Friday, January 10, 2014

The Workbench (Part 2)

And now, it's time to cut my first mortises and tenons ever!

As I discussed in the previous installment, my Workbench was designed to eliminate the need to cut a dozen mortises and tenons. The short stretchers on the ends would sit in notches that were built -- not cut -- into the laminated legs. Unfortunately, I realized that it would be a pain to recreate that process on the long stretchers.

And, I admit, I wanted to try cutting mortises and tenons...just not 12 of them.

So the plan calls for the end short stretchers to set 6" off the floor, and the long stretchers (front and back) would be mortised into the legs. This presented another problem: should I mortise through the short stretchers, or tenon the long stretchers so that they slip under the short ones?

First drill-and-hand-cut mortise of my life.
Notice the layout lines outside the mortise?
I decided on the latter. So I laid out my first mortise, and in so doing, I realized what a mistake it would be to cut the mortises and tenons to the thickness of the tenon board. I ended up taking another 3/8" off the width. Wisely, I think.

My one-fence mortise jig. Doh!
In order to cut the mortises, I decided to hog out the material using my drill and a spade bit (since I have no drill press or mortiser). This proved to be a pain, since the material left between the drill holes ran three inches thick. It left a ton of chisel work. I decided to stop being lazy and spend an afternoon building a self-centering mortise jig for my router. Well, not really; at first, I decided to build a jig with only one fence; once that was finished, I realized how much more helpful the jig would be with two fences, so I built a second one. That's why it took all afternoon. At any rate, the jig was immensely helpful at cutting the mortises cleanly, but I don't have a bit long enough to cut all the way through the stock, even when cutting from both sides, so I ended up drilling away about 1/2" of material. Needless to say, it was a great deal easier to pair away the material the drill left behind since the router had eaten most of the thickness already.

The second mortise jig. Ooh la lah!
Ultimately, I wound up with four legs with fairly well-matched mortises, even with the roughness of the first one. None of them is perfect, but they're all close enough. I'm planning to draw bore the tenons in place, so a little slop is ok. I'm going to try cutting the tenons as close as possible to a slip fit as I can get, but I'm not going to throw the stretchers away if they are just a tiny bit loose.

Next on the agenda: cutting tenons. My plan at this point is to define the shoulders on the table saw and rough cut them to size by hand. I might try to build a tenoning jig, though; it'll depend how much scrap plywood I have lying around.

Four legs; four mortises.

The Workbench (Part 1)

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