What is this style of drill bit called?
All 1/2-inch. Inherited from someone who was in the undercoating/oiling business. So the bits might have been used to drill holes in the body of vehicles to spray oil into. No other text on them other than "1/2" and "Made in U.S.A.".
I want to determine the name so that I can find/purchase a mandrel.
Scale is in inches.
Edit:
I ended up finding the arbors.


