Wheel gauge query

[Graeme Starkey]

Can someone please tell me the back to back distance for n gauge wheels please,

[B.Meldon]

Sadly there is no simple answer to this question! (This is probably why it has taken several hours for a response.)

I use a 7.3mm back to back gauge.

However this is just used as a guide as the actual measurement will depend on the thickness of the wheel flange and this is different for virtually every manufacture!  

The way I do this is to use the back to back gauge as a rough guide and then try the vehicle through the points I use, in my case this is Peco 12 inch and Y points made before 2010. If it runs ok then all is well, but if not the some very fine adjustment is required.

Different makes of track may well require slightly different back to back measurements.

I am sorry that I can not be more definitive about this, but it is just one aspect of 009 that has no exact standard.

Others may quote various recognised back to back measurements such as:

.290 inches (7.366mm)
7.4mm
7.54mm

However in practice the measurements vary from 7.25mm to 7.6mm.

Basically all that matters is that your vehicle runs ok through your points and on your track.

Brian Meldon

[rod335]

Brian is perfectly correct. There are no accepted standards for 009 modelling. But, as he points out, what we are trying to achieve is consistent and reliable running. To this end, an arbitrary standard or set of standards is really of little use when most modellers use proprietry track and often moulded plastic wheels which cannot be regauged. So the answer is, surely, to ascertain what is the greatest distance over check and wing rails in all your pointwork (it varies from manufacturer to manufacturer) and set all adjustable wheels to run freely through that or those points. I have to say that in my experience the earlier Peco points will tolerate a smaller back to back distance than the modern ones. If you wish to adhere to strict standards there is regrettably no alternative but to forgo moulded plastic wheels completely and build your own pointwork. The Society committee discussed for some time the concept of producing a back to back gauge and eventually concluded it would be of little use simply because of the lack of defined standards.

[Graeme Starkey]

Thanks for your help, it just saved me spending

[Graeme Dunbar]

I'm not sure why this is in the Sales (sub) forum, but never mind.

If you don't have a back to back gauge then a set of digital calipers can be used. If a piece of stock is playing up then a check with the calipers will confirm if the problem lies with the wheel (or track) dimensions. A genuine vernier caliper (not a plastic one) with a screw clamp/clutch can be set and used to check a run of items. It itself need not be that accurate if it can be set against a known dimension as it is the locking that is important. I have a fairly ancient and inexpensive one that got dropped, but is still good for transferring dimensions.

[Frank]

I have made satisfactory back-to-back gauges by filing a piece of brass to the correct dimension and bending it into a "U" shape.   Getting it square is the tricky bit, but you can square it up in a vice if slightly out.  You can solder on a brass handle if you want.

Scrap brass from etches can be used and is OK but slightly thicker strip is better.

Of course you do need to decide what B2B measurement you are using before doing the filing!


Frank

[MickT]

 A "rough and ready" solution which came to me from well known and respected 009 modeller Ian Turner is to use the large earth pin of a UK 3 pin plug and file it down to your desired B2B if you have one (around 7.4mm is a fair standard). On the other hand if you have the facility to measure accurately 7.whatever mm then you probably have a vernier caliper which can very suitably be used for a back to back gauge anyway!

So, on the assumption that you don't have this sort of high tech tool, then file the earth pin to be a good snug fit on a known free running moulded wheel and axle set such as a Peco wagon wheel with integral axle and you will then have a back to back gauge that will allow you to set any metal wheelset to the same as the Peco ones which are made to go through all Peco N  trackwork.


Mick

[Hugh Norwood]

Take the plug out of the wall socket first of course!

[MickT]

I only come on here to escape from the comedians on the "other forum".

[Hobby]

Wherever Mick goes, we go... ;)

[Steve Lewis]

I only come on here to escape from the comedians on the "other forum".

What  other  Forum,  is  there  one??  (!!)

[Hugh Norwood]

Sorry!  :'(

[MickT]

You have been fully pardoned Hugh. Nothing wrong with a bit of levity now and again, even in this august place.

Mick

[Dave Cooper]

Hi All. I don't know if it's any help but I did spot a useful table on wheel (and other) standards in Stewart Hine's book "Model Railways"- Haynes explains series 1977/80, which contains much useful info on the hobby and is a good read anyway !

For 'N gauge' he gives a back-to-back measurement of 7.4mm and a flange width of 0.6mm with a 'chamfer' angle of 20 degrees. There are also other useful data given eg clearances for pointwork etc.

A vernier caliper would certainly be useful here plus, I see that the various model railway show dealers are now selling digital calipers at quite reasonable prices. A search through Ebay /Amazon may turn up a copy of Stewart's book which has been very helpful to me as a newbie...
Dave   

[Stefan Krebs]

Before you nail your banner to one dimension you need to do a bit of thinking. Wheel and wheel spacing is only half of a system, the other half is the track.
It's worth studying the NMRA and NEM standards and understanding the system wheel, rail and track; as it is to decide and stick with one. Manufacturers that produce rolling stock and track typically put their own spin on those standards to tie modellers to their brand, i.e. design for incompatibility.

I aim for NMRA RP25, as it seems to be a good compromise between prototypical dimensions and running reliability. NEM, like most European manufacturers, has flanges that require flangeways the size of battle trenches; on level crossings more an cosmetic issue, but at switches an issue of good running.
But most 009 modellers in the UK appear not to be too concerned about prototypical track and use course standards; so this is a matter of personal preference.
If you stick with stock and track from one manufacturer this all doesn't really matter, but once you mix brands you have to know what standard they are made to! It's not just back-to-back, which has to match the distance from guardrail to guardrail at switches and crossings, it's also flange width and depth, and wheel width.

The standards can be found on the internet, and they give you the low-down on the subject.

As, whatever you decide, commits you for the future with regards to both rolling stock and track, it is worth to educate yourself so you hopefully avoid a decision you regret.

Cheers
Waldschrat