Metal Bolts and Studs

Lag Bolts (Coach Bolts)

Coach bolts, also known as carriage bolts in many engineering contexts, are designed with a domed head and a square anti-rotation neck for through-hole connections requiring high shear strength. In contrast, lag bolts (coach screws) feature a heavy hex head and coarse, deep threads engineered to maximize pull-out resistance when driven directly into pilot holes in timber. Lag bolts transfer loads entirely through thread engagement in blind applications, while carriage bolts distribute structural tension via an opposing nut. These fasteners are extensively applied in heavy timber framing, bridge construction, and wood-to-concrete anchoring.