1470 GWR 0-4-2T MOK Kit

Discussion in 'WR Action' started by Stumpytrain, 9 July 2013.

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  1. Stumpytrain

    Stumpytrain Active Member

    As seasoned "armchair" 2mm Finescale modeller, I'm quite surprised at the change of direction I've taken over the past couple of months. My ambitious dreams of Bristol Temple Meads East, Newton Abbot West or the Royal Albert Bridge weren't making any progress; partly because of the huge fleet of rolling stock required to operate them! For reasons that I may go into in an eventual layout thread, I've somehow migrated to ScaleSeven and I'm still being faithful to the original layout concept. What appeals to me the most about this plan is that, to start with at least, only one locomotive is required to faithfully represent the prototype. Others can come later, as and when...

    [​IMG]
    http://railphotoprints.zenfolio.com/p608550011/h2F6B893E#h2f6b893e

    So, a model of ex GWR 1470 is desired. Logically my first, and so far only, purchase has been for some Severn Mill Nameplates numbers and 83A shed plate which appear to get excellent reviews! Tomorrow I'm hoping to make contact with Dave Sharp of MOK to order the 1400 kit. I believe the required bits are...
    • MOK 1400 Kit
    • Slaters 7862GW 5'2" 16 Spoke Driving Wheels x 2 (Turned to S7)
    • Slaters 7843 3'7" 10 Spoke Bogie/Tender Wheel (General Pattern) (Turned to S7)
    • ABC Gears Mini 7S Gear Box (Possibly 30.2:1 Ratio?)
    • Maxon 2022413 Single Ended 22mm Diameter Motor (or maybe the Canon 1833)
    • Axleboxes
    I've read of some threads on here and on RMWeb. I'm currently researching a number of things, I have some questions and ideas that I would love to hear some feedback on.
    1. Suspension - I like the idea of the CLAG Continuous Springy Beam but I'm concerned about the complications of the 0-4-2 wheelbase.
    2. Pickups - The 2mm Finescale modeller in me is leaning towards split axles, but with the axle boxes insulated from the frames. Is that feasible? I don't like the idea of wire or plunger pickups but they may be more practical.
    3. Axleboxes - With the suspension and pickups in mind what axleboxes can be modified to suit my needs?
    4. Roller bearings - do these make a difference in 7mm?
    5. DCC Sound - She's definitely going to be DCC fitted, what I'm unsure about is if it's worth going for sound. Has anyone experienced the Howes 1400 sound chip? Speakers etc. seem to be a bit of a minefield but I must admit this hasn't been given much of my attention so far.
    Thanks for reading!
    Alex
     
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  2. Simon

    Simon Flying Squad

    Excellent!

    The cat's out of the bag - you've got to do it now Alex....

    I'm keeping quiet about "Watersmeet" though -oops:oops:

    Simon
     
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  3. Steph Dale

    Steph Dale Western Thunderer

    Alex,

    As a non-S7, but ex-P4 and still HO-P87 and 0-gauge modeller (!!!) allow me to answer some of your queries;

    1. I've built CSB, sprung and compensated chassis and in my experience an 0-4-2 will pull more if it's built compensated. In either 0-4-4t or 0-4-2t locos I've tended to use the Martin Finney approach of a set of twin beams across the two driving axles and a fixed point over the trailing axle/bogie. Being an MOK design it will have a sensible compensation system designed in.

    2. Split axles are really not a problem in 0. I've got some info up on my own website:
    http://www.euram-online.co.uk/tips/splitaxle/splitaxle1.htm
    http://www.euram-online.co.uk/tips/splitaxle/splitaxle2.htm
    http://www.euram-online.co.uk/tips/splitaxle/splitaxle3.htm
    I use split-axles in all my 0-gauge stuff and even in the odd loco in the smaller scales.

    3. MOK tend to use conventional hornblocks in their kits - with some fiddling Slater's 7961 'Insulated Square Bearings' can be used to replace the journals. As an alternative Slater's 7960 sprung hornblocks and guides have a glass-filled nylon guide which is insulating; tricky to compensate or CSB though. It is also entirely possible to electrically insulate a bearing from a frame using a trick with copper-clad which I should finish writing up (it's covered a bit superficially on the second link, above).

