Friends,
We are all aware of the problem of splitting gears but is there any advice for the possible alleviation of the problem?
(1) Not using the locomotive at all would save them but is there any advice about running the locomotives, lower speeds, possibly, lower loadings possibly?
(2) any strengthening that could be applied BEFORE running the locomotives?
(3) Overhauling the locomotive and replacing gears beforehand?
I ask because I have just purchased an item that is new and made in England, namely a Graham Farish 8117 diesel Locomotive 40145 and am concerned about the possibility of having to replace gearing at a later stage.
Regards, Peter.
Hi Peter,
Sadly I think the problem is to do with internal stress in the gears caused by either or too tight a fit or too weak a material, depending on how you look at it.
The only preventative maintenance I have heard of is removing the gear and reaming it out very slightly to reduce the stress - but I am going to guess that you (and me) would not want to be fagged with that!
I think you just have to be sanguine, get a supply of spare axles or gears and get used to doing the replacement every so often.
I have heard a rumour though that later model gears are tougher and/or thicker, so it may be a diminishing problem.
Cheers
Jon :)
Hi Peter,
You cannot let yourself go down the "what if" road.
If you run any mechanical object, eventually something will need replacing.
Just run the loco at whatever speed you want, enjoy it and when the time comes, do the repair.
It is not as if you won't be able to run any locos whilst waiting for the parts to do the repair, you now have a few locos, so your layout will not grind to a halt ;)
cheers John.
Firstly from my experience it needs to be mentioned that these gears normally last for quite a long time before they split. Being plastic they do eventually harden with age, but there are circumstances that can accelerate this process one being dramatic variation in temperatures, the other is the choice of oil which must be plastic compatible and not contain harmful solvents which can degrade plastic, and will eventually make it harden and become brittle.
As for the later Bachmann Chinese gears they are no different, I have repaired two locos in the last year that have suffered this same problem as the original Farish ones!
I recently helped a friend out repairing a number of his loco's which had been stored in his loft for a few years, all worked when he put them up there, but not one did when he brought them down to test them two and half years later!
What Scotsoft has just mention is the best advice, just don't worry about it and run them, if they do encounter a problem so what ! There's enough people on here that will help you. ;)
Farish gears even split when the loco is in storage, so not running them won't save them.
I have bought quite a few locos from the Bachmann stall, labelled "checked and tested - sold as seen". All have had split gears.
Presumably it goes like this:
Check - yes the gears are split
Test - yes, it won't run, the gears are definitely split
...put a label on it and stick it in the box for TINGS....!
Cheers Jon :)
1 won't help
2 there is no obvious way to do this
3. replace them with the thicker ones and they usually survive
The Bachmann gears on the new locos appear to be pretty crap unfortunately and with the wheels all being different what was an annoyance is now absolutely pathetic.
At least with the older locos you can get the parts and change them if needed.
Alan
As this problem of gears splitting, which has been ongoing for a number of years and over a wide range of models, surely this would be now classed as a form of "manufacturing fault"?
If so, would we not be entitled to some form of redress from Bachmann Farish?
Yes.. I make a point of returning models with gear splits or bugging Bachmann for free replacement axles. Your redess is properly however with the shop you bought it from not the supplier. It's up to the shop to sort it out with the supplier and a shop is in most respects responsible for making sure it doesn't sell crap.
I imagine that if someone took it up properly you'd a) get six years warranty claims without trouble and b) possibly be able to land Bachmann in the brown and sticky for negligence.
Unfortunately in the UK trading standards are more interested in pressing matters (like food safety), and nobody else cares. In the USA I'm sure one reason they fixed all this crap is that they'd have been hit with a class action lawsuit by now if they had not.
Plus US modellers had more choice of better brands, voted with their feet and Bachmann for some years was basically a dirty word ('Botchmann' is still a common name for them)
Alan
Could sudden changes in direction cause split gears? I have been advised to never change the direction of a loco too suddenly and rather to bring it to a complete halt before changing direction, does this make sense?
Quote from: EtchedPixels on November 06, 2013, 06:32:11 PM
The Bachmann gears on the new locos appear to be pretty crap unfortunately and with the wheels all being different what was an annoyance is now absolutely pathetic.
At least with the older locos you can get the parts and change them if needed.
Alan
You can do the same with new locos - the gears are still the same....
Cheers,
Alan
Quote from: silly moo on November 06, 2013, 10:21:26 PM
Could sudden changes in direction cause split gears? I have been advised to never change the direction of a loco too suddenly and rather to bring it to a complete halt before changing direction, does this make sense?
