a 1940's era Bar-Plate Manufacturing co. score cutting knife.  my father was a highly skilled machinist and most of tools related to his trade (a lot of which will be up here in the coming weeks) i understand the purpose of.  micrometers, thread measuring meters, depth gauges, protractors, etc.  what this knife was utilized for is a mystery to me.  they are still made by Bar-Plate in Connecticut with same style/shaped blades (see last picture).