Originally written May 2, 2018

I couldn't find anyone describing how to cut dovetails for non-square corners, so I decided to write this up. This trick will work for any angle dovetails, but you'll have to change up the workholding jigs.

This is a description of how to cut dovetails for a 135 degree corner. This is the angle used on an octagonal box (if all the angles are equal). They're not perfect, and there's probably a better way to do it, but this is the best I found.

My first try cutting 135 degree dovetails used no special workholding. I just threw the pieces in the vise and started cutting. I cut tails first and I cut them pretty much as normal, except with the end of the board at a 45 degree angle, so they were pretty easy.

The pins were fairly straight too. This is feeling easy!

But the fit left something to be desired.

So I sat and thought for a bit and decided that maybe I could use a square piece in the corner, all tails, and put pins on the edge pieces that would go into it, and then cut the 45 degree angle afterwards. It couldn't be any worse than the previous attempt, could it?

Well, that worked okay, and I might end up trying that method again, but I'll have to think harder about the grain direction in that corner piece when I do.

So I tried again. Third time's the charm, right?

I cut the tails square this time, just like you would on a normal dovetail. I even gang-cut them two at a time.

Then I cut the pins on a board with the end angled 45 degrees using a jig I made for the purpose. I made the 45 degree end on the board using a miter jack before cutting.

Those came out pretty good I think. They're a little gappy where I went astray with the coping saw while cutting out the waste, but they glued up solid.

Hopefully someone else will learn from this and find it useful. To get the boards to look good in the corner, just make the corner piece (the walnut in the above photo) 0.7 times as thick as the edge piece (the ash). The example I show has the walnut thicker, and the corner looks kinda goofy to my eye.

#technique #woodworking #dovetails

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Originally written August 2, 2020 – Note that this is long, and covers how I cut #dovetails in what might be excruciating detail if you already know how to hand-cut dovetails. I won't be offended if you skip ahead.

For this style of bookcase, there is a plinth, which serves as a base, supporting the stack of boxes. Since the plinths are mostly hidden, and the weight is mostly carried by the four glue blocks in the corners, I figured they were a good place to start. Half of the dovetails will be hidden, and only one of the four boards is very visible.

Here's my checklist for building the plinths, along with some pictures of the intermediate steps:

1. Cut all the boards to length. There are three different lengths of pine 1×4 and two lengths of ash 1×1 glue blocks. Two 1×4×12, two 1×4×31, one 1×4×29½, two 1×1×3⅜, and two 1×1×2⅝.
2. Mark out and cut tails on side boards (no miters yet).
3. Cut rabbets on side boards, using my kerfing plane with a fixed ⅜ inch fence, and clean them up with a chisel
4. Mark and cut pins on front board, including miter. If you cut the miter on the tail board before marking this, you won't have a full tail to transfer the mark to the pin from, and you'll have to guess where the pin edge should be. That's not a killer, but it'll make for a sloppy joint.
5. Cut miter on matching corner of side (pin) board.
6. Test fit.
7. Cut other corner pins on front board, including miter.
8. Cut miter on matching corner of side board.
9. Test fit and adjust.
10. Cut rabbet on front board.
11. Cut curved cutout on front board.
12. Smooth cutout with knife and spokeshave.
13. Cut pins on rear board, including miter.
14. Cut miter on matching corner.
15. Test fit and adjust.
16. Cut pins on final corner, plus miter.
17. Cut miter on final corner of side (pin) board.
18. Test fit and adjust.
19. Check for square.
20. Glue up, making sure to glue the front cross-brace to the front board before clamping. The cross-brace's purpose is to reinforce the front board, which has material removed for decorative purposes. It's probably not necessary, as I made a smaller cutout than Schwarz did in his version, but it won't hurt anything, and it helps me ensure that the plinth remains square when clamped up. Plus, as I'm going to be stacking the cases 6 high at a minimum, there will be a fair amount of weight. I'd rather not find out I under built in the middle of some night as books and lumber come crashing to the floor. Thus, the brace.
21. Double-check for square.
22. Unclamp after the glue has dried overnight.
23. Glue ash glue-blocks into corners, short ones underneath the cross-brace board. Note the spacers set in the rabbets so that the glue blocks will be flush with the rabbets, giving good support to the cases.
24. Plane smooth with a smoother plane, and chamfer the top-outside corners of the boards with a block-plane such that the chamfer is 3/16 inch wide. This should make the top edges more durable as they inevitably get dinged by the cases being set into them.
25. Three coats of shellac, brushed on. I'm using a 1½ pound cut of blonde shellac.
26. Sand lightly with 320 grit sandpaper to remove raised grain, dust nibs, etc.
27. Apply final coat of shellac.

Here's a stack of three of the finished plinths. The middle one is my prototype and doesn't have the mitered dovetails, so doesn't look as nice as the others. I'll hide it in the corner or something.

And note that while I'm working, I keep all the pieces on my benchtop laid out in order so I can more easily keep track of where I am.

And here's a photo of a completed plinth with the first case sitting on it.

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Jefferson Bookcases Contents #woodworking #bookcases #plinth #cutList

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