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OO9 NGG16

Chapter 9 Detailing(2)

Building manual chapter 09

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April 2010

 

While working on the non-return valve I found it increasingly difficult to handle the part, it being so tiny.

I had a hunch and clamped it in a wooden laundry peg. It worked well: when you clamp the peg in your vice the brass part is pressed rock solid into the wood. Just make sure everything sits straight and square.
Some indication of the size of the non-return valve.

Working on the piping on the left side had been hampered by a part I missed, no 99 in the exploded views of the manual. After some correspondence with Backwoods Miniatures I received it, only to find I didn't even come close to the reality of no 87.

This is black thing attached to the left side of the loco instead of part 99. After puzzling and musing over it a thousand times I decided to fabricate it myself.

I set out with a left over of the fly crank castings. I cut it roughly to size. From 0.5 mm brass strip I made a U-turn to slide over it. The U-turn has a simple logic. I need to get two extremely small 0,5 mm thick pieces of brass sheet soldered on. If I would try to solder them as two separate pieces the first will inevitably come off when soldering the second one. Further it will be next to impossible to align both pieces straight and square thus necessitating oversize and consequently a lot of filing down.
But the U-form solved that puzzle. The alignment of the two pieces of brass could be determined beforehand so oversize was not needed. The U-turn was made to fit tight so soldering was a doddle
Here the rough form after soldering and filing away the U.
By the way I used high temp solder (240 C) to prevent it from falling apart when soldering it to the frame
Next a session of exquisite filing, milling and drilling followed taking the better part of a sunday afternoon.
The end result

You may have missed the diminutive size of the no 99 replacement. At the left the original no 99, not very big either, at the right its replacement.

Scale is in mm's
No 99 II soldered
Once no 99 II was finished, I could progress with the elaborate piping of the left side.
Think it's easy? Think again! The water feed pipe, running diagonally up from the non-return valve to the top feed took my me an hour and seven fresh starts before it would sit satisfyingly!. The fault was that I always started at non-return valve working my way up. The slow bend into the top feed however is the most difficult of all. Once that message got through I neede only one more try to have a perfect fit, work my way down form the top feed.
Another shot
Here you can see the blue spots on the pipes that I make with a permanent marker to indicate where a bend should occur. Virtually no measuring is done except by eye and marker.

Nothing is simple in this area. This is the left main steam pipe. No less than nine bends, and yet the pipe should remain straight in the X-dimension and absolutely true in the Y- and Z-dimensions. Moreover: every bend should be given careful consideration. The place is so crowded with piping that every choice may impede other pipes.
Backwoods suggested 1.6 mm brass rod. I chose 1.2 because I found 1.6 too bulky

And seriously, the loco's left side is a crowded thing
I did some detailing on the bottom, right hand side. Rodding to the ash pan.

Roof

  
Rolling the roof after having annealed it first.
The roof supplied with the kit has three opening. A hatch is supplied which ia far smaller than the largest opening.
No 87's prototype has just one central roof hatch and minute traces of lifting eyes.
After a thorough job of filling an filing, and making a hatch from the thinnest brass I had this was the end result.

I back filled the two smaller holes whith a thin sheet of vbrqass and filled them in with Milliput fine.

In hindsight the hatch is too small , but I only realise that when the roof was finished, so I'll just leave it.

Wakefield presses

 May 7, 2010

The kit's original Wakefields were rather poor white metal clumps, a bit smallish and all but square. I ordered milled brass version from Markits and I was not going to be dissapointed. They were well worth waiting.

Maybe a bit on the big side this time they really impressive. Eye blinding brass displaying pure craftsmanship.

On the NGG16 the presses have handwheels instead of handles. This hand wheel a inset spokes. I simulated this by pressing the center of a brass handwheel dwon with a purpiose made brass rod, while laying on the cutting mat.
The handwheels are from an Iain Rice etch I bought from Mainly Trains.

I soldered the handwheels on brass rods of the appropriate diameter, 1.0 mm, that sounds a little thick but that is what fits in the Markits' Wakefield.

Next thing was to solder three grease feeds in the presees. 0.5 dia brass rod will fit but I found that too bulky so I chose 0.3 mm.

I also chose phosphor bronze wire. It resist a little push better than brass, whicih is importaant as the feeds are on a very exposed position.

As you can see I soldered both presses on the rods in one go. This ensures the rods are horizontal and parallel.
Make sure you enough solder in the channels through the presses as to fill them. The tiny holes that are left at the exit if you solder too sparingly are conspicuous.
End result after "some bending".
It looks easy, but it takes quite some patience to get it all square and parallel. Getting the Wakefields to this stage took me the better part of a Saturday!!
 

The ejector

  
I have sourced several parts either because they where not in the kit or because they didn't satisfy me. It it took me two a three month of fruitless searching for the boiler mounted ejector before I decided to build is myself. This seemed a bit daunting to me. The jector is an extremely complicated thing. But a had yet to learn another lesson: modelling in OO is mainly the art of omitting. Simulating, suggesting is the best you can do.
Shaping the basic form, by turning, using my Proxxon as a would be lathe.
After some patient turning, milling (the square part) and drilling
The whole thing is next to nothing, 5.5 mm long. The brass rods were soldered 240 C
The support was made from a strip scrap brass sheet, 0.5 mm. Drilled undersize , carefully filed to fit and soldered 180 C.
I tried to model the control valve (on the prototype postioned separately behind the ejector) but this was too ambitious: the part needed to be 3x2x1 mm, drilled with five holes. I decided to leave it out, scraficing one major pipe.
   
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