Niagara 4-8-4

[Len]

Thank you Len, but I was aware that delrin gears are low friction.  Also, it makes sense of course that producing delrin/plastic is cheaper than producing metal.  And thank you for the info re: larger (than HO) scale locos.

However none of this or the just prior info provided, answers my original question. 
Perhpas no one knows, which is why I am getting info on everything but.

To answer your origninal question more directly, no, having metal to metal gears does not create excessive wear. At least as long as normal lubrication, as with any gears, is used. In fact the wear characteristics are generally pretty good, which is why heavier S & O locos generally have metal gears.

Len

[richardl]

This does not have anything to do with the OP's question but a lot of good info about model railroading gears.

NWSL has a good gear primer that I found back many years ago which helped me a lot in gear planning. I suggest everyone store the link and do a lot of reading, even if you never do any gear modifying.

http://www.nwsl.com/

As an aside, I remember years ago some mentioning how a brass worm could chew up a fibre spur gear in a brass loco.

Rich

[jbrock27]

At last, were are finally getting somewhere.  Thank you gentlemen.

Please note, I did not use the words, excessive or abnormal doctor and Len.  I used the word more in relation to metal on metal use, as in faster or quicker, wear.   

...it's still the usual practice, when using all metal gears, to use dissimilar metals (usually steel and brass), and to use the softer metal in the gear easiest to replace.
Wayne

Good doctor, there must be a reason for this, correct? Having to do with, wait for it, wear, no?  This practice makes perfect sense when the likelihood of wear is high.  I only mention this bc I never heard of 2 delrin gears wearing each other out.  I don't consider a cracked or split, plastic or delrin gear to be the result of "wear", as I attribute that to a manufacturing flaw or the plastic "drying out" for lack of a better term.  I have seen my share of split axle gears that had no visible wear to their teeth.  I also never heard of a metal gear or worm, wearing out a delrin or plastic gear or worm. 

Just sayin...

[jbrock27]

With most locomotives nowadays, the gears, whatever their composition, are in gearboxes, and run within whatever tolerances are acceptable for the application and the materials used.
Wayne

Certainly, without a doubt.

Earlier locomotives, especial steam, often used a worm mounted directly on the motor shaft and the worm gear on one of the loco's axles.  It was up to the modeller to assemble the components in a manner that achieved the best gear mesh and to ensure that the motor sat square to the geared axle.  Incorrect mesh (too tight or too loose) could cause excessive noise and/or rapid wear.  Some locomotive kits had frames machined so that the motor sat in the correct position, but others required shims under either the front or rear of the motor to adjust the gear mesh.  The worm on a motor skewed sideways on the frame could chew up a gear pretty quickly.
Like any other gears, worms are matched to worm gears, with the teeth on the worm gear set at an angle based on the diameter of the worm.
Wayne

I for one am glad this is no longer the norm.  And I would not include having to perform such machinations, in my question about more wear, as performing such machinations could easily lead to incorrect alignment, thus causing excessive or abbynormal wear.  I would not consider these kinds of circumstances as "normal".

For most applications, Delrin gears won't likely wear out...
Wayne

...but metal against metal can in a hobby locomotive setting.  Thank you for confirming my point.

spin. 
As for metal-on-metal gears, the standard transmission on a car seldom fails due to gear failure, and, when it does, the failure is usually due to damage, not wear of the gears.
Wayne

Okaaaaaay, no argument there doctor....but we are not talking about automobiles here.  I would also point out that those auto gears are immersed in liquid lubrication in a sealed gearbox.

Interesting that the guy I originally asked this question of, is so far, a no show.  Must be out in his Jag, chasing 20 something year old red heads, while his guitar gently weeps...

[jbrock27]

If that's the case, then he must be having more fun than worrying about gears. 
Wayne

I would agree w/you, if not for believing it is more a matter of he just talks a good game

But, no worries here, as I have no metal on metal gears or worms on metal gears and only 1 steam engine to speak of and not a great one at that. Mostly for Xmas time around the tree.  All the rest are diesels and are modern enough to either have metal (mainly brass) worms, on delrin gears or nylon worms on delrin gears.  A good combo that has worked flawless for me thus far.   My preference would be to have that as opposed to metal on metal.   Buying stuff from NWSL can get expensive enough, w/o having to do it very often.

Nice pic!  As I have said before, I have long been an admirer from afar.