Society Gauge Widening Tool

Discuss the prototype and how to model it.
FCA
Posts: 54
Joined: Wed Jul 23, 2008 2:49 pm

Re: Society Gauge Widening Tool

Postby FCA » Wed Mar 30, 2016 4:29 pm

I use a combination of plastic chairs and riveted construction for my points including crossings assembled using the excellent EMGS gauge.

The discussion about storage is pertinent as I have been storing the Kent area group's layout Eridge in my garage for the past two years whilst the group has been searching for new premises. Happily that search is now over and we will be taking the covers off Eridge in the near future. Eridge is all steel rail so it will be interesting to see how it has fared.

Richard

FCA
Posts: 54
Joined: Wed Jul 23, 2008 2:49 pm

Re: Society Gauge Widening Tool

Postby FCA » Wed Mar 30, 2016 5:01 pm

Yes I use Humbrol enamel (#186) over Halfords primer.

Richard

User avatar
Allan Goodwillie
Posts: 762
Joined: Sun Jul 20, 2008 7:00 pm

Re: Society Gauge Widening Tool

Postby Allan Goodwillie » Wed Mar 30, 2016 9:48 pm

Thanks Richard please keep us posted, others out there with different experiences with steel track over a descent time, please consider writing them up here. :) By the way this is not the start of any anti-steel thing :) it is just problem solving and seeing if there are any solutions. I have had a chat with my friend Fergus tonight about the solder used in electronics that does not splutter or fume and he is going to get some and we will try it out. We will still probably have to work on the track to return it to its former glory and anything helpful like this is most welcom - we will see how it goes and report back. Cleaning the rail and rivits might be the bigger problem. We have also found a few tight to gauge problems - perhaps someone not knowing which way round to use the gauge? :shock: We will see. :cry:

Terry Bendall
Posts: 1634
Joined: Sun Jul 27, 2008 7:46 am

Re: Society Gauge Widening Tool

Postby Terry Bendall » Thu Mar 31, 2016 7:59 am

Some interesting notions in responses to this thread.

billbedford wrote:Cars rust more if they are kept in garages than if kept outside, especially if the garages are heated.


I have always kept my car in a garage but never one that is heated. In 45 years I have never noticed any tendency for it to rust more quickly than one kept outside. Perhaps I have been lucky. :)

FCA wrote:Nowadays I prepare my lengths of steel rail by tinning the foot so that the subsequent use of rosin solder will be more reliable. The tinning, using red or green label flux, is followed by thorough cleaning and the rail lengths are then painted; primer followed by "rust". I have encountered no problems in loading the rail with chairs after painting,


Having used Exactoscale chairs on steel rail I am very surprised that it has been possible t\o push them on once the painting and tinning has been done. The ones that I have used have been far too tight a fit to allow that to be done. My track painting has always been done after the track has been laid, wired up and tested. It is then ballasted and painted.

On Elcot Road we have used steel bullhead rail and Exactoscale track bases in the sidings and flat bottom nickel silver rail with Colin Craig components on the main line, loop and bay platform road. There is no noticeable difference in performance and not a lot in appearance since it is only the top of the rails that are the natural colour. :)

Ravenscroft Sidings was laid entirely with Exactoscale steel rail and track bases. It is kept in my workshop which is an un-heated but insulated wooden building in the garden. The heat is only on when I am in the building. The layout is now 10 years old and there has never been any rusting of the steel rail in that time. This layout, and the others that we have are also stored in their boxes so there is the potential for a lack of air circulation. Lucky again perhaps? :)

Allan mentioned the instances of damage caused in transit. This of course is a hazard of taking layouts to exhibitions and I have been known to take local detours to avoid speed humps. We had an instance at Scaleforum a couple of years ago when the van transporting a layout hit a pothole which damaged a couple of point motors. Back in Scalefour News 177 I described the system of layout boxes I have used and these include end protectors which are spaced away from the rail ends. As a result we have never had any problems caused by damaged rail ends. Both Elcot Road and Ravenscroft Sidings have survived the end of one board being dropped on the ground whilst being moved and perhaps the use of boxes helped with this.

