My table has a hinged 2'x4' section that folds out to increase the playing surface from 8x4 to 10x4.
I initially tried to have fold down legs at each corner of the extension but these proved to be somewhat unstable and prone to being knocked out of line. I'm sure this is due to my lack of natural grace and fluid movement skills - a situation that is foreign to the majority of gamers -
I replace the drop legs with arms that are at a 45 degree angle - this solution is more stable and not prone to being bumped
Given that players can lean on the extension, I used a piano hinge along the entire width - it adds a great deal of strength to the joint.
Good luck
Miles