A shaft transmitting 100 kW is to be connected to a coaxial shaft through cast iron flange coupling. The shaft runs at 80 rpm. The key and shaft are to be made of same material for which permissible shearing stress is 60 N/mm2 and compressive strength is 120 N/mm2 The steel bolts may be subiected to maximum shearing stress of 26 N/mm2 Design protected type flange coupling (35P)