An employee was helping a machine operator with a changeover on a side frame welder, which forms a J- or U-shaped wire and welds it onto two other wires. The wire was caught in a groove, and the machine was turned off to fix the wire. The employee's left middle finger was caught in a leg wire and pushed up into a support bracket, amputating it close to the base of his fingernail. His left index finger was lacerated.