Download a complimentary PDF of our Fastener Markings chart. Contact American Fastener with any questions or for a custom quote. Identification Grade Mark Specification Fastener Description Material Nominal Size Range (in.) Mechanical Properties Proof Load(psi) Yield Strength Min (psi) Tensile Strength Min (psi) NoGradeMark SAE J429 Grade 1 Bolts, Screws, Studs Low or Medium Carbon […]Grade 5 Bolts are equivalent to Metric 8.8 bolts, so when finding the right bolt, be sure to match the grades on the bolts being used. Grade 5 bolts can often be identified by the 3 marks on the head. Each Grade 5 bolt from U-Bolt-It are available zinc plated. Have a question about our manufactured grade 5 bolts? Square Head Bolts, Grade 307A, Zinc Finish The information below lists the required dimensional, chemical and physical characteristics of the fasteners in this purchase order. If the order received does not meet these requirements, it may result in a supplier corrective action request, which could jeopardize your status as an approved vendor.