There seems to be a common tendency to bolt two boards together for transport which is one way of solving the packing problem but will automatically make the load twice as heavy. Perhaps a lack of woodworking skills means that people are reluctant to do anything more but that article and the others in the series were designed to try and solve that problem. :D Perhaps the next business opportunity is to have laser cut covers for baseboards as well as laser cut baseboards themselves. :D :D

Terry Bendall

User avatar
Allan Goodwillie
Posts: 762
Joined: Sun Jul 20, 2008 7:00 pm

Re: Society Gauge Widening Tool

Postby Allan Goodwillie » Thu Mar 31, 2016 6:39 pm

Hi Terry,
a number of types of protectors have been tried on Burntisland after damage of rail ends and foam underlay pulling away with the track and not staying stuck down properly at the board edges, however a new type developed by Lindsay were tried which are hinged and simply drop down when not being used and up to now have worked well.

Certainly I had a number of cars which rusted when I used my garage for the car, but when I stopped and trains took over, that also stopped - I have a feeling that the amount of salt added to the effect - if I remember from my science days at school - saltwater and air combined produce the best rusting results. Then again I stopped buying second hand cars and newer types are far better protected these days - remember the Scottsh weather Terry :!:

Spent today with Alasdair and Ray sorting out electrical problems after my team, Chris,David,Bruce and Jim Batchelor had replaced all the connectors on Burntisland's point motors under Ian Terrel's guidance. Major job, team effort - good result. :D Still some areas of the layout to do. :) Wish the track was further forward, but I am sure all will be right in the end. :thumb

Julian Roberts
Posts: 762
Joined: Sat Jan 09, 2010 11:33 pm

Re: Society Gauge Widening Tool

Postby Julian Roberts » Fri Apr 15, 2016 8:00 am

Just to wrap up this topic, and return "on-message", perhaps of considerably less interest to most people than the more recently foregoing discussion -

My mathematician friend and recently retired professor Chris kindly spent some time in the company of Pythagoras recently and has given me the information that a gauge that would give the prototypical gauge widening of 0.75" at 5.5 chains, which scales down to 0.25mm at 4.76378 feet (4 feet 9 and a bit inches), would need to be effectively 54.23938 mm long.

As the legs of the Society triangular gauge have their own thickness, so the question would be, how long is it in terms of its actual action, it might be more instructive to compare this 54mm length with the length of the Society rectangular gauge which is 29.75mm long.

The standards in the Scalefour Digest say that 0.75" was the maximum prototype gauge widening, and that the maximum P4 scale gauge widening is 0.22mm at 528mm. So out of purely academic interest, a 54mm length gauge would give at 3 feet radius gauge widening of 0.39mm, at 4 feet radius 0.297mm gauge widening, and at 5 feet radius 0.24mm gauge widening.

I do wonder why the P4 standard widening at 5.5 chains is so different, and the reasoning for a 0.22mm maximum. Obviously as Keith and Philip said near the beginning of this thread, the standards have served over 50 years, so my question is simply academic, though I may try such a gauge myself sometime if I make a railway rather than just make stock for the club layout.

Somewhere sometime the decision must have been taken to reduce from the prototypical gauge widening scaled down. I surmise it was because the P4 standards have a reduced back to back (BB) value compared to the prototype, and to cater for the sharper than prototypical curves that modellers may wish to incorporate in their railways...?

Julian Roberts
Posts: 762
Joined: Sat Jan 09, 2010 11:33 pm

Re: Society Gauge Widening Tool

Postby Julian Roberts » Tue Apr 19, 2016 7:43 pm

Scalefour North was an opportunity to try and pick the brains of those more experienced in P4 matters than I am, as to why the Society gauge widening tools give less than prototypical widening at 5.5 chains (in our terms, just over 4 foot 9 inches).

The same surprise was registered by all, but a chat with Tony Wilkins who wrote some of the Digest resulted in our conclusion that it is probably because we modellers are likely to quite commonly use curves sharper than the prototype. A maximum gauge widening of 0.25mm at 4 foot 9 would not give any further widening in the quite likely scenario of going down below that radius.

