As a hand tool skills tuneup, I decided to build a case out of solid wood that would have all dovetail joinery. The case is actually for hand tool storage and will sit on the stretchers under my bench (general dimensions are 32″W x 22″D x 8″H). I have a few planks of soft maple left over from a kitchen cabinet job last year and I planed them down to a little over 5/8″, glued up the planks and then flattened them. At least they were flat yesterday, might be again tonight, but aren’t right now 🙂
At 5/8″ thick the panels flex easily enough that they can be flattened again with hand pressure.
There is no stopping dimensional movement that’s a given, but the issue here is dealing with cupping of solid panels. We talk a lot about keeping table tops flat and the various methods for doing that, but what about cases (I suppose most people either build cases these days out of plywood, veneered MDF or just frame and panel). Do you rely on the joinery to keep it flat? Do you use cross grain battens with slotted screw holes to allow lateral movement? Other? What I am also wondering is what tactics you employ during construction to insure that the panels remain flat. If it is for example going to be a few days between the time you layout your joinery and then cut, chop and fit…?
Cheers,
Michael
Replies
I knew a guy once that made expensive pistol cases that soaked his green lumber for the case tops and sides in polyethylene glycol-1000 (PEG-1000). He would bandsaw to about 3/8" then soak the pieces for 2 - 3 weeks. The PEG molecules are absorbed into the wood and prevent expansion / contraction. I've never done this so that's about all I can say. His cases were Smithsonian quality. He lived in Tulsa near 21st Street & Garnett Road. This was 30 years ago so he may have passed on by now. He did lots of intricate gold/silver/mother of pearl inlays on the tops and sides. All hinges and locks were hidden.
Do a Google for "PEG WOOD TREATMENT".
PlaneWood by Mike_in_Katy (maker of fine sawdust!)
PlaneWood
Castlewerks,
For the dimensions you are talking about the dovetail joints will hold everything nice and straight. Even if the sides are mildly cupped when you prepare the joints, the glue-up will pull everything up tight and keep it there. You may need some selective clamping applied at critical points. The bottom of the box should float in a groove that will limit any wayward tendancies. The top should be frame and panel construction.
DR
As I said the glued up panels are thin enough that I can easily flex them straight with hand pressure. So, What I was thinking is that when I layout and cut the dovetails, I could clamp battens across the width of the panel to keep it straight -- as some people do when performing a glue up to begin with. I was just hoping that the dovetails and the glue would keep the panels flat over the long haul.Thanks for replying.--M
The joinery will keep the panels flat once assembled. .You are taking a correct approach by using cauls to keep them flat for layout and cutting of joints.
Thanks everyone for replying -- I'll let you know how it goes....Cheers,M
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