Hi! Currently I am building an OpenRC Truggy,

Hi! Currently I am building an OpenRC Truggy, and I’m really interrested in a locking diff.

It seems that the only diffs available currently are open diffs which means that if only 1 wheel is off the ground, all power goes to that wheel and we’ve completely lost power to the other 3 wheels.

I understand that creating something intricate as a torsen diff with a 3d printer will probably be very hard, as the concept of a torsen diff is one of worm wheels running together and locking each other up if needed, which I find hard to imaging working properly with PLA plastic.

The alternative however is a completely rigid diff, which people seem to do to their 1:1 racecars a lot by welding the axles to the carrier. The downside of this, at least on 1:1 race cars, is excesive tyre wear since the outer wheel will be spinning at the exact same speed as the inner wheel, which causes rubbing againt the tarmac.

Anyway, a completely rigid diff would be something that I coud maybe create in Blender from the parts already available on thingiverse. Interesting to try out sometime…
http://www.youtube.com/watch?v=lDsQAs0Ldes

Out of curiosity I searched if there was anything already made and I found this on Thingiverse: http://www.thingiverse.com/thing:356169

That’s exactly what I am looking for in a OpenRC form factor :slight_smile: Fitting all those gears into an OpenRC sized diff is probably not going to work out because the parts will simply be too small however :-/ I guess my best option is to “weld” the 3 diffs shut thus providing permanent traction to all 4 wheels.

In normal rc diffs we put different viscosity oil inside the diff which helps greatly with how much force and how fast a differential can turn. The printed parts probably wont be able to handle this though.

@Stefan_van_Essen how big is this one and how small should it be? Maybe a test print of one of the small gears will let us decide on how to proceed?

60,000cst silicone oil seems to work pretty good for me.
If you want more locking, put in 100,000.