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7 MM gauge which one?





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#1 hayfield

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Posted 20 January 2014 - 10:49

I have just looked at Templot with regard to O gauge turnouts and found 9 different standards !! and I thought 4mm was bad with OO, EM, P4 and now OOSF.

 

With the advent of high quality RTR models what standards do these adhere to please, or is this a mine field

 

Thanks





#2 RedgateModels

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Posted 20 January 2014 - 10:55

I would use 31.5mm without question if I were starting again with Fourgig, same with 16.2mm if I ever do another OO layout ......


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#3 The Nth Degree

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Posted 20 January 2014 - 11:27

I agree with Redgate, if you were building track, which you appear to be doing, either Scale 7 or 31,5mm standards offer far superior running.


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#4 martin_wynne

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Posted 20 January 2014 - 12:33

Hi John,

 

Agreed. The two sensible options for new modellers in 0 gauge are:

 

0-MF -- 31.5mm gauges from Debs of this parish, see http://www.rmweb.co....ser/13493-debs/

 

0-MF runs all common 0 gauge wheels including RTR and the Slaters "industry-standard" wheels.

 

---------------------

 

Or alternatively S7 (the 7mm equivalent of P4) -- needs replacement S7 wheels and easier curve radii. Full details, gauges, etc., from: http://www.scaleseven.org.uk/

 

---------------------

 

All the other 0 gauge options in Templot are now obsolete or deprecated -- they are there for existing 7mm modellers who are already committed to them.

 

regards,

 

Martin.


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#5 Debs.

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Posted 20 January 2014 - 14:02

The 0-MF standard has rapidly caught-on with 7mm. trackwork builders, with such modellers reporting better running through common crossings and visibly 'finer' flangeways, which appear much more prototypical compared to the standard Gauge-0.....the foregoing, combined with the full compatability with RtR and 'aftermarket' finescale wheelsets, makes 0-MF a very attractive choice.
To make adopting 0-MF standards even easier: I can supply 0-MF track gauges, adjoining-line gauges and 1.5mm. slip-gauges, off the shelf.
 
 
*The above gauge-range is now also available for those modelling to Scale 7 standards.

 


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#6 Kenton

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Posted 20 January 2014 - 17:19

Which one is compatible with Peco. I have a O slip to build but the rest of the track is Peco (unless I really become accomplished and go completely insane)

I also have this as a track gauge and nothing else (other than my trusty digital calliper). I was informed (not by anyone in the know) that was all I needed. There are no markings on it - so I am now even more confused.
O-gauge.jpg

#7 RedgateModels

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Posted 20 January 2014 - 17:32

You could build the slip to 31.5mm gauge at the common Crossings then ease the gauge out to 32mm at the ends to match up with the Peco flexi.

Having said that, you have probably got a 32mm roller gauge there, looks just like the one I bought from Marcway, so I'd build the slip to 32mm in this case :)
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#8 Kenton

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Posted 20 January 2014 - 17:48

 

You could build the slip to 31.5mm gauge at the common Crossings then ease the gauge out to 32mm at the ends to match up with the Peco flexi.

But that puts me in a corner - I might get to enjoy track building and want to build the rest .... ;)

I still have not opened the kit but it did say something about gauges enclosed - still very confusing. It sounds like 31.5 would be ideal ... I guess that .5mm would be too much of a bump to get over.

#9 Debs.

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Posted 20 January 2014 - 21:07

 But that puts me in a corner - I might get to enjoy track building and want to build the rest .... ;)

I still have not opened the kit but it did say something about gauges enclosed - still very confusing. It sounds like 31.5 would be ideal ... I guess that .5mm would be too much of a bump to get over.

 

Hello Kenton,

I think you`d find that building plain track with wooden-sleepers, plastic chairs and B/H rail to be so easy (esp. so when using Templot print-outs as a 'build-on' template) and being able to colour-match and ballast the completed panels to match perfectly with any turnouts similarly-constructed, I can`t see you`d remain attracted to Peco moulded track for long.

With 0-MF: that little 'half-millimetre' makes a big difference to both the appearance and the running qualities of the finished trackwork. :yes:


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#10 hayfield

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Posted 20 January 2014 - 21:47

Thanks everyone for replying, O-MF  if using hand built track. Having said that Peco is 32mm gauge with wider flange and check rail gaps

 

Thanks again



#11 hayfield

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Posted 20 January 2014 - 21:56

I agree with Redgate, if you were building track, which you appear to be doing, either Scale 7 or 31,5mm standards offer far superior running.

 


 

I would use 31.5mm without question if I were starting again with Fourgig, same with 16.2mm if I ever do another OO layout ......

 

Thank you both for the advice, I was asked to put a turnout together in time for the clubs show for the clubs 7 mm layout. I need to check what gauge they are using on Thursday. Having said that I really am enjoying building it, my thoughts are turning to build a few more of what is required but before I go too far down the line I was thinking of getting my self a small RTR loco and wanted to know what's best.

 

Martin and Debs thanks again thanks again for the assistance


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#12 nswgr1855

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Posted 22 January 2014 - 02:24

I would use 31.5mm without question if I were starting again with Fourgig, same with 16.2mm if I ever do another OO layout ......

 

I always question and I have a problem with any track 'standard' that does not include tollerances for complex trackwork. According to my figures and observations you need to work to with an accuracy of around  +/-0.025mm if you want to have complex trackwork with crossing K's using the 31.5mm minimum track gauge, 1.5mm flangeway combination. For O gauge a more practical solution is the AMRA Fine tolerance standard, with  nonimal recommended dimensions of  31.75mm track gauge and 1.65mm flangeways. A tolerance of =/- 0.05mm is allowed. The AMRA standard is on the associations webpage.

 

http://www.amra.asn.au/standards.htm

 

Terry Flynn.


Edited by nswgr1855, 22 January 2014 - 02:25 .


#13 martin_wynne

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Posted 22 January 2014 - 03:34

I always question and I have a problem with any track 'standard' that does not include tolerances for complex trackwork. According to my figures and observations you need to work to with an accuracy of around  +/-0.025mm if you want to have complex trackwork with crossing K's using the 31.5mm minimum track gauge, 1.5mm flangeway combination.

 

Hi Terry,

 

The prototype does not use +/- tolerances. Track dimensions are Max or Min.

 

For 0-MF:

 

Track Gauge is 31.5mm MIN. It can be more, and often is on sharp curves.

 

Check Gauge is 30.0mm MIN. It can be more.

 

Crossing Flangeway is 1.5mm MAX. It can be less.

 

However, the scope for variation of the last two is limited because the Check Span is 28.6mm MAX.

 

i.e. you can reduce the flangeway by 0.1mm, or increase the check gauge by 0.1mm, but not both by the full amount at once.

 

It's impossible to say that you have to work to this or that accuracy, because we don't know the wheel profile or back-to-back dimension -- there are variations between current manufacturers, and between current production and older models.

 

What we do know however, is that almost without exception everyone who has adopted 0-MF has been delighted with the results, running a variety of different wheels.

 

Older wheels tend to be set to 29.0mm back-to-back, with thicker flanges (1.0mm max). Current "industry standard" wheels are usually set to 29.2mm back-to-back with thinner flanges (0.8mm max). In all cases the BEF dimension must not exceed 30.0mm.

 

regards,

 

Martin.


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#14 nswgr1855

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Posted 22 January 2014 - 06:41

Hi Terry,

 

The prototype does not use +/- tolerances. Track dimensions are Max or Min.

 

For 0-MF:

 

Track Gauge is 31.5mm MIN. It can be more, and often is on sharp curves.

 

Check Gauge is 30.0mm MIN. It can be more.

 

Crossing Flangeway is 1.5mm MAX. It can be less.

 

However, the scope for variation of the last two is limited because the Check Span is 28.6mm MAX.

 

i.e. you can reduce the flangeway by 0.1mm, or increase the check gauge by 0.1mm, but not both by the full amount at once.

 

It's impossible to say that you have to work to this or that accuracy, because we don't know the wheel profile or back-to-back dimension -- there are variations between current manufacturers, and between current production and older models.

 

What we do know however, is that almost without exception everyone who has adopted 0-MF has been delighted with the results, running a variety of different wheels.

 

Older wheels tend to be set to 29.0mm back-to-back, with thicker flanges (1.0mm max). Current "industry standard" wheels are usually set to 29.2mm back-to-back with thinner flanges (0.8mm max). In all cases the BEF dimension must not exceed 30.0mm.

 

regards,

 

Martin.

 

Hi Martin,

 

I am sure you will find prototype manufacturing drawings that use the =/- tolerance convention which means exactly the same as the maximum minium alternative method of expressing the allowable size range of an object. Note the AMRA standard I wrote uses the maximum and minimum convention, but I was critised on a Aussie news group for this, claiming modellers and manufacturers could not work out nominal values easily.

 

I have no trouble determinimg the tolerance range that complex model track needs to be built to because I have put all the relevent sums into an XL spread sheet to get the relevent sizes.

 

Are you sure the crossing flangeway is 1.5mm maximum. I would think using the construction method of using a 1.5mm metal shim, you get a 1.5mm minimum flangeway in practice.

Yes how accurate you build your track is determined by the variation in wheel sizes. Using my spread sheet, the closest I get is as follows. If you limit your wheels to a 28.9mm minimum back to back you can have your maximum check face to check face at 28.7mm, resulting in flangeways between 1.44mm to 1.51mm, track gauge 31.51mm to 31.58mm for a K crossing. To be honest, I you are happy working to these tolerances you might as well build to scale 7 dimensions.

 

If I was building 0 gauge track, I would design my track  for a easier to build wheel back to back range,  (down to minimum back to back of 28.8mm), and work to the easier tolerances in the AMRA fine tolerance standard. Same check gauge 30mm, easier to build within tolerance with only a slight increase in flangeway gap.

 

By the way I like the improvements in Templot 2.

 

Cheers,

 

Terry Flynn.



#15 Kenton

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Posted 22 January 2014 - 10:35

 

easier to build

I'm all for that!

also, easier to understand, please.

All these variables and different standards only seem to be designed to confuse the novice and thoroughly put them off. It is bad enough that the question in the OP had to be asked in the first place (thanks, saved me the show of ignorance)

Frankly, a discussion of +/- 0.025mm or even +/- 0.0anything mm is beyond the achievable (or at least what I can hope to achieve) great for the track theorists but lets remain practical. Gaps between check rails and the crossing/stock rails simply has to be big enough to take any O gauge wheels set in O and a S7 wheelset in S7. A minimum will do.
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#16 PatB

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Posted 22 January 2014 - 10:53

Does it make me an old fart that I can remember when, if a layout used Peco track, instead of Bonds/Lowke/Milbro/LMC stuff, it was, almost by definition "finescale 0"? :D


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#17 martin_wynne

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Posted 22 January 2014 - 10:59

I am sure you will find prototype manufacturing drawings that use the =/- tolerance convention which means exactly the same as the maximum minimum alternative method of expressing the allowable size range of an object.

 

Hi Terry,

 

No it doesn't. The NMRA have wrecked their standards by not understanding the difference. Please read again my previous post. The allowable variation on the check gauge is controlled by the current dimension on the crossing flangeway, and vice versa. One or other dimension can vary by up to 0.1mm but not both if the max check span is to be achieved. There is no way to express this as a simple +/- tolerance on each dimension.

 

Are you sure the crossing flangeway is 1.5mm maximum. I would think using the construction method of using a 1.5mm metal shim, you get a 1.5mm minimum flangeway in practice.

 

Let's be practical. The crossing flangeway is normally set by clipping the gauge shim between the rails while soldering or glueing the fixings. Unless the rail is distorted in some way, the result is a 1.5mm flangeway. If it turns out to be slightly wider, it doesn't really matter, it simply means that narrow wheels may not be so well supported on the wing rail. They may bump down a fraction, but not nearly so much as on GOG Fine. The GOG Fine flangeway is 1.75mm, so you can see that even if the flangeway turns out to be 1.55mm, it is still a big improvement.

 

The reason for saying that it should not exceed 1.5mm is to ensure that 3.5mm wide wheels (the current industry standard) are fully supported when the 3/4" blunt nose (0.4mm scale) is properly modelled on the vee:

 

Gap across in front of nose = 1.5mm + 0.4mm + 1.5mm  =  3.4mm

 

An object 3.5mm wide cannot fall into a gap 3.4mm wide, so the wheel is fully supported through the crossing at all crossing angles.

 

Using your suggested 1.65mm flangeway, the gap becomes 3.7mm, and 3.5mm wheels will fall in with a bump as they run over the crossing. The only way to avoid that would be to use non-prototypical awful-looking sharp-nose vees.

 

I would just repeat that almost everyone who has tried 0-MF is delighted with the results and the improvement in running over the old GOG Fine standard when using modern wheels.

 

By the way I like the improvements in Templot 2.

 

Thanks. :)

 

regards,

 

Martin.


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#18 martin_wynne

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Posted 22 January 2014 - 11:27

Gaps between check rails and the crossing/stock rails simply has to be big enough to take any O gauge wheels set in O and a S7 wheelset in S7. A minimum will do.

 

Hi Kenton,

 

It's not that simple if you want smooth running. If the gap at the crossing (frog) is too wide, wheels will fall in with a bump. if the check gauge is too small, wheel flanges can hit the nose of the vee with a bump.

 

However, it really is very simple -- get some gauges from Debs and build your track using them. The results will work well without your needing to know any dimensions or tolerances.

 

A frequent problem on RMweb is the wide variation in skill sets and experience among 20,000+ members. Some modellers like to discuss engineering stuff without having to dumb it down to the level of a raw beginner. Perhaps we need spanner symbols on posts, so that readers know what to expect, like this:

 

1_spanner_icon_dark.gif  Basic information for beginners.

 

2_spanners_icon_dark.gif  More detailed information for established modellers.

 

3_spanners_icon_dark.gif  Technical stuff for experienced modellers.

 

:)

 

Martin.


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#19 Kenton

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Posted 22 January 2014 - 11:58

 

1_spanner_icon_dark.gif  Basic information for beginners.

Yes, I like that idea.

I am not trying to dumb down, and to some extent enjoy the discussion. But there is a genuine risk of putting folk off what is essentially a simple and very basic topic question.

I for one am not a track fanatic and am a long way from ever going S7 - indeed at the moment I am edging slowly closer to actually building my first O hand-built kit - initially to go with Peco RTL O track and points. So that is Slater's wheels and the gauge I have indicated. All these details and the availability of other gauges are at the moment purely academic. Now if the first kit is a success and not too traumatic then maybe I'll be converted/convinced to go the next step and build everything track-wise. At which time I think I have been convinced that O-MF might be the right way to proceed.

But as of now I find that even the GOG standards are being trashed in favour of the 'perfection' and wonder if this is deja vu in that other scale with P4 lording it over EM?
 
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#20 martin_wynne

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Posted 22 January 2014 - 12:08

But as of now I find that even the GOG standards are being trashed in favour of the 'perfection'

 

They are not being trashed. They are old, out-of-date, and not compatible with the current "industry-standard" wheels. The GOG are currently engaged in a review of their standards, and the latest developments (including 0-MF) will be included in the updated version.

 

Martin.


