Concentric "Doughnut" Turntable

tdtastic

Active Member
Joined
Sep 16, 2014
Location
Alabama
Looking for clever ideas on building a doughnut in the floor that can revolve around a fixed inner circle -- only the outer ring of a concentric turntable set-up. We would actually want abut a 30' diameter with a 4' wide ring with scenery constructed on a solid inner circle of decking.

I can understand a complex concentric install with an inner circle designed to rotate counter to the outer ring to 'appear' stationary, but is there some way to accomplish this with an actual 'island' of stationary stage deck?

also any clever and relatively inexpensive drive ideas would be appreciated.
 
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tdtastic

Active Member
Joined
Sep 16, 2014
Location
Alabama
Quoting you: "30' radius". That's 60' diameter plus your 4' wide ring encircling your 60' diameter stationary deck. That would work out to an outside diameter of 68'. You must have an impressive amount of deck space.
Toodleoo!
Ron Hebbard.
you are correct! I meant diameter -- changed the post. thanks.
 

soundman

Well-Known Member
Joined
Sep 4, 2003
Location
Nashville TN
Just spit balling here but what if your fixed center had a few guide wheels around the outside and the doughnut part rode against that to act as a bearing?
 

cdiamondz

Active Member
Joined
Jun 29, 2016
Location
Michigan
As for the drive, you could put some non-swivel casters on the internal circle for a bearing surface for the outer ring, then use a motor with a small tire from your local Tractor Supply Co. and drive from the inside or outside of the outer ring. Such a friction drive is used in some roller coasters. Of course all methods of drives depend on how this is all being constructed.
 
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Van

CBMod
CB Mods
Premium Member
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Jul 27, 2006
Location
Portland, Or.
Why do I always see these at work and forget to answer them when I get home.... I'll try to remember tonight.
Been here, Done this.
 

BillConnerFASTC

Well-Known Member
Joined
Jan 30, 2010
Location
Clayton NY 13624
Is any part of the ring always masked, or is it all visible? Wondering if drive can project above deck elevation. Also re: drive, stay within 360 degrees - ie" 180 one way and 180 the other, of continuous? It's hard to beat a wire rope wrapping on the "drum " of the turntable in my opinion. I am distrustful of friction drives - the rubber tire. A rack on the perimeter and a pinion would be sure and safe - if expensive. The rack and pinion driven wagons at the Royal Opera House are very cool.

How important is noise? This is hard to do silently but just need to know the limits. The lowest force to move and lowest noise has to be steel wheels on a steel rail - up or down. Two steel tube rings about 32-36" difference in diameter and double ply for deck; flanged steel wheels mounted to deck maybe 2-3' apart. Would be easy to run with a simple hand crank. Lots of other steel wheel and rail options - just quiet and very low friction.
 

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