The “space frame” idea for the tower part turned out feasible, so I went ahead with that one. The space frame construction, made of the same 12 mm aluminum tubes, 2 mm steel cable, and 35 mm hardwood balls as the stand for the cabin part, is rock solid, even by itself. I didn’t dare sitting on it, but I piled about 16 kg of stuff on it and it didn’t budge. I suspect the weakest points are the wooden balls, and I half expect that at some point one of them will burst with a bang. This should not cause too much damage however, as the tubes can’t move very far without them, still being held together by the cable – except in one case with the joints at the bottom center, where there is one piece of cable that is not wrapped around the other ones because there wasn’t space for it inside the ball, so if the ball breaks along that plane, the joint will fall apart into one piece with two tubes and one with four. This can be mitigated by reducing the tension in that direction using an additional belt around the legs.

The wooden legs, which are maybe a bit overdimensioned, as two of them alone turn out to easily hold my weight, are designed to both bear the majority of the load and hold the tubes in place in the event that a ball breaks. All the wooden parts are CNC-routed from 9 mm birch plywood. Their sizes push the limits of the CNC router at FabLab Zürich, which was also the reason why the table is split into three parts (apart from allowing it to be assembled in two mirrored arrangements). Making efficient use of the material is hard when the parts are so large that only one of them will fit into the router at a time, so I now have lots of oddly shaped plywood residuals sitting in my home. I will think of something to build out of them…

On top of the table, a truncated pyramid of three more plywood parts will hold all the components. I routed the last one of them today, but still have lots of rough edges to sand on all of them.