I built this door in 2012. The main door is pretty heavy, so I equipped it with a counterweight system.
Materials used : fir planks , asphalt waterproofing membrane , expanded polystyrene board , steel wire , nails ,
Step 1: Counterweight System
The system is very simple. I even used some recovered parts. For example, the pulley is the gearbox of an old lathe. I made the counterweight from a bag full of sand.
Step 2: Joint
Because I had just finished building a CNC milling machine , I wanted to test it so I made the joint.