The Nth Degree Posted January 10, 2012 Share Posted January 10, 2012 I'm just trying to get my scale measurements correct. I downloaded the 2mm scale converter from someone here a few weeks ago and I'm just starting to plan out my first scratch loco but, my GOD, it looks small. It's a Fox Walker 0-6-0, one of the first generation (No. 170, I believe) and here are my measurements from the tech specs: Part Prototype Scale Wheels 3' 6" 7mm Wheelbases 4' 10" 9.7mm Chassis 21' 42mm (buffer beam to buffer beam) Is this correct? If so, that's even smaller than I thought! Link to post Share on other sites More sharing options...
richbrummitt Posted January 10, 2012 Share Posted January 10, 2012 Is this correct? Yes*. Your picture looks a little bit big though. *If you think about this for a moment a 21' length vehicle with 3'6" wheels is approximately the size of a largish grouping era horsebox. Link to post Share on other sites More sharing options...
Chris Higgs Posted January 10, 2012 Share Posted January 10, 2012 I'm just trying to get my scale measurements correct. I downloaded the 2mm scale converter from someone here a few weeks ago and I'm just starting to plan out my first scratch loco but, my GOD, it looks small. It's a Fox Walker 0-6-0, one of the first generation (No. 170, I believe) and here are my measurements from the tech specs: Part Prototype Scale Wheels 3' 6" 7mm Wheelbases 4' 10" 9.7mm Chassis 21' 42mm (buffer beam to buffer beam) Is this correct? If so, that's even smaller than I thought! Looks correct to me. But what do you expect when you choose something so small as a prototype? Chris Link to post Share on other sites More sharing options...
The Nth Degree Posted January 10, 2012 Author Share Posted January 10, 2012 Thanks for confirming. Chris, I didn't 'expect' anything until I transferred the measurements using the scale calculator. I was 'hoping' for something bigger though... Link to post Share on other sites More sharing options...
The Nth Degree Posted January 10, 2012 Author Share Posted January 10, 2012 Chassis layout with friction drive arrangement. Link to post Share on other sites More sharing options...
RMweb Premium Kris Posted January 10, 2012 RMweb Premium Share Posted January 10, 2012 Do you have enough room for a motor? Link to post Share on other sites More sharing options...
The Nth Degree Posted January 10, 2012 Author Share Posted January 10, 2012 Good question Kris. I knew space was going to be tight (but not this tight!) so I found a 15mm x 2.5mm pancake motor with a 3mm axle (the larger disk in the pic). The two smaller disks are both lower gearing and friction drives to the axles of the rail wheels. I can't work out the dear ratios. I know the following: Motor axle: 1mm Friction wheel: 6mm Rail wheel axle: 1.3mm Rail wheel: 7mm Can anyone work out the reduction from that info? Link to post Share on other sites More sharing options...
The Nth Degree Posted January 10, 2012 Author Share Posted January 10, 2012 This is the prototype: http://www.steampicturelibrary.com/low.php?xp=media&xm=4039615 Link to post Share on other sites More sharing options...
2mm Andy Posted January 10, 2012 Share Posted January 10, 2012 2mm wheels run in plastic axle m*ffs (see details on the 2mm website - the standards diagrams are on there) - so your drive belts will have to fit over those, not the axle. I would avoid that pancake motor if possible - far better to design an arrangement of spur gears to fit in the firebox of the loco and have a small can motor (the Nigel Lawton ones seem quite popular) mounted horizontally in the boiler. Have you built a 2mm loco before? I would really recommend having a go at one of the kits available to get an idea of how things work before you dive straight into a scratchbuild of what looks like quite a challenging model. Andy Link to post Share on other sites More sharing options...
The Nth Degree Posted January 10, 2012 Author Share Posted January 10, 2012 Hello Andy. I've glanced over the 2mm site and its resources and, while I fully intend on becoming a member, I'm sure there are other ways of doing things. Unless you're producing some sort of live or split chassis I don't see a reason to use a sleeve over the axle. I may well end up doing it the 'right' way but, for now, time is on my hands to experiment. I'm interested in your comment about the motor. Please let me know if you have any information on these as I know nothing. I just planned in my head what would be best and found a solution. This arrangement also has the advantage of 4 wheel drive so should be better at traction and electrical pick-up. Personally, apart from the extremely small size, I can't foresee any problems. There would be many more obstacles with a standard construction it may even be impossible? As plenty of ex-girlfriends have pointed out before, I'm a stubborn b*stard and I will doggedly pursue what I believe is right before I bow down, defeated. I'm definitely keen to do this, even if it is just to prove it can't be done, or can be done better. So to answer your question; no, I haven't built anything that didn't come with a sheet of instructions and a tube of glue. I'm willing to give it a go though! Link to post Share on other sites More sharing options...
