I was looking at buying some of the Walthers E unit replacement axles for my Green Diamond. The newer Walthers models have that 14:1 helical gear ratio, with a pretty pronounced angle in the teeth, from what I have seen. Do the older Proto 2000 models have a less pronounced angle or are they simple spur gears? From the photo, I see no helical cut. From what I know, the Proto is a knockoff of the Blue Box drive. What do the other drive components look like? Do any of the idlers have any angle in the teeth, even a little bit? Do you think I could mesh the worm directly with the axle gear? I took apart a Bachmann drive to look at it, and the gears have a slight helical cut. Since the angle alternates with each gear, the axle gear’s tooth angle is the wrong way to mesh cleanly with the worm directly. If the Proto gear does indeed have perpendicular teeth, could the worm mesh with it without an idler?