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Nick Dunhill's workbench - NGG16 Garratt


nickd
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Well folks the Whitby tanks are on hold while Slater's make suitable wheels, so I have moved on to my next commission for the time being.  It's a Backwoods Kit for one of these:

 

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I've made the coupling rods and detailed them with oil caps and knuckle joints;

 

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Then I moved on to cutting the frames and modifying them to accept hornblocks from the Alan Gibson range (a bit 4 mm-ish here, apologies!)

 

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I sold the inappropriate Romford spoked drivers and acquired some disc wheels that are the correct diameter and nearly the correct pattern.  They look a lot better.  I milled off the crankpin bosses and added balance weights to hide the mess.

 

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There are more pictures to see on my Flickr page here

 


 

Next I'm going to make some prototypical frame spacers.......

Edited by nickd
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....I have started making prototypical frame stretchers, firstly the inner ones.  I measured everything up from the drawings and decided to go ahead.  The modification will also involve alterations to the inner bogie and the frames supplied in the kit.  I think the kit is a generic thing that allows wiggle room for the many variations, and the WHR No. 87 has quite a few differences!  Anyway this is the upper part of the stretcher made from 0.4 mm scrap brass.  I'll make the bottom portion tomorrow, I think the pics are pretty self-explanatory.

 

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The thing in the foreground of the last picture is the stretcher supplied in the kit.  More tomorrow......

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...so as you can see I have made some frame stretchers for the Garratt.  I had a problem trying to decide where they should fit on the chassis supplied in the kit.  When I cross referenced the drawings with the chassis etch it turns out its a whopping 8.7 mm too short!  So I have cut out and fit some suitable extensions.

 

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I cut out one extension part and soldered it to a piece of scrap NS and cut round it etc etc.

 

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I hope this isn't a reflection of the rest of the parts in the kit.......

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Frankly it's bloody aweful.

The origins of the kit is that it was hand drawn to 8mm scale to be photo reduced to 4mm for 009. The 7mm kit is the same artwork. The bit of frame over the inner trucks was a necessary ommision of the 009 version.

 

I did 3D CAD for valve gear parts and had them printed in brass.

 

You'll enjoy laminating the flycranks - not! There aren't two the same! Also the kit hadn't noticed that each axle has different shaped balance weights. I got someone to mill new cranks.

 

I'm writing this on my tablet and it's not letting me post pictures without a lot of faff. I'll do some from my laptop later

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Thanks Paul. I think I have what I need now. The frame stretchers bear no resemblance to the real thing so will have to be scratchbuilt. And the motion bracket is a bit sparse too. Will have to scratchbuild a lot of the chassis. All part of the fun I suppose. Hopefully the upperworks will be a bit more detailed.

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Ok, so now I am at a laptop instead of an infuriating tablet here’s some images from a project I started but have yet to complete. I have a loco here that is actually one of the ones that were sold as complete having been assembled by San Cheng brass and three kits. 

 

The assembled one is actually the second that’s been here. I had one sat on the shelf just above my modelling bench at my eye line until the 1970’s Triang quality valve gear finally offended me to the point I sold it. Another came my way in a favourable deal and I started these mods but as it’s a project for myself it keeps getting side lined for customers work.

 

As you can see in these two images there’s one hell of a lot of detail that just isn’t there in the model. It was probably more than enough in 009 but it just doesn’t do it in 7mm

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The real one is the front end of 130 currently being restored with a bit of the red one 138 off to the right. If you do FaceBook find and ask to join "Friends of 130" for access to a lot of detail photos

 

From having decided something needed to be done I started with 3D CAD models

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Then I went on to have parts printed in brass by Shapeways. Even if you ask them not to they insist on coating it in a lacquer so I ran them through my fine powder sand blaster before using them

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Even if you ask them not to they insist on coating it in a lacquer so I ran them through my fine powder sand blaster before using them

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One part that really didn’t work for me on the original model was the valve rods and valve guides and as a result completely new bits were made

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The valve rods are actually 2mm tinned brass tube with an 0 scale short handrail knob soldered in the end.

