Text: ISO Metric M8 bolt, coarse pitch with Property Class 8.8, is used on a structural member of equipment where the total loading magnitude is determined as Ptotal = 18,000 N (from an external source as well as from initial preload). If the bolt preloading is limited to 75% of its published proof strength, devise the total load to be taken by the bolt if the value for the joint stiffness constant, C = 0.175, is presumed. Mechanical design.