1 hr. constructing a tool for sanding down the main gear.

I'll have to check the other blogs (and the Sling Builders Facebook page) as to whether that notch faces forward or backward.

One thing I have to do is grind/sand down a bevel on the forward edge of the gear to accommodate those rivnuts.  Don't want to smash those.

I quickly put this together to sand down the gear based on what I saw BobZ use.