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The valve guides are castings from the shiny sprues above having been reamed 2.1mm and having had thin copper wires for the lubrication pipes added.

 

It was about this time that a combination of the inadequacies of the kit and paid work from customers resulted in my project stalling.

Like you I planned new frames and work on the suspension. The designers view was with all those wheels pickup isn’t a problem. I planned piano wire sprung drivers and some proper suspension on the trucks rather than the just dangly ones allowed for. If you see these models run and one derails its always one of the trucks. 

 

Also adding to the enormity of the project were things like the tanks. Early batch NGG16’s had one shape of tank and were rivetted, later batches were welded but were a different shape. Guess what? The kit is welded shape covered in rivets!   I will get back to them but with several to do I will probably etch and/or print new parts by which point one isn’t far off having designed a new kit.

 

I spend quite a bit of time around NGG16’s. I used to drive them but now I only drive on the FR but there’s usually one of them at Boston Lodge. I did a pretty comprehensive photo survey of both 143 & 138 when I first started on these models.

 

I’d be happy to look at anything else or go through my photos but it will be tricky to do so for the next 10 days as I am off to Devon as Lyd’s minder for its holiday in Devon

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....I have finished the pivot stretcher.  The pivot plate is a bit simplified as I haven't decided how the boiler cradle will sit on it.  The work looks a bit scratchy for a couple of reasons.

1.  I'm a poor photographer, and photography is not in my top 50 so the quality is unlikely to improve.  Sorry.

2.  The chassis are so small that it's very hard to solder up, let alone clean up afterwards.  I ended up grinding scalpel blades to various shapes to be able to scrape away the excess solder in the little corners of all the stretchers.  Because its so small you have to be quick and use a lot of tissue soaked in water as heat sinks, this way you don't unsolder previous work with heat transfer.  Not lingering with the soldering iron causes your soldered joints to look a bit blobby and requires extra cleaning in those inaccessible corners.  (Sorry, this all sounds a bit moany doesn't it!  Very long day.)

 

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Cylinder blocks next.  This is the bit where someone with more NG experience than me gets in touch and tells me the etched cylinder parts are wrong too..........

Edited by nickd
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Are there any 4 mm modellers out there who know where I'll get some white metal or brass wagon or tender leaf springs for this build?  I'm looking for 15 mm and 20 mm (between fixing points) items.  Ta.

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Are there any 4 mm modellers out there who know where I'll get some white metal or brass wagon or tender leaf springs for this build?  I'm looking for 15 mm and 20 mm (between fixing points) items.  Ta.

Potentially;

 

http://website.rumneymodels.co.uk/wagon-castings

 

or

 

https://www.dartcastings.co.uk/mjt.php#WagonandCarriageComponents-Axleboxes&Springs

 

Andy

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.....and I have now completed the stretcher that holds the frames between the cylinders.  The kit just has a slot-in cylinder block that doesn't look anything like the structure that should be there.  The stretcher is basically a rectangular box with lots of lightening/access holes.  It's pretty obvious from the piccies how I made it.  It required a lot of measuring and marking out and a lot of hole cutting and careful filing.

 

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Either cylinders or wheels next, I haven't yet decided.........

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Help.  I've just realised that I can't use the Faulhaber motors that the kit is designed to take.  They're supposed to mount where the cylinder stretchers are situated!  Still not a bad thing as I can now use an axle mounted gearbox and have full suspension.

 

 

So, firstly where can I buy suitable 4 mm eighth inch axle motors and gearboxes?  Longish reach please.  And secondly does anyone want to buy a pair of unused Faulhaber motors and gearboxes?

 

 

Thanks......

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....the first wheelset rolls off the production line.  Thanks to David LO Smith and Tony Geary for your advice.

 

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Anyone know who sells any 4 mm  OO jury axles?.......or could lend me some?

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...I have a running chassis.  The wheelsets were assembled using my pedestal drill as a press.  When I've done a final test with the motors attached I'll solder/glue them up.  They worked first time so I suppose I was lucky?

 

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More chassis construction to come when the motors arrive....

Edited by nickd
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