The last thing I’ve left to explain in the construction of a splay leg stool is finding the length of the rails which connect the legs on all four sides.
There’s nothing like the moment of assembly to find out if all the careful calculation and drawing work was correct. These splay leg assemblies come together all at once, with all the joints tightening progressively.
Everything looked like it was going so well, and then the legs bottomed out in the joints and there was still about an 1/8″ of travel left in the rail tenons for the joints to come together. Like I said, moment of truth. The problem then came down to finding out where I had made the error.
At first I was dumb, and didn’t think about the relationship between the leg length and rails. For every inch that the rail tenons come together the leg tenons have to move into the mortises about two inches…
But like I said, dumb, right? Out came my little saw with no set to try kerfing the joints on the legs to get a bit more travel. I wasted about two hours trying to get the rail tenons together, maybe .020 inch at a time. Kerfing is a great technique for getting nice tight joints, but the shoulders for the leg mortises needed to move back something like a quarter of an inch. where did I go wrong?
It was in my assumption that the distance of the rails was measured along the centerline of the top and bottom edges, and I had the drawing all along that showed how I was wrong, but didn’t see it. Funny how that happens. Effectively I cut the rails too short between the tenons. Rather than re-cut new rails, it made more sense to make the legs a bit shorter at the tenon shoulders. Thankfully this is a correctible problem, I’ll just end up with a stool that is a tiny bit shorter than I had intended.
The above excerpt from “How to use the Sashigane” Shows another small stool, with the length of the rail transferring directly down from a elevation view to the view of the rail from the top. Notice how the length points are along the edge? Yeah.
In my own drawing I had the correct lengths, but thought that the measurement point once the stool was folded up along the ground axis on one side was now the center line. I failed to reference the corresponding length of the edge on the other half of the rail. If I had, I would have found that the length does not change along the bottom edge of the rail in either side of the view, elevation to fold-up.
By placing a trace line on the center line and transferring it up to the fold out view I was able to find how much too long my legs were, a whopping .276″. There was nothing to it now but to disassemble the stool and re-cut the leg tenons.
But doing that was not simple either. Seeing as all of the joints tighten together as once, you pretty much need to pull all of the joints apart at the same time. The solution? The humble wedge used under the rails, constantly providing pressure to lift the leg assembly from the top as the rails were tapped apart with a hammer.
In a way I’m pleased this happened, because I ended up understanding the drawing relationships better.
I had already chamfered the edges of the legs, so it made laying out the new cut lines difficult, but not impossible, and this time the stool assembled properly. It could still use some kerfing on the joints to get a perfect seamless fit, but that can wait until the doug fir I made this from will dry out a bit, as I resawed the material from a timber framing beam off-cut that was still green.
I was looking for a challenge in taking on this stool build, and it doesn’t surprise me that I made some mistakes. In any woodworking endeavor that is often the case, and it equally takes skill to figure out how to fix the problem that was unforeseen. Don’t give up when you run into an obstacle like this! Its something we all learn from, and it will not be the last time I learn from my mistakes more so than if everything went perfectly to plan.