We decided to go back to making simple flat panel doors in-house. We buy S4S material such as soft maple in 2 1/4" width to profile, cope, and assemble. The problem we are having is longer pantry doors having some length "twist" in them once hung on the frame or box.
Using a squaring frame clamp helps its intended use but not this problem. We select the most flat lengths of frame and panel material for these doors. We have had some success using old winding T sticks on a flat table with hand clamps to tweak the joints but that takes a lot of time and space. Does anyone have any suggestions?
From contributor K:
I have found that any lumber used that comes in the door with any twist at all eventually shows up in the cabinet doors. No matter how much time I spent flatting the stock it shows up in the finished product. I clamp on a Ritter frame table and it's critical to be sure your clamping table is flat to start with. Next, if I have long doors, I'll take the time with a chisel to shave just a little extra off the tenons so they fit a little looser and can twist a bit in the joints to help the door lay flat on the clamping table while being glued and pinned. After that, I hope and pray. I also deliberately avoid doors taller than 42". Also, if you're buying door stock already milled S4S, try making your own just for those taller doors. No moulder is going to straighten and flatten any piece of lumber. You need to do it by hand.
In addition, check and recheck the square of your cope cuts (and your cope clamping device). If the cope cuts are not virtually perfectly square, the clamping table is going to "force" all to be square. If cope cuts are not square the only way for the assembly (door or panel) to comply when clamping is to warp! Of course the effect will be the more noticeable the larger the assembly.
Gene is correct about MC, but for most of my clients, (and my experience in the shop) getting consistent, properly dried wood stock is not only difficult, but getting harder and harder to find all the time.