    4. You probably mean ball races, and their use is all a bit subjective. My preference is not to use them, but I'm using split axles, DCC and know what electro-erosion is.

    5. Not (so far) impressed with Howes steam locos although their diesels are pretty good. For speaker installation can I refer you to http://www.qsisolutions.com/products/techinfo/acoustic_designs.html which is QSI's paper on installing DCC sound systems; it's a superb reference for all DCC+s installations.

    6. Inside motion?

    In your estimations you may also want to consider the materials and tools (etc.) necessary to convert your loco's chassis to S7 width. This might be a little tricky as Dave's a clever guy who tends to design his chassis so they only go together one way. So saying, they do work rather well and are a joy to assemble. For motor/gearbox choice you're therefore likely to need to use whatever is recommended for the kit.

    I hope that's a start. The S7 guys will be along in a minute or three to add further to the debate...

    Steph
     
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  4. Stumpytrain

    Stumpytrain Active Member

    Simon, your plan to build a 1/32nd Bulleid Light Pacific next? My lips are sealed, after all, careless talk costs lives! Have you contacted the possible Bulleid-Firth-Brown wheel supplier yet? We should "race", my advantage of having a kit is clearly offset by my past form and lack of progress to-date!

    Firstly, thank you for taking the time to write such a detailed response Steph. The MOK kit has been ordered and should arrive tomorrow (very exciting!), based on your experience I will probably adopt what MOK intended, modified as required to suit the wider frames. I will have a better idea when I've read the instructions.

    What an excellent guide. I think I'd stumbled across something similar in my internet travels but certainly not such a detailed article. I'd imagined the 2mm approach of stub axles and insulating muff but I think your method will be far more elegant and suitable for the larger scale. I'm pleased to hear that split axles are practical in 7mm, they work beautifully in 2mm and are far superior to anything else I've seen.

    This is actually how I imagined it can be done. I suppose I'll have a better idea when I've decided on the best form of suspension. Based on what you've said and other posts I've found on the internet there certainly seems to be many ways to achieve this. Or, to keep with Simon's cat theme - more than one way to skin a cat.

    Yes, you're quite right I did mean ball races. I'm no engineer but I guess they have a purpose in gearboxes, where the bearing speeds are higher? I'd rather adopt split axles than ball races, the problems with electric current passing through them sounds obvious when I think about!

    Another excellent link. I've heard some well executed steam locomotives with DCC sound but it seems at the moment the limited recording capacity of the chip loses the "organic" / living character of a steam locomotive that isn't so apparent with a diesel / electric. Maybe building for possible conversion to sound later, when the technology has advanced, would be a more logical route?

    Funny you should mention that, I had considered working (I assume that's what you were referring to?) inside motion. On a 1400 wouldn't the crank axle be the driven model axle? Is that possible? I quickly dismissed it, as a signalman / shunter on a preserved railway I spend a lot of time watching steam locomotives pass and I've only paid attention to the motion on 3205, where the Signal Box gives a grandstand view as she passes. Would it be at all noticeable from equivalent model railway distances, like a nearby car park, or passing helicopter?

    I guessed I'd have to at least make new frame spacers. I haven't yet paid too much attention to how wide ScaleSeven frames should be, I guess axle box design plays a small part in this too. But any advice would be appreciated. I'm assuming that side play isn't generally desirable and certainly not on a small wheelbase locomotive like an 0-4-2. In a thread about the a ScaleSeven MOK 1400 it's mentioned that the splashers can also be reduced to scale dimensions.

    Let's hope so! Thanks once again Steph.

    Cheers,
    Alex
     
  5. Steph Dale

    Steph Dale Western Thunderer

    You might like to check the SDMP website (in my signature, below) in a couple of months time...

    Steph
     
  6. Wagonman

    Wagonman Western Thunderer

    Hi Alex

    Welcome to the S7 Group. Slaters wheels are of course plastic centred so you need to bridge the gap if you want split axle working. Walsall (http://www.walsallmodelindustries.co.uk/) do cast iron blanks which can be obtained uninsulated I believe. There used to be a bloke who's name I have shamefully forgotten, who would turn these wheels to S7 profile at a modest cost. Otherwise Colin Dowling of this parish will oblige with Slaters wheels and maybe others. I won't speak for him – his contact details will be in the August S7G Newsletter.

