[drBonkers]

Wow, I deeply want the cube and this couch. How much do you think it would cost to make the couch? How dangerous are these objects if one of the reactive wheels fails? I imagine if one was to fail, the object could be violently launched across the room.

[s0rce]

Do you mean a piece of the reaction wheel getting thrown across the room? You could shield that with something like they do on jet engines to avoid turbine blades being launched through the fuselage. I think the object itself is heavy enough compared to the energy in the reaction wheels that it would just fall over.

[newaccount74]

I think a stainless steel reaction wheel is unlikely to break. Now those 3D printed reaction wheels using ball bearing balls for weight are another story: https://www.youtube.com/watch?v=AJQZFHJzwt4

[toss1]

The cube? Not severe but enough to definitely wear safety glasses when things are activated in development. The couch? That's a fair amount of mass at a good height above floor level; definitely don't want to drop it on your body parts. Tje reaction wheels failing, Calc the max velocity & mass of the ring, and that'll give you an idea of the energy levels you're dealing with. I see nothing that would prevent me from doing either project, just enough to take good ordinary safety measures. Start on much smaller projects, enjoy the builds, and by the time you get to the cube & couch, you'll be able to estimate all that you need.

Also, when you have a question in development, remember: One test is worth a thousand opinions (especially re. your own opinions).