Square Head Bolts

Square head machine bolts were the industry standard before hex bolts became widely adopted. Today, square bolts are used primarily for aesthetic purposes, adding a rustic character to new structures, and for matching existing fasteners in older constructions. Square lag screws are also sometimes used for these applications. Machine bolts, also known as cross arm bolts, are supplied mainly to the utility industry and typically feature an added cone point for secure installation.

Manufacturing

BBI manufactures superior-quality square bolts in diameters ranging from 1/2″ to 2″, meeting most ASTM, SAE, and AASHTO specifications. We also offer custom manufacturing through special tooling to produce non-standard bolt heads and head dimensions with your preferred logo and/or company name. In addition, we stock square head blanks to support small orders and expedited deliveries.

Stock

Baseline Bolts does not stock square head machine bolts, and in most cases, square head bolts are not readily available through standard fastener distributors. As a result, these bolts typically need to be custom manufactured to meet specific project requirements.

Standard Thread Lengths

Bolt lengths < 6″: Thread length = (2 X diameter) + 1/4″
Bolt lengths > 6″: Thread length = (2 X diameter) + 1/2″

Square Head Dimensions