This might be my first post on this forum. I like the atmosphere! Thanks for keeping it family friendly! I put a 3/4" birch plywood top for a router table. When I run a raised panel bit, it starts making it thin, gets thick in the middle of the cut, and then it narrows toward the last part of the cut. Checking the flatness of the table, I found that it sags, so I took a hydraulic jack and leveled it for a temporary fix. My question is: What material am I going to use to replace the table top. Am I going to have to put stiffeners on the underside to prevent sagging? I am thinking that MDF might be a good choice. I will appreciate your help.