Gear replacement or restoration

[jasontaylor7]

Existing gears:



What I need them to look like to work better:



Possible options I need quotes for (take your pick if you can do any):

1) make from scratch the middle gear, but larger. Requires owning a hobbing machine.
2) coat with titanium nitrate (e.g., TiAlN or AlTiN). Requires oven?
3) coat with xado for gears. Cost is $30 plus labor.
4) use belt between motor sprocket and right-most gear, removing middle gear, and carving v into two remaining gears for the belt. Requires lathe & dremel.
5) add new outer layer. Heat it, hammer on.
6) Try teflon, PFA, FEP,PTFE, etc.

I need to add about 1-2 mm or so some how. Please account for shipping cost. It is about 15 lbs unless I just send the two right-most gears. Feel free to ask question, supply comments, etc.