Im aiming for my gearbox to weigh about 10 grams and cost about $10 each
That will be short lived. When you start figuring in your time and material, you will find you will be selling yourself short. By the way what material you plan on using ?
Bret If you read this I need another gearbox (not a replacement for the one I have) but for another Corona. Do you have anymore closed gearboxes ? PM me as to what you have and cost. I have several Coronas Im working on.