[DesertRatTom]

I think you want it to be a bit larger than a sheet of paper, maybe the fit the long dimension so a #10 envelope fits, and wide enough for a a sheet of paper, perhaps 9 to 10 inches. That will allow for all kinds of ephemeral items to fit. So that would be about 10 by 10 inches inside dimension square, with a depth of about 5 inches. Should handle most uses. If it's too large, papers will get messy.

The outside dimensions will be the inside measure, plus twice the thickness of the stock, plus 1/8th extra to allow the joint to be slightly proud. My thoughts anyhow.

 

[DesertRatTom]

Hi Steve, How's the box project going? I was thinking about it and what I'd do. I don't find dovetails attractive. I know, but it's a matter of personal taste. If I were making boxes, I'd probably cut the ends to 45 degrees and use a spline to join them. I'd probably round over each corner. I like the idea of the grain being continuous all round the box. Just personal preference. Here's a picture of a splined corner and how to cut it on a table saw. Notice the stop block next to the fence so make sure the spacing is identical for each spine slot. Use a Wixey digital angle gauge to get that blade to 45 exactly.