Nick Dunhill's workshop NGG16 Garratt

Discussion in 'Area 51' started by Nick Dunhill, 18 September 2018.

  1. warren haywood

    warren haywood Western Thunderer

  2. Nick Dunhill

    Nick Dunhill Western Thunderer

    Worappened?
     
  3. Nick Dunhill

    Nick Dunhill Western Thunderer

    .....bits and bobs done in the last few days. I put some much needed detail on the cylinder head covers.

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    I offered up the suspension springs and equalising beams etch supplied in the kit. Not acceptable in my view, so an alternative was sought.

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    I got some 4 mm scale BR brake van springs which were a very good substitute from Rumney Works. Thanks Justin you were very helpful. The equalising beams were cut off the supplied etches and drop links cut out.

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    I hope this captures what I set out to achieve. The whole thing now has a prototypical look to it. Maybe the pic doesn't capture it as it's a bit scratchy and my photographic skills don't hide it! The chassis is so small its not easy to clean up with abrasive paper.

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    More spring detail to come.....
     
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  4. Nick Dunhill

    Nick Dunhill Western Thunderer

    ...and here it is. I've added the equalising beam and it's bracket to connect to the spring on the rear pony truck. A driver told me it's called the 'Zebedee' spring! The brackets are made of channel and the beam is sculpted from brass bar.

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    Front pony equalising beam and spring, although I may have to fit the buffer beam first......
     
    Last edited: 24 October 2018
  5. Nick Dunhill

    Nick Dunhill Western Thunderer

    ...for those not watching on RMWeb I have acquired a set of castings for the valve gear for each unit from NGTrains in York. They are amazing and will save hours of scratchbuilding.

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    In the meantime the equalising beams have also been constructed for the outer bogies. They will attach to the drop link from one end of the spring. The other end of the spring (leaf, sorry) is attached to a bracket on the buffer beam. So to complete the installation I will first have to attach the beam, and I need a coupling first. The centre of the spring is indeed attached to the bogie axlebox.

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    Buffer beam next (or whatever they are called on NG locos with no buffers).............
     
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  6. Peter Cross

    Peter Cross Western Thunderer

    Are they 3D printed? They look very crisp.
     
  7. Nick Dunhill

    Nick Dunhill Western Thunderer

    Well Peter I assume they're 3D printed waxes and brass investment castings, and yes they're very crisp in comparison with stuff I've had in the past.
     
    Peter Cross likes this.
  8. jc2001

    jc2001 Western Thunderer

    They look excellent. I didn't know Paul did these (they don't appear to be on his website). Were they a special for you?

    John
     
  9. Nick Dunhill

    Nick Dunhill Western Thunderer

    No John. I think he had them done for an NGG16 commission that stalled. So looks like I'm doing the test build on them. They are the best 3D derrived castings I've seen so fingers crossed. Whatever though they're much better than what's in the kit!
     
  10. Ricketrescue

    Ricketrescue New Member

    Hello, I'm new here but as Nick has twigged that he is proof building my castings in his NGG16 build I first came to have a look at the build and the comments and then decided to chip in.

    Now I used to drive the NGG16's but these days I stick to the Festy engines and only do Porthmadog to Blaenau but it does mean I see them on a regular basis as, in normal working, one is stabled at Boston Lodge. Occasionally we get two at BL and once this summer all three of them which caused something of a stabling crisis (can't recall why all three were at one end of the railway).

    The model Nick is building was produced from artwork that was intended for 009, was hand drawn and to 8mm scale. For 009 the 50% photo reduction was just about enough and to get it to work in 009 some compromises were made that were acceptable like trimming the inner ends of the frames to clear the inner trucks. When it was then released in 7mm of the same artwork the photo reduction was wholly inadequate, highlights some of the drawing errors, leaves a lot of parts looking thin and underweight and, as Nick is finding, its not any NGG16 but bits of all of them with features such as the welded tank shape of tha later batches but covered in rivets like the early ones. The one batch it can't really be is the first batch built by Cockerill as they are really different and are nearer to being NGG13 but with a different inner truck. WHR's 87 is one of these.

    Backwoods Miniatures offered the NGG16 in ready to run form assembled by SanCheng Brass. These differ from the kit as San Cheng replaced some of the kit parts to ease assembly. It was one of these that came to me and I then sold on. I started this rework for the new owner but when we realised how extensive and time consuming it was going to be and what it was going to cost a lesser option was his choice.

    What inspired my work was this
    Vgear.jpg
    Now this may not bother many but spending a lot of my time around real loco valve gears, and the NGG16's in particular, this worse than 1970's triang rendition offended me big time. The angular Union Link really hurt my eyes.

