View single post by mwiz64
 Posted: Fri Jul 26th, 2013 01:53 pm
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Joined: Mon Mar 26th, 2012
Location: Fenton, Michigan USA
Posts: 1329
If the lash in a spur gear is set properly then you are right they have very little friction. Some people tend to tighten them together too much and the the friction is noticeable. Why do people thighten too much? They are trying to adjust out the "slop" in the system. There is always some slop in a spur gear system, at least there is in one where the gears are not very precisely cut and lubricated. That's where helical cut gears come in. By nature of their geometry they are less prone to slop but then they do produce more friction.

It's been my experience that nylon spur gears can be adjusted tightly with very little friction loss. That's because nylon is slippery itself.

So what creates a jerky motion in a model gear train? #1 A gear train with slop. #2 friction in the gear train. #3 A low quality motor..... #4 This one is model train related only.... Dirty track and pickups.

With all 4 present in many train models, is it any wonder so many trains operate in a jerky manor?

All of these are magnified in smaller models. The smaller the model, the larger the jerk appears to be and to make matters worse, the more precise everything has to be to eliminate it.

Last edited on Fri Jul 26th, 2013 01:54 pm by mwiz64

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