Gear noise

with metal gears (Markits or whoever) if the worm and gear are perfectly alligned at 90 degrees then gears just have a slight whirr, but if not then
theres a sort of gnarly whirring sound - if you've heard it then you recognise it. With some they can be quiet as anything with just chassis but add white metal body or a load then can become gnarly whirring - plus wheels slow considerably. Also often slower and noisier running one way compared to other. Have checked alignment - by eye, have checked theres the easily the rollup paper space between gear and worm, have checked gear box sides are parallel and 90 degrees to motor. Is there anything else that could be done. Someone did mention giving a run with toothpaste to grind sharp edges, but would that fix this ?
Cheers, Simon
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Thrust bearings?
There is usually some in and out slop between the shaft and the motor body.
Couple this with the metal-to-metal contact area of the worm which means a lot of friction.
This means the gear wheel either pulls the shaft out or pushes it in, depending on the direction.
So if the meshing is perfect in one direction it isn't in the other.
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simon wrote:

There will be rough bits on the gears. Running with a grinding paste will remove those edges, but you need to be able to remove the grinding paste and debris thoroughly afterwards, otherwise the grinding continues well past "good running" and takes you rapidly to "worn out". Toothpaste is one fine grinding paste. Valve grinding paste (car repair specialists) is another. I'd only use them if I could dismantle and thoroughly clean things.
Once it runs well, you need some lubrication on the gears. A light grease might be better than oil.
And, as Christopher said, there is an issue of back-lash in any motor bearings. Adding thrust washers between the worm and worm support bearings might help.
- Nigel
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Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
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Thanks for the ideas/advice everyone (but where was Greg ?). Had done some extensive surgery on chassis and body to get motor in and not pushed to one or tother side - that had improved it. However had only removed large bit of spacer in front of worm instead of extensive amount. When motor tips up - when put in body or chassis running under load - front of worm rubs against chassis ! More surgery coming up.....
Cheers, Simon
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You need something like a loop of wire to stop the motor moving.

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Normally yes or just some tape, but the motor goes into a slot inside the boiler. Its a Mercian Peckett which has a gap between footplate and boiler.
http://www.modelrailways.tv/images/catalogue/larger/SG1.jpg
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Pretty - I like the Peckett 0-0-0STs. I remember a pair of them on the Met.
I've got an unfinished O-scale Agenoria Peckett, GWR ex-Cornwall Mineral Railway Burngullow Branch. It uses a tiny motor but then this is only going to work/shunt short trains.
What about small blocks of foam strategically placed to stop the motor tipping too far up or down?
Ideally the motor should not move at all. Sometines you can put a piece of wire through the gearbox.
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0-0-0STs? Do they run by magnetic levitation? ;-)
--
Martin S.

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wrote:

Might be easier to get working than plastic centred wheels :-)
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You would still find members of various scale societys have opinions which are Poles apart.
G.Harman
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wrote:

havent given up, hopefully its just technique (mine needs improving)
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On 05/11/2010 21:24, snipped-for-privacy@yahoo.co.uk wrote:

It's this North versus South thing again...
--
Dave,
Frodsham
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wrote:

Could be EU, think we need to check
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This has a small motor, but is packed with lead. Have tried it with 14 wagons and it doesnt hesitate. Between the lead and the small slot its not easy to get foam in - would have to be after motor almost in place.
They are nice locos, I intend to build other types - got one waiting, but there not that easy for those of us with less good skills. Especially if theyre scaled down from O guage. Also if theres not a lot of documentation - Trevor from Mercia has already heard my opinion, but cant be snappy with him as he's a nice person who supplies nice kits ;-)
cheers, Simon
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simon wrote:

There will be rough bits on the gears. Running with a grinding paste will remove those edges, but you need to be able to remove the grinding paste and debris thoroughly afterwards, otherwise the grinding continues well past "good running" and takes you rapidly to "worn out". Toothpaste is one fine grinding paste. Valve grinding paste (car repair specialists) is another. I'd only use them if I could dismantle and thoroughly clean things.
Once it runs well, you need some lubrication on the gears. A light grease might be better than oil.
And, as Christopher said, there is an issue of back-lash in any motor bearings. Adding thrust washers between the worm and worm support bearings might help.
- Nigel
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
  Click to see the full signature.
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A less abrasive grinding medium is BiCard of Soda. Once satisfactory it is readily soluble in water (distilled & cotton buds). We used it extensively in instrument work.
Regards
Peter A Monatrlot
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simon wrote:

If a loco becomes noisy when you add the (whitemetal) body then the body is loose. That doesn't neccessarily mean it needs screwing down tighter. It may be that the body is sitting on a couple of lumps (eg metal flash) so that it is tight in one direction and loose at 90 degrees. It could be tightish at one end and loose at the other. Figure out where the body touches the chassis - it needs at least to have 3 points of firm contact to stop it vibrating seperately from the chassis. A possibility is to have a non-metal to metal contact - a couple of cardboard gaskets. An advantage of gaskets is that you are less likely to overtighten mounting screws whick can strip out threads in whitemetal/ pewter.
However, there has to be vibration in the mechanisim to get the body vibrating - that needs attention!
With plastic bodies, I've always made sure that any empty spaces are filled to stop noise amplification. Foam rubber blocks (roughly shaped with sissors) usually does the job, but I stick sheet lead cut to size on the insides of flat panels.
Greg.P. NZ
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Whilst it doesnt apply for this particular loco, thats very interesting. When I first started building kits, chassis to body was the last thing considered and hence tended to result in wobbly bodies. Will re-visit a couple of locos hat should be quieter runners.
Thanks, Simon
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