WHILE HELPING REPLACE THE HAMMER TIPS IN SURFACE CRUSHER, THE TIP OF THE INDIVIDUAL'S FIFTH LEFT FINGER WAS PINCH BETWEEN CRUSHER ROLLER AND HAMMER TIP HOLD DOWN ROD WHILE IT WAS BEING INSERTE D. THIS CAUSED A LACERATION AND SOME TISSUE LOSS TO THE TIP OF THE FINGER REQUIRING STITCHES AND DEBREDMENT ON END OF FINGER.