The structure will be pretty rigid. The problem as I see it is the joints pulling apart over time with the day to day movement and use of a dining table. The drawing above will be pretty strong especially if you use some kind of epoxy glue to hold it all together. I'd be tempted to put some kind of metal bracket at the top and bottom of the leg for a bit of extra strength.
Thanks again and sorry for the late reply.
I plan to join close to the top and bottom ro minimise leverage. I have a quite complicated idea for the rest of the frame that will hopefully help the keep the top part stable...
The structure will be pretty rigid. The problem as I see it is the joints pulling apart over time with the day to day movement and use of a dining table. The drawing above will be pretty strong especially if you use some kind of epoxy glue to hold it all together. I'd be tempted to put some kind of metal bracket at the top and bottom of the leg for a bit of extra strength.