4mm Lynton & Lynmouth - 4mm scale, 8mm gauge.

Discussion in 'Area 51' started by Tim Watson, 1 May 2020.

  1. john lewsey

    john lewsey Western Thunderer

    The shed detail is really good Tim
     
  2. Tim Watson

    Tim Watson Western Thunderer

    One advantage of following a prototype as well covered photographically as Lynton is that weathering is rather easier. The shed now has its roof permanently fixed and the ends blended in: the heading photo shows how this was in Southern days.
    [​IMG]

    At the Lynton end, the smoke staining was rather more prevalent: the only outstanding details are now the point rodding, power line insulators and water pipe at this end.
    [​IMG]

    The building is now awaiting the rest of the world around it.

    Tim
     
  3. jonte

    jonte Western Thunderer

    I must say, Tim, I’ve really enjoyed reading through your thread and like many other fellow Westerners, have admired the quality of your handiwork.

    The ‘puddle’ put me very much in mind of a photo I discovered on the ‘net a couple of years or so ago and has become a favourite of mine and which I too hope to replicate eventually, so have been taking note :)

    Simply entitled ‘Shed Puddle’, it’s a source of inspiration as well as detail, to say nothing of atmosphere:

    32252A8D-9884-4391-B6A4-25B8F7BD089C.jpeg


    Looking forward to more, Tim.

    Jonte
     
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  4. adrian

    adrian Flying Squad

    Curious to find if there were any more and google images returned this - was this your source?
    a few more pictures...
    and a little more of his work
    Welcome to Liverpool!
     
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  5. Threadmark: Engineering
    Tim Watson

    Tim Watson Western Thunderer

    I have made a start on the axles and wheel sets for Yeo, the first engine for Lynton. The standards are based on those of the 2mm Scale Association, but minus 1.42mm.

    The Heljan wheels are actually very fine as made, but to work in the narrower FS flange-ways require a thinner flange. The wheels were thinned mainly on the rear and a little bit off the front face, being held in a step collet. There is no need to modify the tread diameter, so maintaining concentricity.
    [​IMG]

    The new 2mm axles were turned from watchmakers pivot steel: it is very hard and has a highly polished surface. A 1.5mm diameter by 1mm deep shoulder was turned on the end using a TC tool.
    [​IMG]

    The fly crank webs will be made next using 1mm thick steel, fitted up against the shouldered axle. What will become apparent, when the valve gear is complete, is that the engine won’t look as if its got it’s elbows sticking out, compared to the commercial model.

    Tim
     
    Last edited: 19 May 2020
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  6. matto21

    matto21 Western Thunderer

    Love the shed! A simple "like" doesn't seem enough - it's really excellent!

    Matt
     
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  7. jonte

    jonte Western Thunderer

    I hope you don’t think it curt of me to say ‘not sure’, Adrian; it’s that long since I found it, I can’t say for certain, but probably :)

    The second link is certainly new to me which I shall enjoy perusing a little later :thumbs:

    Jonte
     
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  8. Tim Watson

    Tim Watson Western Thunderer

    The crank webs were made by drilling a strip of 1mm thick steel with the relevant 1.5 & 0.9mm diameter holes, just using the dials on my co-ordinate drilling table for setting out. Lots of cutting oil was needed, and a very gentle action with the small TC drill.

    [​IMG]

    The strip was then tidied up prior to chopping off the individual crank webs.
    [​IMG]
    The use of two twist drills helped to hold the stack of cranks together for filing in the vice and also indicated that they had identical throws.
    [​IMG]

    [​IMG]

    The cranks are just lightly placed on the shouldered axle in this image. The backs will need thinning for frame clearance and, of course, crank pins fitted. They will be a force fit, once quartered accurately.
    [​IMG]

    It’s a excellent hobby that let’s you go from playing at being an artist to an engineer in the blink of an eye isn’t it?

