Hi all, I’m looking for advice to finish my cat wheel’s base. Photos below are a cheap pine prototype, but for the final base I’ve purchased a length of 8/4 hard maple.
This needs to support the shearing forces generated by one or two cats up to 15lbs each plus the ~15lb weight of the wheel itself. Its basically a bit hamster wheel. I would prefer to complete this as a central pivot design instead of sitting the wheel on casters.
Design elements
2 skateboard bearings pocketed 30mm apart inside an upright beam with 45° side braces
8mm alloy steel axle fixed to wheel
base: 20x20 inch frame (beams 2 inches wide by 1 inch deep) on 1/2 inch Sandeply plywood
Upright: 2 x 2 x 22 in
Wheel 36 in diameter
wood glue + screws
The levered force of the axle will try to tip the upright forward, so I’m thinking of adding a cross brace directly in front of it (not shown in photos).
Please reply and let me know your thoughts.
I’ve circled the base screw locations in green and the upright screw locations in orange.
Maybe a wider board on the back of the 4 x4? Supporting pole attached to the base. Seems that the stress is going towards the rotating wheel. Not sure how heavy the cat/hamster is.
If I am understanding correctly, you need more/beefier triangles. Either bringing those cross braces up higher, or add another mitered/angled brace on the opposite side of the wheel, and extend your base to be more of a rectangle so you have more mass and a place for that new angled brace to connect to.
I agree with everyone that the upright will need more rigidity either by making it larger or adding more bracing. I’m not worried about it breaking, just bending a lot.
That axle looks kinda small for the amount of weight it will be supporting. I’m worried that it will also be very flexible under the weight of cats.
I totally understand the urge to make a big cantilever. Cantilevers are cool! I made the TV stand below and wanted the cantilevered corner so bad. Its has held a TV plus my fat cat for going on 8 years now… But wood is very flexible and it did not inspire confidence with the cat jumping around. I ended up adding a small support under the cantilever after a few years.
I say all of this to say that you should consider a small support directly under the wheel. I know you said you dident want to. You can always try it unsupported but build it in a way that allows more support later.
The twisting around the pivot at the bottom of the vertical support for the axle will be quite strong with the weight of the wheel and the cats Perhaps move the upright more toward the center of a bigger base so that a tensioned cable secured through the bottom of the base with a turnbuckle can pull the axle support back to a true vertical position.
The axle also doesn’t seem strong enough to me either. This is a “out there” suggestion but maybe you could use a high end lazy susan “bearing” for the axle. Here’s an amazon link for what I was thinking. Amazon.com
Ok, larger axle and bearings. Got it. @sknodl I can’t figure out how to use that Lazy Susan bearing, but the original tutorial I followed used a large caster. That design required a ball bearing assembly down below to counter the rotational forces. When I tested that out, it made a horrible racket, so I scrapped the idea. When I built my original cat wheel 16 years ago I used a utility cart wheel and axle with a welded base. Hmmm…
If it needs more support, maybe you could also cover the outside of those spokes in something flat, then support it with wheels from below that roll across the underside of the cat wheel?
For the lazy susan you would need a bigger flat piece of wood on the upright for mounting. Imaging taking a lazy susan where both the base and object are firmly attached and rotating it 90 degrees to see what it would look like.
Yeah that small ball bearing on the bottom would likely dig in and be wobbly because it is so small. Maybe instead of that small bearing just put another fixed caster wheel that’s a little bigger (1-2”) on the bottom of the post to help manage the twisting force of the axle. It would still be hidden from the front so you keep the cool floating wheel effect.
