then you should have put a stretcher on it.
I thought the drawbored mortise and tenon joints would be enough, but the ash sitting bench has turned out to be a bit wobbly. So paraphrasing Queen Bey, I’ve decided to retrofit a stretcher to back legs. In my world, “retrofit” is a synonym for “lap joint”.
A friction-fit lap joint can be very strong. Between the long grain-to-long grain glue surface and the mechanical strength of the intersecting joint, it can be nearly as strong as a proper mortise and tenon joint, even without a metal fastener.
Because the joint will never be seen, though, I may add a slotted screw to each joint for a little bit more lateral support. Or perhaps a walnut peg, to mimic the other drawbored joints in the piece.
There was some subtle twist in the entire assembly, so I’ve left the joint clamped for the full 24 hours. That will give me time to think about whether to screw or peg.
The only other remaining question is whether this one stretcher will be enough. I’d prefer not to add a second stretcher to the front legs. I tend to cross my legs at the ankles when I sit, and that stretcher would get in the way.