# Practical physics question: casters and wagons and weight.



## Doug Lowthian (Sep 19, 2017)

Problem: Wagon with 4 adults, furniture, bedding, etc for Wonka that will need to be moved upstage and downstage (about 12 feet) several times during Act 1. Estimated weight, nearly 1000 lbs. (considering 4 healthy American adults, etc; Has not been built yet).

Need to be able to move it using as few people as possible (likely 2-3 youth). 

Question: To make such a thing easier to overcome inertia and move, is it better to have many smaller (but sturdy) casters or fewer larger diameter casters or some other combo of the above? Will larger diameter casters move such a load easier? 

Thoughts? Still in design phase, but need to start building this week. 

Thank you all in advance...


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## Robert (Sep 19, 2017)

My take on this. Larger harder plastic wheel will roll very easy. I've been using a red polyurethane wheel and most of the time my problem is the platform moves too easily. The biggest problem I have with swivel casters is that to move the platform in the opposite direction you have to force the wheels to rotate into the proper direction. I would use the fewest wheels I could. 4 if possible or 6 if the weight is too great. More wheels will cause more noise as they rollover irregular floor surfaces.
Smaller hard surface wheels will probable dig into your floor more and cause damage. 
What you really want are zero-throw or triple wheel casters. They will solve most of these issues, but the are very expensive, although only a one-time purchase.
Here is a wheel guide from Rosebrand.
http://www.rosebrand.com/subcategory211/rigging-stage-hardware-theatrical-casters.aspx?sid=lpRRZzxTRT7mqtfCQnMIc0vS/AvMkGzfRoXQFzgUUc8MeENU37E+/g==


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## gafftapegreenia (Sep 19, 2017)

Is it just moving upstate/downstage? If so straight casters are preferred. 

How big are you planning to build the actual platform?


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## BillConnerFASTC (Sep 19, 2017)

There is no less friction option than steel wheels on steel. While flanged wheels and some angles are great, plain steel wheels and flat bar will work, with a guide of course.

The more both the wheel and rolling surface squish and deform, the more force required.


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## kevinatblinn (Sep 19, 2017)

BillConnerFASTC said:


> There is no less friction option than steel wheels on steel. While flanged wheels and some angles are great, plain steel wheels and flat bar will work, with a guide of course.
> 
> The more both the wheel and rolling surface squish and deform, the more force required.


Ah, but steel casters on a not-flat floor - IMPOSSIBLE! I didn't know that until recently. I thought they would work great on my concrete floors, but they aren't perfectly flat and always have something granular on them. Impossible to move a wagon of stock platforms. I recastered with 8" swivels (some from Northern Tools, some from Amazon, some from a legit caster company).


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## techieman33 (Sep 19, 2017)

kevinatblinn said:


> Ah, but steel casters on a not-flat floor - IMPOSSIBLE! I didn't know that until recently. I thought they would work great on my concrete floors, but they aren't perfectly flat and always have something granular on them. Impossible to move a wagon of stock platforms. I recastered with 8" swivels (some from Northern Tools, some from Amazon, some from a legit caster company).



That's why he said steel wheels on steel. If you put some steel flat stock on the deck for the wheels to roll over then it should roll very smoothly.


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## RonHebbard (Sep 19, 2017)

techieman33 said:


> That's why he said steel wheels on steel. If you put some steel flat stock on the deck for the wheels to roll over then it should roll very smoothly.


 @techieman33 If you put equi-sided steel 90 degree angle face down on top of your steel flat bar and use V-Groove casters to roll along the back of your steel angles you almost need to hold things back from wanting to roll. Seating wagons atop orchestra pit lifts are often supported and motorized this way.
Toodleoo!
Ron Hebbard.


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## kevinatblinn (Sep 19, 2017)

techieman33 said:


> That's why he said steel wheels on steel. If you put some steel flat stock on the deck for the wheels to roll over then it should roll very smoothly.


