Abstract: On June 2, 1997, Employee #1, a skilled machinist, was setting up and running a computerized lathe one step at a time from a program on screen. The part was held by jaw pressure that was hydraulically controlled with manual adjustment by the machinist, who had just completed work on an 18-in.-diameter part. The employee advanced the lathe program to the next step, which involved machining the inside diameter of the part. The program advanced the tool cutter to make an inside cut while simultaneously increasing the speed from approximately 500 to 1,500 rpm. Apparently, as the tool contacted the part, the 60-lb part flew out of the chuck jaws, knocking off the interlocked door, striking the employee on the side of his forehead, and landing 22 ft away on another machine. Employee #1 suffered a fractured skull and was killed. The hydraulic jaw pressure for this operation was normally set at 300 psi but was still at 170 psi from a previous job.