To better get a handle on the final design and also work out the construction details we decided to build a detailed massing model at the scale of one inch equals one foot. The model worked out to be twenty inches tall. This makes the finished piece twenty feet tall. The realities of the ride safety envelope meant we had to scale down the stump diameter a little.
The structure will be built in three sections to facilitate shipping it legally on the road. The first break will happen between the drum top and the bug's feet. To make for a good and strong connection we cut two rings of half inch plate steel. The accuracy of the MultiCam CNC plasma cutter ensured things line up perfectly. These were bent slightly to match the model and then the rings were bolted together. We then welded the amateur below it. A stand (the a matching bend) was also fabricated to transport the top portion to the site.
The structural steel frame and bracing is all heavy square tubing. I then welded a sub frame using lighter one inch square tubing which was followed by a hand formed pencil rod grid to form the armature. By the time the upper portions of the armature are welded there will be more than a kilometre of steel in this piece.