The thread of building stools went dormant in May as the second test stool, having almost exactly the characteristics of the target stool, proved to be something of a failure. The seat was a little bit like a surfboard, one could lean it a few degrees in any direction, and while that was cool it was not really a characteristic one wants in a stool. It was asking to fail more profoundly and to this one must say ‘No’.
The cause of this wobbliness was that the mortises dug to accept the tops of the legs were too wide. This, abetted by the fact that the four 3/8 inch dowels pinning the legs through the seat really had no mechanical advantage, allowed the wobble.
Too wide mortises shown:
The solution? Epoxy-resin, perhaps overkill at 2500 psi. Pouring that into the space where there was but an air joint really changed the performance of the joint. It’s rock solid now, no wobble, no fail. This is proof of concept that I’ll be able to go forward with the original idea – even though the original idea contains the same flaw, the over-wide mortises, because this remediation covers it.