Chris Higgs Posted January 10, 2012 Share Posted January 10, 2012 Thanks for confirming. Chris, I didn't 'expect' anything until I transferred the measurements using the scale calculator. I was 'hoping' for something bigger though... Then choose a bigger protoype then. Or a bigger scale? Personally I have never understood the obsession with buldiing the smallest loco imaginable in such a small scale. Just to prove it can be done I suppose. But sadly many have been put by not choosing a nice spacious prototype as their first attempt in 2mm FS. Chris Link to post Share on other sites More sharing options...
Chris Higgs Posted January 10, 2012 Share Posted January 10, 2012 Hello Andy. I've glanced over the 2mm site and its resources and, while I fully intend on becoming a member, I'm sure there are other ways of doing things. Unless you're producing some sort of live or split chassis I don't see a reason to use a sleeve over the axle. I may well end up doing it the 'right' way but, for now, time is on my hands to experiment. Planning on making your own wheels as well then? Because agree with it or not, only stub axle loco wheels for use with muffs and split frame construction are being made. Chris Link to post Share on other sites More sharing options...
The Nth Degree Posted January 10, 2012 Author Share Posted January 10, 2012 Chris, there's a lot of unwarrented accusations and assumptions there. I'm calling it a night and will assume you've had a bad day. No hard feelings. Link to post Share on other sites More sharing options...
-missy- Posted January 10, 2012 Share Posted January 10, 2012 Hello This is an interesting project and as others have said scratch building one of those in 2mm scale is quite a challenge for the inexperienced. This is intended as constructive so please dont take it the wrong way! The pully method you have drawn will not work, the problem is that the drivebelts will be prone to slipping or stretching and as the driving wheels are coupled together (with coupling rods) the chances of things not binding up is very slim. Personally if you are insistant on using drivebelts then drive one set of wheels only and let the coupling rods do the rest. From what information I have seen drivebelts are also notoriously difficult to set up right, too tight and they put excessive load on the motor, too loose and they will slip. I know its been done before but I thought it was worth mentioning. As for a pancake motor, I would agree with Andy and rather stick to something a little more tried and tested like the Nigel Lawton motors (.http://www.nigellawton009.com/VeeTipper.html) The only other thing I can really suggest right now is to take a look at my entries on the Showcase about chassis design, the one that probably most useful is the first page (http://www.rmweb.co.uk/showcase/?p=1850) Please dont think I am trying to dismiss this because Im not, it CAN be done but now is probably not the best time to try and 'reinvent the wheel', do that once you have a few chassis under your belt... Missy Link to post Share on other sites More sharing options...
Guest Natalie Graham Posted January 10, 2012 Share Posted January 10, 2012 I can't work out the dear ratios. I know the following: Motor axle: 1mm Friction wheel: 6mm Rail wheel axle: 1.3mm Rail wheel: 7mm Can anyone work out the reduction from that info? Yes, it will be next to nothing as your final drive from the friction wheels to the axles isn't a reduction it is an increase and assuming your friction discs have a groove in them to accommodate the belt which will reduce the effective diameter in the initial drive, the overall ratio may even end up as an increase on the motor speed. If you are using a friction drive you need a small drive running against a larger friction wheel mounted on the driven axle Link to post Share on other sites More sharing options...
