Yes, with quarters I get 4.75 rims to a sheet easily.Eric The Viking":3qoa8k86 said:If you do semicircles, you can just about get one set per sheet of 8'x4':
If you scale down to 48" outer diameter (proportionally), you can get one and a half sets (three circles) per sheet:
Those are to scale, using the dimensions you gave. If you stick with quadrants, you get much more from the material, obviously, but semicircles should be far easier to glue-up, as you just have the two parallel glue lines.
It all comes down to your time versus materials cost really.
And I almost forgot: given what you're using them for, you really will need some sort of jig to true them up with once they're glued, and even if you cut them as whole discs.
Even though it's rotating at slow speed, much more than a few millimetres out of round will make the finished item look pretty rough, as will the drum if it doesn't have a proper cylindrical shape rather than slightly conical.
I think I'd make some sort of cross-shaped frame with clamps so you can spin the ring against a sander before you rout the groove. The inside face would be a bit trickier but not insurmountable. Doing the thin 'treadmill' cylinder will need very accurate cutting and clamping I think.
I'd recommend trying a carbide centre-cutting endmill if that's suitable - they are available much cheaper than the spiral fluted router bits. You can also get them with more flutes (up to 4), which makes the bit stiffer. Only thing to bear in mind is that the shank size will be the bit diameter, so for anything that isn't the same size as your router bit you will need something like an ER20 collet adapter, which Axminster sell.Louise-Paisley":kf3v1lap said:One thing has become quite clear, if I am to continue with the mortice & tenon plan then I need to get me some upcut spiral bits because its a pain cutting the mortice with a normal straight cutter with the dust in the mortice
With the kerf cut bend we were planing on back filling the kerfs with resintite/ sawdust. The inside surface will be carpeted when finished so plenty of grip but also a level of soundproofing - My wheel has a textured paint finish inside and when they gallop in it it sounds like a heard of elephants charging about!Eric The Viking":384sj5ww said:Cor this is an interesting thread!
Thanks for raising the subject, Louise.
One other thought, while I remember it: Your kerf cut version would have excellent grip, but I can see the fragility of it. Years ago, when I used to do a bit of dinghy sailing, we used to mix fairly coarse but clean sand with polyurethane to get a grippy finish for wet plimsolls (no trainers back then!!!).
Do you get a good enough finish just by painting the wood or are you doing something similar with grit?
I already have a cat wheel, different design to this completely. My two bengals spend a huge amount of time in it, they fight over it even! The two moggies have never been near it and just seek out a warm spot to sleep :roll:heatherw":3llbkok8 said:I will be fascinated to see whether you can persuade a cat to use the thing after all this hard work, contrary animals that they are. Mine spend most of their time lying down when they're not eating playing or hunting.
Oh, and I've never made a mortice and tenon in MDF, but I have joined it edge to edge with biscuits.