Grade 8 hex cap screws, course thread, have a minimum tensile strength of 150,000 psi.  They have a rockwell hardness of c33-c39, exceeding SAE J429, ASTM, ANSI, GM, FORD, and CAT speficications.  Roll threaded to a class 2-A thread fit, yellow zinc Dura-Plated for added corrosion protection and head marked with the manufacturers symbol and with 6 radial lines as shown below.  Certifications and destructive test results available upon request.  5/16" diameter by 3" length.

 Grade 8