Sticking to that prototypical maximum gauge widening, with the Society tool we get to that maximum at a smaller radius than 4 foot 9. (Mm, I am beginning to see why the Protofour Track Gauge Mark 1, the triangular gauge, was discontinued in favour of the Mark 2 gauge that was a roller type gauge into which you inserted a 0.2mm washer for any curve).

As to why the maximum quoted in the Digest is 0.22mm rather than 0.25mm, he suggested that it is perhaps a typing error...

Another mystery: the Mint Gauges on the Society Stand on Sunday are 40mm long - why? - there was no one who could say just then on Sunday morning there...

Incidentally, Bill Bedford said near the beginning of this thread, "don't forget the check rails". Check rails were/are(?) used on curves less than 8 chains, though I don't know if that's just for passenger lines. This is 6 foot 11 inches in our terms. I wonder how many of us regard that as a sufficiently sharp looking curve to merit a check rail?

I realize I am talking to myself but thought I ought to put this down in case anyone else interested enough in the topic ever got to here.

User avatar
jon price
Posts: 476
Joined: Mon Jun 07, 2010 2:34 pm

Re: Society Gauge Widening Tool

Postby jon price » Tue Apr 19, 2016 8:41 pm

I'm in total agreement on check rails. I'm going to have to have them on my slowly developing set up, but the reason is because in the only photo I have they are there. Wouldn't have thought about it unless that was the case, because there are no particular instuctions or guidance pushing me that way.

Terry Bendall
Posts: 1634
Joined: Sun Jul 27, 2008 7:46 am

Re: Society Gauge Widening Tool

Postby Terry Bendall » Wed Apr 20, 2016 7:26 am

Julian Roberts wrote:Check rails were/are(?) used on curves less than 8 chains,


There will probably be some track experts on here who can discuss this point but my copy of British Railways Track, fourth edition 1971, states "... all curves with a radius of 10 chains or less must be provided with a check rail, (fitted to the inside rail of the curve)." According to the book this was a Ministry of Transport requirement which also required that check rails were fitted to flatter curves if high speed is contemplated.

At the LBSC station at Midhurst, West Sussex, now long gone, there was a 10 chains radius curve on the line leading south to Chichester which had a check rail fitted all the way round the curve and a 20 mph speed limit imposed.

Julian Roberts wrote:Another mystery: the Mint Gauges on the Society Stand on Sunday are 40mm long - why?


Probably because that was the size selected by the person who "invented" the gauge, and who is a member of the Society. :)

Terry Bendall

Julian Roberts
Posts: 762
Joined: Sat Jan 09, 2010 11:33 pm

Re: Society Gauge Widening Tool

Postby Julian Roberts » Wed Apr 20, 2016 8:25 am

Terry

That 8 chains figure came from one of the Protofour articles available on the Society website

http://www.scalefour.org/history/mrc03.html

If it's 10 chains it illustrates the point of my question all the more.

Why did Mr Mint select 40mm? - if that is the name of the gauge's "inventor". I assume it is to prevent it being used on curves, but is that right?

User avatar
Flymo748
Posts: 2180
Joined: Sun Jul 20, 2008 6:00 pm

Re: Society Gauge Widening Tool

Postby Flymo748 » Thu Apr 21, 2016 5:10 am

Terry Bendall wrote:
Julian Roberts wrote:Another mystery: the Mint Gauges on the Society Stand on Sunday are 40mm long - why?


Probably because that was the size selected by the person who "invented" the gauge, and who is a member of the Society. :)

Terry Bendall


Hi Terry,

The question was more "why are the current Mint gauges the size they are?".

Having been involved in this conversation on the Demo bench, I am also curious. The reason being was that my newly purchased (as in right there and then) Mint was measured as being 40mm long.

Apparently the previous ones were shorter - a figure like 36mm or 28mm or something was mentioned.

Now, whilst that doesn't matter if you're using it on straight track, once you put it on a curve the geometry changes. Should the current Mint be longer than normal, it will require more gauge widening to run cleanly along track. That's probably only a fraction of a fraction of a millimetre and I'd rather have track over gauge than under but it still begged the question.

So - I don't know of a Digest that describes the dimensions of a Mint gauge, but what size (length) do other members have in their toolbox?

Cheers
Paul Willis
Deputy Chairman
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

User avatar
Flymo748
Posts: 2180
Joined: Sun Jul 20, 2008 6:00 pm

Re: Society Gauge Widening Tool

Postby Flymo748 » Thu Apr 21, 2016 5:12 am

Julian Roberts wrote:Incidentally, Bill Bedford said near the beginning of this thread, "don't forget the check rails". Check rails were/are(?) used on curves less than 8 chains, though I don't know if that's just for passenger lines. This is 6 foot 11 inches in our terms. I wonder how many of us regard that as a sufficiently sharp looking curve to merit a check rail?

I realize I am talking to myself but thought I ought to put this down in case anyone else interested enough in the topic ever got to here.


Nope, you're definitely not just talking to yourself :-)

Keep it up - it's interesting to discuss these things amicably and understand more about the hobby that we have.

Cheers
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

Alan Turner
Posts: 548
Joined: Sun Jul 20, 2008 4:24 pm

Re: Society Gauge Widening Tool

Postby Alan Turner » Thu Apr 21, 2016 7:00 am

I find the "Mint" gauge a bizarre instrument and I am baffled why anyone buys it. People do, both in this gauge and S7.

However on anything but straight track the result it produces is a nonsense.

The widening of gauge on the prototype is a step function - it is not continuous. Therefore for a gauge to produce this effect of the "Mint" style of design requires a gauge whose length can vary with track radius.

However if we take the prototype gauge widening of 10 - 7 chains = 1/4", 7 - 5.5 chains = 1/2" and less than 5.5 chains = 3/4" then the results for the length of mint gauge (set to the track gauge of 18.83mm) to produce these are:


10 chains, length of gauge required =24.35mm (1/4")
7 chains, length of gauge required =20.42mm (1/4")
7 chains, length of gauge required =28.88mm (1/2")
5.5 chains, length of gauge required =25.65mm (1/2")
5.5 chains, length of gauge required =31.41mm (3/4")

regards

Alan

User avatar
Andy W
Posts: 819
Joined: Thu May 21, 2009 8:11 am

Re: Society Gauge Widening Tool

Postby Andy W » Thu Apr 21, 2016 7:03 am

"...what size (length) do other members have in their toolbox?"

Are you turning into Frankie Howerd Paul?
Make Worcestershire great again.
Build a wall along the Herefordshire border and make them pay for it.

User avatar
grovenor-2685
Posts: 3167
Joined: Sun Jun 29, 2008 8:02 pm

Re: Society Gauge Widening Tool

Postby grovenor-2685 » Thu Apr 21, 2016 7:31 am

The widening of gauge on the prototype is a step function - it is not continuous.

Indeed, so if you want to model that exactly you need a series of gauges, or the P4 Mk2 gauge with a series of washers.

However the prototype does not use steps because that is theoretically correct, more for the practicallity of building it.

With either ply and rivet or chairs and glue use of a triangular gauge gives us variable gauge widening with no practical difficulties.

If you can tell the difference when looking at a layout you must have exceptional eyesight.

So far as a mint gauge goes, I thought it was intended for checking flangeways and, due to its length would only work on straight track. But then I have never found a need to buy one.
Regards

Alan Turner
Posts: 548
Joined: Sun Jul 20, 2008 4:24 pm

Re: Society Gauge Widening Tool

Postby Alan Turner » Thu Apr 21, 2016 7:43 am

grovenor-2685 wrote:

With either ply and rivet or chairs and glue use of a triangular gauge gives us variable gauge widening with no practical difficulties.

. But then I have never found a need to buy one.
Regards


I agree, I was simply pointing out the bizzar nature of the"Mint" concept.

It has a very (and I mean very) limited application in straight turnouts to check the flangway.