2mm Andy Posted January 10, 2012 Share Posted January 10, 2012 Hello Andy. I've glanced over the 2mm site and its resources and, while I fully intend on becoming a member, I'm sure there are other ways of doing things. Unless you're producing some sort of live or split chassis I don't see a reason to use a sleeve over the axle. I may well end up doing it the 'right' way but, for now, time is on my hands to experiment. I'm interested in your comment about the motor. Please let me know if you have any information on these as I know nothing. I just planned in my head what would be best and found a solution. This arrangement also has the advantage of 4 wheel drive so should be better at traction and electrical pick-up. Personally, apart from the extremely small size, I can't foresee any problems. There would be many more obstacles with a standard construction it may even be impossible? I admit I don't know what modelling skills you possess, so it's difficult to make a judgement, but I really do think you'll struggle with your approach to this (I'd love to be proved wrong - I want to see as many successful 2mm modellers as possible!). 2mm scale loco wheels are only available from the 2mm Scale Association at present, and they only sell to members (something to do with tax), so I do wonder where you're going to get the wheels from (unless you buy through a member, fancy making your own or turning down some N gauge ones, the latter two of which approaches really require a lathe). The range of wheels currently available from the 2mm SA are designed around the split frame principle - ie. each sideframe is electrically live and insulated from the other. The wheels are machined with integral 'stub axles' which are pushed through the sideframes and into plastic muffs which hold the wheels to gauge and insulate them from each other. The reason for doing this is to avoid the need for pick-ups which are notoriously difficult to set up in 2mm scale. There is no need to drive 4 wheels if you're fitting coupling rods to the wheels - they'll do the driving for you (to all six wheels). Others have built locos of a similar size to this one using 2mm SA components and methods, so it is possible! My only experience with 'pancake' motors is those evil things that the likes of Lima and Hornby used in the 1970s and 80s, so there may be better units available now, but will your motor fit - I think it projects into the boiler, so will need some sort of cut-out? I'm not sure you're going to get anything other than a very slight reduction in speed from the motor to the wheels - worm gears would be far better in a loco like this (the prototype would probably only have got up to 25mph on a good day with a fair wind behind it!). I would read the links in Missy's posting - they're for a similar size of chassis to the one you're thinking about (albeit yours has a slightly wider gauge). Hope the above helps. Andy Link to post Share on other sites More sharing options...
The Nth Degree Posted January 11, 2012 Author Share Posted January 11, 2012 Thanks for all the replies with encouragement, advice and ridicule. I appreciate it all. Just to clarify, my 'obsession' is not with small, or unique or impossible challenges, but with Cardigan. In particular the first day or at most, first week of operation of the branch extension - just at the time when it was handed over to the GWR. My handicaps are space, experience and my innate refusal to accept 'the norm'. I've been thinking and planning a bit more. I reworked the pulley system after Natalie reminded me of extremely basic mechanical work principles (I got an A in physics unbelievably...) and I also placed a 6x10mm motor in position as a comparison. I'll need to find a good gearbox reduction system to plan it properly. Missy, I read your (and others) construction pages last year. Yours is an excellent article in the way its organised, written and illustrated, and I was planning to talk to you about it at Ally Pally last year. By the time I got to the 2mm stand you had gone for lunch but I did spend an hour or so talking to a chap who was soldering wagons. Nice bloke who had plenty of time for an incessant prodder like me. Andy, I think I'm coming round to the 2mm way. Although I'm beginning to feel a bit like a Stepford Modeller, I do realise that there is reason behind the method and it's been tried and tested for a generation or so. If I can't find a reasonably successful way of doing it my way I will gracefully slump down into a comfy wingback in the 2mm Assoc. smoking lounge. Further scribbles attached. I heard of a really good axle-mounted reduction gearbox but have lost the link... Link to post Share on other sites More sharing options...
Chris Higgs Posted January 11, 2012 Share Posted January 11, 2012 My only experience with 'pancake' motors is those evil things that the likes of Lima and Hornby used in the 1970s and 80s, so there may be better units available now, but will your motor fit - I think it projects into the boiler, so will need some sort of cut-out? I'm not sure you're going to get anything other than a very slight reduction in speed from the motor to the wheels - worm gears would be far better in a loco like this (the prototype would probably only have got up to 25mph on a good day with a fair wind behind it!). Andy Fleischmann used to use pancake motors in HO and they were a bit better quality than the British versions. No longer, as they found normal motors with flywheels to be a better choice. Pancake motors have been successfully done in 2mm. By the legendary Stewart Hine no less. But he built his own motors. In fact he made his own everything - to his defence there wasn't much choice then - we are talking the 1960s. He used a gear train - you can get a big reduction with the size of gears that could be fitted into his big GWR locos (yes he made the gears too). Chris Link to post Share on other sites More sharing options...
The Nth Degree Posted January 12, 2012 Author Share Posted January 12, 2012 Hello Chris As a newcomer to this hobby I'm unaware of anything that has gone previously. It's only in the last year or so that I've been looking at it in my own squinted way. I have a few N Gauge items after making a little runabout track for my son. A couple aborted (in the planning stages) layouts under my belt just about lays out my experience so far. However, I've always been handy with tools and a tube of glue. One of the reasons for trying this arrangement was to provide a flywheel to smooth out movements. I've noticed they can be quite jerky at times, especially with dust or dirt on the track. A relatively large flywheel may over come this. I'm not sure about making gears and pulleys but with modern etching facilities it may be worth investigating. I've got plenty of time to experiment - it's going to take me a while to learn how to do everything. I still have to plan and produce a baseboard, lanscape it, make and lay the track, etc. before I can run anything. Thanks for the info on Stuart Hine, I'll look him up and see what he came up with. Link to post Share on other sites More sharing options...
