Abstract: At approximately 11:00 a.m. on August 7, 1997, Employee #1, a welder at an oil field equipment manufacturer for the past 5 months, was putting a chamfer on one end of a 1/2 in. diameter by 8 in. metal pin. He was using a Rankin Brothers abrasive disk grinder, model 20-S, serial #5006. Employee #1 was wearing leather welders gloves while holding the pin at a 45 degree angle to the work table of the grinder. His left thumb was wrapped over the top of the pin, while his right hand held the back end of it. The distance between the work table and the disk was between 1/8 in. and 5/8 in., and the work table was perpendicular to the plane of the disk. Employee #1 was pushing the pin against the disk when the pin was suddenly pulled into the gap between the table and the disk, and his gloved left thumb became pinned against the disk. He was able to turn off the grinder with his right hand, but not before his thumb was drawn below the table surface. Employee #1 sustained a traumatic amputation of the joint of his thumb.