Regards

Alan

Terry Bendall
Posts: 1634
Joined: Sun Jul 27, 2008 7:46 am

Re: Society Gauge Widening Tool

Postby Terry Bendall » Thu Apr 21, 2016 8:16 am

grovenor-2685 wrote:So far as a mint gauge goes, I thought it was intended for checking flangeways


Keith is of course quite correct. Look at the ordering page for the stores and you will find the following:

"Roger Sander's 'Mint' gauge for fine tuning pointwork" which gives the name of the person who invented the gauge and its intended purpose. Some people may have used it to give gauge widening but that was not what it designed for. :o

Flymo748 wrote:The question was more "why are the current Mint gauges the size they are?".


Because that is the dimension stated on the drawing. :) My mint gauge is a very early one, probably one that Roger had made and measures 34 mm long. The drawing used for the manufacture of the current ones gives a dimension of 40mm. I produced that drawing, and all the dimensions were taken from an actual gauge that Jeremy had in stock at the time - and that was in 2012. I have no idea why the length was changed.

The mint gauge was devised following an extensive period of checking the track on Pulborough, probably around 1990. When this was done it was found that there was a need for a gauge to check the parts that other gauges could not reach and in particular the area around the common crossing where it can be slid through the vee. It is also useful for checking the distance between the switch rail and the stock rail. The checking was necessary because running was not good enough so Roger and one of the other members of the group started at one end of the layout and literally checked every inch of the track and in 25 feet of scenic section that is quite a lot.

If you use the gauge for its intended purpose, then the overall length is not really relevant. The Mint gauges for 5ft 3 ins and broad gauge track are also 40mm long

Terry Bendall

User avatar
Paul Townsend
Posts: 775
Joined: Mon Sep 14, 2009 6:09 pm

Re: Society Gauge Widening Tool

Postby Paul Townsend » Thu Apr 21, 2016 9:44 am

Alan Turner wrote:
grovenor-2685 wrote:

With either ply and rivet or chairs and glue use of a triangular gauge gives us variable gauge widening with no practical difficulties.

. But then I have never found a need to buy one.
Regards


I agree, I was simply pointing out the bizzar nature of the"Mint" concept.

It has a very (and I mean very) limited application in straight turnouts to check the flangway.

Regards

Alan


I have used it for years as a diagnostic tool rather than a construction aid.
For this it is quick and easy to find undergauge areas of track as the sliding friction rises and, with a bit more skill to find overgauge bits too as the wiggle feel changes. It is also invaluable when dealing with bumps as you can press down on a naughty rail end while re-soldering...obviously this is a knack as the heat-sinking effect is large.

So I disagree with Alan about limited use.
However I find it less easy to use on pointwork so agree caution is required there.

I have recently used mine daily and continue to use it to help Highbridge recover from home-moving traumas.

I have recently commented that to make this super tool perfect requires it to be made of say Tufnol or an even tougher and better insulating and heat-resistant material, then you won't short out the juice!

NB
a recent thread on Merg Forum recorded an unfortunate destruction of a DCC booster by use of earthed soldering iron on live track. So check your iron is NOT earthed, modern ones intended for static prone electronics are good in this respect.

When I have restocked roundtuits and have a mill in service again I may have a go at one of those Tufnol jobbies.

Comments?

User avatar
Will L
Posts: 1655
Joined: Sun Jul 20, 2008 3:54 pm

Re: Society Gauge Widening Tool

Postby Will L » Thu Apr 21, 2016 4:30 pm

In summary, re the Mint gauge, it seems to me....

Unlike the traditional 3 point gauge, the mint gauge was never intended to be used for creating/checking* gauge widening. So it has no relevance to this thread and its length was a distinct red herring.

* so long as it isn't too long it does have a use is checking for under gauge track and is probably easier to use, in this role, than a traditional roller gauge. However, being strait there are clearly limitations to its usefulness in checking the flange way on a curved check rail.

User avatar
Flymo748
Posts: 2180
Joined: Sun Jul 20, 2008 6:00 pm

Re: Society Gauge Widening Tool

Postby Flymo748 » Thu Apr 21, 2016 5:46 pm

Will L wrote:In summary, re the Mint gauge, it seems to me....

