Secure 4x4 post to rolling wagon

[Compbob]

I need to create to spinning rolling wagons with staircases. What is the best way to secure the 4x4 posts to the wagons so it is sturdy and doesn’t tip? Any hardware specs? Wagons will have 4inch casters and it needs to support two people on the top of the stairs 7 feet high.

 

[Crisp image]

I think what we need to help you is a picture or sketch. of what you are trying to do. Then we canmake some educated guesses but this might need some engineers eyes to look over and confirm a design.
Regards
Geoff

 

[sleepy.cj]

Is the wagon only the size of the staircase or does it have more playing space? Ditto on needing to see a sketch.

if it’s a just a staircase that you need to roll around, i’d attach the caster plates directly underneath to the 4x4 posts(legs?) of the staircase so that the weight is transferred directly to the wheels.

if you need more playing space on the wagon, You can attach the wagon framing to the legs at the same level as the bottom of posts/legs and just strategically cut holes in the plywood top to accommodate the posts going through the platform top. and add additional casters as necessary.

i don’t feel comfy recommending specific size screws/bolts/hardware though so i’ll leave that to someone with more expertise.

whether or not the staircase will tip over is another issue depending on the height and overall footprint of your staircases and their center of gravity.

 

[Van]

Welllll, I'd be most comfortable if you were to reinforce the area where the 4x4 will be attached by adding a 12" x12" square piece of 3/4" ply under the deck. Drill a 3/8" hole through the center and straight up the center of the post. about four inches above the bottom of the post, drill a 1" hole <Forstner or Spade bit> a little over half way though until it goes just past the vertical hole. Bend a fender washer to the same curve as the diameter of the hole. Insert it and a 3/" nut into the hole run a 3/8" bolt through the reinforcement plate and up the center of the post, screw that sucker down. For added stability you might want to add a Simpson BC40Z Post brace to the bottom and cover it with a base molding of some kind. and the bolting system I'm referring to is essentially the same as what's pictured below except that you want to through bolt it NOT use a Lag screw. If you can't find a a long enough Bolt get a piece of ATR and cut to fit.

 

[Lextech]

I would use air casters and drop the platform when anyone is climbing the stairs. It would be much more stable and you could counter weight the platform if needed.

 

[TimMc]

I need to create to spinning rolling wagons with staircases. What is the best way to secure the 4x4 posts to the wagons so it is sturdy and doesn’t tip? Any hardware specs? Wagons will have 4inch casters and it needs to support two people on the top of the stairs 7 feet high.

I'm old fashioned, I think actors should not be elevated on set pieces that are actively moving.

Is this academic theater, community theater, public school? It only takes ONE incident/insurance claim to set back a program 10 years; 20 years if there is a lawsuit.