For my Design of Machine Elements class this problem is being posed. This is exactly as the problem is stated. The torque on the 400mm -diameter shaft connecting the flywheel with the jaw mechanism should never go above 700kN m. Dimension a copper square tapered key so that the shaft is not damaged. So really just trying to find the length/width/height of the key. I know that the the only stresses on the key are shear and bearing stress. Tau(design)=2T/dwl Sigma(design)=4T/dlh Copper Sy=69e6 Pa Su=220e6 Pa I am not too sure on where to begin with this (I have started it and went no-where). Does anyone have any insight on where to go with this problem?? By the way I am not looking for an answer just general guidance. Any suggestions? Thank You.