Japanese Stool, Version 4 (or 3)

[Alan Turner]

Here is Version 3, in process. I have decided to make the seat 17 x 9 x 1.25", and it will be scooped. The main problem with this stool as a production piece is the stretchers, and how to attach them both securely, and without a lot of fussing around. So, I have come up with an idea, and am testing it on this third sample.

Mark Singer suggested through wedged M&T for the stretcher to leg joint, but this is a tricky joint as the shoulders are angled, as is the tenon, and there is no easy way to get an accurate mark on them. But it was from this suggestion that I borrowed.

Each stretcher is a small breadboard ended assembly, and the main part of the stretcher is mortised and tenoned, and double wedged, into each of the end pieces. I am comfortable that this assembly is strong. Pix 1.

I made a pattern of plywood just to set the shape of the stretcher, drawing it with a french curve, bandsawing it, and then finish shaping it with spokeshaves. Pic. 2

Pic. 3-5 show the stool, with the stretcher taped on only. Pretty chunky, huh? This will improve, and lighten, when I shape the legs and seat. I will also profile the stretcher, but not with a router. Sort of a soft oval, I think, but that will await final assembly.

My thinking here is that with the long grain of the breadboard ends of the composed stretcher, I will have a firm glue joint to the legs. Note that the stretcher has to be cut on the ends at a 6* angle, and then cut compound at about ½* angle the other way. The primary angle is cut with the TS and a Kreg miter gauge, which I set off of a sliding bevel. The 1/2* or so angle is cut with a # 9 Miter plane, and just to show off a bit, I shot a shaving containing the end of the stretcher, complete with end grain tenon and wedges showing. This is a fabulous plane for this work since it is big and easy to control, and has the low angle needed for end grain work.

Next I will shape the legs and seat and stretchers, and then assemble.

Open issues remain: Do I need or want side stretchers? I will await decision until I can see the piece assembled, as shaped, to get a feel for the weight. Is the stretcher shape right? Time will tell a bit more. Will just a glue joint be strong enough for the stretcher, or do I need something mechanical as well, such as a pocket screw in the bottom, or an ebony dowel through the side of the leg, into the tenon and stretcher, or blind from the bottom? Should I use epoxy or will yellow glue be strong enough?

Comments are invited.

[Alan Turner]

A couple of more shots.
1. The router gimble used to scoop the seat. I had to make a second for the larger seat. The scoop over the width is 1/2", from 1.25 to .75 in the center.
2. The shaving from the end of the stretcher.

Thanks for looking.

[Tim Sproul]

Alan,

I think a stretcher tying the front and rear together is going to be required. The racking and shearing the legs will have to endure dictate this. You know that folks will tip the stool and most will put a lot of weight on just the rear legs tipping the stool back as they're sitting....without a stretcher or two tying the front and rear legs togther, the legs will work themselve loose from the seat or even worse...the joint(s) will completely fail.

A 150# person rocking the back legs will put a tremendous amount of stress on the leg to seat joint. Better to spread that stress out over 4 joints rather than just 2.

[Richard Wolf]

Oh boy Alan, I love your persistence on this project. More than I could muster up.
I really like the new stretchers, and I do think a mechcanial faster is needed, maybe an accent dowel from the outside. I think you will also need a side stretcher of some kind.
Like I said, you have the tenacity of a bulldog.

Good luck,

Richard