Round Head Bolts

Round head bolts feature a button head and are largely used in wood connections. Round head bolts are same as the carriage bolts; however, they don’t have the square neck. As round head bolts are mostly used with wood, they do not exhibit high strength and are usually supplied in a standard ASTM A307 specification.


Baseline Bolts manufactures quality button head bolts. With a diameter of 1/2″ – 1-1/4″, these bolts fulfill most specifications of the ASTM, SAE and AASHTO. In fact, we can even create special tooling to help produce nonstandard bolt heads, button head bolts, or head dimensions larger than 1 ¼” diameter with the client’s preferred name and/or logo.

Standard Thread Length

Bolt lengths ≤ 6″: Thread length = (2 X diameter) + 14
Bolt lengths > 6″: Thread length = (2 X diameter) + 12

Round Head Bolt Dimensions

Click table to show drawing
Bolt DiameterCH
Head DiameterHead Height

*Dimensions per ASME B18.5 1990 (R 1998) cover diameters up to 1″. Bolts over 1″ use custom head dimensions.