At my old School in the late fifties, our metal/wood work masters asked us to plan, draw and make a working model of a single cylinder engine from wood, with gear driven cams to work side valves, in the cylinder head box, they promised if we could do it within term time , the next term we could make one from steel, we all had a portion that needed to be done with correct measurements so they mated with the other sections and we overcame alsorts of problems, not only on the size and bore but in working out how to make the gears with angled teeth so as to operate smoothly, it really tested us, but we just managed to finish it in our Autumn term, we all received a headmaster award for that wooden engine, but when asked not many of us wanted to then go on to a steel replica, then we found out the lathes were not big enough to do what was needed and so sadly the project in steel was abandoned, our Wood and metal instructors were ex military and ex RR , so they then gave us lumps of mild steel and a measurement to make a cube to fit into a hole we had to make in a flat piece of 1/4"thick steel plate, now at 14/15yrs old that really tested us.. but that taught us much about files and filing.. I don't think they do that now..!