Very good idea. The screw looks like leveling legs for scaffold, if you could find another "nut", you would have a locking device to keep it from turning while you work.
Cut it in half, match it back together over the threads, and then tack weld it together again?
It's hard to watch a five minute youtube clip!
What? No power? No hydraulics? No complicated clamping stuff? No Arduino controlled nuclear grade weirdness?
I only see stuff like this on the internet. I saw another one that had a scissor jack and sliding square tube inside another sq tube. I kinda liked what you started with. Needs an umbrella.
Glad to see you're training a new helper.
I like to see the youngster getting involved. Especially wearing gloves, safety glasses, and shoes.