megroeg

I have been waiting (very, very, very patiently) for this. Thank You. Graham, you are talking as much nonsense now as you and your cronies were before I joined the thread. And that includes Dobbin. You lot, and your 3mm knocker friends, and there are quite a number, why do you all hate 3mm so much, what did we ever do to you? Just who are the trolls? Um? I wonder. Anyway I digress.......... Everything in your post proves you can run around with a calculator and add 2 + 2, (or minus 2 and 2) splendid, well done, top of the class and kiss the teacher, but, it also proves that you have NO practical experience of the subject that we, the more discerning and knowledgeable members of 3mm are discussing Everything in your post proves to those of us in 3mm who have looked beyond the end of our nose, that you have no PRACTICAL, and that is what counts, experience of the subject at all.. I for one am just not not interested in arguing with you or your ill fated attempt at face saving, until you have achieved in 3mm what I have achieved and you at the moment are at Zero. Oh, and I may be wrong here, and probably will be I usually am, I for one have never heard your name mentioned in 34 years of 3MM Society membership, and yet you do claim to have met me, more than once, but I do have a bad memory for names, and faces, maybe it's just as well eh? megroegm

I model in both these gauges as well as 12mm so I will try to explain to those that are genuinely interested the pros and cons of 3mm / 14.2 and 13.5 First of all let us be quite clear that it is quite possible to model loco with outside valve gear in 14.2 gauge and many have done so but what they and you cannot do build them to scale dimensions, you need to cheat. There is just not the space to do the valve gear mechanically strong enough. The most common way to cheat, there are other ways, is to set the cylinder centres out over by 0.5mm. ( take note of that dimension as it will turn up again later) This will give enough clearance to fit the valve gear. Most loco kits in 3mm are ‘shot down’ from 4mm or even 7mm so the parts are etched to scale and the operation of easing out the cylinders up even by just a small margin and getting that margin equal on both sides of the loco is laborious and a real pain at times depending on the kit. Secondly, 14.2,done properly, and to the standard will allow 0-6-0 locos of say, N.E.R. P3 (LNER / BR J27’s) proportions to negotiate curves of about 4ft, tighter than that you are either cheating or chancing your luck, or maybe both? So where does this leave 13.5? The first mistake the outsider looking in makes is this:- 14.125mm – 13.5mm = 0.625mm or 0.3125mm each side, so then outsider immediately makes the mistake that 13.5 has the same problem as 14.2 there is still not enough room for valve gear. Wrong. Ken Garret, who penned the TM standards donkey’s years ago realised this as well as the large radii needed by 14.2 locos so the crucial dimension is the back to back which in TM (TM is what Ken called 13.5) is 11.8 mm. The back to back in 14.2 is 12.8mm so that is a whole 1mm difference or 0.5mm per side of the loco and where have we heard that figure before? In 13.5 there is no need to alter anything, usually using the EM spacers for the frames is all that is required. Reducing the back to back also means that the relationship between track and wheel has altered to the extent that the minimum radius decreases from 4ft to 3ft, even less depending on loco. So turnouts can be sharper, transition curves shorter, hence layouts smaller for the same content and yet the only guy that can tell the difference between 14.2 or 13.5 is the guy with a vernier calliper. But of course there are doubters and there are those who like to have a shot at anything different to the norm or shakes their cradle. All I can say is I have tried both, I still build in both, but then I also build in just about every other scale less than 7mm, I just enjoy model railways.

I admire the dedication that something like this takes.Inspiring and fantastic. I look forward to seeing the finished job. megroeg m

I have been a regular visitor to the 3mm section of rmweb ever since it was set up but I have never felt the need to contribute until I read these recent postings where I found my name being bandied about and a subject about which I have a great deal of experience being belittled by correspondents who quite obviously know little or nothing of the subject. I do not lie in wait for little Billy goats gruff to cross my bridge. First of all lets get a couple of things clear. One - anyone who is a regular reader of the 3mm mag Mixed Traffic or a member a member of the egroup is well aware of the limitations of the 14.2 loco. It is a fairly regular subject. That is why I said ‘common knowledge’ in 3mm. And two, 3mm despite all the nastiness and abuse thrown at it by usually by those not good enough modellers to work in it, 3mm is in my opinion THE best scale to work in bar non. I should know, I have tried most of the others. So what experience have I got? Well, I have been a railway modeller for over 40 years and 34 years experience of 3mm modelling, I design, do the artwork, and build all kinds of etched kits for, coaches, wagons, signals, trackside bits and pieces and, oh yes, locomotives. I also do the 3d drawings necessary for 3d printing and as someone observed I build locomotives, lots of them. Well over 250 so far in all scales from 2mm to gauge 1 and in just about every variation in between but especially in 3mm. My own personal collection of hand built locos in 14.2 and 13.5 extends to over 30. I have built and exhibited the largest 14.2 mm gauge layout seen in 3mm and also the proud owner of a 3mm scale 28ft x 6ft 4 track main line in 13.5 mm gauge. This exhibition layout has hand made track and incorporates 22 points, crossovers and double slip and runs perfectly. Now tell me I am trolling or I do not know what I am talking about.

I have built in all gauges in 3mm and it is without doubt the best of all the small scales to model in - that is if you enjoy scratch building, kit building or just like talking model railways. If you want to go out and buy RTR off the shelf then 3mm is not the scale for you, unlike 2mm - N gauge and P4 - 00 stuff. But to answer your initial question in straight forward terms:- 12MM = OO in 4MM 13.5 mm = EM in 4mm 14.125mm (commonly called 14.2 but actually 14.125) = P4 in 4mm megroeg.m

I find the replies to this topic quite honestly astonishing! I honestly thought it was common knowledge that locos with outside valve gear could not be built to absolute correct scale in 2mm and 3mm, I cannot comment on P4 because I have not built a loco with outside valve gear in P4. but in 2mm and 3mm I agree with Mr Blackberry it is impossible. The 2mm 9F is no where near scale. How can it be when the 2mm finescale wheels used on it are 0.4mm too wide anyway? To a certain extent 3mm suffers the same problems. I have had the pleasure and it was a pleasure to construct a chassis for the said loco and I can assure you it was no where near absolute scale. It is a wonderful loco to build and the end result most satisfying but to scale - no. For a start the smaller bits of the motion are getting very near to etching extremes in 4mm let alone 2mm. It is a wonderful example of the kit manufactures art, if not the best, but to scale - no way.