Replacing casters on Wenger shells

[ShoulderMonkey]

Hello all, thanks for all the information and indirect help from this forum over the years.

I have an issue. We have a set of Wenger acoustic shells that is a custom design from 1988. Recently, two of the rear casters (steering) have broken so that the wheel has a flat side. I called Wenger, but they don't have the specs anymore and have no suggestions for how to go about changing out the caster.
I can get replacement parts from Albion through their local supplier, but I'm not sure how to safely do the replacement on a shell piece that is about 15' tall, 6' wide and 4' deep. The back portion only needs to raise up about an inch to get the caster past it's bolts, but tipping seems like asking for a half-ton lever to crash down on my stage. The other idea we had was rolling it to the stage lip, and moving the wheel off the edge, like a car service pit, but once it sits on the lock foot, I can't think of how to get it back onstage. This also poses serious risk of a fall-over.

With two wheels failing inside of four months, I'm worried about the other 52 wheels, many of which are showing some chipping or cracking.

Have any of you done this sort of thing before?

Thanks so much.


Flat wheel:

Front of shell open:

Rear of shell open:

Rear shell frame top:

Rear shell frame side:

Caster bolts:

 

[farmerjo1111]

When I had to do this we used 3 car jacks and 2x4s to lift it evenly off the floor. It felt very stable and was not to difficult to replace. If I were you I would look at replacing as many as I can since they all will get this way sooner or latter.

 

[MNicolai]

Lean on Wenger more. You can't be the only person to have ever seen this problem and they should be able to provide you advice on a method of replacing the casters. Those towers don't ship fully assembled. I'll bet they have a trick for how to dismantle the towers from the bases long enough that you could replace a set of casters. I would be surprised if you couldn't get someone from Wenger on-site to help you, though it may come at a fee.

I would not go for the car-service pit solution. T'were it me (and in my case, I have several motorized battens rated for a couple thousand pounds), I'd take some large diameter wire rope cable and connect the tower frames to the winch system, use the winches to lift the tower just a little bit off of the ground, and then remove the casters and perform the service. If you have motorized winches, you could potentially do this, but you'd need to have sufficient rigging materials, a sufficiently rated motorized winch system, and you'd need verification from Wenger that the towers can safely be lifted in this manner.

You could probably rent the necessary rigging materials from a local production company. If you do not have [extensive] rigging experience, I'd also recommend hiring a rigger for a day to lead the process. Minus a motorized winch system, a professional rigger could likely engineer a way to do a similar process to lift a tower at a time with manual or electric chain hoists.

I've made this sound easy, and for a professional rigger it likely would be, but don't get me wrong -- if done improperly, it can be dangerous. Once a tower is lifted, its center of gravity would cause the tower to hang at an angle and give it an initial tendency to swing. Do not try without a professional on-hand.

However you do it, I'd do all of them at once. The others will inevitably fail sooner or later, and it's best not to risk that they fail in a way that may allow a tower to fall.

 

[techieman33]

I haven't done this before. If it was me though I would put moving blankets over the shell, tie a couple of ropes to the back frame toward the top, move it about a foot from the back wall, block the front wheels so they can't move and then slowly jack up the back with something like a car hydraulic jack with one or more people on the ropes to keep it from potentially slamming into the wall if it reaches it's tipping point. Place wooden blocks under the back to keep it from falling back towards you in case the jack fails for some reason. Replace the caster and then set it back down. Something else that came to mind while writing this is that the rear frame looks pretty solid from the pictures, you may be able to lift it with one or two chain motors to allow access to replace the caster as well. Obviously someone on site would need to check the feasibility of that since the pictures don't show everything. And plan on replacing as many of the casters as you can afford to. We have a few carts that are about that age all with one model of caster and once the first one failed we ended up having to replace all of them over about a year. It would have been a lot easier to do it all at once and be done with it.

 

[BillConnerFASTC]

I think your concern for more failures suggests looking at replacing all at once. Your floor materiel looks most suited to a soft wheel which these appear to be. Find a caster with same bolt hole spacing and approx same diameter and do them all. If no motorized sets, then get a chain motor and some slings. Yes, you need rigging experience or find someone with it, but I think much easier and faster than jacks.

 

[DuckJordan]

How they build these things is they rig a motor up build it flat on the floor (face down) and lift it up and place on the ground. Near the top there should be two points dedicated to lifting these heavy beasts. We have 30' wengar shells.

 

[ShoulderMonkey]

Thanks for the quick replies, everybody.
For those suggesting chain motors or heavy winching, I only have counterweight single-purchase hand-line flys at my disposal, unfortunately. We have four counter-weighted winch-assist lines for our electrics, but nothing that doesn't rely on counterweight arbors. I suppose we could get a similar effect for keeping the shells from tipping over by running chain/cable to the top (I'll check for those lift points, DuckJordan) and heavy-weighting the arbor at the ground to act just as ballast, not a lift crane. MNicolai, as you cautioned, I am not a rigger, I have great respect for the professionals who can do it right, and always enjoy having them around to watch and learn from.
techieman33, I honestly hadn't thought about turning them around to face the wall... That's a nice simple idea.

I'll check with Wenger again to see what they do for current models of shell, that may give some further direction.
Thanks again.

 

[cbrandt]

It has been years since I worked with something like this personally, but would a pallet jack work? I'd only try it if you could lift the entire piece on one pallet jack, evenly and safely.

 

[BillConnerFASTC]

Most motor assisted counterweight sets should be sufficient. Determine weight - Wenger should have a record - and see if it isn't under 2x capacity of motor assist. Most I've seen are in the 1000 pound range so should be good for a tower up to 2000. Or use two.

 

[ShoulderMonkey]

Most motor assisted counterweight sets should be sufficient. Determine weight - Wenger should have a record - and see if it isn't under 2x capacity of motor assist. Most I've seen are in the 1000 pound range so should be good for a tower up to 2000. Or use two.

Wenger doesn't have records of this system other than that it happened. It's from 1988 and a custom job, they tossed the plans after ten years or so.

 

[BillConnerFASTC]

Well, as a rule of thumb, a shell tower's weight can be estimated at five pounds per square feet of tower. You could also after attaching to rigging remove some of the counterweight in the base. Finally, if you lifted it and it was too heavy, it simply would lift. The motor will stall.

Too bad they ditch the drawings - most companies keep them forever. ETC probably sets the standard for that. On the other hand, I got submittal drawings from Clancy this year for a 1993 project.

 

[marmer]

Yeah, my experience with Wenger is that they want to be helpful. I'm kind of surprised they haven't had you send some pictures to one of their engineers. I agree you need to escalate. They send install teams around the country a lot, maybe they could piggy back a quick site visit to you. Or even have a sales rep take a look when they're in the area. Let them know that "we don't know and it's not our problem" is not an acceptable answer and that you are trying to keep someone from being killed by a piece of equipment with the label "Wenger" on it.

 

[venuetech]

I would replace just the castor wheel. After raising and blocking up the structure about one quarter inch. Looks like the axle bolt could easily be removed then.

 

[BillConnerFASTC]

Replacing wheel is a possibility but make sure that it's an exact fit match and that the fork's swivel mechanism is good for another 20 years.

 

[venuetech]

add a bit of grease to that zerk when uou are under there.
from the photo it looks like you may have 4 wheels under the front and the two swivels in the back, if so you may not need to replace the front wheels for a few years