I have toyed with wire stripping off and on for years. Once when copper went thru the roof I collected a bunch and made a pretty good penny off it. But stripping it was painful. This tool build looks like a good way to strip wire, thought a little on the dangerous side too. Also I think I would have just used 2 pieces of wood cut into a circle instead of cutting one thick piece, then cutting that in half the long way.
https://www.instructables.com/id/Another-Poor-Persons-Wire-Stripper-for-Stubborn-Ca/