Nick Dunhill's workshop, M&GN 4-4-2T Melton Tanks

Discussion in 'Area 51' started by Nick Dunhill, 28 July 2019.

  1. Nick Dunhill

    Nick Dunhill Western Thunderer

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    Time for a new build. This project is the construction of 2 M&GN 4-4-2T Melton Tanks (LNER C17). They were built in Melton Constable from 1904 and survived into the 1940s. They were built using many parts from MR locos. There is an ACE Kit available that I'm sure will build a perfectly acceptable model, but for this project some custom etches were commissioned (available on request.)


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    My original plan was to build a donor ACE kit body on the chassis and footplate etches above. But on reflection I considered it prudent to commission more etches for a basic body (more later.)


    The chassis etches follow prototypical practise and are in three overlapping sections pinned together by the drag box or frame stays. All the stays are prototypical allowing easy fitment of other parts such as brake cylinders and inside valve gear.


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    Next the valences and buffer beams were soldered to the footplate to give a flat rigid structure.


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    The drag beams for the couplings are in interesting places. The rear coupling is attached to it's drag box under the cab and the front coupling is attached to the front drag box which is part of the valve chest/ cylinder block.


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    And I have made them sprung.





    more fun soon......
     
  2. adrian

    adrian Flying Squad

    Stunning work and an interesting prototype. Although I hope you don't mind me saying as I've just been doing sprung couplings on my Tube wagons - my feeling is that the springing is far to soft. Personally I'd stiffen the springing such that it's very difficult to extend, not impossible but a lot harder than shown in the video. In its current state I suspect a dozen wagons would pull out the coupling to some extent which I suspect wouldn't be that prototypical.
     
  3. simond

    simond Western Thunderer

    There has been a debate about this on the G0G forum. There are views that no springing is needed, and that springing is probably easier than not springing, and other combinations. It is certainly my opinion that many RTR 7mm models do seem to have unduly soft springs, and look awful when pulling a train with the hook halfway out of the bufferbeam.

    I have taken to using a short length of silicone rubber hose in place of the spring. This has the advantages of softening any shock loads, and being easy to fit usign the washer and splitpin. It does not have the advantage of being terribly prototypical so far as I am aware...

    It also has the advantage of leaving the springs spare, I use them for floating pick-ups.

    atb
    Simon
     
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  4. Nick Dunhill

    Nick Dunhill Western Thunderer

    Well it's easy to fit a stiffer or second spring, but really I just wanted it to be like the real thing and not just a spring and split pin shoved through a hole in the hook shank.
     
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  5. Dave Holt

    Dave Holt Western Thunderer

    I can't speak of the Melton tanks, but some full sized locos have draw-bar "springs" made from multiple sandwich layers of rubber sheets and steel plates which are extremely stiff, being pre-squeezed/compressed by the nut on the inner end of the hook. There wouldn't be much visible extension of the draw hook, even with a substantial train attached.
    Dave.
     
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  6. simond

    simond Western Thunderer

    Probably a bit fiddly, but very feasible in 7mm...
     
  7. adrian

    adrian Flying Squad

    Agreed it is a better solution as from the images there is a small amount lateral movement required on the hook which this solution provides where as the usual spring and split pin solution can't.

    An old bicycle tyre cut to shape might provide sufficient "give".
     
  8. Nick Dunhill

    Nick Dunhill Western Thunderer

    ....so on with the show! Well this week a lot has been done, although the project doesn't seem to have moved on much. The footplate has had lots of angle fitted, as per prototype, which would on the real thing reinforce the buffer beam/valence/footplate structure. The angles being present between frames and buffer beam have necessitated the buffers being modified. They are Slater's MR Kirtley short buffers with packing pieces, and have been converted to being self contained. This is quite a lengthy task.


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    The steps were added next, along with the frame extensions above the footplate. This required copious amounts of tea.


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    Laurie Griffin does some cast horn blocks and guides. They take a lot of fettling to make them work nicely, but are excellent when finished. Crucially they are very, very similar tho the real ones. The axle boxes were lightly modified to grasp the horn cheeks (rather than running in a slot, like other makes) and have a nice keeper plate too. I will endeavour to use them again.


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    The balance weights for the wheels were marked out and cut from NS sheet, loco no.41 has boxy pattern ones and the later no.9 loco has more conventional curvy ones.


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    And as usual you spend days prepping stuff and then a lot happens in one day. The horn guides and axleboxes were assembled in the chassis using jury axles and the coupling rods as a jig. Note that I temporarily braced the chassis with some scrap strip to prevent the springs locating the axlebox assemblies spreading the chassis.


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    Using this method and with careful alignment of the axleboxes, a smoothly running chassis results.



    And finally a gratuitous bedroom shot.


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    Bogies and radial trucks next......
     
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  9. Scale7JB

    Scale7JB Western Thunderer

    Steady on..
     
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  10. Nick Dunhill

    Nick Dunhill Western Thunderer

    ....there are no parts in the etchings for bogies or radial/pony trucks, so out with the saw.


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    So I marked one out cut it from the sheet and soldered it onto another sheet, cut round it......etc, etc.


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    The die block is made from telescoping square and round sections of brass, as I have no lathe.


