Hi Twisty Puzzles fans,

Dumbbell Skewb are two Skewbs (Holey Skewbs, actually), connected by gears. The mechanism is similar to Dumbbell Cube, and it is also a challenge for intellectual weightlifters.

Bonus question: in how many different ways can the Dumbbell Skewb be assembled? And how many of those have the property that if you solve one Skewb, you have also solved the other?

Watch the Youtube video.
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Check out the photos below.

Enjoy!

Oskar

Magnificent! Not only the ingenuity that we can only expect from you, but also the turning is really impressive to be able to transmit the force through the bar without too much friction and effort. Congratulations!

Amazing work as usual!

Though, something struck me as i watched the video.
Would it be possible to add different gearing ratios to this and the "normal" dumbbell cube to add another depth to the solving challenge?
(maybe even variomatic gears )

One step at a time! But I agree, it would be a nice idea to combine these two ideas to get opposite ends turning at different rates.

However, I'm not sure you could apply variometric gears to the skewb because the corners rotate in 3 rather than 4 steps, so I can't see how the variable phasing would correlate between the two ends. Unless you could make 1/3 turn to get 2/3 turn and then make 2/3 turn to get 1/3 turn, but then you may as well just add an intermediate gear to get the other side to rotate in the opposite direction.

It's incredible to me how smoothly this turns. It has no right to turn like that...
I love the visible gears!

I think every Dumbbell Skewb is automatically solved when one skewb is solved. Am I wrong?
EDIT: I think there's two different configurations for the Dumbbell Skewb connections: either the skewbs are identical or chiral copies. They're both not automatically solved if they're chiral copies, are they?

That is my guess too. If the one Skewb configuration is the mirror image of the other, then its stays that way and they are always solved synchronously. The other configuration is the chiral copy, as you call it, with a 180-degrees rotation symmetry axes orthogonal to the middle of the connecting bar. There are also the degenerate cases of rotating one Skewb over the long axis with respect to the other, but I do not think that we should be counting those, as those assemblies are identical to the two mentioned before from the solving perspective.

Oskar

So which is the version here, the chiral or non-chiral version? It would be nice if the two skewbs are not automatically solved at the same time otherwise there's not much point, besides marvelling at the engineering.

And same question for the dumbell cube: are the two cubes automatically solved at the same time?

Please watch the video again and deduce which assembly I chose. Or make the deduction without watching the video .No. Note that there are multiple non-mirror ways to configure Dumbbell Cube (Andreas, how many fundamentally different?). I chose the one configuration that has no symmetry whatsoever.

Oskar

Good man, thanks. To have thought all this through beforehand, you're a genius!

But we all knew that anyway.

You are missing Jaap's help don't you?

If I can trust my old notes there are 22 essentially different ones.
In three cases the second one is solved when the first is already solved.
In the remainings cases the size equals the size of Oskars original Dumbbell.

Andreas