These ball socket thumb screws have round or flat ball at the contact end. The flat style is excellent for supporting a soft workpiece, exerting a clamping force or supporting a workpiece at an angle. The ball rotates in the screw socket as force is applied allowing contact to be maintained on moving or contoured surfaces as force is applied. Screw made from heat-treated 304 stainless steel. Ball made from stainless steel heat-treated to Rc59-66.