Hoping for a neato idea.

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PL1:

--- Quote from: Zakk on June 20, 2024, 02:28:02 am ---I'll likely start with printed gearing, but if need be, I'll get gears either routed out of something solid, OR have the cad files cnc'd. Again, trying to keep it simple. The less pieces, the less to go wrong sort of thing.

--- End quote ---
I wouldn't trust anything 3d printed to transmit torque to your 6 lb. cube.

A direct drive setup will be more simple than a gear box.

See if you can find a flange shaft coupler for your motor's shaft.

Maybe fabricate something like this:
- Flattened oval plate 1/4"(?) thick plate or thinner with bent edges for rigidity?
- D-shaped hole for the motor shaft or attach the flange shaft coupler.
- Two holes (green) to attach the cube.
- Semi-circular slot for the wiring.
- The edge of the plate can hit the limit switch. (red) Narrow down this end of the oval to reduce weight and allow more range of rotation.

--- Quote from: Zakk on June 20, 2024, 02:28:02 am ---I haven't found a nice bearing yet either, I'm thinking a proper roller bearing, perhaps even a packed one, would be less rickety than a lazy susan roller.

--- End quote ---
A roller bearing like a trackball/skateboard bearing is designed for the load to be perpendicular to the axis of rotation.
- That could work if you're going to put a bearing on each end of the bolt through the top of the tube that you described earlier.
- The height of the bearing might be a problem, given the limited clearance.

You may want a bearing like a lazy suzan that is designed for the load to be parallel to the axis of rotation.

Pretty sure the search term you're looking for is "thrust bearing". You'll probably want to get one with washers.
- Bonus: These are much more stable and thinner than a lazy suzan bearing. (3mm and 5/64" for the two linked below)

https://www.amazon.com/XIKE-TC3244-Thrust-Bearings-Washers/dp/B0CYZMZ15V/

https://www.amazon.com/uxcell-AXK5578-Bearings-Diameter-Thickness/dp/B07GC7VWMM/?th=1

Scott
EDIT: Updated plate image to include slot for wiring.

JudgeRob:
Hey dude, that project sounds nice!

Why don't you just use a servo motor? There are plenty of 360 degree ones, they have a built-in gear box for torque and with the explosion of hobby robotics, there are some really beefy ones that should have plenty of power. And programming the movement speeds and direction would be super simple.

Good luck, can't wait to see how it turns out!

PL1:

--- Quote from: JudgeRob on June 22, 2024, 11:15:15 pm ---Why don't you just use a servo motor? There are plenty of 360 degree ones, they have a built-in gear box for torque and with the explosion of hobby robotics, there are some really beefy ones that should have plenty of power. And programming the movement speeds and direction would be super simple.

--- End quote ---
Thanks for the rabbit hole. :P :lol

A servo sounds like an interesting option.

Pros:
- Don't need limit switches.
- Wide variety of inexpensive high-torque models.
- You can get ~2"/50mm dual-arm 25-tooth aluminum servo horns since plastic ones won't handle the torque.
-- Dual-arm allows you to apply even force to both sides of the tube for smoother rotation and provides room for the wiring.
-- If you want to get closer to 360 degrees of rotation, you might need to use a single arm horn or a right angle horn.

Cons:
- Some servos are noisy.
- Some only provide 1/2 the torque they are supposed to be rated for.
- There might be a problem with sudden motion when initializing the servo position of a standard 3-wire servo.
-- Looks like you can avoid that by using a feedback servo motor like this one or this one.

Scott

Zakk:
I'm sort of just waiting for this cube thing to arrive. I'll admit that I am a bit concerned that it really will look like an updated disco ball, so kind of just going to set it in place and see, do from there.
I worked with that space this weekend, made a shelf for it, and think I do want it to be flexible use. For example if people are coming over (and honestly...we're 20 miles from even the smallest town, but hey you never know), I want to be able to put a monitor up there, either twin the arcade screen OR twin the main screen, which usually has sports of some sort on it. I'm thinking a monitor in an enclosure that just slides in there and plugs in. So that got me thinking that I look at the space as a cartridge based receptacle. Sort of be able to just swap out components. I don't want to get bored with a cube, if that makes sense. We'll see this week.

That said, the servo motor does seem to make more sense. I watch enough battlebots I should have thought of that.

Really enjoying playing that machine again though, that's for sure. Putting it in its own space was totally the right call.

Zakk:
Cross member is in, shelf is in, and monitor set in place for now.
I am digging the swappable use idea. It would be neat to be able to put say a Christmas scene in there at Christmas, TV for hockey season, maybe even do the whole cube thing in a swappable box. That would make it easier to tweak/repair.

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