In a word, no.
The problem is too tight an interference fit at manufacture. The same Farish gears do not split if correctly fitted to the axles.
For the original post:
Don't worry about it!! Run the loco, enjoy it as it should be enjoyed, and if the gears split they can easily be replaced in the future. Preventative action isn't really worth the bother - if the loco hasn't got splits by now (bear in mind any Poole Farish loco is now at LEAST 15 years old) then there's a good chance it'll carry on fine. There were clear periods in the Poole production where the gears always split, and some where they appear not to.
hi Guys
I'm more inclined to go with aging of plastic than too tight a fit at manufacture as the white gears don't split - same mould, same axles, same fit but the fit does have an effect. Temperature changes seem to make it worse - nothing makes it better. Gears are still available, we can fit them and make our locos work again so don't worry about it - worrying only detracts from enjoyment of your rolling stock. If its new then send it back if you can as per EPs warranty info (thanks Alan) if not then fix it yourself or ask and help will be given - that's what were here for - inst it?
As for changing direction - new dapol 73 (ex set) with a glorious plastic chassis (stupid idea). I changed direction while going briskly along, loco promptly fell of the track and a drive shaft popped out - well that's a new one! Bagged it for fixing later.
Gears all the same? Possible exception is the warship - was told they have a14 tooth gear - not seen one fail yet so cant confirm.
Also not worth slaging of just Bachmann when Iv seen Dapol 73s with a full set of split gears - the fun bit is with careful work you can fit a set of Bachmann wheels in the 73 and they don't wobble anymore.
Enjoy your locos!
Regards
Russ
That's a new one to me Russell about fitting Bachmann axles to Dapol 73's! I'll certainly keep that tip in my note book!
:thankyousign:
Hi Mr Sprue
Yep - it works. Just need to widen the inside of the tower to accept the raised area of the axle (one of those ball shaped burrs works), and the axle slot needs to be slightly larger without being sloppy. Make sure you get them dead centre as the rims are very close to the frame.
If you like that then the farish 16 tooth gear also fits the top gear in the Dapol 9F that meshes with the worm (the one that gets chewed to bits).
eNjoy
Russ
Quote from: RussellH on November 07, 2013, 02:00:11 AM
I'm more inclined to go with aging of plastic than too tight a fit at manufacture as the white gears don't split - same mould, same axles, same fit but the fit does have an effect.
I think all are an effect. The initial build was definitely an issue though - I bought a couple of brand new locos around 1997/1998 when I started in N, and they had split after a year, with little running, stored in temperate room! Also, out of interest when I started changing gears out I tried fitting a gear from the same bogie to an axle that had split, (so same gear, made at the same time) and the fit is generally hugely tight, putting a lot of stress on the gear. If this is the way they were fitted in the factory, it's no wonder there's problems!!
There's been a huge list of possible reasons for splits over the years and I think it's fair to say there's been no 100% conclusive answer. But the situation has definitely improved somewhat, although there are still some cases in newer models. The ones I've changed out have all still used the 16 tooth standard gear on their axles, but there may be oddities about.
The white gears seemed to be a less brittle plastic (though there seems variation in the black plastic too - some of it seems very brittle, some less so). Seen a couple of split white gears too so they aren't immune, and the white drive couplings used in the armature blocks of 1984-1993ish Poole Farish regularly split too.
The replacement of Dapol 73 wheels with Bachmann ones is an excellent fix - though if you get any more let me know - I have a few spare 73 wheels here!
In terms of supplies, currently all gears for Poole Farish apart from the 16 tooth type 2 (101/Railcar armature end gears) seem to be readily available. The type2s are out of stock at BR Lines, but Lytchett Manor models are apparently doing a new run of their own tooling of the gears. Hopefully this will replenish supplies of all the different types for a while to come.
Cheers,
Alan
Quote from: RussellH on November 07, 2013, 09:03:47 AM
If you like that then the farish 16 tooth gear also fits the top gear in the Dapol 9F that meshes with the worm (the one that gets chewed to bits).
Interesting you've seen this too - I've had one 9F with a chewed gear. Supplies of actual Dapol gears can be obtained via DCC supplies these days, though they are currently out of stock (perhaps that tells a story ;) )
Also - the Dapol B1 has a bit of a major design flaw in the gear meshing - the worm only just meshes with the top gear meaning it can easily wear the corners of the gear teeth away and lose drive completely. Seen at least 3 with this problem...
