Wednesday, June 29, 2011

How to Make a Revolving Stage

A human-powered turntable for low budget, low tech theater companies.
by Peter Konopak, Allan Robins, and James Wojciehowski
    
Back in November of 2010 my  friends Alan and Jim, my wife, my son, and my son's theater teacher/ director/ sister-a-different-set-of-parents and I were all sitting around the dinner table when sister announced it was her intention to stage the Broadway version of Les Miserables.  This surprised none of us, because she has a penchant for doing big, no-BIG things.  She said she wanted to do the things right, complete with the famous barricade and revolving stage.  How, we wondered, was she to accomplish this?  "Yes", she wondered, "How are we going to do this?"   And so it began.

The first thing to do was to search the web and see what had already been done.  This turned up precious little.  I am, however, indebted to the Drama Department at BHS in Burlington, WV for the pictures of their turntable.  It gave us a good place to start.

What follows is the plan for making a sixteen foot diameter turntable, drive mechanism, and ramp assembly.

First, the physical plant of the stage is  46 feet wide, with two-eight foot wings, total width 64 feet.
The stage is 26 feet wide from psychlorama to footlights.  The floor is hardwood (Inviolate) with a 1/4" laminar covering.  The play needed three feet between the turntable and the footlights.  The turntable must, perforce sit ON the stage, may not be screwed to it, and be low enough that stage pieces may be easily rolled on and off.  Ramps would have to be designed to allow this.

At first we thought we would be able to motorize this thing, but looking at the cost of motors strong enough to drive the table soon put that idea out of our heads.   We needed to keep the cost of the turntable as low as possible, the drama department has no budget;  all expenses are paid with the proceeds of previous plays.

Once we told the director that she was limited to manually operated equipment, an idea which she was
ok with, we started working on the idea of just how it was going to turn.

The director wanted as large a disc as possible:  we settled on 16 feet.  This gave a few feet in front of the footlights for actors and a few feet behind for set pieces and movement behind.  It was also convenient because of the dimensions of sheets of plywood, and simplified construction.

Borrowing heavily from Burlington High School’s  design,  we came up with the following:
Stage plot for Les Mis @ Sherman E. Burroughs HS

                                      
        A center piece of 1/2 ( 15/32’s actually, nobody makes 1/2 “ plywood anymore, chiseling cheapskates) cut into a four foot circle.  In the very center, screwed  in from the bottom  and glued to the top, is a 18” 2x8,  with a galvanized 3/4 female pipe flange screwed onto it.  A  4 inch galvanized nipple was used a spindle, around which the table would turn.
Illus. A    Center piece with spindle

Next we took 1x4  composite “wood” boards( Next time I’d  use Doug fir) 1 x 4 and cut them 6 ft lengths.  These would radiate out from the center at 45 degree angles.

Illus. B     Spokes and Spider

     Next we connected each of the spokes with two stringers of more 1 x 4.  One stringer joined the outside edge of all spokes together.   The other stringer was placed 3 feet from the centerpiece.  The completed structure resembled a spiderweb, and was duly christened so.  We realized that the spiderweb would  adequately support  the circular turntable along the chords of the circle, but not at the circumference.


We secured 6” “spurs” to the midpoints of each of the outside stringers, which would then give support to the circumference of the table.  In hindsight we decided that triangles would be better, as they would be less likely to be pulled away from the stringer. ( This happened more than once, if the drive rope came off the gears, we called it being casterated.
                                                Illus. C    Spider web with triangular stingers


       Next we attached 90 , 2-1/2 swivel casters. 
4 on the centerpiece, six on each spoke, one on each of the inner stringers midpoint, two on the on the outside stringer equidistant from the midpoint, and one on each spur.  We don’t recommend using casters with locks.


Illus. D    Nail plates at Spider joints. 
Each of the spokes and stringers was secured with 3 x6 nail plates.
We used 3/4 “ coarse thread drywall screws.  Also, for ease of reconstruction every joint was labelled.
Each spoke was given a letter, with each stringer given a number.    Care should be taken to not set the screws too deep, as a stripped screw doesn’t hold as well as one which isn’t.

