Coal Tank test build

Discussion in '2mm Lounge' started by David Varley, 17 January 2016.

  1. Yorkshire Dave

    Yorkshire Dave Western Thunderer

    All I could hear from my house was the USATC S160 whistle echoing through the valley :). I see they were using the 'Continental' stock coach.

    I admire your coal tank build in this scale and look forward to the seeing the completed loco :thumbs:. Having seen the safety valve and dome on the 1054 in your photos I think we worry too much about seating them without gaps.
  2. David Varley

    David Varley Western Thunderer

    They're still at it - just heard that Yankee whistle going up past Oakworth!

    I did think that myself when I was uploading the photos - looks like somebody's put some rubber sheet underneath when they were putting them on!

    Had been meaning to make a start on the chassis today but other things getting in the way :mad:
  3. unklian

    unklian Western Thunderer

    Funny that, I had to notice the ill fitting boiler mountings too. I think its called modelmakers eye, or something......
  4. David Varley

    David Varley Western Thunderer

    I've spent quite a bit of time recently pondering how to make and affix the rear pony/radial truck and whilst I've got a few ideas, I still haven't made my mind up how to do it, but having got talking to Mick Simpson at York show on Saturday he suggested that I concentrate on getting the chassis running as an 0-6-0 and then worry about the truck.

    The way I've built things I needed to get on with the chassis anyway to check for clearances and to decide what combination of motor and gears to use, so I've soldered the bushes into the frame and loosely affixed the wheels and muffs (I've opened out some muffs to make fitting and removing the wheels almost a drop in/drop out exercise) before starting playing around with motors and gears (the favourite at the moment is looking like a Nigel Lawton 8mm with a 30:1 worm wheel on the rear axle).

    I've got another long weekend coming up next weekend (using up the last of my annual leave before we lose it) and will hopefully make some more progress then but for now the pictures below show the current state of play.










    Clearances are tight in a number of places and there's going to be some fettling needed here and there, but I'm pleased with how things are going together.


    David V.
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  5. adrian

    adrian Flying Squad

    Thanks for the update - it's looking good.
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  6. David Varley

    David Varley Western Thunderer

    Late evening surgery yesterday for the body to make room for a Nigel Lawton 8mm x 16mm midi motor and a worm driven 30:1 gear on the rear driven axle - had to cut away part of the footplate, part of the cab floor and the lower half of the front of the cab.

    More work still required to sit the motor properly and also had to lengthen the cut away part of the boiler but it all looks to fit, albeit rather snugly!

    Probably easier to do all the cutting before assembling the body but would make locating and affixing the cab front more difficult - the upper portion of the coal rails came adrift during the operation and needs to be re-affixed and the upper parts of the cab sides need strengthening, but otherwise the patient seems to be in reasonable health following a tricky procedure!

    I'm still playing around with ideas for the pony/radial truck but I think the next job will be to get the frame spacers in and get the motor properly seated.





  7. adrian

    adrian Flying Squad

    Thanks for the update - the motor location is looking good, compact and well hidden. It looks like it shouldn't protrude beyond the front of the tanks. Just wondering if you can get the worm gear in black? With it being white I think I would consider putting a cover over it as it shouts out a bit, if it were black I'd be tempted to leave it as it is.
  8. queensquare

    queensquare Western Thunderer

    Hi David, must admit I'd have put the motor in the other way around with the bulk of it in the cab bunker. So long as it is below the level of the cab doors so that there is daylight through the top a strategically placed crew would hide it. A number of my locos have the crew, often with lumps of lower limb and torso removed, attached to the motor and nobody ever spots it. The great advantage of this is that the motor is very light, keeping it toward the rear means that the tanks and most of the boiler, which sit over the drivers, can be stuffed full of lead or preferably copper tungsten. The more weight you can get over the drivers the better in 2mm for traction but particularly pickup.
    Regarding the 30:1 ratio, combined with nigelLawton motor it will require a gentle hand on the throttle but will be perfectly controllable. If DCC, a CT chip would give good results.

  9. adrian

    adrian Flying Squad

    Thanks for the suggestion about mounting the motor the other way - food for thought especially for getting more weight into the loco.
    As for gearing do you think a further reduction would be useful? Down to 50:1 or something else?
  10. David Varley

    David Varley Western Thunderer


    Thanks both for your comments.

    I'm still at the playing around stage and there's nothing set in stone yet, but I must admit that when it comes to gears and motors I'm very much a novice. The Nigel Lawton motor/30:1 gear combo driving the rear axle was suggested by Nigel Hunt as a starting point and I wanted to try that first to at least make sure there was some way of powering the loco that wasn't beyond me.

    I'm sure there will be ways of hiding the worm or the motor (as the case may be) where it pokes into the cab (butchered crew and/or or a false floor) and with the rest of the existing cab floor removed the motor should sit quite happily the other way round (though I'll need to allow for the pony/radial truck) but when it come to talking about gear reductions I start getting lost. I understand the concept (one gear drives another gear) but the practice of it is, for the moment at least, a dark art to me.

    Further illuminating thoughts and explanations would be appreciated!


  11. queensquare

    queensquare Western Thunderer

    Further reducing the gearing is a definite advantage. I like the 100DP gears the Association used to do which you can still get from Ultrascale - a 14/22 or 14/28 if it will fit second stage reduction gives 48:1 (almost!) or 60;1 which is perfect with the Nigel Lawton motor. That said, with delicate touch 30;1 should be fine and much simpler for a first build.
    Getting more weight over the drivers is another one of those 'think 2mm' things. what you and others will marvel at is how smoothly something so small runs, not the fact that your one legged, torso challenged driver is hiding a motor. what 2mm lacks more than anything is mass so the more you can shoe horn in where it counts the better.

