Abstract: Employee #1, age 19, and a coworker were working with a Morgan #10 full revolution nailing machine that had been modified over 2 years earlier, but little used since. They placed gang nails and 1 in. by 4 in. boards onto the jig to make a 44 1/4 in. by 56 1/4 in. frame. The gang nails were set on top of the corners of the frame and hand-pressed. The jig was then fed into the machine by a hydraulically fed chain. A foot treadle was depressed, causing an electrically powered gear to lower the modified feet and drive the gang nails into the front corners of the wood frame. The jig was fed further into the machine and the foot treadle was again depressed. Employee #1 was reaching into the machine through a 9 5/8 in. by 60 in. opening to adjust a crooked nail when the right foot descended, crushing his hand.