Yep, I was reinforcing what he said with my comment about the dangers of using steel casters on anything but a very smooth, clean, hard surface.


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## BillConnerFASTC (Sep 20, 2017)

FWIW the 40,000 pound seat wagons at Schermerhorn Hall are steel rollers on wood floor in use, on concrete slab for storage. They do clean pretty thoroughly before moving.


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## RonHebbard (Sep 20, 2017)

BillConnerFASTC said:


> FWIW the 40,000 pound seat wagons at Schermerhorn Hall are steel rollers on wood floor in use, on concrete slab for storage. They do clean pretty thoroughly before moving.


@BillConnerFASTC In the same FWIW vein, There are four seating wagons in Hamilton, Ontario's Hamilton Place Great Hall, two per lift x two lifts with rows EE - HH storing one level down and rows AA - DD storing two levels down below the trap room, instrument storage and the hydraulics room for the two lifts. In their storage areas, they run on permanently installed steel tracks comprised of approximately 1/4" x 6" flat bar with inverted steel angles welded atop. The two wooden stage lifts have flush metal inserts with threaded fillers installed. When the seating wagons are required on the lifts, similarly constructed tracks are rolled into place, their storage / transit casters removed, the fillers are unbolted from the inserts, the tracks positioned and specially machined Allen head cap screws secure the tracks laterally while gravity holds them securely in place. Been that way since 1973 and, to my knowledge, still works well. I've seen people try to reinvent the wheel a few times but, thus far, the wheel appears to keep on winning. The architect's original design had the wagons supported by ~8" to 10" swivelling casters with locks for the swivel's rotation and the rolling of the caster. This just *DID* *NOT* work as it was too, too, time and labor consuming trying to correctly align the four wagons when on the lifts. Trying to have them line up neatly around all of their perimeter edges without damage due to overhanging edges was its own little time and labor intensive nightmare. Once we got through the six week opening festival, the general contractor brought in his brother in law and the steel tracks with vee-wheels system came into being. The four wagons motor along with each powered by a reversible electric motor through reduction gears to a pair of approximately 10" pneumatic rubber tires forced tightly against the floor by a stout compression spring. The pneumatic tires attain adequate grip on the concrete floors in the storage areas and leave only easily washed off dirt marks on the darkly finished wooden stage decks. 
The hall is one of two Russell Johnson / Artec designs in my area with the other being in Kitchener Waterloo.
Toodleoo!
Ron Hebbard.


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## Doug Lowthian (Sep 20, 2017)

This is good stuff. Great food for thought....

Some answers to clarifying questions above. 

Stage is smooth hard wood (like a gym floor), with no option to drill into to secure rails or tracks, and a need to protect from any gouging. 
Wagon will be about 9' x 7' approximately. 
Wagon needs to move on stage from wing on SR to CS, then US/DS several times until curtain at end of Act 1. 
I'm leaning towards the 6-8"" diameter polyurethane wheels mentioned above. If I can find ones that are swiveled with a locking swivel (like the ones Ron said did not work!), I may do that. In the case Ron described I can see the pain-in-the-ass factor. In my case it may be the better way to go. 
Thanks all!


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## BillConnerFASTC (Sep 20, 2017)

Based in this new info, consider a high quality zero-throw(AKA triple swivel), with probably double 1.5 x 4 hard poly-urethane tires on each swivel, so 6 on each triple swivel. Stiff frame and one of these in each corner should work fine.

Maybe these: http://www.rosebrand.com/product212...Elastomer-Stagemaster.aspx?tid=2&info=casters

Sucks you can't anchor into stage.


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## BSchend (Sep 20, 2017)

Second for the triple swivels Bill linked to above. That's what I used for my 4'x16' barricade for Les Mis, and was able to do a DS move, 180, 180, 360, and US move with only 2 people at any time pushing (there were 12 people on the barricade while moving). It will tend to want to drift slightly left or right, but that usually has to do with the level of the floor as opposed to the casters.

