Fractured upper plate through line of rivet holes. Fractures began at the rivet holes weakening the whole plate at the same time, the bent and marked edge apparently not effecting the manner of fracture Fractures fine silky; metal well drawn down. The fractured plate had the die-side in. " iron rivets, "Burden's best." Punched holes: Punch, ".695 diameter; die, ".752 diameter. Fractured lower plate across line of rivet holes; appearance of fracture, silky; metal well drawn down. Punched holes: Punch, ".695 diameter; die, .752 diameter. 10" X:"250 Fractured upper plate through line of four rivet holes. The fracture began at the holes. Metal silky in appearance and well drawn down. slip of the plates at the calked joint measured ".15. greasy from oil used in punching. After fracture the The joint was very g" iron rivets, "Burden's best." Punched holes: Punch, ".695 diameter; die, ".752 diameter. |