1. The problem statement, all variables and given/known data I have this problem. I'm trying to calculate the minimal servo torque for the gripper to hold the part in place. http://img52.imageshack.us/img52/8784/96199865.jpg [Broken] Mass of load is 170grams. u friction between load and walls is 0.5. the diameter of wheel on which the pegs that pull the grippers is 2cm. 2. Relevant equations Force to squeeze * Friction between load and gripper walls > Mass of cube Torque=Force * radius 3. The attempt at a solution F(friction)=0.17kg x 0.5=0.085N F(G)=0.17kg x G = 1.666N F=F(f) + F(g)= 1.751N T=1.751N*0.01m=0.01751Nm This is probably wrong... Any ideas?