Making replacement gear

[peteski]

Yes, this thread turned into a very interesting tutorial about gear design.
As far as our models go, most (if not all) of the current mass-produced N scale models use plastic (POM, aka. Celcon or Delrin) injection molded gears, so no hobbing takes place. Those gears are as good as the mold design.  The only metal part of the gear train is the brass worm, and sometimes those are plastic too.

[SkipGear]

As for the origin of this topic.....



Will probably make the "gearheads" cringe but it should work just fine. If I had the gear in hand, I might be able to fine tune it more but I think this should work. I created 3 sizes, 98%, 100%, and 102% of the original measurements so there is some room for mistakes in the measure and design, one of them should work well.

[peteski]

Tony, the gaps between the teeth should have the shape similar to the teeth.  In your gears those areas look like they are smaller. The teeth look too "fat".  Could it be due to the "bloom" during printing?

Something like this.  The gap between teeth has a shape of a reversed tooth (since the tooth a meshed gear will have to fit into that space.