National, Challenge & Early Seybold Knife Bolt – B48
For Challenge 370 E and G series models, and 420, National, and early Seybold Paper Cutters. This 1/2-12 thread steel hex head cap screw fits the Challenge 370 E and G models, Challenge 420, most National, and early Seybold Paper Cutters. (Equivalent to the original Challenge “1/2 x 1″ V-Thread knife bolt, part number S-645, with the equivalent washer, originally part number S-353.)
The 1/2″-12 thread is 1-3/32” long below the washer. The washer is captive, it spins in place but it will not fall off.