For the bolted assembly of Prob. 8–29, it is desired to find the range of torque that a mechanic could apply to initially preload the bolts without expecting failure once the joint is loaded. Assume a torque coefficient of K = 0.2.

(a) Determine the maximum bolt preload that can be applied without exceeding the proof strength of the bolts.

(b) Determine the minimum bolt preload that can be applied while avoiding joint separation.

(c) Determine the value of torque in units of lbf ∙ ft that should be specified for preloading the bolts if it is desired to preload to the midpoint of the values found in parts (a) and (b).