The first one I built some time ago, and proved to be too unweildy. Too big, too heavy, and all of the wheels swiveled, making it hard to control.
This is version 2. Smaller, lighter, pneumatic wheels (no dolly track) and it has fixed axles. That means it only goes straight. However, considering that straight dolly shots are by far the most common (like 90%), I think it's a good compromise. And I designed it to be disassemblable.
Aluminum spine, steel axles, wood deck. I have the main body assembled. All I have left is to cut & attach the wood deck. We might be able to use it this weekend.
There is a version three in the back of my mind. Runs on dolly track.
Of course, this means that I actually accomplished something useful today, which surprises me. It just kinda happened. Babs & I were talking about this weekend's shooting, and I kept coming back to dolly shots. Tony has a steadycam for his camera, but it's not overly smooth. For my camera, I'd need the heavy-duty rig with the vest, and that's waaaaay too expensive.