For braking purposes I would get high quality wagon brakes, and add a block with rubber on the bottom to the end of the stop. Using 4 of these across the back you should be able to lock the US edge down enough to keep the unit from swinging around in place. AS per the discussion in another thread these should be applying pressure to the floor, but not lifting the wagon.


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## Doug Lowthian (Sep 20, 2017)

Any opinions on these 'Rotocasters" from Rose Brand?



http://www.rosebrand.com/product3626/5-Rotacasters.aspx?id=3626&tid=2&info=caster+polyurethane


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## BSchend (Sep 20, 2017)

Doug Lowthian said:


> Any opinions on these 'Rotocasters" from Rose Brand?View attachment 15271
> 
> 
> http://www.rosebrand.com/product3626/5-Rotacasters.aspx?id=3626&tid=2&info=caster+polyurethane



Those are really quite bumpy and loud


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## Van (Sep 20, 2017)

I would suggest a Large diameter, "Urethane over Steel" wheeled swivel caster. Yes, you will have to allow for directional rotation when you change the axis of motion but, Zero throws are ridiculously expensive and unless you pay a LOT of money typically have a smaller diameter wheel so as to create an over all lower profile device.


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## BillConnerFASTC (Sep 20, 2017)

The zero throw cost more but it's a great investment. Definitely more applications but definitely expensive.


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## gafftapegreenia (Sep 20, 2017)

Based on the information provided, I agree that triple swivels would be the ideal choice.


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## TyeDye (Sep 22, 2017)

Doug Lowthian said:


> Any opinions on these 'Rotocasters" from Rose Brand?View attachment 15271
> 
> 
> http://www.rosebrand.com/product3626/5-Rotacasters.aspx?id=3626&tid=2&info=caster+polyurethane



They work alright. They aren't as smooth as a triple swivel but they have a few advantages.

They can be put further out near the edge of a unit as they don't have a swivel radius. This doesn't seem like a big deal but when you have tall skinny units having to put the center of the triple swivel 6" or more in from the edge can be a big deal. These are nice because they can be flush against the inside of the framing/facing.
They take up a lot less room in the framing. Leaves more room for batteries, weights, whatever people want to put in the base of wagons.
They are cheaper than a triple swivel. The quad wheel is only 70$ from Rosebrand.
The disadvantages to them, from my experience at least:

They are louder than a triple swivel.
While they do roll very easily straight (the direction along the 'main wheel') they don't roll very well perpendicular to that. It will still roll that way, but the rolling friction is about double from the main direction.
Because of the above disadvantage, a wagon with these kinds of casters is 'squirrely' if you need to do arcing movements or smooth choreography with the unit.
Their weight capacity isn't as high as a triple swivel, depending on the model.

Having said all that, I regularly use triple swivels and have only used those Rotacasters once or twice for very specialty situations. I second what BillConnorASTC said that the triple swivels are a good investment. Buy them slowly unit by unit as the budget allows and build up a stock of them over time.


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## dheuvelman63 (Sep 27, 2017)

I also agree that your best option are the Triple Swivels. Great investment. Years ago we took a small pickup and modified it into a set piece. Then mounted a steel subframe and used low profile 1.5"x4" swivel casters. Unit weighed about 600# empty. 3 actors "drove/rode" the truck at one time. All action was completed by 2 very small stagehands who weighed in at 125# each. They had lots of trouble. 

We went in, modified the framing and mounted 4 Triple Swivels. The unit moved effortlessly around the stage and the young stagehands were very thankful.

Sold me on the value of the Triple Swivel.


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## cadcoke5 (Sep 27, 2017)

I second gafftapegreenia's recommendation for using straight wheels. However, if it is not tracked, then be sure to allow space for it to wonder a bit, over the multiple trips back and forth. Making sure the wheels are all mounted parallel is important.

