Dado, tenon, or both?

[Jessica Pierce-LaRose]

Planning out how to build some sort of tool cabinet thing. The design being somewhat similar to Jan Zoltowski's tool cabinet that was in an issue of FWW a few years back. Basic construction is basically a large dovetailed box, probably with a plywood back screwed, rabbeted and glued into the back. There will be at least one shelf dividing it as well, where the separation between the couple of planned drawers (which knowing me will end up being cubbies to stash stuff for a year before I finally make drawers to fit) and the large upper compartment occurs.

So I'm wondering how to best fit that shelf/divider/whatever. Are tight-fitting dados enough? I was originally thinking a couple of small, wedged, through tenons. If I went that route, should I also dado the rest of the board? Seems like if nothing else, that could make the joint appear more flush.

I never really know how much effort to put into something to make it sturdy enough for the job. I need to put down the saws and read up more on the basics, I guess.

[Karl Andersson]

On early American casework horizontal drawer dividers- like your shelf- they dadoed the shelf inside the case, then glued a longer strip of wood to the facing edge of the shelf and put a single dovetail on each end which was inlet into the edge of the case sides. This might add rigidity to the case sides that would help if you load the doors with tools, plus would keep the case sides parallel, preventing the shelf from popping out of the dado if you overload it waiting for the drawers to be finished...