After I finished the dovetails, and was satisfied (reasonably), I cut the ends to a final length of 19″. Yes, I know that I said the bench would be 20 1/8″ tall. However, like Ron Herman’s bench, mine will have feet added to the bottom. This provides a replaceable bearing surface so that the end of the sides don’t get torn up, and provides a ledge to support the ends of boards clamped vertically. I made it a point to do this after the dovetails were cut to my reasonable satisfaction. By not cutting to length any sooner than necessary, I had the option to redo a dovetail that went bad.
Ron used a screwed haunched tenon for the upper stretcher, and a screwed butt joint for the lower. Both are perfectly serviceable and quick to make. However, I’m always concerned about screwed joints in components that will get a lot of “wiggle” and, while Ron’s stool has stood up quite well, I decided (as usual) to try something different.
I opted for a lap dovetail for the lower stretcher, and a lap half-dovetail for the upper. I’m not sure why I opted for the half-dovetail for the upper joints. It doesn’t have any real advantages over the full dovetail. It just seemed like a good idea at the time. A close inspection of the above photo will show that the shoulders still need a bit of cleaning up prior to assembly. Not to worry – I didn’t forget.
After all the tails were cut, I cut the matching sockets (the term pins doesn’t really apply here) in the edges of the end boards. The basic cuts were similar to dovetail pins. I sawed to the line, and then removed the bulk of the waste, leaving a small amount to be removed to the baseline, as shown below. However, this was not the time to grab the chisels and start paring.
While lap dovetails resemble conventional dovetails, they are structurally quite different. On a regular dovetail, the matching sides of the pins and tails are the primary glue surfaces, and provide the strength. The baselines where the parts butt together are all endgrain, and have no glue joint strength. As a result, we usually undercut the baselines a bit when chopping out the waste without weakening the joint. On a lap dovetail, the matching surfaces are edge grain on the tail, and end grain on the socket. The baseline of the socket is actually side grain, which mates with the face grain of the tail. This is the part that provides the greatest glue strength, while the dovetail shape provides racking resistance. As a result, the baseline can’t be chopped as in a dovetail, but must be smooth and flat to provide the best glue surface with the underside of the tail. The question is, what’s the best way to do this?
My tool of choice for this was the router plane. This modern take on an ancient tool allows you to trim smoothly to a precise depth. Yes, the power router can also do this, but the router plane has one tremendous advantage: A slip of the hand won’t ruin the entire piece. Yes, you can make a jig for the router, but that’s an extra step, and requires electricity. Aside from this, the setup for either tool is remarkably similar.
The first step was to clamp a block of wood level with the edge of the workpiece. This will provide an additional bearing surface for the router plane’s base to ensure that it remains level throughout the cut.
My Veritas router plane has an excellent depth stop. This allows me to set the maximum depth of cut to the finished depth of the socket. Then, I can back off and slowly work down to that point. Believe me, the last thing you want to do is try to cut too deep with a router plane! As you can see above, a good sawing job on stock removal doesn’t leave a lot for the router plane to remove. If you’ve got a bit more, you could of course use a chisel to get close to the baseline before switching to the router plane. The result is a glass-smooth bottom on the dovetail socket in a very short period of time.
After a good dose of Old Brown Glue, the whole lot goes into the clamps. Hmm, you know, it’s actually starting to look like something! Next time, we’ll make the feet and attach them. Stay tuned!