Funny. Just a crappy paint drawing. No need for precise to scale drawing in autocad.
Heck, the tool is just a screwdriver with a grinder disc plunged into the side a bit to form a hook. So that aint a precision machined tool. Just a tool that does the job. And on the larger diameter snaprings in an automatic transmission case (~6-8" diameter) they do work well. Not sure if it will work well on the smaller diameter stiffer snap ring in question. I guess it depends on the size and quality of the screwdriver to begin with
