This is one of the sphere flanges being marked out on 18mm MDF board. A CAD template was printed from the Photonic design drawing. It was important to ensure that the bolt holes lined up between the top and bottom flanges. So one flange was marked out with 8 no. equispaced diameter 12 bolt holes, the two flanges screwed together at the corners, and then the holes drilled through both flanges ensuring good accuracy. A drill press helped with this operation.