Tuesday, February 24, 2015

Signature joinery

When I want to make a box quickly, I prefer mitered corners.  I can saw them out on the miter box quickly and accurately and they make it easy to plow in a groove for the bottom that won't show.  I usually glue in splines.  They look fine, if a little bland, and they definitely add strength as long as the glue holds, but they only provide limited mechanical strength, as compared to a dovetail for example.  I began wondering if I could come up with something unique to strengthen the corners.  I have always admired the Greene brothers; they took a popular style, arts and crafts, and made it their own through creative genius.  One example is that they took the box joint and made it a thing of beauty by incorporating protruding, pillowed fingers and ebony plugs.  Paradoxically, the reason I like mitered corners is because they are quick and easy and provide a blank background.  I see them as being like an artist stretching their canvas and painting it with a washcoat.  Maybe that means an unobtrusive spline is the way to go.

Wouldn't it be great if I could come up with some creative, visually attractive way of enhancing and strengthening miter joints that could become a sort of personal signature?  I realize this is somewhat silly because I don't have the Greenes' creativity, but you can't blame me for trying, can you?

Here's what I'm after:
  1. Strengthened and enhanced mitered corner
  2. Fast and easy to make with hand tools
  3. Attractive
  4. Creative and unique
Not looking for much, am I?  I decided to make a test piece to see what I could come up with.  The first thing I did was use my router table to make dovetailed splines, which I think I remember reading about somewhere.  They looked good to me but, on a whim, I used a roundover bit on the corner and I think the result is very attractive for some applications:

 (The reason for the blue tape will become clear in a minute.)  It has a butterfly-like appearance that I really like. It's sort of like a dovetail joint with no end grain and tails on both sides that meet at the corner.  There is a problem with this joint though.  It meets criteria 1,3, and 4 but seems to fail 2.  I made the prototype on the router table just to see how it would look, but I don't see a way to make it quickly and easily with hand tools, at least not yet.  You might be able to make a template and, if you could saw and chisel very precisely and then use pre-made spline material, it might go fast, I don't know.  It's a little unintuitive because the spline doesn't look like it would fit in the hole, an optical illusion created by the 45 degree angle between the face of the board and the spline, but I think a template could overcome that.  The roundover is easy enough.

What else could I do?  I don't like pegging this joint because there is so little material between the tip of the miter and the peg, so I don't think it is very strong.  But what if you put a peg diagonally through the joint so that it appeared on both sides?  It would be much stronger and you'd see an oval that might look nice, so that is what I tried next:

I would have to work on getting a clean entry hole with the drill at a 45 degree angle.  The result seems to satisfy 1, 2 and 4 but I think it fails 3.  To me it's ugly and, as Forrest Gump says, "ugly is as ugly does."

I had hit a dead end ... and then I thought of the Greenes.  I drilled a larger hole a quarter of an inch deep straight in on the top of the diagonal peg, grabbed one of the hollow chisels from the old mortise attachment for my drill press that I haven't used in years and whacked it in, then glued in a piece of square stock to fit the hole.  I sawed off the insert about an eighth of an inch above the surface and, not expecting it to work, I went over it with a sanding sponge.  To my amazement, the sponge pillowed the square peg, just like the ones Greene and Greene made.  (Actually it was the Hall brothers who made them, but that is another story.)

This is so easy I can hardly believe it.  None of that tedious effort you always hear about.  OK, my square pegs probably aren't as good, but I like them and they sure are fast.  Fast is as fast does.

This is the best idea I have come up with so far.  I haven't heard of running a dowel diagonally through a mitered joint before and the peg is so far away from the corner that it looks like an attractive decoration, not a part of the joint.  Still like the butterflies better though and I think I have a better appreciation of why splines are the usual choice.


  1. I like the peg and the square idea. Any plans to stress the joint to see how much force it can handle?

  2. Ralph,

    Since it has both the peg and the dovetail splines, I can't really test it for strength. I'll bet it is very strong though.

  3. How about mitered and dovetailed? It's my favorite box construction because it hides the grooves for the bottom, while giving a nice clean look. Here's an example, and here's another.

  4. I was familiar with this so I did some research and found this: https://www.canadianwoodworking.com/tipstechniques/mitred-through-dovetails Look like a good solution, though somewhat challenging.