muff disease (split gears)

Jeff Schumaker · July 08, 2015, 19:03

Hello,

I am looking for suggestions on how to combat split gears on Bachmann N scale 0-4-0 mechanisms.

Jeff S.

JulienW · July 08, 2015, 22:36

There are essentially two options.

1. Slip a brass collar over the axle. I can't recall the exact size tube you need (3 mm?) to get but Ian Turner did an article on this in 009 News a few years ago.

2. Neville Kent at N-Drive productions sells replacement axle muffs for the Bachmann 0-4-0 and 0-6-0 chassis. I think that these are moulded in a stronger plastic that that used by Bachmann.

From what I recall the issue with the chassis arose when production moved to China as there was an issue with engineering tolerances between the metal stub axles on the backs of the wheels and the holes in the axle muffs. This being the case it may be worth very carefully opening the holes out in the axle muffs (either the repaired ones or replacements) to avoid any splitting reoccurring.

Jeff Schumaker · July 08, 2015, 23:02

Thanks for the info, Julien. I was aware of the brass collar, but am hoping someone can tell me the size of the tubing. I will also take a look at what N-Drive has to offer.

Jeff S.

rod335 · July 09, 2015, 07:04

The important thing to remember is that most plastics do NOT like oil and this is the major cause of Muff Disease. I think, but am not sure, that the N drive replacements are Delrin which seems to be impervious to just about everything!

Alan Feldon · July 09, 2015, 07:43

It has to be very thin walled brass tubing at 3mm otherwise you will have to ream out the tube to fit.
I slighty chamfer the existing muff ends to ensure the muff goes in the tube.
To be honest its a lot of work and easier to get replacements from N Drive at

JulienW · July 09, 2015, 09:21

Quote from: Alan Feldon on July 09, 2015, 07:43
It has to be very thin walled brass tubing at 3mm otherwise you will have to ream out the tube to fit.
I slighty chamfer the existing muff ends to ensure the muff goes in the tube.
To be honest its a lot of work and easier to get replacements from N Drive at

B.Meldon · July 09, 2015, 11:23

In my experience the N drive gears sometimes need a drop of super-glue to hold the wheels on tight, but apart from that they work very well and are a lot less trouble than using a collar.
You also need to be aware that the holes in metal side frames on the chassis can ware quite a lot with the result that the axle assembly can be far to lose causing the wheels to wobble.

I have used the N drive gears in both the 0-4-0 and 0-8-0 Bachmann 'white box' chassis. (I do not know if they also fit the Bachmann 'white box' 0-6-0 but I would think they do.)

Brian Meldon

Jeff Schumaker · July 09, 2015, 15:02

I could not find the replacement gears on N-drives website.

Jeff S.

Jeff Schumaker · July 09, 2015, 15:04

Quote from: Alan Feldon on July 09, 2015, 07:43
It has to be very thin walled brass tubing at 3mm otherwise you will have to ream out the tube to fit.
I slighty chamfer the existing muff ends to ensure the muff goes in the tube.
To be honest its a lot of work and easier to get replacements from N Drive at

Alan Feldon · July 09, 2015, 16:36

If they are not on the web site then e-mail Nev
The 3mm diameter is what it is normally sold as ,and would be o/d.Hence Ian said use thin wall tubing.
Living where i do I had to rely on a non modelling friend to send me some and it was quite thick,hence i had to drill/file out the interior diameter to get them to fit as the muffs are about 3mm.AS I said ,on that basis,its far easier to buy new from Nev.
I have used them on several 0-6-0's
I normally order 4 at a time for

Jeff Schumaker · July 09, 2015, 20:17

Quote from: Alan Feldon on July 09, 2015, 16:36
If they are not on the web site then e-mail Nev
The 3mm diameter is what it is normally sold as ,and would be o/d.Hence Ian said use thin wall tubing.
Living where i do I had to rely on a non modelling friend to send me some and it was quite thick,hence i had to drill/file out the interior diameter to get them to fit as the muffs are about 3mm.AS I said ,on that basis,its far easier to buy new from Nev.
I have used them on several 0-6-0's
I normally order 4 at a time for

WALLSHIRTS · July 10, 2015, 00:20

I just replaced all the gears in a Windle 2-6-2T that uses the Bachmann chassis, with N-Drive gears, it runs smoothly but now the motor is running hot. Anyone else have similar problems?
Mal.

B.Meldon · July 10, 2015, 07:51

It could be that the motor brushes are worn down and/or the brush springs are no longer as strong as they once were.
The heat generated by this can also weaken the springs further!

You could try re-tensioning the brush springs.

That said I have found that the Bachman motors do get hot when run on feedback controllers like KPC's for example, especially when run at a slow speed for a long time. In fact I have known the small plastic frame motors used in the 'white box' 0-4-0's and 0-8-0's to burn out and I always now limit their use on my layouts that have KPC's as a result.

At one time Nigel Lawton produced a motor replacement kit for the 0-4-0

JulienW · July 11, 2015, 16:31

Quote from: Jeff Schumaker on July 09, 2015, 15:02
I could not find the replacement gears on N-drives website.

Jeff S.

In which case I'd try contacting Neville directly through his website's contact page as he certainly sells them at exhibitions.

Jeff Schumaker · July 12, 2015, 00:59

Quote from: JulienW on July 11, 2015, 16:31
Quote from: Jeff Schumaker on July 09, 2015, 15:02
I could not find the replacement gears on N-drives website.

Jeff S.

In which case I'd try contacting Neville directly through his website's contact page as he certainly sells them at exhibitions.

Julien,

I have been in contact with Nev. He's planning to mail me some gears.

Jeff S.

muff disease (split gears)

rod335