A small G3 loco

Discussion in 'G3' started by jamiepage, 9 April 2015.

  1. JimG

    JimG Western Thunderer

    Simon,

    I do remember that I was influenced at the time by a G1MRA member who I used to meet at get-t0-gethers in the Somerset area (Maurice ????? ) who modelled two rail electric and to finer track standards. I don't think Proto:32 (or whatever it is called :) ) had appeared by that time. The wheel castings were from Locosteam (now long gone) and I spent long, dirty hours filing the spokes down to be much finer than they were originally.

    Jim.
     
  2. jamiepage

    jamiepage Western Thunderer

    The Slimline Slomo has arrived from Australia. It has been designed to suspend sedan chair like, with the paired legs sliding into one frame cross member and the single leg into another. The single leg is threaded and fitted with lock nuts to allow adjustable chain tension.
    Overall width at 38.5mm is good for G3, and will allow it to disappear within a cosmetic firebox on this loco, but would still be too wide for G1.
    It is a very nice piece of work.
    IMG_0002.JPG
     
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  3. Steph Dale

    Steph Dale Western Thunderer

    Jamie,
    I have been waiting until now, so I can see what you're referring to, but what is it? Friction brake? Damper? Some form of flywheel energy store?

    I realise I now sound like my mother when presented with one of my 'unfortunate' pieces of junior school art projects; "Oh, that's very nice dear; what is it?"

    Steph
     
  4. jamiepage

    jamiepage Western Thunderer

    Steph,
    Thanks for the chuckle. Yes, it's a load of gears and a gert big flywheel to flatter the slow speed running somewhat. I don't know how to do it myself, but Steve Cook kindly posted a link to the manufacturer near the start of this thread.
    Jamie
     
  5. Steve Cook

    Steve Cook Flying Squad

    Looks like it will do the job nicely Jamie :)
    Post 3 if you haven't found it yet Steph.
    Steve
     
  6. Simon

    Simon Flying Squad

    I went one better than that;

    "Oh that's really lovely, well done - can we put it in the bin now?"

    Scarred for life:))
     
  7. jamiepage

    jamiepage Western Thunderer

    Some reasonable progress over the last fortnight, mostly building a kit of parts in anticipation of some assembly soon.
    Still in two minds about the valve gear, but I decided to use the pantograph to mill out the various bits for Stephensons, so I'll try them first. . (Sorry, didn't realise how out of focus the photo was).
    IMG_0001.JPG
    Cylinder assembly is progressing quite well. In the end, DJB auto draincocks were fitted inboard of the frames, serviced by yet more long passageways from the bores. Cosmetic draincocks will be fitted under the bores.
    Cosmetic front endplates, with scale studs, screw onto the structural covers and the overall effect when combined with wrappers looks ok. The central steamchest has been drilled for various M2.5 bolts, the two central holes however are part of the exhaust passageways. Valve rod glands still require drilling, reaming and tapping through the steamchest's rear face.
    IMG_0001.JPG
    Smokebox components are ready for silver soldering. The front plate was again pantographed, complete with central hole. It was then wrung onto an aluminium mandrel and the door recess bored out.
    If, and it is quite a big if, the smokebox silver soldering goes well enough, the frames, smokebox, cylinders, wheelsets, coupling rods and Slomo can all be assembled, at which point it will hopefully feel as though progress has been made.
    IMG_0002.JPG
     
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  8. jamiepage

    jamiepage Western Thunderer

    Have just enjoyed an assembly of some of the chassis bits so far, mostly to check quartering and to fit the streamchest but also to sort out the Stephenson's gear and clearance around the Slomo.
    The chance to take a photo or two was too good to miss.

