1, Competitive Price 2, Good Quality 3, Excellent Service Team 4, Own Development Department 5, OEM 1. What is the Hex Cap Screws?ASME standard B18.2.1 -1996 specifies Hex Cap Screws that range in size from 0.25–3 in (6.35–76.20 mm) in diameter. These fasteners are very similar to hex bolts. They differ mostly in that they are manufactured to tighter tolerances than the corresponding bolts. ...