Unlike the traditional 3 point gauge, the mint gauge was never intended to be used for creating/checking* gauge widening. So it has no relevance to this thread and its length was a distinct red herring.

* so long as it isn't too long it does have a use is checking for under gauge track and is probably easier to use, in this role, than a traditional roller gauge. However, being strait there are clearly limitations to its usefulness in checking the flange way on a curved check rail.


Thank you Will, for the summary. I now feel educated, and will use my newly acquired chunk of brass appropriately!

Cheers!
Paul
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

Julian Roberts
Posts: 762
Joined: Sat Jan 09, 2010 11:33 pm

Re: Society Gauge Widening Tool

Postby Julian Roberts » Thu Apr 21, 2016 11:41 pm

Flymo748 wrote:
Nope, you're definitely not just talking to yourself :-)

Keep it up - it's interesting to discuss these things amicably and understand more about the hobby that we have.

Cheers
Flymo


Thanks Paul. Yes, exactly what I am trying to do, with people's help, understand more about this hobby. I have learnt a lot from this Forum

Terry Bendall wrote:
There will probably be some track experts on here who can discuss this point but my copy of British Railways Track, fourth edition 1971, states "... all curves with a radius of 10 chains or less must be provided with a check rail, (fitted to the inside rail of the curve)." According to the book this was a Ministry of Transport requirement which also required that check rails were fitted to flatter curves if high speed is contemplated.

At the LBSC station at Midhurst, West Sussex, now long gone, there was a 10 chains radius curve on the line leading south to Chichester which had a check rail fitted all the way round the curve and a 20 mph speed limit imposed.



Just for interest, 10 chains equals 8 feet 8 inches in our terms. Do we run our trains at a maximum of 20mph round such a curve, and does it have a check rail?

Flymo748 wrote:but what size (length) do other members have in their toolbox?



I don't want to sound like Frankie Howerd, still less like my namesake Mr Clary (!), but this question is exactly the point of this thread, if the Mint gauge is used for anything other than straight track. Not to get personal Paul (Townsend), how long is yours, and do you use it just on straight track on "Highbridge"?

Terry Bendall wrote:
"Roger Sander's 'Mint' gauge for fine tuning pointwork" which gives the name of the person who invented the gauge and its intended purpose. Some people may have used it to give gauge widening but that was not what it designed for. :o

Flymo748 wrote:The question was more "why are the current Mint gauges the size they are?".


Because that is the dimension stated on the drawing. :) My mint gauge is a very early one, probably one that Roger had made and measures 34 mm long. The drawing used for the manufacture of the current ones gives a dimension of 40mm. I produced that drawing, and all the dimensions were taken from an actual gauge that Jeremy had in stock at the time - and that was in 2012. I have no idea why the length was changed.

The mint gauge was devised following an extensive period of checking the track on Pulborough, probably around 1990. When this was done it was found that there was a need for a gauge to check the parts that other gauges could not reach and in particular the area around the common crossing where it can be slid through the vee. It is also useful for checking the distance between the switch rail and the stock rail. The checking was necessary because running was not good enough so Roger and one of the other members of the group started at one end of the layout and literally checked every inch of the track and in 25 feet of scenic section that is quite a lot.

If you use the gauge for its intended purpose, then the overall length is not really relevant. The Mint gauges for 5ft 3 ins and broad gauge track are also 40mm long

Terry Bendall


I don't get all this. I understand that the gauge will be very useful to check the straight road of a turnout, though I don't see how it is so useful for the curving road, but you are saying it was used for every inch of the layout. Presumably "Pulborough" is not entirely made of straight lines? If not, then it sounds like the gauge is being used for curving lines, and in that case surely its length is not irrelevant, but fundamental, in which case, how can there be such question marks over how long it is meant to be?

