Hex Cap Screws and Hex Bolts – Are they the same?
While most think these parts are the same, they do have some slight differences. Hex head cap screws have a flat washer facing under the head that meet specific tolerances per ASME B18.2.1 whereas a Hex Bolt is flat underneath the head. Hex cap screws also have tighter tolerances on the body dimensions and a chamfered end while hex bolts have a flat end. When ordering bolts, it is best to be clear about whether your application requires cap screws or bolts.