I think @DanRathbun has the right idea. Here’s a stab at using two helical gears. It gives a 1:1.5 ratio to the output. They don’t quite mesh right, but a little sanding should do it (assuming your printer will print the small sizes needed for the teeth). This is based on your model having 9.691591m between axle centers.
Eddy_Gears.zip (13.6 MB)
Note that helical gears produce an axial thrust (depending upon the slant and direction of spin.)
This means that they are often used with thrust bearings.
For example, the little driven gear would want to slide one way or the other along it’s axis. The shaft might need to have a step to keep the gear in the middle. For such a small application a flat washer and a bit of lubricant could act as the bearing.
Thanks for the time spent Jim
I have come to the same conclusion that those gears are my best bet.
I have found a plug-in for Blender that is great if you are not sure on what type of gears you want.
It can be rigged so you can see if your design will mesh properly.
The design I went for can be FDM printed which will give better longevity, rather than brittle resin.
I know there are some tough resins but it is only a model railway at the end of the day.
I have printed and tested this design and was very surprised how smooth they mesh, a tab of white grease and all is good.
Got to setup a test track for longevity test.
Thanks Dan, like most things on my layout, superglue is my friend.
A dab of superglue either side of the gears and so far, no movement at all.
I did give the train a thrashing with fast forward and reverse movements and it all held up.
If things fail it is easy just to print a replacement, the joy of 3d printing.
Cheers Eddy
Thanks for the information!
