Idea for eccentric rotational sealed couple.
(The vaseline grease gasket works perfectly as long as the shaft doesn't move, after ten minutes of rotation, it starts leaking)
For the sake of expedience I'm currently going with a different option, but I
think this one's actually better and will come back to it when I get
I don't know how self explanatory the animation is, but basically it
converts rotation into eccentric rotation/motion and then back again.
Since the circular housing between the two shafts isn't spinning as
such, it can be sealed with a rubber sleeve. The system is therefor
completely sealed. I've tried it and it does work, with low
resistance, but tends to wobble a little and the two shafts can get
out of phase. I think both these problems can be solved by having two
'outrigger' rollers, rather than one as in the animation.
Link to animation that hasn't been messed up by instructables resizing it: