1. An M14 X 2, class 8.8 bolt with rolled threads is preloaded to 75% of its proof strength when clamping a 3-cm-thick sandwich of solid aluminum. Find the safety factors against static yielding and joint separation when a static 5-kN external load is applied.‡
2. A 7/16-in-dia UNC, class 7 bolt with rolled threads is preloaded to 70% of its proof strength when clamping a 2.75-in-thick sandwich of solid steel. Find the safety factors against fatigue failure, yielding, and joint separation when a 1000-lb (peak) fluctuating external load is applied.‡