A scarce vintage split nut screwdriver or turnscrew.

Home made split nut screwdrivers are seen quite regularly however factory made examples are much harder to find.

A little over ⁵/₈ inch (17mm) wide at the tip with a ³/₈" (9mm) gap.

Good hardwood handle with steel ferrule.

4⁷/₁₆" (112mm) blade length, 9⁵/₈" (244mm) overall length.