This is something I did consider. I think you’re right, it would relieve the tension. The only problem is I can’t exactly detemine where in the ribs the tension originates from. I have a feeling it’s 6 or 7 different ribs in a certain area. Last night I spent about an hour with my straight edge trying to locate where exactly it would be and I couldn’t narrow it down enough for any level of confidence.
Suffice to say lesson learned, building a perfectly flat table on a very not flat surface is very difficult. What I attempted to do was make sure all my individual measurements were accurate, and then force each piece into place flush with the others, and presumeably (my theory, at least) the table would be flat as the sum of all parts are square. That was not the case as the force I had to apply to get everything level ended up storing energy in the structure and releasing it in a non-uniform fashion.
Saw through one rib at a time until the stress is relieved??? Then glue up all the cuts. In theory, this should work, but I will not/can not promise this.
Edit: Just occurred to me that the stress could even be in the bottom skin, not the ribs. Not sure how to fix that if so.
I ended up foaming the table and securing the work surface. It did retain the slight bow, but in the end it’s not signficant enough to really matter. I simply shimmed the machine on the one side which was slightly lower, but the other 90% of the table is perfectly flat. Honestly, it wasnt’t too bad for being constructed on a very warped table, and that was probably the best I could have hoped for. I will say the MDF top made the table damn heavy. I have it wall mounted so it can be flipped up, and it’s definitely not a task for women and children, to say the least.
“All the women are strong, all the men are good looking, and all the children are above average”