Chris Higgs Posted January 12, 2012 Share Posted January 12, 2012 Hello Chris As a newcomer to this hobby I'm unaware of anything that has gone previously. It's only in the last year or so that I've been looking at it in my own squinted way. I have a few N Gauge items after making a little runabout track for my son. A couple aborted (in the planning stages) layouts under my belt just about lays out my experience so far. However, I've always been handy with tools and a tube of glue. One of the reasons for trying this arrangement was to provide a flywheel to smooth out movements. I've noticed they can be quite jerky at times, especially with dust or dirt on the track. A relatively large flywheel may over come this. I'm not sure about making gears and pulleys but with modern etching facilities it may be worth investigating. I've got plenty of time to experiment - it's going to take me a while to learn how to do everything. I still have to plan and produce a baseboard, lanscape it, make and lay the track, etc. before I can run anything. Thanks for the info on Stuart Hine, I'll look him up and see what he came up with. Stewart's work was all written up in the 2mm Magazine, the full run of which can be obtained as a DVD from the Association shop. I seem to remember it was also described in mainstream model press articles, probably "Model Railways" in the early 1970s. But I haven't heard of anyone making their own motor in decades. It is not easy - I did try once. If you want to know about large flywheels, heres an interesting example: http://www.fs160.eu/fiNeweb/Lconstruction/G8/type81.php But I will repeat what I was implying yesterday withiout any intention to give offence. Build a decent sized loco the 'standard' way first. Once you have seen this in real action, then think about alternatives. Chris Link to post Share on other sites More sharing options...
-missy- Posted January 12, 2012 Share Posted January 12, 2012 Missy, I read your (and others) construction pages last year. Yours is an excellent article in the way its organised, written and illustrated, and I was planning to talk to you about it at Ally Pally last year. By the time I got to the 2mm stand you had gone for lunch but I did spend an hour or so talking to a chap who was soldering wagons. Nice bloke who had plenty of time for an incessant prodder like me. Sorry I missed you and wasnt around, it sounds unfortunate that you were there when I was having my lunch. I think I am there again this year although I dont know what day or anything yet. I heard of a really good axle-mounted reduction gearbox but have lost the link... I am guessing that one if from Mikroantriebe (https://www.shop.kkpmo.com/), one of these maybe? (http://www.shop.kkpmo.com/index.php/cat/c46_Gearbox-kits.html/XTCsid/76736b064fb3080eb585716781bd6478) Missy Link to post Share on other sites More sharing options...
RMweb Gold Donw Posted January 12, 2012 RMweb Gold Share Posted January 12, 2012 While most of us find it best to follow the paths trod by others there are some who find their own way. You may be one. Stuart is one and Missy is another. Stuart's things were written up in Model Railway News. I have an article on his pannier. Homebuilt motor gears either found or made, Wheels homemade typical of Stuarts models. However in those days you had little choice. I have no doubt today he would be pushing other boundaries. It was nice to see him at the 2mm AGM. I suggest Missy's work on her narrow gauge loco may be more appropriate for today worth viewing. Don Link to post Share on other sites More sharing options...
Thos Posted January 13, 2012 Share Posted January 13, 2012 I wonder if you could perhaps use a (permanenently attached) wagon or carriage as a tender-drive or nbrass tender-mounted drive. Link to post Share on other sites More sharing options...
Chris Higgs Posted January 13, 2012 Share Posted January 13, 2012 Stuart's things were written up in Model Railway News. I have an article on his pannier. Homebuilt motor gears either found or made, Wheels homemade typical of Stuarts models. However in those days you had little choice. I have no doubt today he would be pushing other boundaries. No doubt about that. As he was involved in 3mm scale (proposing an S3 standard), that Gauge 1 live diesel built by him and Bob Symes, and a nice article on a model of the then brand new HST in 4mm in Model Railways. Chris Link to post Share on other sites More sharing options...
The Nth Degree Posted January 13, 2012 Author Share Posted January 13, 2012 Chris, this Stuart Hine chap seems to have been way ahead of his time. Very talented man indeed! I may well end up getting myself a brass kit to try out first - perhaps a diesel shunter as there are plenty of 'How-To's' available on the web, including Missy's. Missy, great link but it wasn't one of those. I'm still trying to find it again. The gearbox was actually mounted on the driving axle and was about 6 or 7mm square and about a 40/1 reduction. Amazing engineering. One more thing, I found out the price of the flat pancake motor today. £150 each! No thanks... Link to post Share on other sites More sharing options...
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