 25 pieces, and 25 each is the order minimum. Other sizes and quantities are available by request if 9 inches or a 25-count box is not what the job needs.

The CB9G is flagged as both ARRA compliant and Buy American compliant. Country of origin is listed as multiple, so if your specification requires a single documented origin, get that confirmed against the shipping lot.

Outside diameter runs 0.483 to 0.515 inch, so a 1/2 inch bit is tight on the high end of tolerance. In wood, drill 1/2 inch so the square shoulder has material to bite into; in steel or a bracket, go 9/16 inch for clearance.