Alan Turner wrote:
However if we take the prototype gauge widening of 10 - 7 chains = 1/4", 7 - 5.5 chains = 1/2" and less than 5.5 chains = 3/4" then the results for the length of mint gauge (set to the track gauge of 18.83mm) to produce these are:


10 chains, length of gauge required =24.35mm (1/4")
7 chains, length of gauge required =20.42mm (1/4")
7 chains, length of gauge required =28.88mm (1/2")
5.5 chains, length of gauge required =25.65mm (1/2")
5.5 chains, length of gauge required =31.41mm (3/4")



I absolutely am not qualified to make any mathematics correction to anyone. But I am not sure this can be correct. The thread opened with Russ Elliott saying that the Society Gauge Widening Tool gives half the widening the prototype might have done for a given radius. The gauge is a bit difficult to measure, in that the legs have a thickness, but the rectangular one which has the same function is 29.75mm long. My friend Chris calculated that prototypical widening of 3/4" at 5.5 chains or in our terms 0.25mm at 4 foot 9 inches, would be obtained with a length of 54mm, thus pretty much corroborating Russ' statement.
Will L wrote:In summary, re the Mint gauge, it seems to me....

Unlike the traditional 3 point gauge, the mint gauge was never intended to be used for creating/checking* gauge widening. So it has no relevance to this thread and its length was a distinct red herring.
]


Well as you can see Will I don't quite understand whether the Mint gauge is being used beyond its original purpose. But might I suggest that if it is, and is being found to be useful in picking up faults that other gauges don't, it might be partly because it is longer than the Society gauge?

Which is where I came in, might not a 54mm gauge giving prototypical widening, though not used for curves below 4 foot 9ins, give better running? The 40mm gauge is nearly half way from P4 to prototype. In such a scenario, below 4 foot 9 a roller gauge set at +0.25 would emulate the prototype, with no further widening.

Earlier I said Tony suggested the P4 0.22mm maximum widening could have been a typo. But looking again at the Digest, the 0.22 is plainly written several times, for the three gauges (standard, Irish and Broad).

Looking at the "chronology of P4" on http://www.clag.org.uk/protofour-chronology.html I see that the first triangular gauge was devised by Brook Smith in 1956 and is thus fundamental to our hobby, and my questions are not meant to rock this boat unless my question, whether running could be improved with prototypical widening, was found to be answered in the affirmative.

Alan Turner
Posts: 548
Joined: Sun Jul 20, 2008 4:24 pm

Re: Society Gauge Widening Tool

Postby Alan Turner » Fri Apr 22, 2016 7:43 am

Julian Roberts wrote:
Alan Turner wrote:
However if we take the prototype gauge widening of 10 - 7 chains = 1/4", 7 - 5.5 chains = 1/2" and less than 5.5 chains = 3/4" then the results for the length of mint gauge (set to the track gauge of 18.83mm) to produce these are:


10 chains, length of gauge required =24.35mm (1/4")
7 chains, length of gauge required =20.42mm (1/4")
7 chains, length of gauge required =28.88mm (1/2")
5.5 chains, length of gauge required =25.65mm (1/2")
5.5 chains, length of gauge required =31.41mm (3/4")



I absolutely am not qualified to make any mathematics correction to anyone. But I am not sure this can be correct. The thread opened with Russ Elliott saying that the Society Gauge Widening Tool gives half the widening the prototype might have done for a given radius. The gauge is a bit difficult to measure, in that the legs have a thickness, but the rectangular one which has the same function is 29.75mm long. My friend Chris calculated that prototypical widening of 3/4" at 5.5 chains or in our terms 0.25mm at 4 foot 9 inches, would be obtained with a length of 54mm, thus pretty much corroborating Russ' statement.
[/quote]

Well the "Mint" gauge cannot produce anything as it is not capable of positioning the rails. It's intended use is to check existing track and specifically turnouts, and even then it will not adequately check the curved portion of the turnout for the reasons I give below.

However if it is used on existing plain track then if that track is curved it will only be able to freely pass along that track if the curved track is gauge widened by an amount dictated by the "Fixed wheel base" of the gauge. Of course this Gauge Widening is a minimum dimension.