Illus. E   A better view of the spider and spindle

Illus. F   Note:  we didn't use the triangular spikers in the middle of each stringer.    I advise YOU to use them.
 So  spiderweb is constructed.  Now we construct the top.  We used 15/32” flakeboard rather than plywood.  Plywood is much stronger than flakeboard, but also much heavier and more expensive.  The flakeboard bowed slightly at the edges when there was a heavy load directly on them, but for the most part they were strong enough.  And with a manual drive, weight, particularly inertia is something to  consider.  We laid the sheets out in this pattern.  Then we put a second layer on top of the first, but the pattern was rotated 90 degrees, that way no joints were identical from top layer to bottom, which greatly increased the strength.    Every joint was covered with gaffers tape.  No glue was used because the director wanted to be able to tear the stage down and use it again.
  
Illus. G   This shows Humpty cut out and joints taped.  Below are the patterns for setting out the lumber preparatory for cutting.
                      

We shot 1"   coarse thread drywall screws through the top and into the bottom,  every screw was six inches from its nearest neighbor  NOTE:  because the material was 15/32 rather than half inch, we were forced to grind the top  1/16 “ inch of every screw.  This was necessary  because the screws were now too long, and would protrude onto the roller surface.  Next, we used a piece of pipe with a nail through it and a sharpie at the other end, and set up a compass, and traced a circle.  A sabre saw was used to cut a 16 foot, two ply disc.  A 3/4 inch hole was drilled through the center point for the center spindle to fit through.  The two parts, base and top were christened Humpty and Dumpty. 
Illus. H  This shows how the pieces overlaid oneanother.  This picture is actually taken at tear down.

Illus. I  This shot shows the two plys of wood, the lay of the rope in the cog, and the cog itself.




In this picture you can see how the two plys fit together.  A piece of doweling was stuck in the center flange, and with one strong thespian at every point of the clock, Humpty was carefully lifted and laid on Dumpty, the dowel marking where the center was.  The dowel was removed, and the spindle was inserted and screwed into place.  Voila.  The table is complete.  Now we had to design the manually powered gear drive.*  Here is the complete table, with ramps.  Humpty looks scuffed, because this picture was taken after  3 weeks of rehearsals and  8 shows.
Illus. J  Completed table & ramps
Illus. K      78 feet of rope with notes & splices visible
           As mentioned earlier, powering this by mechanical means was out of the question.  So the job devolved to manual labor.  We decided to use 1/2 inch cotton/poly  multistrand rope.  The rope was knotted every foot originally, but we revised that to every three feet.  The rope was spliced into one continuous loop by doubling the bitter ends into  two small eyes, one of which was threaded through the other, then wrapped with twine and taped.  We did not use eyes because we wanted the splices to have a very low profile.  The rope had two sides, a “feed” side, which was downstream from the guy pulling the rope,   and “pull”  side, which was from wherever the point of friction was to the puller.
On the  circumference of the disk, humpty, we screwed every foot, a cog made out of dadoed and beveled 2 x 4.  Each piece was 6 inches long.  Each screw had a pilot hole to keep the wood from splitting when screwed into the bottom of humpty.
    
Cog with rope cup, screw points, showing bevel
      When screwed in with the “rope cup” facing outboard, the bevel made the rope cup cant upward, making it less likely for the rope to fall out of the cog.  One of the knots on the rope would catch the trailing edge of one of the cogs, the point of friction, and the disk turned.

        The number of casters made the whole stage relatively easy to turn.  When empty, a 16 year old girl was able to turn it overspeed( 30 -35 rpm).  When the stage was loaded with the props for the barriacde scene  for Les Mis, and 14 actors of varying sizes it took a strong hand to move it at speed, which was one full turn in about 30 seconds.
         tensioners                                            bind point


We soon discovered that the knots were getting bound in the cogs at the point where the rope
left the disk.  We improvised a series of tensioners.  Each was composed of a cast iron wheel, which at some time might have held either a volleyball pole  or a lighting rig.  They were threaded to 1 1/2.  So we placed them at three points on the loop.  They made it possible for one person to move the table without a second person keeping proper tension on the “feed”