    Good luck!


    Richard
     
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  7. eastsidepilot

    eastsidepilot Western Thunderer

    Alex,
    I think Steph and Richard have answered most of your questions but with regards to side play on an engine a lot really depends on tightness of curvature on your point and track work and if you introduce any gauge widening on these curves.
    With a loco such as the 0-4-2 you could allow some side play on the trailing axle (0.5mm at most) if you think it will help, and you may not need that much to be honest. S7 loco's and stock need to be sprung and there are various versions of sprung horn blocks and bearing available Slaters being one of them.
    If you use cast wheels as Richard mentions then insulated telescopic axles are available from S7 stores as is frame spacer material .
    I offer a wheel re-profiling service for plastic centered wheels and I can also turn cast wheeels and fit axles if required ( he said blowing his own trumpet:D)



    Components for inside working motion, if you decide to fit it, are available from Laurie Griffin.

    Welcome to the S7 group mate:thumbs:
    ATB, Col.
     
  8. Dan Randall

    Dan Randall Western Thunderer

    Hi Alex and welcome to the world of S7. You posed some good questions in your opening post and it's nice to see they all appear to have been answered. As a Western Region modeller, I'm really looking forward to seeing the progress reports on your 14xx in due course, especially as I fancy building one myself at some point.

    Regards

    Dan
     
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  9. Steph Dale

    Steph Dale Western Thunderer

    Alex,

    I just noticed you're here in sunny Bris'l. If you're going to the Larkrail show then feel free to bring the kit along. I'll be there all day trying to get wifi-DCC working...:rolleyes:

    Steph
     
  10. AdamF

    AdamF Western Thunderer

    I am looking forward to this enormously :thumbs:

    My two penny worth from my limited experience in building the JLTRT 517 would be to go for compensation on the 0-4-2 wheelbase. It works a treat on the 517 and has the advantage of distributing the weight more evenly across the loco - I am not sure whether CSBs would do that, although I would be interested to know if I have got that wrong!!

    Having had a bit of a fiddly time with wire pick-ups, split axle is something I would definitely consider on the next build - if you go for it, I shall be following with interest :))

    If they fit, I would also recommend Martin Finney hornguides with insulated blocks - I think Steph may have actually posted something about this on my 517 build thread... They are really lovely units and helped me with the correct ride height when the Slaters units (which are also great) proved to sit the chassis too high.

    Inside motion? I wimped out big time on my build - technically it would be visible but I could not work out how to drive the model - if the MOK 14xx is like the 517, it is the driven axle which would otherwise take the cranks.

    With regard to frame spacers and sideplay - as Col says it's down to the track on which you will be running the loco, but I would only put the sideplay into the trailing axle. Also watch out for a mistake I made which was to get the frame width wrong. I ended up with them being too narrow which did not look prototypical. As JB pointed out on my thread, frames for 0-4-2 tanks are usually close up to the wheels. Getting a good GA drawing is a must to get the frames right!

    Can't wait to see this one get underway!

    A
     
  11. I strongly recommend the Jas Millham approach to this issue: there is very little visible movement for Stephenson inside motion, so model the slidebars and have moving crossheads. If you wish, you could add a representation of the valve gear.
    This way, there is also enough space between the cranks to fit a gear, whether it be spur, helical or wormwheel.
     
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  12. Scale7JB

    Scale7JB Western Thunderer

    If you're going down the road of motor betwix cranks, take a look at the 'rover' gearbox from ABC gears 9.5(ish) mm wide..

    JB.
     
  13. Stumpytrain

    Stumpytrain Active Member

    Thank you Richard. I had imagined just bridging the gap of the Slaters wheels, but the cast iron blanks are interesting. On a 1400 the trailing axle was 3' 8'', a size absent from the Slaters range but to be honest even in 7mm scale I imagine 3'7'' wheels, hidden by the axle box and outside frames would be within the allowances of tyre wear? I hadn't heard of Walsall Models before, I wonder how are their products regarded, do they turn up nicely? I have a lathe but I think 7mm wheels may be pushing its capabilities so will definately be looking to recruit someone to do the honours for me! ;)

    More to follow... I'm at work so can only reply as and when! :rolleyes:

    Alex
     
  14. mickoo

    mickoo Western Thunderer

    I believe 3" is the accepted variation in wheel dia due to wear, I've read of Castles with that amount of variation and class 66 certainly vary that much these days, as do Freightliner wagon wheels.

