DURING A BELT SPLICE AN EMPLOYEE WAS LACING THE MACHINE ON TOP OF BELT WHILE ANOTHER WAS ADVANCING THE MACHINE AND RAN OUT OF ROOM ABOUT HALFWAYACROSS. VICTIM CLIMBED ON BOARD, GRABBED FRAME O F SPLICE RIG, REACHED OVER WITH HIS RIGHT HAND, AND PLACED IT ON TOP OF FRAME AS LACING WAS PROGRESSING. VICTIM'S THUMB WAS IN THE WAY AND THE TIP GOT SEVERED.