Gearbox DIY (4,5:1)

Great! Where did you get the pinion gear in the end? I’m still struggling to get one into the US.


Great thanks! I’m burning the midnight oil so not sure I understand how you are linking the motor shaft to the input. Looks like you pulled the motor shaft or have created an input shaft for the gearbox to be connected by a coupler? I’d love to check out your cad files if you’d be willing to share them.

For now the input pinion is made it go into the 1/4" collet of a wood router for testing. The whole pinion assembly is a 4mm pin with a bearing on one end, a printed adaptor to go from 4mm pin to 5mm pinion, printed adaptor to go from 4mm to 8mm second bearing, and printed adaptor to go from 4mm to 1/4" for coupling.

Basically is a 4mm steel core and plastic spacers to get everything to fit onto it.

Id rather not share my cad files… they are super hacky and probably wont work for anyone else. I’ve got all the sizes tuned to work with my printer and obscure parts. If you want to look at what Ive done for information purposes Ill gladly post screen shot of the parts.

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I was on a river to make the first real test, for the beginning it was done only with 6S LiPo. Unfortunately, the PLA pinion got to hot and melted. It was replaced by plan B, the composite solution with POM and steel.
This afternoon will be the next test on the river, hope with 12S LiPo, too.


How long did it run before it melted?

The test before were abot 15 min, the test on the river was about 2 minutes before melting.
I used Polymaker Polymax PLA.

Hi Daniel,
after changing the pinion I tested it with 12S on the river.
Ater 10 min, the sound changed a bit. Looking in the gearbox, I saw that the 3 plastic pinions from looked very used. Now I will change them by steel, too. This is no problem, all pinions are standard sizes from and there are no changes at the gearbox needed.
The max. current was 96 Amp, that is 4,2 KW, a lot. But we had great fun. :grinning:


I’m having trouble getting stuff from … Pretty sure it’s because I’m in Canada. I’m gonna try printing everything out of nylon.

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Look at this datasheet I found for nylon gears:
It should give you a rough estimate on which torque values you can expect your gears to survive. There are tables for tooth count, module, etc. If you want more torque, you can always increase the width. You might need a stiffer mounting though.

Sure, your explanation covered it thanks

They will supply via their German branch to international customers. The website states that countries without representation may order through email or phone to their home branch. I emailed them and they were able to to provide an invoice. The problem was that shipping was 145 usd. I’m trying to work with them on a different delivery method.

How much were all the parts before shipping?

14.48 euro per 10t gear (ss)
1.59 euro per 17t gear (acetate)

For better durability, I switched to steel gears.


Looks mint! Let us know how this goes. Has got to be the cheaper geared solution if it proves durable enough.

Where did you source the steel 17t M1 gears?

They are from maedler, too.
I’ll actualize the list of materials this weekend.


Seems like Pingu6 and I are having the same problem with ordering from Maedler from North America. Any chance you’d be willing to make up a kit for us with the steel gears? I’m more then willing pre PayPal you the full cost before you order anything.

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