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    The axleboxes and equalising beam springs are harvested from a set of LGM LSWR cast bogie side frames.


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    I cut out my own equalising beams from scrap etch.


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  11. Nick Dunhill

    Nick Dunhill Western Thunderer

    And here is a finished bogie complete with side control.


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    I checked the wheelbase on a 6' radius curve and it just squeeks through. a couple of mm to spare! This is mainly because the frame is solid behind the rear bogie wheel, but a miss is as good as a mile, as they say......


    A look at the drawing revealed the trailing wheel to be held in a pony truck, and not a radial truck as I had assumed. Again no etched parts so...


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    A bit of drilling and sawing later we have a basic pony truck. Will detail it in a couple of weeks after my holiday, yay!!


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  12. Lancastrian

    Lancastrian Western Thunderer

    Nick,

    Inspiring work as always :thumbs:

    Ian
     
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  13. paulc

    paulc Western Thunderer

    Inspiring work as Ian said and more so without the use of a lathe .
    Cheers Paul
     
  14. Nick Dunhill

    Nick Dunhill Western Thunderer

    ...back from my windy holiday in Orkney and on with the show. I have added all the side control for the rear pony truck. I just followed the drawing, what I have built is very similar to the real thing. There's a downward spring to help it all along too, and some dummy leaf springs.


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    I also added some prototypical bump stops on the banana shaped brackets poking out of the front of the motion support frame stay. They limit the travel of the rear of the bogie so that the rear bogie wheels don't hit the frame, as there are no-cut outs in the frame for the rear wheel. I then had a bit of a test run and all was well.

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    It ran nicely on a 6' rad curve, with no shorting, and a bit to spare too. Happy days, the rest is just cosmetic. Do you like my Heath-Robinson test track, it's sitting on a Templot printout (thanks Tony!)


    Now on to the springs and hangers. The hangers are etches on the body etch, and the springs and rubber bumpers are from an LGM set of Princess Royal castings.


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    The springs for the front wheels are removeable because I'll need to drop out the axle when the inside motion is fitted up.


    Talking of which, to bring me up to date;


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    Here's one in a jig so I can solder the ends on the eccentric rods reasonably accurately.


    More this week, and then off to Telford. See you all there on the Modelling Competition Stand...........
     
    Last edited: 26 August 2019
  15. Nick Dunhill

    Nick Dunhill Western Thunderer

    ...so back from Telford and on with the valve gear. It's standard Stephensin link motion from the Laurie Griffin range, it needs a bit of modification but nothing drastic. Wooden jigs were made for making the rods and drop links. I thought the new style cast eccentric sheaves would be a nightmare but they cleaned up very nicely.


    The trick with valve gear is to assemble it carefully so everything is straight and in alignment, and theres a good chance it won't bind. Cross drill everything carefully.


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    It worked well, so I moved on to the outside cylinders. I built the connecting rods, then ran out of castings for the cylinders, ordered new ones and moved on to the ashpan.


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    The ashpan is fabricated from the waste round the etchings. Measure, measure, cut, cut, solder, solder. I like to make the lower part of the firebox too. It partly hides the motor and gearbox.


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    And here's the assy. installed in the frames.


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    And finally I cut out the brake parts ready to go.


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    Brakes and outside cylinders next........
     
  16. Nick Dunhill

    Nick Dunhill Western Thunderer

    ......I have made the brake system. Mainly scratchbuilt.

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  17. Scale7JB

    Scale7JB Western Thunderer

    Gees, that's come along quickly..

    Looks great!

    JB.
     
  18. Nick Dunhill

    Nick Dunhill Western Thunderer

    ......well now the NGG16 is in Canada at it's new home and the W1s are delivered too, it's back to this. I have been looking forward to building the cylinders, and there were some basic bits in the etches for the cylinder block. So I bought some bolt heads for the cylinder covers and scratchbuilt some slide bars. I used crossheads from the ACE rendition of this loco.


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    I scratchbuilt some slide bar support brackets and closed up the cylinders with rectangles of thin nickel silver sheet.


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    Next job is the cylinder drain cocks and operating levers, sanding pipes and to finish the chassis some vacuum brake fittings. Then the bodies.......
     
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  19. Nick Dunhill

    Nick Dunhill Western Thunderer

    .....now the chassis is nearing completion and won't be handled too much I have put on some of the more delicate bits. I have added the cylinder drain cocks and their operating levers, the sanding pipes and the plumbing for the vacuum brakes.

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    The sanders have the steam pipes added too.

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    This marks the end of the chassis build, so a big wash tomorrow and on with the bodywork........
     
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  20. Nick Dunhill

    Nick Dunhill Western Thunderer

    ...bodywork! Started with the beading round the cab (riveted strip on the inside) and went on to the tank tops and beading, all well so far. I solder a strip of waste strip over the half etched lines on the body sides. This prevents them getting bent by mistake, especially the half etched line for the cab rear. It's very close to the return that has to be formed for the cab doors.


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    The cab doors were made, and then promptly taped shut to prevent damage. I then made and detailed the cab front and rear and splashers.


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    Next the tricky bunker rear and attaching everything to the footplate without tabs and slots!
     
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