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  12. David Varley

    David Varley Western Thunderer

    Given that this is a test build I think I'll keep it simple and go with the 30:1 gear and maybe try something different on the next one.

    I was thinking about fitting the motor the other way round whilst I was out for a walk earlier, and there'd need to be further cutting of the footplate to fit it in that way, which I'm a bit uneasy about it in that I think it could significantly weaken the whole footplate assembly. Again, that might be something to try on a further build but for this one I think I'll stick with it as it is and see what weight I can get into the side tanks and the smokebox end of the boiler (there's approximately 13mm of uncut boiler to play with beyond the non-worm end of the motor).

  13. adrian

    adrian Flying Squad

    Thanks very much for the advice - I have been looking at the Ultrascale site and may well order a few gears to try a few options.

    My first look was to see if the 14/28 option would fit. The 2mm Yearbook says the metric 28T is 9mm in diameter, now the Coal Tank drivers are 4' 8 1/2" which by my reckoning is a gnats whisker over 9.4mm so maybe just enough room? However the 2mm shop has the H spoke drivers down at 9mm in diameter. Which for the loco appearance I'm more than happy with but this makes it rather tight for the 14/28 option.

    I then had a look at the Ultrascale options with the 100DP gears - for working the 14/28T option on these the 28T gear is listed as an outside diameter of 7.62mm which gives me a bit more breathing room on a 9mm driver. In fact the 30T 100DP at 8.13mm could be squeezed in. There's too many options with Ultrascale :confused:. There is also a 1:38 worm and wheel set in 100DP, which if combined with the 14/28T would give me a 1:76 reduction. Would this be a step too far and should I stick with the 1:30 worm and wheel and 14/28T using ultrascale 100DP? As I have put my name down for 3 sets of Coal Tank etches (don't ask!!) I would like to sort this out.
  14. john lewsey

    john lewsey Western Thunderer

    Hi David the coal tank is looking good in fact to me it's very nice every bit a coal tank
    I've ordered two
  15. queensquare

    queensquare Western Thunderer

    Morning Adrian, 60:1 is more than enough reduction for one of these. I'm sure the 38:1 plus second stage gearing could be fitted in but I don't think you would gain much and you would probably find it sits high making the motor more difficult to hide and taking up valuable space for weight.
    I would agree about the 9mm H spoke wheels. They are so characteristic and the over scale 2mm flange would more than compensate for the .4mm undersized wheel. If there are fifty of these etches sold then I would get your order for wheels in pretty quick as there is likely to be some demand!
    Regarding Ultrascale gears, they quote up to six months for delivery. I've never had to wait that long but it depends where they are in their cycle. The last couple of orders I've put in have between about three weeks and three months.

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  16. David Varley

    David Varley Western Thunderer

    Just a point on the wheels - I've been liaising with both David Short and Steve Dunkeyson (in fact they've both ordered etches) and more H-spoked wheels have been ordered.

    N Brass Locos have also been commissioned to produce some more Webb buffers as supplies of those were running a bit low.

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  17. 2mm Andy

    2mm Andy Member

    All the sources I can find quote the Coal Tank drivers at 4' 5 1/2" (or 4' 5 1/4") diameter, so the 9mm ones in Shop 2 are very slightly over scale size (ignoring the larger than scale flanges).

    If you want more options for the gears, you could try the chap in Poland that the 2mm SA source their metric gears from. There is a huge variety (far greater than stocked in 2mm Shop 3), and he can make them in brass or black plastic too.

    Mikroantriebe KK Produkcja Zahnrad, Schnecken und Car System Onlineshop - Zahnräder, Ritzel, Triebe und Schnecken von M0.1 bis M0.5 Evolventenverzahnung

    I've not bought direct from him, but delivery should be a bit quicker than that quoted by Ultrascale!

  18. adrian

    adrian Flying Squad

    Ha - that was my fault reading the wikipedia page and reading the track gauge by error.:oops: Fortunately it doesn't change my calculations as they are still tight on the metric gears.

    Thanks for the link to the Polish source - one to file if I need special gear sets, unfortunately the metric gears seem slightly larger in overall diameter for a given number of teeth so I'll think I'm going to opt for the 100DP gears. Also the Polish source seems to be about £1 and a bit more expensive than Ultrascale and given that I have about 30 wagons to build I've got plenty to do whilst I'm waiting for the gears!
  19. 2mm Andy

    2mm Andy Member

    Yes, the metric gears work out as approx. 80DP, so will be slightly larger for a given number of teeth than the 100DP gears. Mikroantriebe do also do M0.25 gears which are closer to 100DP, and also M0.2. I've seen a gearbox designed for a 2mm loco using the latter but meshing such small gears could be fun!:eek:

    I'm looking forward to seeing the wagons. I also bought the recent sheet of etched 2mm LNWR wagons:) (and have a couple of coal tank etches reserved too). There does seem to be a resurgence of interest in 2mm pre-grouping modelling at the moment.

  20. David Varley

    David Varley Western Thunderer

    After a long weekend in LNWR territory in Penrith last weekend and a day on the Worth Valley yesterday, I finally found a bit of time this afternoon to do a bit more on the chassis.

    The holes for the brake hangers are in very good locations for Simpson Springs so they can double up and do both - clearances have been checked on all three axles and are fine so phosphor bronze wire has been soldered in place, though has yet to be trimmed to length on the outside of the frames.

    Front and rear spacers have also been added and the next job will be to put in the centre spacer/motor support.

    47 sets of etches have been sold so far and are winging their way to various parts of the country with a few sets heading oversees as well and now seems a good time to thank everybody for their support with the project as well as thanking John Redrup at London Road Models for making it possible.