    Just as a reminder this is what it should look like - this is #130 part approaching the end of an overhaul
    130.jpg

    Anyway, spurred on by how offended my eyes were I set to work in SolidWorks 3D CAD and modelled the valve gear. CAD.jpg

    On the model the support arms for the expansion links just looked wrong. This was the result of my efforts
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    The valve spindle guides really didn't cut it either made out of flat etch so this was my version complete with lube lines added
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    The castings were reamed 2mm bore and valve spindles made out of 2mm brass tube with a 7mm scale short handrail knob soldered in
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    And that's as far as I got.

    The castings you have seen in Nick's post above were my CAD creating STL files and uploaded to Shapeways. Ordered in plain brass or plain nickel silver they printed waxes and had them cast. As a result these are first generation castings and haven't lost a little resoliution by being cast from waxes made in a silicon mould of the original part. They were arranged on the chunky sprues to defeat the Shapeways rejection of sprued objects. Despite ordering them plain they came coated in a lacquer and have been grit blasted to remove this so they would solder.

    I suspect Nick will have to do some fitting work to get the valve rod fork end around the combination lever top and the hand rail knob end of the valve rod into the cut out as I recall problems with minimum thicknesses in the Shapeways auto check process.

    If anyone wanted castings I could get more done but if Nick feeds back his experieces of using them I would be to do a mk2 version of the CAD.

    I still have a couple of the Backwoods Kits here and one day I'll build them for myself but each time i look at them i think it might be easier to make my own kit
     
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  11. Nick Dunhill

    Nick Dunhill Western Thunderer

    .....so the chassis have been embellished with some cylinder drain cocks. 138 has steam operated rather than mechanical ones, and the Maunsel ones that Laurie Griffin sells are perfect for the job, I'll add the rest of the supply pipes after paint.

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    In order to complete the suspension system the buffer beams need to be attached. In the kit the beams are part of the footplates. A quick depressing look at the photos of 138 showed that both the beams and footplates in the kit are wrong, so I wasn't to bothered about adding the buffer beams separately. The buffer beams were modified to look like those on 138, and the bracketry added to the rear. The cow/sheep catchers were added and the Kadee couplers fitted up. I drilled out the end of the fixing screw for the couplers and glued in a light coil spring to press down on the outer pony trucks.

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    And the whole lot will go round a 36'' curve (cheers for the Templot Tony!)

    Next more soldering and groaning.....
     
    Last edited: 8 November 2018
  12. adrian

    adrian Flying Squad

    That's a huge improvement - they look superb. Thanks for posting.
     
  13. Nick Dunhill

    Nick Dunhill Western Thunderer

    ....decorating postponed for a week, so a bonus post. As you can see from the attached photos I have finished the suspension systems at last. The outer pony trucks now have springs above the axleboxes. The springs are integrated into the rest of the system by beams under the cylinders. The linkages are all scratchbuilt and the springs are 4mm wagon springs from the Rumney Range.

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    Does anyone know where I could get some suitable brake blocks? They need to be about 6mm high and about 2.5 mm wide (from front of curved shoe, through the pivot and to the rear?) 7 mm wagon or coach brake shoes would be fine. Thanks.
     
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  14. P A D

    P A D Western Thunderer

    Hi Nick,
    Fantastic.

    I've no clue where you can get the brake blocks you need, but can you tell me in which section of Laurie Griffin's website, I will find those nice castle nuts you put on the joints of the coupling rods.
    Many thanks,
    Peter
     
  15. freelance7

    freelance7 Active Member

  16. P A D

    P A D Western Thunderer

    Many thanks Paul.
     
  17. adrian

    adrian Flying Squad

    That's looking very nice - I do like the meaty coupling rods on these locos.

    I make my own these days in plastic laminations. as shown in this post #94. If you don't have any sucess source something suitable then by all means let me have a drawing and I'll cut a set for you.
     
  18. Genghis

    Genghis Western Thunderer

    We might have some suitable whitemetal blocks available. If you can hang on for a couple of weeks till I am home next I can measure up what we have then.
    David
     
  19. Steph Dale

    Steph Dale Western Thunderer

    Nick,

    Slaters do a sprue of carriage brakeblocks which are used in their etched Southern 8' bogies. Would definitely be worth a try if none of the other options work out.

    I'll grab a sprue of them this evening and will post the part number for you.

    Steph
     
    Nick Dunhill likes this.
  20. Nick Dunhill

    Nick Dunhill Western Thunderer

    ...well while we're waiting for brake blocks I thought I'd assemble the valve gear. I fitted up the valve guides (the castings are excellent BTW,) and made some valve spindles.

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    The motion bracket parts in the kit bear absolutely no resemblance to the real thing so a bit of fabrication was required....luckily!:) Here goes...

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    More scratchbuilding fun tomorrow.......
     
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