Several years ago, I had the opportunity to attend a short lecture on turntables, which spawned the basis of this article. I just spent some time doing additional research, and now I hope to create a guide for those first learning about theatrical revolves.
Types of Revolves
In general, there are two types of revolves: the classic circle and everything else. Once one thinks outside of a static circle revolve, there can be odd-shaped revolves, revolves within revolves, revolves mounted on elevators that lift up to reveal a scene below, or revolves that can move on and off stage on a giant wagon.
Using a few basic principles, the simple circle revolve can be scaled either up or down, can be driven in different ways to account for different budgets, and even has the possibility to be staged near other revolves for a true DJ-desk type of staging experience.
Mounting the Castors
On a normal wagon rolling onstage and offstage, the wheels are mounted to the wagon, and every uneven dip in the stage floor affects the motion of that wagon. This unevenness reduces the efficiency of the wagon, and forces whatever is moving the wagon (stage crew, a motor…) to work harder than they need to.
As a turntable is, essentially, stationary, any resistance to its motion will be felt every time the turntable is revolved. To reduce unnecessary work, castors are mounted to the stage floor (wheels pointing up) and shimmed, so that the revolve is perfectly level and unnecessary work is minimized. However, because the castors are pointing up, they require a smooth contact surface to roll on: a smooth turntable requires a smooth underside.
Turning the Revolve
Once decked, there are two general ways to turn any revolve: either use crew/actors to push the revolve or use a motor to turn the revolve. Of these, using a motor requires less labor (and looks more ‘magical’, but is costlier and can be noisier.
There are three ways to use a motor for a turntable: attach the motor to a tire and use friction to drive the revolve, wrap a chain around the entire turntable and have the motor advance the chain (belt-driven), or mount the motor under the turntable and use a wheel on a track to drive the revolve (center-driven).
Friction-driven revolves are most popular for those with a lower budget, as there is a maximum amount of power with least amount of fuss, however, a second (visible) tire is often added on top of the turntable to ensure proper contact with the turning tire. With the stage slightly cluttered with mechanics or masking to hide the second tire, a friction-driven revolve will not give the cleanest look.
Chain-driven revolves provide a cleaner look, but with an increase in cost and complexity; this revolve can be built into a deck, as no mechanics are required on top of the revolve. This type of revolve requires a channel for the chain around the circumference of the disk, and likely some sort of increased friction in that channel to encourage the chain from slipping. Near the motor is a series of pulleys and a winch to put tension in the chain: the more tension in the chain, the less likely the chain is to slip, but the more the chain may damage the channel it’s wrapped around.
Center-driven revolves are what those with the largest budgets usually use: the motor is underneath the turntable, so the revolve can be built into a deck, and it requires no fussing with a chain. On the downside, the motor is now in a difficult place to maintenance, and a beefier motor is required due to the closer proximity to the pivot point.
Center-driven revolves also allow for more flexibility: want a turntable within a revolving ring? The center turntable is center-driven. An oval? Center-drive. A turntable on an elevator? Center-drive.
Further Reading:
Ben Teague’s “How to Build a Revolve or Turntable: An Illustrated Guide”
Wikipedia’s “Revolving Stage”
Stage Direction’s “Revolving in a Straight Line”
The Guardian’s “A 360-Degree History of the Theater Revolve”
Videos:
Jigao Willie Wu’s “Hamilton Turntable Model”
Jetijs’s “Rotating Platform”
ImagineNation2’s “SceneAround Theatre System”
Dean Montgomery’s “Rotating Stage for Community Theatre”