In the absence of C-clips, D-rings, and countersunk Phillips head machine screws, what held this thing together?
In the absence of modern machine tools, those have to be hand cut gears; or the wax blanks were, if they were cast. That many (~120-150 on that main one in the photo) fine teeth, on so many small gears, which have to mesh precisely, all made by hand, seems an incredible feat. IF it’s 128, then multiple bisections could be used to lay it out; otherwise how was it laid out? Brown & Sharpe weren’t born yet.
So, considering its complexity, relative accuracy, etc., it should be obvious that this was far from a first attempt.
Any multiple of five or six would also work, Greeks knew their geometry. To hold it together, they used rivets, and/or the shafts themselves with the protruding end peened over. The state the thing is in (80+ fragments and apparent parts missing) makes me wonder if this one was being shipped as scrap, a common practice then as now.