Abstract: At approximately 10:00 a.m. on June 3, 1988, Employee #1 was preparing his automatic lathe machine to bore soft jaws in preparation for a government project making 8 in. in diameter aluminum nuts. The chuck was bolted in place using six bolts measuring 1 1/2 in. The chuck, when fully assembled, measured 10 in. and weighed 21 lb. The chuck is expandable, as the jaws are bored to specific tolerances depending upon the job being machined. When the lathe reached maximum rpm, a bolt failed, causing the three sections of the chuck to be ejected. One section struck Employee #1 underneath the chin, causing a deep laceration and a fractured lower jaw on both sides, damaged teeth, and a contusion to the upper left torso.