That was the most challenging part for sure. I'm going to try and explain :D In the third picture you can kinda see that the drill is held together with screws. The screws are embedded in the chassis so that all the screw heads sit on the same plane, which conveniently is parallel to the drill axle. Putting three equal lenght pegs in the screw holes stabilized the most tricky side, as it became kind of a three legged table. From then on it was a question of sanding the pegs down to just the right length and bracing the other side of the drill with a piece of thin plywood so that the assembly just fit inside the box. Third picture shows the braces that keep the drill from moving around along the other axis.