If your gauge is 54mm long then a simple calculation shows that for the gauge to freely pass along a curved section of track the track will need to be wide to gauge as per this graph:

Gauge Mint 3.png
Gauge Mint 3.png (38.29 KiB) Viewed 3387 times



As you can see, for a 54mm gauge, it requires far more gauge widening than does the prototype to pass freely along the track.

The Green line represents a "Mint" gauge that approximates to the prototype. This gauge would be 45mm long. Although it does coincide with the prototype at 5.5 chains.

regards

Alan

edited to correct minor error.
Last edited by Alan Turner on Fri Apr 22, 2016 10:52 am, edited 2 times in total.

Julian Roberts
Posts: 762
Joined: Sat Jan 09, 2010 11:33 pm

Re: Society Gauge Widening Tool

Postby Julian Roberts » Fri Apr 22, 2016 8:47 am

Thanks Alan. Obviously very different result to what I was thinking.

Can you talk me through your red lines? 1 chain = 66 feet, 4mm scale = 4mm to the foot, right?

5.5 chains (X 66) = 363 feet (X 4) = 1452mm in our scale
7 chains = 462 feet = 1848mm in our scale
10 chains = 660 feet = 2640mm in our scale.


Got to go out now, sorry if I don't respond further for a while.

Cheers
Julian

User avatar
Will L
Posts: 1655
Joined: Sun Jul 20, 2008 3:54 pm

Re: Society Gauge Widening Tool

Postby Will L » Fri Apr 22, 2016 10:22 am

Julian Roberts wrote:
Will L wrote:In summary, re the Mint gauge, it seems to me....

Unlike the traditional 3 point gauge, the mint gauge was never intended to be used for creating/checking* gauge widening. So it has no relevance to this thread and its length was a distinct red herring.
]


Well as you can see Will I don't quite understand whether the Mint gauge is being used beyond its original purpose.


I think that is exactly what I was trying to say

But might I suggest that if it is, and is being found to be useful in picking up faults that other gauges don't, ?


Agreed that is probably true, but if you use a gauge beyond the design spec you must expect that the result are at best undefined.

..it might be partly because it is longer than the Society gauge


No I think that it is just rather easier tool to push round your track work than previous gauges and hence is better at picking up under gauge faults.

One of the objectives of the P4 standards is to have a consistent set which ensures that locos built to P4 standard will run satisfactorily on P4 layouts.

Having arrived at the point where the mint is used to check for under gauge track-work, I think that we should consider setting the mint gauge length so that it will fit within exactly same gauge widened curves as produced by the standard 3 point gauge, in that cause of consistency.

While I would admit to coming from the "getting at all right"tendency and thus suspension free vehicles and over size flanges are not my thing. Practicality dictates I try to build my loco so they will run happily round a given minimum curves (3'6" in my case) built with the standard three point gauge, despite the fact that I end up having to build in more chassis flexibility than the prototype. I rather think that a desire to be pedantic about the prototypical use of gauge widening demands specialist knowledge and something more than a basis P4 standard gauge sets.

Terry Bendall
Posts: 1634
Joined: Sun Jul 27, 2008 7:46 am

Re: Society Gauge Widening Tool

Postby Terry Bendall » Fri Apr 22, 2016 11:39 am

Julian Roberts wrote:I don't get all this. I understand that the gauge will be very useful to check the straight road of a turnout, though I don't see how it is so useful for the curving road, but you are saying it was used for every inch of the layout. Presumably "Pulborough" is not entirely made of straight lines?


err... what I said was
Terry Bendall wrote:Roger and one of the other members of the group started at one end of the layout and literally checked every inch of the track
I did not say that the mint gauge was used to do the checking of every inch, just that every inch was checked. :) The need for the gauge was realised during the course of the check and it was designed and produced afterwards.

Paul Townsend wrote:requires it to be made of say Tufnol or an even tougher and better insulating and heat-resistant material


Glue, screw or bolt a piece of heat resistant material to the top surface. :D I am not sure that any electrical insulated material would be sufficiently robust to remain accurate. Turn the power off sound a better idea. :)

Terry Bendall


Return to “Track and Turnouts”

Who is online

Users browsing this forum: No registered users and 1 guest