4. Rivets and bolts subjected to both shear stress (?vf , cal) and axial tensile stress (?tf , cal) shall be so proportioned that the stresses do not exceed the respective allowable stresses ?vf and ?tf and the value of exceed does not exceed
8. If S is the switch angle and ? is diamond angle, r is the radius of slip, the distance between middle point slip and the nose of obtuse crossing, is