I have built a wooden chest and lid. It will likely have people sitting on it. It's about 36 inches wide, 20 inches deep, and 20 inches high.
A sketch of the frame can be seen here: https://www.tinkercad.com/things/iK2g60WCdmG
The frame was made from 2x4s (douglas fir) and the panels from fence posts (cedar wood).
I finished it with oil-based polyurethane.
When I rest the lid on, it rocks slightly. If you sit on it, it is very solid, but I can imagine that the rocking could put a bit of strain on the hinges. I'm also not totally sure how the polyurethane surfaces will do in direct contact with each other.
The alternative is to get some little rubber stoppers (eg https://www.amazon.com/Cabinet-Adhesive-Dampening-Especial-Circular/dp/B07S646BZN?ref_=ast_slp_dp) and put 4 or 6 or whatever onto the lid (I was thinking the 4 corners + the middle of the long length.
The question is would be better to have the little rubber stoppers (how many and where?) or just let the coated wood lid sit on the chest.
It will be closed for probably months at a time. Sat on infrequently, but maybe daily. Just wondered if anyone with more experience would have a view on how to finish this project.
The current plan is that I'll just screw in a couple of little brass hinges and maybe add a chain inside to prevent the lid from opening too far. Any thoughts on better/prettier/more interesting ideas are also welcome.
Photos of the incompleted chest:
After making this I thought that the framing idea might not be so good because of lateral wood expansion. I have left a little space between the panels and it's going to be indoors, but still. I also made sure that the panels were orientated parallel to the longest edge. Time will tell if this will be enough. I also simplified the jointing for the framing a little bit from what I had in the tinkercad.
Feel free to weigh in on this or anything else. I'd love to learn from people who know what they're doing!