The design has an interesting use of single-shouldered tenons set in opposing directions. Normally, single-shouldered tenons are less stable than two-shouldered tenons, but set against each other, they work against the twisting force on the post. This opposing set of joints form the real strength of the frame. The single bottom rail gets conventional double-shouldered tenons.
Following the instructions, I clamped the three rails together, and marked the shoulder line of the tenons on all three rails. Underhill's article suggests at least 4", so that there is lots of wood left to hold the wedges. Not having paid close attention to making sure each length was identical, I have quite a bit more than that on at least one. I'll trim them to somewhat symmetrical later on.
A four inch tenon is the longest tenon cheek I have ever ripped. Roy uses a ripping hand saw, I am not quite that confident. However, my Veritas tenon saws cut to a depth of almost 4", and that seems a much better idea for my skill level, the rigid back will help keep the cut straight. He suggests ripping the cheeks first, and this is where I realize my decision to make the ways another two feet longer has consequences. A four foot rail clamps comfortably at an angle to show two faces for cutting the cheeks to a straight line. A six foot rail puts the edge awkwardly high. I ended up using a stool to stand up to get a better sight and hand line to start the cuts. Somehow did not get the photos of the setup that I thought I did.
Mixed results over the four single-shoulder tenons, I will need to spend some time cleaning up the cheeks to create a nice flat surface. No disasters, however some rough edges left by corrections.
I have to remind myself that this project is a learning exercise as much as anything. By the fourth, I was getting somewhat better. As expected, the almost 4" was not deep enough, but I completed the cuts down to the baseline with a ryoba. I suppose that is heresy to some. Most of the time I prefer Western saws, sometimes a Japanese pull saw is perfect. At some point, I'd like to develop some real mastery of Japanese tools, for now, they are useful to enjoyable to use.
The crosscutting was fairly straightforward, mostly managed to respect the baseline. The soft wood of the spruce cuts quickly, once I start to assemble the joints I might notice more mistakes, for now though I have four single-shouldered tenons with cheeks needing cleaning. I will move on to cutting the double-shouldered lower rail, then clean them all up together.
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