prelude to the pascaline part 2

Building and simulating the octet truss has caused me to get over my fear of working with larger parts. I am thinking it might be time to revisit a mechanical calculator in earnest, like actually design one before I start building anything...starting tomorrow. Here is something I am pretty sure I will need: 10 spoke spur gears

So far I like this design because they are robust, and I can trim off spokes to create a "ones" gear. Plus I should be able to attach diamondoid shafts or cnts to the sides. This is a shot in the dark, but does anyone have any engineered drawings of a pascaline?