Found in my deceased fathers toolbox

My father was a draftsman and a pattern cutter (fabrics industry). During WORL WAR II he was a ‘nose artist’ (painted pin up girls, etc on fighter planes). I only know that my father really appreciated and cherished his tools and I’d love to know what this tool might be used for. He was an all-around VERY handy guy and taught me so much. I cherish his tools. Thanks for your reply and best regards