    So 1" in 7mm I think would be acceptable :thumbs:
     
  15. Ressaldar

    Ressaldar Western Thunderer

    Hi Alex,

    don't forget JPL for cast wheels, they do a 'turning' service as well and if needed,

    IMG_1293.JPG

    insulation is on the rim rather than Walsall cutting through the spokes and then 'aralditing'.

    www.jplmodels.co.uk

    tel: 01942 896138

    Dave Brooks is the owner
     
  16. eastsidepilot

    eastsidepilot Western Thunderer

    Alex,
    Theseare Walsall's product ( a B17 wheel in this case) if they need to be insulated from the axle I turn up a bush for fitting at the boss. DSCF2617.JPG DSCF2618.JPG

    ATB, Col.
     
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  17. Stumpytrain

    Stumpytrain Active Member

    Wow, I'm quite overwhelmed with everyone's enthusiasm and assistance! I can't possibly duck out of seeing this model through to the end now can I? :eek:

    So, the kit has arrived and I've spent spare moments glancing through the instructions and looking at the construction photographs.

    Suspension

    The kit incorporates a "rocking axle box" for the rear trailing wheel and rocking beams for the driving wheels. I've not had much experience with compensation but as assume as Steph said that MOK will have come up with a sensible design! I've got the Mike Sharman book "Flexichas" at home, are there any other good reading materials?

    Axleboxes

    Axlesboxes are provided in the MOK kit, these may well be adaptable to split axle pickup. I will take up Steph's offer for a chat on Saturday at Larkrail and hopefully I'll have a better idea after that! In the meantime I'll investigate the Martin Finney examples as they look very 'pretty'!

    Frame Width

    On scenic areas I'd like the model to be able to negotiate curves the prototype could handle and off scene what a 4-6-0 could be expected to handle, both presumably would be gauge widened where required. As you'd expect most underframe components are linked to the designed frame width so considerable tweaking of parts may be required!

    Wheels

    This is going to require further investigation after lunch but is of high priority! Both the Walsall's and JPL's look good after turning...

    Thanks once again!

    Alex
     
  18. Dan Randall

    Dan Randall Western Thunderer

    Alex

    It's just occurred to me that Cynric Williams (Western Thunder's founder who sadly passed away in January), has built the MOK 14xx in S7. A few pictures of it featured on an earlier version of RMweb and this link will hopefully take you there....

    http://www.rmweb.co.uk/forum/viewtopic.php?f=89&t=14492

    Hope it's of use and/or inspiration to you - I was certainly impressed by the excellent job Cynric had made of it. :thumbs:


    Regards

    Dan
     
  19. Mike majors on having a fixed axle throughout that book: this leads to lumpier movement of the loco, as the hole thing moves with the fixed axle. Mike does mention methods involving twin beams and a rocking axle briefly, but misses out the point I have just made about body movement, and the massive benefit such an approach has when there are more wheels - a 4-4-0 or an 0-4-4 simply uses the bogie pivot instead of the rocking axle. There is a side-benefit in that all the wheels can dropped out of the chassis, which is a god send for building, testing and painting. I would suggest following the MOK instructions. There is no need to read anything else and the flexichas book is of questionable value, IMO.

    Personally, I haven't built any chassis with more than six wheels. For carrying axles I have used a simple pivot - piece of tube over a bolt - but coupled/ driven axles have a cross-wise bar, pivoted at the centre an resting on top of the axle boxes.

    Hope that helps: can't comment on the other questions.

    Simon
     
  20. Overseer

    Overseer Western Thunderer

    I agree that twin beams over the driving axles and a rocking trailing axle work very well in S7 and avoid the clunking movement inherent in having a fixed axle. A fixed axle is not helpful in an 0-4-2 as it would have to be the front axle fixed which would make the driving gear impossible to conceal. I have used twin beams and a rocking rear axle in an 0-4-2T and 2-2-2T with success. Compensation is quite easy to set up and doesn't go out of adjustment, as springs sometimes do when being transported.

    Thanks Dan for the link to Cynric's build of the MOK kit. It is inspirational.