Best way to create a reversible projector screen?

Question

I'd like to build a reversible projector screen like this one:

https://www.youtube.com/watch?v=EMRYCJCZ3Fc

and I'm wondering how you might build the rotating trolley/rail setup.

My first guess is to build the screen and rails out of Unistrut and to add these trolleys to the top and bottom corners of the screen (four in total):

If I go this route, how should I build the pivots that allow the trolleys to turn as the screen reverses? Could I get away with running a piece of threaded rod up each side (from the bottom trolley to the top one on each side of the screen) and then… add a pivot somehow?

Maybe screw a cylindrical standoff around the rod and pair it with a bronze bushing at each corner to allow it to spin?

I don't know much about this sort of construction, so I'd appreciate any advice.

Answer 1

You wouldn't want any standoffs. That would create a problem when you reverse the panel. The pivots must be in plane with the screen.

I'd look for a single bearing wheel that you can mount on a pin or bolt inserted directly into the frame. Luggage wheels might be just the ticket. They'll need to be very close to each corner to allow pivoting without interference.