Locking casters are more prone to wonder, because that lock may permit some wiggle to the caster's direction when it is traveling backwards.

As an aside, the word Caster refers to how much a wheel is offset from its swivel. So, it really can only be properly used to refer to swiveling wheels. Thus, the phrase "swivel caster" is redundant.

-Joe


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## KanataJim (Sep 27, 2017)

We did Wonka a few years back and used low profile casters from Lee Valley with no problems whasoever - they are our go-to caster for our theatre, other than using Air Pux for more specific applications. Each caster is rated for 220 pounds (100 kilograms). So six casters would more than satisfy weight requirement. Two youth would have no problem moving this and these casters are so smooth that controlling direction is extremely manageable.
http://www.leevalley.com/en/hardware/page.aspx?p=70055&cat=3,51976


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## kendal69 (Sep 27, 2017)

Since the main question was a weight issue. They make casters that can handle 20,000 pounds. http://www.casters.com/darnell_rose/products/casters/extraheavy.html

These units can do 1,800 pounds each.
http://www.casters.com/darnell_rose/products/casters/stagemaster.html


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## jwolfkill (Sep 27, 2017)

2 thoughts:

1. In general, larger diameter wheels have lower rolling resistance than smaller diameter wheels, all other things being equal. 

2. Remember that inertia works both ways - objects at rest tend to remain at rest and objects in motion tend to remain in motion. Building a wagon to start rolling more easily also makes it harder to stop. A 1000 lb wagon moving at a decent clip could easily steamroll a couple of kids. It might be wise to build in some kind of mechanical limits to the movement of this wagon.


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## BillConnerFASTC (Sep 27, 2017)

I would not assume that the total weight is distributed evenly over the casters, and suggest maybe plan for 150% at least, 200% possible.


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## microstar (Sep 27, 2017)

This is simply a job for air casters. No rumbling noises, but maybe some hissing. Omni-directional. Frictionless (platform easily moved by one youth). Practically unlimited weight, 1000's of pounds (depends on size of air caster) .Platform rests solidly on the floor when pressure released.
Yes it involves some thought and engineering, but many of the air caster manufacturers will provide guidance. Not that costly when you consider it's an investment that can be used over and over like buying rolling casters.

Unfortunately if you need to whip this up in a hurry, it's probably not the best solution for now.


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## jdenora (Sep 27, 2017)

If weight is the concern, do your best to make sure the weight is evenly distributed. We did a production of "Pirates of Penzance" a few years ago. We had a 30' pirate ship with as many as a dozen or so actors on it. We used a bunch of large poly casters, maybe eight or ten. With four of us inside we were able to maneuver the ship around the stage relatively easily. The only problem was one of the casters seemed to be taking more of the weight than the others, and after a few trips around the stage, the poly just came apart. So we kept a small floor jack, tools and extra casters in the "engine room" of our ship. When a caster broke during a performance we had plenty of time to replace while we were on stage. The actors had no idea we were jacking up part of the ship and changing the caster, and the audience was completely oblivious. We also learned to work the tools in time with the score so that any sound we made would just blend in. Ah, the things we do for our art!


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## TimmyP1955 (Sep 28, 2017)

What about these? https://www.mcmaster.com/#5674k16/=19kq5xj (Harbor Freight has cheapie versions.)


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## BillConnerFASTC (Sep 28, 2017)

TimmyP1955 said:


> What about these? https://www.mcmaster.com/#5674k16/=19kq5xj (Harbor Freight has cheapie versions.)


Concentrating the load on a stainless steel ball is likely to leave a rut in the wood floor. You need the urethane tire (or air) to spread the load out.


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## gafftapegreenia (Sep 28, 2017)

TimmyP1955 said:


> What about these? https://www.mcmaster.com/#5674k16/=19kq5xj (Harbor Freight has cheapie versions.)



They like to leave divots in anything that isn't concrete or steel. Also they usually aren't very quite.


