Backdated to Oct 8th, 2016:
Armed with my FERMIAC blueprint I started modeling wheels and drums, the main calculating components. The original components were manufactured on a lathe but I'll be using a 3D printer. Due to the overhangs in the design I decided to split each drum into two segments which will eventually be glued together.
The following is an image of both components of drum F, which is used to calculate the distance a neutron has traveled.
In the actual operation of the machine a neutron under study is given a certain amount of "distance points" which are deducted at different rates depending on the material its traveling through, these rates correspond to the ratios established by the multiple steps of the drum. When the neutron runs out of distance points a collision has occurred and it might trigger a fission reaction.