Square threaded screws.... 1. The problem statement, all variables and given/known data http://img180.imageshack.us/img180/6789/statics2kq3.gif Picture ^^ High-strength bolts are used in the construction of many steel structures. For a 1-in.-nominal-diameter bolt the required minimum bolt tension is 47.25 kips. Assuming the coefficient of friction to be 0.35, determine the required couple that should be applied to the bolt and nut. The mean diameter of the thread is 0.94 in., and the lead is 0.125 in. Neglect friction between the nut and washer, and assume the bolt to be square-threaded. 2. Relevant equations tan(theta) = L/2*pi*r Q = M/r 3. The attempt at a solution All I was able to figure out is that...well, I wasn't. I tried drawing some pictures, but my big source of confusion is that I don't know how to draw a diagram for the thread and where the numbers all go. :( Please give me an umph in the right direction!