Summary

update 9/14/18 have completely reworked this gear box with higher ratio gears and better mesh between gears more reliable working
i plan to make a adapter to turn this box into a self centering steering box
went to walmart to find nails they did not have anything that would work
the mystery of the nails is solved they are 10 gauge roofing nails i have also found in my hanger collection hangers with a 2mm dia so you should be able to find something around the house to use for shafts i refuse to have to purchase anything for any reason

this is only a 2 stage gear box it is going to be easily modified for 4 stage for version 2

for the shafts i used a nail i cant remember what these nails was for but they are exactly 3mm i think they are roofing nails

print the gears on a raft this will keep the teeth clean and sharp on the bottom better to sand the raft than to clean the teeth

no supports needed on the other parts

for the longest time i have tried downloading gear boxes from thingy verse only to find that the parts don't fit gears can not be printed and just plain non functional have a huge folder full of these bad gear boxes and generally bad experiences with these

the gear tooth pattern has ben driving me absolutely nuts trying to get these small gears to print with enough meat on them to mesh with the other have tried all the gear generators for openscad but these printers just can not print them properly

i have finally figured out the problem and that is to not use any gear generator and make them manually this gives me the ability to make the teeth longer for more bite and not put the point on the teeth making them square turns out that when they are printed they print with a round tooth end who would have ever figured that out

since i have found polo GM gear boxes for under $10 they are realy cheep and well built i may or may not make the 4 stage this project was just to scratch a very annoying problem itch