Cheers,
Alan
Quote from: RussellH on November 07, 2013, 02:00:11 AM
I'm more inclined to go with aging of plastic than too tight a fit at manufacture as the white gears don't split - same mould, same axles, same fit but the fit does have an effect. Temperature changes seem to make it worse - nothing makes it better.
I'm inclined to agree that age and environment is definitely a contributory factor - I stored Farish locos in the loft for several years and all the ones with plastic gears split.
H.
Quote from: Dr Al on November 06, 2013, 11:36:03 PM
The problem is too tight an interference fit at manufacture. The same Farish gears do not split if correctly fitted to the axles.
I talked to people in the plastics trade when wondering about what would be involved in making better replacement gears. It's not just the tightness of fitting. I was told its two things
- poor choice of gear pitch (the pitch and arrangement of teeth govern the stress on the material)
- using the wrong plastics. You make gears out of materials like nylons. Actually what was said about their choice of plastics isn't repeatable here but did cast doubt upon both the species and the parentage of the decision maker 8)
H: Storage definitely seems to have an effect. If they get very cold or they get heat cycled a lot they appear to break more often.
The 2mmSA replacement finescale axles/gears don't split - but they don't run on N gauge track either 8)
Alan
Could some enterprising modeller make replacement gears from nylon, I wonder?
Jon :)
Quote from: PostModN66 on November 07, 2013, 01:40:53 PM
Could some enterprising modeller make replacement gears from nylon, I wonder?
Jon :)
Lytchett Manor models have their own tooling to make replacement Farish gears, so clearly yes. I'm not sure whether they use nylon or a different material for their replacement gears though. Maybe worth asking them?
Fitting the existing gears so there is a much less stressed fit is the easiest way round all this IMHO though.... ;)
Cheers,
Alan
Hi Al - I guess this means a bit of reaming - could you suggest a tool/method?
Cheers
Jon :)
Hi Guys
Copy of what I posted elsewhere for fav tool for "reaming" gears..
DIAMOND REAMER & COUNTERSINK SET - FLDR18...to be found here (any many other places!) page 94 of squires.
http://www.squirestools.com/11-06a.pdf (http://www.squirestools.com/11-06a.pdf)
Dont use a broach - thats designed for metal, dont use a drill as thats got the potential to cut the hole eccentrically.
Regards
Russ
Quote from: RussellH on November 07, 2013, 09:03:47 AM
Hi Mr Sprue
Yep - it works. Just need to widen the inside of the tower to accept the raised area of the axle (one of those ball shaped burrs works), and the axle slot needs to be slightly larger without being sloppy. Make sure you get them dead centre as the rims are very close to the frame.
If you like that then the farish 16 tooth gear also fits the top gear in the Dapol 9F that meshes with the worm (the one that gets chewed to bits).
eNjoy
Russ
Thanks once again Russ, another valuable tip noted! :thumbsup:
Regards
David
Quote from: RussellH on November 07, 2013, 03:46:55 PM
Hi Guys
Copy of what I posted elsewhere for fav tool for "reaming" gears..
DIAMOND REAMER & COUNTERSINK SET - FLDR18...to be found here (any many other places!) page 94 of squires.
http://www.squirestools.com/11-06a.pdf (http://www.squirestools.com/11-06a.pdf)
Dont use a broach - thats designed for metal, dont use a drill as thats got the potential to cut the hole eccentrically.
Regards
Russ
Sorry Russ for once I have to disagree about using a broach as they are designed to open holes gradually, hence why they are only slightly tapered and have five cutting sides. Ok agreed they were originally designed for working with metal but I find them equally as good with other materials including plastic.
I have to add over the years they have been a great asset to my modelling.
Hi Mr Sprue
The broaches I tried had only 4 edges for cutting (smooth square profile) and with the flexibility of the 12 tooth gears seemed to have little effect - maybe if I had gone on long enough I might have got somewhere. The diamond reamers are quick and can even be marked up so you know how far to work them in for a good fit. Can you send me a link to what your broaches look like etc?
Regards
Russ
Quote from: RussellH on November 08, 2013, 10:38:43 AM
Hi Mr Sprue
The broaches I tried had only 4 edges for cutting (smooth square profile) and with the flexibility of the 12 tooth gears seemed to have little effect - maybe if I had gone on long enough I might have got somewhere. The diamond reamers are quick and can even be marked up so you know how far to work them in for a good fit. Can you send me a link to what your broaches look like etc?
Regards
Russ
Hi Russ adding to the collection I already have, I bought a nice set at the Ally Pally last year. I'll have a root about later to see who sold them to me and get back to you.