I need advice on how to keep a 48" diameter "cat exercise wheel" axle made from 3/4" pvc pipe free floating on an [18" lag screw] (http://www.amazon.com/dp/B009ZZJCB4/ref=biss_dp_t_asn?&tag=rnwff-20) that I'll screw 3" into the stud in the wall, affixed so the 15" deep cat exercise wheel spins in place but doesn't move too much from side to side?
(picture a 20lb price is right wheel spinning on a bolt coming from the wall) The 18" lag screw is only partially threaded so i can't screw a bolt on each side of the wheel to keep it in place.

I went with an 18" lag screw to hold up the wheel & cat (~20lbs max) to minimize the footprint of the structure .
How do I address concerns about the daily movement on the bolt from use of the cat wheel to keep the bolt from coming out of the wall?
The design had to be sub-$50 and super easy as my cat may not even use this wheel so I can't do the more expensive designs that include plywood, etc. Thanks

  • -1 this is an off topic hobby project and I'm having a hard time figuring out any application of the answers that would be on topic.
    – BMitch
    Mar 1, 2016 at 19:03
  • First, I'd ask myself if my concerns are legitimate. Are they? Are you looking for an answer to a question that hasn't been asked? :)
    – isherwood
    Mar 1, 2016 at 19:14
  • LOL quite the project. I would try to support the end of the screw with tie wire or some other cheap wire like ceiling hanger wire. That should help keep if from sagging and ripping free. Good Luck!
    – ArchonOSX
    Mar 1, 2016 at 19:40
  • I have no idea what a Cat exercise wheel is it similar to a hamster wheel just larger and wider? I do think the shaft collars would keep it from moving around.
    – Ed Beal
    Mar 1, 2016 at 19:48
  • 1
    Why not use something like metal conduit and a conduit flange? That would spread the load on the wall and probably be easier/sturdier to manage. Mar 1, 2016 at 20:47

2 Answers 2


I would add a collar with a set screw on each side of the wheel bearing. These come in many sizes and finishes to match your project. You may need an additional brace to prevent the shaft from sagging.


A lag screw going into the wall probably isn't going to cut it, because it will sag too much. You can test this by screwing it into a 2x4 and putting 20 pounds of weight on the end and measuring the deflection.

Is there any way you can support that screw head via an adjustable wire to the ceiling?

The one you linked in your comment is a hubless design that probably has a lazy susan bearing or slewing bearing behind it, probably a foot high and bolted to a piece of plywood which is in turn bolted to the wall. Lazy susan bearings are only meant to handle compressive force, and in this configuration they will have shear throughout and tensile force at the top, and may tend to bind. This is why a true slewing bearing is desired.

The least rolling resistance will come from your approach, particularly if you use roller bearings (which can be very cheap). You need to keep the drum from wandering on the screw and rubbing against the wall. A stack of washers should suffice, adjusting lash by tightening or unscrewing the lag screw.

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