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48dp diff 46T or smaller

Posted: Fri May 28, 2021 11:02 am
by Chewbacca
Ok all I need some help here.

I am designing a new transmission case that is supposed to resemble the stealth as close as possible but is filled with readily available internals no matter what brand.

The boundary conditions (for now) are:

- gears use 48dp sizing
- diff gear 46 tooth or smaller (40 - 45 would be perfect)
- bonus would be available as gear and ball diff
- readily available so no discontinued parts
- preferably metric (oh NO! ;) ) but I can go both ways.


I've done some research and maybe you guys can at least answer the question of the pitch used
So far I've come across the following:

Diff of the Traxxas Jato (since it is a Nitro I assume that will be 32dp)
Kyosho Diffs (?) RB5 / 6 ???
Losi Mini T 2.0 --> I assume the outdrives will be too small for the axles
Tamiya (?) I think they use the 0.6 module

I just realized the Rustler / Bandit diff is exactly 45T DUH!! But that is too wide for my taste. I actually have 2 of the ball diffs I could play with but that would be a last resort.

Alternatively I could go completely with gears from a different brand but so far I am designing around associated top shaft(s), Traxxas, AE and Serpent idlers (not sure about the serpent pitch) and whatever diff I might find.
Diff.JPG
Bandit Diff
Diff.JPG (25.68 KiB) Viewed 593 times
Bandit Diff
Bandit Diff
Diff.JPG (25.68 KiB) Viewed 593 times
So I would appreciate any input you might have for me.

Thanks, Tony

Re: 48dp diff 46T or smaller

Posted: Fri May 28, 2021 1:13 pm
by juicedcoupe
If it helps any, the Dynotech GT idle gear is an exact replacement for the original Stealth gear.

Re: 48dp diff 46T or smaller

Posted: Tue Jun 01, 2021 6:12 am
by Chewbacca
Thanks for the hint, but the modern B6 idlers are planned for this project.

I have made some progress, I got a Traxxas 1/16 e-Revo gear Diff for a cheap 20€.

That Diff is TINY! 35 teeth and 4mm outdrive axles.

So that leads to the next question:

Are there dogbane “cups” out there that are a direct fit to 4mm shafts? I will most likely need to sleeve the shafts from 4 to 5 mm.
AF7D8AD2-49BA-4B21-AB12-6A6DBCD3D6EB.jpeg
Traxxas 1/16 Diff
AF7D8AD2-49BA-4B21-AB12-6A6DBCD3D6EB.jpeg (30.53 KiB) Viewed 555 times
Traxxas 1/16 Diff
Traxxas 1/16 Diff
AF7D8AD2-49BA-4B21-AB12-6A6DBCD3D6EB.jpeg (30.53 KiB) Viewed 555 times
Outdrive cups
Outdrive cups

Re: 48dp diff 46T or smaller

Posted: Tue Jun 01, 2021 4:41 pm
by Chewbacca
Chewbacca wrote: Fri May 28, 2021 11:02 am
........
I just realized the Rustler / Bandit diff is exactly 45T DUH!! But that is too wide for my taste. I actually have 2 of the ball diffs I could play with but that would be a last resort.

Alternatively I could go completely with gears from a different brand but so far I am designing around associated top shaft(s), Traxxas, AE and Serpent idlers (not sure about the serpent pitch) and whatever diff I might find.

Diff.JPG

So I would appreciate any input you might have for me.

Thanks, Tony
I stand corrected, the diff shown is a different pitch (Nitro ??) and would not work.

The current Magnum 272 Diff has 60T and uses a 22T top shaft gear. 60/22 = 2,72 which is the gear ratio.

i am currently adjusting the CAD for the mini Rev Diff.

I'll post updates.

what is the experience with the shapeway parts, their precision, and the real world gear distances vs. calculated?

Thanks, Tony