A307 Grade A Carriage Bolts are manufactured from low carbon steel to meet or exceed ASTM A307 Grade A. Material is manufactured with rolled threads. Lengths out to 6 inches will be fully threaded.  Lengths over 6 to 12 inches will have 6 inches of thread; Zinc plated material will meet or exceed ASTM F1941. Hot-Dip Galvanized material will meet or exceed ASTM A153. Typical hardness will range from HRB 69-100 and a minimum tensile strength of 60,000 psi is required.

Grade 5 Carriage Bolts are manufactured from medium carbon steel. Our Grade 5 material meets or exceeds SAE J429 Grade 5 specifications and is manufactured with rolled threads. Zinc plated material meets or exceeds ASTM F1941. Typical hardness on diameters of 1/4 to 1 inch is HRC 25-34. Tensile strength on diameters 1/4 to 1 inch will meet a minimum of 120,000 psi.

18-8 stainless steel carriage bolts are manufactured to meet or exceed ANSI B18.5 and will have a typical composition of 18% chromium and 8% nickel. These percentages exist in 303, 304 and 305 series stainless steels so 18-8 is used at times to designate any and all of those alloy groups. 18-8 stainless steel offers good corrosion resistance and machines easily but will over time stain in coastal environments. They are also acceptable for use in ACQ pressure-treated lumber.