Quote Originally Posted by tkms002 View Post
the new ones do, yes. But at the school I mentored a robotics club at we bought one several years ago (a 4848) and it has a 3x3 gantry beam.
The 3x3 heavy extrusion is quite a bit stiffer than the 1/8 in wall tube by itself. It has the added benefit of all the inner webbing to help support it.