A hex head cap screw is a six-sided bolt with a washer face on the bearing surface. Hex cap screws are commonly used in OEM applications where precise tolerances are needed. Grade 5 fasteners are manufactured from medium carbon steel and hardened for greater strength and durability. A grade 5 bolt is distinguished by 3 radial lines and promises tensile strengths between 105,000 and 120,000 psi.