Two commercial enclosed gears (Grade 1 with Brinell Hardness of 300HB each, 20 pressure angle) are in contact. The pinion has 12 teeth with a diametral pitch of 8 teeth/in and the gear has 48 teeth. The pinion speed is 4000 rpm and 3100 ft-lb/s is transmitted. The gears are manufactured to a quality standard of Q, 9 and have a face width of 0.75 in. The gear teeth are uncrowned and mounted midway between two bearings. The electric power source is uniform, but the machine loading results in occasional light shock. Find the safety factor against failure due to excessive bending stresses.