    Cosmetic cylinder end caps show up quite well here.
    IMG_0001.JPG

    Coupling rods fitted, albeit with temporary knuckle pins.
    IMG_0002.JPG

    Final photo just to have a look at the face with smokebox front pushed roughly into place.
    IMG_0003.JPG
     
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  9. jamiepage

    jamiepage Western Thunderer

    Very slow progress at the moment due to other stuff, but the eccentrics have been temporarily fitted along with the Slomo's final gear to check clearances.
    The Slomo itself will sit in the foreground space, within a cosmetic firebox/ ashpan.
    Roundhouse boiler, gas delivery system etc have been purchased and should speed things up once the chassis is running on air. The gas tank, lubricator etc will sit fairly well within the cab and R/C gear and batteries are destined for the tanks.
    The commercial boiler would fit well, but its boiler bushes are not quite right to prototype so I will make up a new boiler, identical other than the bush locations.
    It is a simple single flue boiler so hopefully shouldn't hold things up too much.
    IMG_0001.JPG
     
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  10. Scale7JB

    Scale7JB Western Thunderer

    This is all looking magnificent, and plenty of food for thought for modelling in my next life... ;)

    JB.
     
  11. jamiepage

    jamiepage Western Thunderer

    Thank you, JB. It is good fun.

    The first thing to address when I get back to it will be the lifting arms/ suspension links. Currently they are planned to be 'inboard' with the expansion links suspended on their inside.
    However, the boiler sits low and it looks as though there may not be enough room for the links to 'lift' the gear fully into reverse in that position.
    If it is the problem it appears, separating them and moving them outboard of the eccentrics, just inside each mainframe, will provide a lot more headroom as the boiler curves up and away. That will mean a bit of a rethink to the pins etc to make sure it can all be assembled/ taken apart when needed.
     
  12. unklian

    unklian Western Thunderer

    Out of interest where did you get the design/layout of your valvegear from Jamie ?
     
  13. jamiepage

    jamiepage Western Thunderer

    Ian,
    Martin Evans' G1 'Southern Belle' Brighton Atlantic.
    Although the lifting links are different- well, at the moment anyway. The steamchest is also of course completely different (based more on Paul Forsyth's 'Director') but the ports are similar.
    In other words, nothing original, just poaching bits from here and there.
    Jamie
     
  14. unklian

    unklian Western Thunderer

    Thank you for that Jamie, I will have to look that one out. Its interesting how the detail of large G1 designs can be fiddled to suit small G3 locos.
     
  15. jamiepage

    jamiepage Western Thunderer

    Ian,
    I do agree. The G3 4-4-4T is to all intents and purposes a Paul Forsyth G1 design with different platework- cylinders, slip eccentric valve gear, meths tank/ burners, boiler etc. are all to his published designs.It wouldn't work so well for the larger prototypes of course, but works well for the small Edwardian types.
     
    Last edited: 27 August 2015
  16. Mike W

    Mike W Western Thunderer

    And medium sized engines can draw on Gauge 1 designs, if not actual parts. Barrett Engineering used their Gauge 1 experience and design to make Gauge 3 cylinders for my LNWR 18in Goods. Benefits included a tried and tested design made by a renowned builder, before one has even been steamed.

    Mike
     
  17. jamiepage

    jamiepage Western Thunderer

    A record of some little progress.
    Cosmetic front cylinder covers had already been made, these simply screwing onto a central boss and so effectively camouflaging the covers proper.

    Cosmetic rear covers were more problematic. The gland, slidebar mountings etc precluded a similar arrangement, and the cosmetic covers also required a couple of steps incorporated.

    Silver soldered fabrications were made up, incorporating the steps and some bolt head detail (or rather, bolts will be fitted) and which fit
    over the rectangular central boss. The fit is a light push fit, but the slidebars should hold all in place whilst still allowing dismantling if subsequently required.
    IMG_0003.JPG
     
  18. jamiepage

    jamiepage Western Thunderer

  19. unklian

    unklian Western Thunderer

    Hello Jamie, a small question about your Slo Mo unit, do you have any idea what the overall gear ratio is ?

    Thank you Ian
     
  20. jamiepage

    jamiepage Western Thunderer

    Ian,
    Sorry, but I don't. Nor do I have enough knowledge to make an educated guess, I'm afraid.
    Jamie