What is the primary role of the bolts in a bolted joint? Why do many designers of safety related joints, and most codes, favor joints that could support four or more times the anticipated service loads? You have roughed out the design of a joint and believe that four, 5/8-12 = 3 SAE J429 Grade 5 bolts will provide sufficient clamping force if tightened to 50% of yield. How much preload will this create?