    Tim
     
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  9. Giles

    Giles Western Thunderer

    *Gets Popcorn* ........ this is going to be amazing!
     
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  10. Chris Veitch

    Chris Veitch Active Member

    Yes, definitely looking forward to this. I think we can be sure that Tim's MW won't have a painted plastic dome cover.
     
    Last edited: 20 May 2020
  11. Tim Watson

    Tim Watson Western Thunderer

    You’re right about the dome, Chris, but it would be a rather large lump of gold!

    Tim
     
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  12. Threadmark: The Joys of valve gear
    Tim Watson

    Tim Watson Western Thunderer

    Making this work will be a challenge.
    [​IMG]

    [​IMG]
    Photos by Owen Chapman


    It would be useful to have some dimensions for the valve gear, as these are going to be very critical. I spent most of today working out chassis dimensions and roughing out the frames.

    Tim
     
    Last edited: 21 May 2020
  13. JimG

    JimG Western Thunderer

    You could probably do without that link and return crank. :) I've been digging through my references and I can't find any where the fixed link on the Joy gear has been replced by a link driven from the crank pin via a return crank. I've just had a look through the NRM's BR/OPC Microfiche list and can only find two weight diagrams - Card Nos 15547 and 15548.

    Jim.
     
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  14. Chris Veitch

    Chris Veitch Active Member

    Not sure if it's of much help, but Catchpole's old Oakwood Press book on the L&B has a separate scrap view showing top, side and end elevations of the RHS valve gear. No dimensions, but it looks to give a good view of how it's laid out with a view of the gear from the rear showing the motion bracket, and a section through the cylinder. It looks like it came from one of the engineering journals, presumably at the time of their construction.
     
    Last edited: 22 May 2020 at 12:11
  15. oldravendale

    oldravendale Western Thunderer

    Excuse the slight diversion, but good to have you back, Jim.

    Best regards.

    Brian
     
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  16. Phil O

    Phil O Western Thunderer

    I have only just spotted this thread and what a joy to behold it is. The shed could be a diorama in itself, such is the craftmanship and attention to the small details.
     
  17. JimG

    JimG Western Thunderer

    I've just found a simulation of the Joy gear particular to Lyd - in Charlie Dockstader's simulations, now hosted on the following site :-

    Dockstader Valve Gear Simulations

    It's the Joy 2 Outside admission simulation in File 10M if you don't want to download all the simulations. It might be of some help when laying out your 4mm version. :)

    Jim.
     
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  18. Tim Watson

    Tim Watson Western Thunderer

    Many thanks for all the help with the valve gear, much appreciated.
    The chassis is now cut out: it will replace the front 2/3rds of the Heljan set up, but integrate with their fixings. As ever, the two sides were sweated together, drilled and filed to shape.
    [​IMG]
    The frames are 1.5mm hard brass, with sighting rods in the axle holes in this picture. I am very lucky to have an incredibly accurate mill / drill and the chassis is pretty true. Various holes are for mounting the cylinders, motion support bracket and valve gear rocker. The rebate at the rear will take the frame widened part of the Heljan chassis.
    [​IMG]
    One thing I have noticed was that the Heljan crank throw was about 0.5mm short. Can’t think why.

    Tim
     
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  19. Steph Dale

    Steph Dale Western Thunderer

    Well, reducing the crank throw is one way of improving clearances at the front and back of cylinders and slidebars. I think it's reasonable to expect that your hand-built model will be assembled to closer tolerances (!!) and therefore that you'd find the dodge unnecessary. It's turning into a lovely build, I have my popcorn and am watching with interest. :)

    Steph
     
  20. AJC

    AJC Western Thunderer

    Ha! 'reasonable' (based on the 4mm Heljan locos I have) can be read as 'ceertainly'.

    I have a 1366 upstairs and one of the EM conversion things I have to look forward to is removing all the side play (a couple of mm at least) from the front axle. I'm not quite sure why it's there at all as the wheelbase is minute.

    Adam