Carriage Bolts

carriage-bolt-dim-525Carriage bolts are a round-headed bolt with a square neck typically used in wood construction. The square neck will seat into the hole in the wood to prevent the bolt from turning.

Click table to show drawing
Bolt Diameter D C H P F
Body Diameter Head Diameter Head Height Square Width Square Depth
Max Min Max Min Max Min Max Min Max Min
1⁄2 0.515 0.483 1.094 1.032 0.270 0.250 0.515 0.492 0.281 0.250
5⁄8 0.642 0.605 1.344 1.219 0.344 0.313 0.642 0.616 0.344 0.313
3⁄4 0.768 0.729 1.594 1.469 0.406 0.375 0.768 0.741 0.406 0.375
7⁄8 0.895 0.852 1.844 1.719 0.469 0.438 0.895 0.865 0.469 0.438
1 1.022 0.976 2.094 1.969 0.531 0.500 1.022 0.990 0.531 0.500
11⁄4* 1.277 2.850 0.531 0.500 1.250 0.625
*Dimensions per ASME B18.5 1990 (R 1998) cover diameters up to 1". Bolts over 1" use custom head dimensions.