14.2 and 13.5mm gauges

[keidal]

Hello, I was just browsing through the Internet and came across this site. Being a doddery old 80 years geezer with a not very brilliant memory, I am still going to hold my hand up, having seen 13.5 mm gauge mentioned several times.

I believe it was in the early 1970's that I scratch built an L.M.S. 0-4-4T loco  to 3 mm scale and I seem to remember that I wrote an article on it, for the Railway Modeller magazine.

I remember it was, purely by chance for 13.5 mm gauge, by putting packing washers on the Romford axles. Whether this was coincidental with other attempts at this gauge or whether I started something, I can't remember; in fact I don't remember much these days !

Some time after and as a member of the L&Y Society, I was persuaded to manufacture [purely as a hobby] 7 mm and then 4 mm loco kits for L&Y and N.E.R. prototypes. Eventually I couldn't cope with the demand for these kits, sold as "O7 Kits" and George Norton took them on and I understand that they have been passed on since to others.

I mention this because my artwork for these kits was used by the 3 mm Society for some kits. 

I am very interested in development of the Stewart Hine Scale3 standards and I have just found on eBay, a copy of the Model Railways magazine for January 1973 in which I believe his proposals were published.

Does anyone have any experience with his proposals, of which I know nothing at this time ?

Stewart produced some "fine scale" bullhead rail for me decades ago, I presume by heating commercial rail to red hot and stretching it, in 9" lengths. I always thought that he did this by holding one end in an engineer's vice - a marvellous product !

I'm thinking about building a 3 mm scale round-top boiler L.N.E.R. O4 loco to his standards, if I possibly can.  

Apologies to all, if I'm completely wrong; it was a long time ago !

Keith Dales

Edited January 30, 2016 by keidal

[Phil Copleston]

More the other way around 3mm times 4.5 = 13.5mm hence 13.5 is the direct equivalent of EM.

3mm times 4.75 = 14.25 then take off the surplus half inch equivalent you get 14.2, hence 14.2 is the direct equivalent of P4 so far as gauge is concerned.

I don't know about wheel standards.

Regards

Keith

 

Just picked up on this thread. Actually, P4 is not about gauge, but is a set of track and wheel standards that can be applied to models of broad, standard or narrow prototype gauges. So 3mm scale/14.2mm gauge 'finescale' is in fact (despite the correct gauge) equivalent to EM in standards, as is 13.5mm in that respect.

 

The only standard in 3mm scale equivalent to P4 are the published Scale 3 standards (John Delaney & Stewart Hine, ‘Mixed Traffic’ No.29, July 1972), which apart from some trial models built in the 1970s, for some reason have not been adopted by the 3mm Society. Pity, as these should work fine (as they are not much finer than 2mm Finescale) and being based on the prototype and would look stunning!  

 

For interest, here is a Comparison Table for 3mm Scale Track & Wheel Standards:

 

3mm Scale Track & Wheel Standards

Edited January 31, 2016 by Phil Copleston

[keidal]

Thank you very much Phil for this information. Has anyone ever built anything to these standards and continued to use them please ?

I for one would very much like to see a photograph of a model - of anything ? I hope that there's a photograph in the back issue of MR Jan '73 that I've ordered.

This really fascinates me !

[NCB]

Thank you very much Phil for this information. Has anyone ever built anything to these standards and continued to use them please ?

I for one would very much like to see a photograph of a model - of anything ? I hope that there's a photograph in the back issue of MR Jan '73 that I've ordered.

This really fascinates me !

I'm pretty sure nobody has, apart from the experimental models Phil mentions. I think there were two thoughts behind the 3mm Finescale standards. One was that they gave a fine scale look but were considerably more forgiving than S3 would have been. The other was the difficulty in manufacturing stuff to S3 standards with the required degree of consistency (consistency of manufacture is something that the 3mm Society needs to keep a close eye on even today and even with the tolerances built into the Intermediate and Finescale standards). There are reasons why 2mm Finescale, which Phil mentions, isn't finer than it is. Personally I'd like to see somebody give S3 a go, if only to see if it could be realistically achieved, but so far nobody has come forwards. Me, I'm happy in my 14.2mm gauge Finescale comfort zone!

 

Cheers

Nigel

[Phil Copleston]

I'm pretty sure nobody has, apart from the experimental models Phil mentions. I think there were two thoughts behind the 3mm Finescale standards. One was that they gave a fine scale look but were considerably more forgiving than S3 would have been. The other was the difficulty in manufacturing stuff to S3 standards with the required degree of consistency (consistency of manufacture is something that the 3mm Society needs to keep a close eye on even today and even with the tolerances built into the Intermediate and Finescale standards). There are reasons why 2mm Finescale, which Phil mentions, isn't finer than it is. Personally I'd like to see somebody give S3 a go, if only to see if it could be realistically achieved, but so far nobody has come forwards. Me, I'm happy in my 14.2mm gauge Finescale comfort zone!

 

Nigel,

 

I'm pretty sure no one else has tried Scale 3 either, apart from the experimental models built by John Delaney and Stewart Hine. Some 2mm modellers have indeed tried a version of "P2", but for reasons unconnected with this discussion didn't persue it.

