I know I can just mill the top and make it flat. What I’m wanting to do is actually take the bow out. I ran a straight edge on the table prior to setting up XXL and it was perfectly flat. The sheet of MDF was flat. I drilled the holes a little larger to allow for squaring and not binding when assembling. So I know that can’t be pulling up the center. I replaced the M5 bolts with shorter ones and can see daylight between mat and cross supports. I’ve also noticed a fair amount of downward deflection in the center when pressure is applied. The supports have to be bowed don’t know what else could be causing unsupported span with two sheets of MDF on top to be the highest point.
What I’m trying to figure out is if there would be any issues with removing 9 of the M5 bolts, drilling them out, then replacing with 1/4” bolts. The bolts would run through top of first wasteboard and come out the bottom of the actual table top. These I could then tighten down to force entire XXL frame into the rubber mat from center and work way outward to straighten the bow and also in theory stiffen up the entire XXL by making it more rigid. This would be checked using a dial indicator.
I thought about shimming but don’t see how raising outer front and rear sides will cause the center to push itself down.
Never used a CNC so not sure if bolting it down to table top to stiffen it will cause any issues or problems that I’m overlooking. I have it setting in back cove in the shop so wasn’t planning on lugging it around anywhere.
Thanks again for advice