I did my good deed for the week and rescued an old round/oval table.
A table with a central leg will only last if it is made from steel. A wooden table that is light enough that human beings can still lift it, will eventually split, due to the enormous leverage from the table edge onto the central leg.
The central leg is made from four planks glued together and then turned on a lathe - which also weakens it. The four feet, are invisibly bolted through into the hollow.
When a knight in heavy armour leans on the table, the central leg tends to split at the bottom or top.
I wedged the spars open and poured in some while glue and let it run down, while spreading it with a little swizzle stick and wiping up with a damp cloth. Then I clamped it and drilled four holes for dowel rods (the little white points above the clamp jaws in the picture) - while trying to miss the hidden bolts.
To put an 8 mm dowel into hard wood, requires an 8.1 mm hole if you want to be able to tap it in without splintering the dowel in the process, but where to find such a drill bit? Not all drill bits are made equal. I have multiple 8 mm bits and one of them, is ever so slightly bigger than the others, so it performs dowel duty. With MDF, it is not a problem - you can mash an 8 mm dowel into a 5 mm hole if you have to...
There is not much point in putting too many dowels, since next time a heavyset knight leans on the table, it will break somewhere else!
In a couple days, I'll grind the dowel heads down with a Dremel cutting wheel.
One way to prevent repeated breakage, is to loosen the table top, so that it is balanced precariously and if anyone would lean on the table, then it will wobble threateningly and teach them not to, but this particular extendable table design unfortunately doesn't lend itself to such an evil solution.