 

The point I was making here (apart from any personal preferences) is that Scale 3 is not substantially "finer" than the already well-proven 2mm Finescale standards, and is helped by the fact that 3mm scale has the advantage of 50% more mass then 2mm scale to keep things on the track. I think Scale 3 is a concept worth exploring, or at least discussing, in relation to options for 3mm track and wheel standards on this thread. 

 

To see how things looked, I drew up a table a while ago showing the Scale 3 figures compared with 2mm Finescale, 3mm 14.2 'finescale', P87 and P4 - as attached here (the non-3mm gauge-dependant figures are adjusted to suit 1:101.6 scale to make comparison easier). Based on this table, I'd be interested in what others' think of the relative technical and aesthetic merits of Scale 3 (not personal preferences).    

 

Scale 3 - Comparison Table - Comparison between Scale 3, 14.2.doc

[keidal]

Thank you everyone for your interest.

For me, this is a fascinating concept and one which I hope to pursue. I have just asked the question on another thread, relating to the appropriate bullhead rail code to use for these standards. More to the point I suppose, who can supply the rail without having to buy commercial track ?

Please share your thoughts on Scale 3 and whether you have ever considered having a go ?

Keith

[fallen]

Phil,

 

Thanks for the info, the table in particular is very useful.

 

One query, the table, like most of the others I have seen, gives dimensions for wheels, and for track in relation to points etc.

 

How does this relate to the acceptable radius of curvature for the track? One of the big issues with fine scale for many people is the large radius curves that have to be used. How is this defined?

 

Frank

[keidal]

Perhaps gauge widening on curves, as used on full-size track ?

[Phil Copleston]

Thanks for the info, the table in particular is very useful.

 

One query, the table, like most of the others I have seen, gives dimensions for wheels, and for track in relation to points etc.

 

How does this relate to the acceptable radius of curvature for the track? One of the big issues with fine scale for many people is the large radius curves that have to be used. How is this defined?

 

Frank,

 

I'm not aware of any 'minimum radius' being recommended for 3mm scale standard gauge as this depends on your prototype and space for a layout. But in modelling terms, minimum curvature is usually a process of trail and error dependant on the longest wheelbase of the stock you will use. But as Scale 3 is the same actual gauge as 'Fine Standards' 14.2 gauge, the same minimum radius should apply. However, as a rule of thumb the "Four Chains Rule" is as good as any. Here's how it works: 

 

A chain is 66ft (20.1168m), thus 4 chains is 264ft (80.4672m), and in 3mm/ft scale that is 792mm or 31" (2ft 7in) radius. So Scale 3 should be no more onerous regarding minimum radius than working in 'Fine Standards' 14.2 gauge (or 12mm for that matter).

 

There is a most useful discussion regarding the minimum radius for 3mm scale/14.2mm gauge on the Templot discussion board, here: http://85a.co.uk/forum/view_topic.php?id=2183&forum_id=1

 

Hope that helps. Glad you found the various Scale 3 tables useful.

Edited February 2, 2016 by Phil Copleston

[fallen]

Thanks Phil, useful links.

 

Frank

[NCB]

Re minimum radius, in 14.2mm finescale I try to work to a norm of 40" radius, with 36" OK and an absolute minimum of 32", which is along the lines suggested by Phil. However, due to an error of mine in measuring up the site for the layout, where the running line curves across a corner I've had to shove in a 29" radius curve at one point. On the bit of test track I put in place to check this it appears to be OK for nearly all of my stock. I don't think S3 would cope, because in S3 the distance measured over the outer faces of the wheel flanges is noticeably larger than 14.2mm finescale, hence less slop on the track. On the other hand, that bit of track of mine didn't use gauge widening, and with that in place S3 might be OK.

 

Nigel

[5050]

Following on from my thread 'TT3 the Next Big Thing' on the Collectables area, I thought I would have look here to see what was being discussed.  All very interesting - in a strange way!  However, I realised from the start of the 'discussion' about valve gear etc. that possibly a fundamental error is made.  Surely the valve gear plays no part (as Graham Hughes states) it is the clearance behind the crosshead with the front crankpin that can create clearance problems.  This applies to all outside cylinder locos including GWR ones that have no outside valve gear.  Even in P4 I 'sink' the front crankpin 'nut' into the rod and/or turn my own threaded bushes that screw in from the outside.

 

As a long term P4 modeller I hold anyone who can model to real finescale standards in 2mm or 3mm in awe. I find 4mm scale hard enough!

[NCB]

The basic problem is that parts are overscale, in particular the finescale wheels, although fine, are still wider than scale. So anything on the prototype which gets near to the face of the wheel may give problems, particularly if that axle has sideplay. For example, I built a Mitchell 517 class to 14.2mm gauge:

 

There was no way would the front wheels fit between the inner faces of the splashers, so I had to drift the splashers outwards.

 

The obvious problem is when you have outside cylinders, and the configuration is such, as stated in the previous post, that the crosshead passes in front of a crankpin. In that case the solution is to cheat. On my 42XX, I thinned the coupling rod at that point, filed the crankpin nut to half thickness, and still had to drift the cylinders out about 1mm on each side to be sure of things clearing. Here's the beast:

 

 

Not surprising; even Churchward had to recess the crankpin boss into the coupling rod.

 

Bottom line: if using 14.2mm track then on some prototypes you have to cheat.