EXAMPLE 8-1 A square-thread power screw has a major diameter of 32 mm and a pitch of 4 mm with double threads, and it is to be used in an application similar to that in Fig. 8-4. The given data include : fc = 0.08, dc = 40 mm, and F = 6.4 kN per screw. = (a) Find the thread depth, thread width, pitch diameter, minor diameter, and lead. (b) Find the torque required to raise and lower the load. (c) Find the efficiency during lifting the load. (d) Find the body stresses, torsional and compressive. (e) Find the bearing stress. (f) Find the thread stresses bending at the root, shear at the root, and von Mises stress and maximum shear stress at the same location.