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#21 Campaman

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Posted 22 January 2014 - 13:43

Which one is compatible with Peco. I have a O slip to build but the rest of the track is Peco (unless I really become accomplished and go completely insane)

I also have this as a track gauge and nothing else (other than my trusty digital calliper). I was informed (not by anyone in the know) that was all I needed. There are no markings on it - so I am now even more confused.
O-gauge.jpg

 

Try the gauge on a piece of standard Peco track, that should tell you if its a 32mm gauge



#22 mike knowles

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Posted 22 January 2014 - 13:54

Ignoring the complexities of maximum/minimum and +/- tolerances all I can say that the trackwork I have built so far to O-MF standards, usings the gauges from Debs looks and works beautifully with all the various wheelsets we have - Heljan, Slaters and Easibuild.

See thread titled "More First Ventures in O Gauge" for further information - apologies I don't know how to add a link.



#23 Kenton

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Posted 22 January 2014 - 15:48

 

Try the gauge on a piece of standard Peco track, that should tell you if its a 32mm gauge

Now why didn't I think of that ....
Trouble is it sounds obvious but still doesn't quite answer the question
tack_gauge.jpg
Quite a bit of force is required to get this gauge to drop down on both rails (it then doesn't exactly roll - bumping over the sleepers). As you can see it rests on one rail - by a smidgeon (guessed at 0.5mm) and when pressed down the rails are definitely pushed apart.

But the calipers show 32.02 between the inside faces of the outer gauge so that sort of confirms O at GOG current standards? When I finally open the kit I'll see what the "enclosed gauges" are, then possibly contemplate a O-MF set. Though building the kit with a wider gauge at the adjoining track and O-MF through the crossing sounds like adding one more thing to go wrong, two different gauges - neither of which will roll over the entire length - asking for trouble.

#24 hayfield

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Posted 22 January 2014 - 17:18

Kenton

 

Thank you for taking the thread on a bit, as you know I have taken a step further as I am building a 7mm turnout for the club. Again you know I enjoy building track and I must say building a turnout with Exactoscale parts is being very enjoyable and whilst 0-16.5 will be my main passion I fancy building a small O gauge layout. Maybe the exact opposite of pointless.

 

Martin, 

 

Again thank you for taking an interest in a track building question session, I must admit sometimes when those more knowledgeable on the subject debate the finer aspects it does get quite confusing and difficult. having built turnouts in both 16,2 mm & 18.2 mm gauges it is quite easy building to these standards providing you have the correct gauges. So having seen with my own eyes OO-SF work much better than OO gauge,  I am more than happy to build to 31.5 mm gauge to obtain the same results. What I am looking for is a gauge that looks good (fine flangeways) and works with RTR locos and stock, I have had a quick couple of messages with Debs and she has explained about gauge widening on O-MF.


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#25 Debs.

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Posted 22 January 2014 - 19:17

As an aside.....

 

One has to be careful with claims to precision measurement........

Being in the fortunate (or is it sad) position of owning in excess of 10 digital vernier-callipers (some with extremely high, pro-quality aspirations); I can truthfully say that in reference to a precise known-standard, only two show agreement as to an accurate reading to three decimal places.......the rest, show differing indications at two-decimal places and one (of a very well regarded industry name) can`t repeat any measurement even at two decimal places.

I also have several DRO/CNC machine tools which can`t agree to three decimal places, and others which can repeatably agree to six places!!!!

'Precision' is often not what it claims to be...........

 

Now, just imagine all these various companies` track gauges being batch-manufactured without use of reference-calibrated measuring tools!......for that`s the state of affairs that I discovered when I bought gauges from a wide-variety of suppliers, in an attempt to see the tolerances which were extant in the various scale`s marketplaces.

 

The 0-MF and S7 track standards both perform and look extremely well and are not difficult to correctly execute, the latter of the two is slightly more demanding; but only really in the sense of rolling-stock undercarriage construction, but faced with the discrete choice between 'excellent' or 'brilliant', I can`t see why any 7mm. scale builder would look elsewhere for a track gauging specification, or contemplate any "road less travelled".

 

 


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