About this time you are asking yourself”  How did you keep the puller out of sight”.  In this theater there is a void behind the psych.  We were able to raise the psych a foot or so, since it was behind
Illus. L  Backstage hub of tensioner assy.  We DID screw this one lightly into the laminate flooring. The tape shows the proper angle of attack for the rope out to the stage.
a 20 x 45 foot canvas flat, and unseen, that was no problem.  Fortunately, too, the canvas flat was ancient and we made a rent in it about 6 inches high.   It was through that tear that pull side was pulled behind the backdrop and psych, and then fed back out to the table. This is the space where the puller sat.  You can see the pipe nipple with the rope around it.
Illus. M     This is the heart of the tensioner assembly.  These we did screw lightly down into the laminar stage.  We were concerned about a trip hazard, but we rehearsed with it enough that the actors got used to it, and the director moved her blocking downstage from it.
Illus. N   Another view. You can see the two slits in the backdrop.  When the stage was lit for production you could see them, but only if you  were looking for them and knew where to look.



The very last part of the stage were the ramps.  They were made of 2 x 6  x 6 foot which were ripped diagonally, and then had two layers of flake board screwed to them.  The leading edges of the ramps were sanded as close to flush as we could make them, to allow large set pieces to be wheeled onto them.
Illus. O  The leading edge of the ramp.







Illus. P  Inside front view of the ramps.


Illus. Q  The Ramp and Stage meet.  The tape was there to let the Stage manager see when the table was set to its optimum

position.
They were also cut on the trailing edges to fit as closely as possible to match the arc of the stage.  There had to be a gap of about 1/2 “ between the ramps and the stage , that was unavoidable, due to the imprecision of the cutting of the ramps and Humpty.  The techies knew to get a good head of steam up the ramp with set pieces, and all worked out. 

Just as an aside, the thing worked just fine!  And it has been taken down and is being stored, ready for use again.

Supplies:  24 sheets of  4x8 31/32" flakeboard.
                  128 lf 1x4  pine or Doug fir
                   96 2 1/2 non-locking, swivel casters
                   8  2x 6 x 8' pine or Doug fir
                   1 sheet 31/32 plywood ac
                   32   4 x 6" nail plates
                   5# 1" drywall screws
                   gaffers tape
                   paint
Total cost @ $ 900 ( 2010)

So there you have it.  My friends and I hope this will help you.  What you do to this will be of more than passing interest to us all.

Peter Konopak
Theater Dad for Burroughs High School Drama Department
Ridgecrest, CA

2 comments:

  1. Thank you so much for sharing this! I am a playwright and I have been looking for a low budget way to build a rotating stage (to no avail). I will study what you have posted. One question, how long did it take to build it?

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  2. I really appreciate you taking the time to post this. I would like to make some comments and questions, if I could. First of all, great undertaking. This really looked like it was a fun build. I question, however, your use of OSB - Oriented Strand Board (what you refer to as "flakeboard"). Not only it is NOT lighter than its equivalent in plywood, as you claim, but it is not something that really it strong enough for multiple uses. Screws pull through it MUCH easier than ply and when it begins to fail...it just falls apart. Cheaper, THAT it is...and if this was a budgetary concern I don't blame you in the least. 24 sheets at $8 is much better than 24 sheets at $20. On a practical side, OSB swells a little with age. If this, or anything else made of OSB, were stored for a few years and were exposed to any level of humidity it would be practically unusable when you got around to it again. Other than cost plywood is the superior building choice on almost all levels.

    You never cover what the actual drive mechanism was, other than it being manual. Was it simply someone pulling the rope? Is that what the knots are for? If so how did you keep tension? How easy was it to move when you were all done? How many people did it take? Here is the main question. After you finished it, what did you think to yourself that you would do differently if you had to build another one. Again, thanks for your time in putting all of this together. (Oh, btw, it is spelled "cyc" not "psych." It is short for "cyclorama.")

    Oh, one more thing. If you were to do this again you might consider fixed (or "dumb") casters instead of the swivel kind. You would have to mount them perpendicular to the radius of the circle as you went around. Not only are they much cheaper than the "smart" castors you wouldn't have any issues with swiveling the smart casters if you decided to rotate the state the opposite way.

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