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## Nicholas Day (Sep 28, 2017)

Here's the rolling resistance page from Hamilton castor <www.hamiltoncaster.com/Portals/0/.../White%20Paper%20Rolling%20Resistance.pdf >
The larger the wheel diameter, harder the tire and better the bearing the easier the pushing. If you don't need to steer use ridgid castors if you need to steer I agree with the above, use a tri castor if you can afford it over swivels. The recommendations from the manufacturers generally are for industrial applications, so you should up the specifications a bit for the stage I reckon.
Nick


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## Doug Lowthian (Sep 28, 2017)

kendal69 said:


> Since the main question was a weight issue. They make casters that can handle 20,000 pounds. http://www.casters.com/darnell_rose/products/casters/extraheavy.html
> 
> These units can do 1,800 pounds each.
> http://www.casters.com/darnell_rose/products/casters/stagemaster.html


Does that mean I only need one?


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## JohnD (Sep 28, 2017)

Doug Lowthian said:


> Does that mean I only need one?


But your actors have to have mad surfing skills.


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## BillConnerFASTC (Sep 28, 2017)

Doug Lowthian said:


> Does that mean I only need one?


If you don't have to go far, maybe just half of one.


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## RonHebbard (Sep 28, 2017)

BillConnerFASTC said:


> If you don't have to go far, maybe just half of one.


@BillConnerFASTC FWIW, rolling right along in the same vein; in your esteemed professional opinion, which half would you recommend; top half, bottom half or one of the sides?
Toodleoo!
Ron Hebbard


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## BillConnerFASTC (Sep 28, 2017)

RonHebbard said:


> @BillConnerFASTC FWIW, rolling right along in the same vein; in your esteemed professional opinion, which half would you recommend; top half, bottom half or one of the sides?
> Toodleoo!
> Ron Hebbard


I think from 45 degrees to 225 degrees.


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## lightingtek (Oct 4, 2017)

BillConnerFASTC said:


> The zero throw cost more but it's a great investment. Definitely more applications but definitely expensive.



I love zero throw casters. I hate their price. I did research on them a few years ago when I had a set that was going to require 40 of them... not economically feasible. I found a paper online from a student at MIT which included plans on making your own out of scrap plywood, hardware store casters, and a lazy susan bearing. I have been following this thread for a few days now, and have not been able to find that paper online anymore, but as my pack-ratting skills have manifested into the digital world, I found the file saved onto my google drive. I have uploaded it to this post, with the disclaimer that I do not claim to have any ownership over this material, but can attest to its functionality. I have used the 40 zero throw casters that I made several years ago many times. I have thrown out or rebuilt and added to my collection many times, and find new uses for them every year. I hope this is as helpful for you all as it has been for me. Plus, added bonus for teachers out there, it's a great resource for your classroom.


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## Doug Lowthian (Oct 4, 2017)

lightingtek said:


> I love zero throw casters. I hate their price. I did research on them a few years ago when I had a set that was going to require 40 of them... not economically feasible. I found a paper online from a student at MIT which included plans on making your own out of scrap plywood, hardware store casters, and a lazy susan bearing. I have been following this thread for a few days now, and have not been able to find that paper online anymore, but as my pack-ratting skills have manifested into the digital world, I found the file saved onto my google drive. I have uploaded it to this post, with the disclaimer that I do not claim to have any ownership over this material, but can attest to its functionality. I have used the 40 zero throw casters that I made several years ago many times. I have thrown out or rebuilt and added to my collection many times, and find new uses for them every year. I hope this is as helpful for you all as it has been for me. Plus, added bonus for teachers out there, it's a great resource for your classroom.


I like it. Thanks!


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## BillConnerFASTC (Oct 4, 2017)

The fisrtvones i saw were made at Yale. Used a swivel caster base with a plate and three casters welded to it. Its always a question of jow much is your time worth.


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