Abstract: A machine operator was machining type 757KB428 gears in a serial number GCU2080 machine shaver. The gear shaver is used to shape the teeth of the gears to bring them into specification tolerance. To shave a gear, the operator places a gear on an arbor and is placed into the machine on a steady rest. The tail stock is brought in by pressing the tail stock button. The operator adjusts the gear as needed and presses the start cycle button. The hydraulic door closes, lubricant begins to flow, and the gear is processed. If the operator fails to press the tail stock button but presses the start cycle button, the machine automatically adjusts and the tail stock is brought in before the cycle begins. The employee was working on gear machine number 5992 of the plant. As he was placing a gear for machining, the machine actuated amputating his right thumb between the cutting edge and the gear. He was hospitalized. A maintenance employee inspected the machine and concluded the improper connection of the timing mechanism caused the machine to actuate. The machine was repaired and returned to service.