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A new 'Old Engine' - GWR 184 - part 5

MikeOxon

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I feel it is time for an update on progress with my model of GWR No.184. After a rather static period, when I did little actual modelling but thought quite a lot about the details of this engine, I have at last been cutting metal.

 

In fact, apart from the fact that it is now made of brass, I have made few changes to my initial paper template. My method of construction followed that used on my first scratch-built model (GWR 'Queen'-class - described in Railway Modeller July 2014). In summary, I cut out the components from scale paper drawings and stuck these (using a glue stick) to 10 thou (0.25 mm) brass sheet.

 

One simplification that I made, following experience with 'Queen' was not to make a double-fold in the main chassis in order to mount the splasher fronts, but instead to provide tabs on the splashers 'module', to fold under the chassis sides. The main components that make up the body look like this:

 

blogentry-19820-0-29802200-1416696131.jpg

 

As before, I had little difficulty with rolling the boiler, although I suspect that it helped to have a paper layer stuck to the outside of the brass sheet while rolling. This seemed to help with the smoothness of the curvature and also protected the surface of the brass from scratching. Since the prototype boiler had a diameter of 4' 2", I calculated the scale circumference (3.142 x diameter) and then cut out a rectangle of brass, to roll into a cylinder. I made this tube the full length of firebox + boiler + smokebox, to provide a rigid structure and then added the raised firebox and smokebox as simple wrappers. The stages in assembly are shown below:

 

blogentry-19820-0-26714500-1416691985.jpg

 

I used a diamond slitting disk on my mini-drill to open up the apertures for the wheels in the floor plate. For the photograph, I've just rested a chimney and safety-valve cover in place, to make it look a bit like a locomotive (!) and have not bought a dome yet - probably a 517-type. The next step will be to fit 'cosmetic' outside frames with embossed rivet detail and then use thin (5 thou - 0.125 mm) brass sheet, to form the curved running plates between the outside frames and the splasher fronts.

 

Anyone who read my last post on this engine might remember that I had planned to begin with the chassis but, in the end, I decided to repeat the part that was already familiar, having done a very similar body for 'Queen'. I may produce a simple rolling chassis that can be pushed along by my 2,500 gal. motorised tender. I find that tackling a job in easy stages helps to keep up motivation, when I see the outline of an engine start to appear, and allows me to consider different options as I start to add the details.

 

So far, the outlay on brass sheet has been minimal but costs start to rise once all the detailing components are added, especially wheels, gearbox, and motor. At this stage, I feel that there is a reasonable chance of producing a model that will have at least a passing resemblance to its prototype.

 

blogentry-19820-0-09710200-1416692085.jpg

GWR No.184 in 'Wolverhampton' livery

 

As an aside, I have mentioned before that many interesting old books can be downloaded from the Internet Archive website. I recently found that Ahrons' classic 'The British Steam Railway Locomotive 1825 - 1925' can be downloaded and, although I have a facsimile copy, it is useful to be able to copy drawings directly from the digital version. Another interesting find was Sekon's 'The Evolution of the Steam Locomotive 1803 - 1898', which has lots of fascinating detail about many very early engines, and many anecdotes about events during their trials and early use.

 

Mike

 

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Hi Mike. Well this to me is of immense interest. Both the particular loco and the methods you use. I may have mentioned it before, but what I like is that your techniques makes it all seem within reach - in this case scratchbuilding locos in brass, something I wouldn't have considered until you started showing it.  I realise there's lots of skill involved, but still - a whole world of prototypes suddenly become a possibility.

 

Can I ask how you did the folding and rolling on this one?

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Very nice Mike. It is good to seem someone making their own. I would mind one of these in 0 gauge I wonder if one could have worked down to Dolgelley?

It looks quite fetching in the Wolverhampton livery. Mind you everyone seems to have their own interpretation of the shades.

 

HAve you thought of using NS sheet instead of brass?

Don

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Excellent stuff Mike, you've captured the proportions of number 184 beautifully! as Don says "I wouldn't mind one of these in 0 gauge" I'm looking forward to seeing this progress to the next stage.

 

Dave

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Hi Mike,

 

Looks like you are making good progress. One question, though. Where did the 4'2" boiler diameter come from? RCTS Part 3 has 4'1" for the original boilers and 4'7/8" for the type 34a fitted when rebuilt in 1871. A trivial difference you might say, but the boiler diameter given is usually the diameter of the bare boiler. Cladding will add five or six inches to this size.

 

Nick

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Hi Nick,

 

My model, based on the photo, represents the 1893 re-build,with the raised type 35 boiler.  I have listed the various dimensions below:

 

GWR Class 182 info (from RCTS Part 3)

Six 2-4-0 engines arrived at OW&W from E.B.Wilson in 1853.

Double frames (outside sandwich)
wheelbase         7' 6" + 8' 0"
coupled wheels  5' 8"
leading wheels   3' 8"

Boiler barrel     10' 6" x 4' 1"
Raised casing   5' 2" x 4' 1"
Firebox            4' 6" x 3' 61/2" x 5. 5" high
(with transverse midfeather)

No.184 specifically:

rebuilt with 34a boiler (similar to No.178) in Sep 1871
Three rings, middle dome, flush firebox
barrel               10' 6" x 4' 0 7/8"
casing               5' 1" long

received R3 boiler (middle dome, raised casing) in Aug 1893
(as 34 but with raised casing)
Three rings, middle dome,raised fiebox casing
barrel              10' 6" x 4' 2"
casing              5' 1" long
firebox              4' 4 15/16" x 3' 5 1/4" x 5' 9" high

when rebuilt at Wolverhampton

coupled wheels  5' 9"
cabs added late 70s
splashers filled in during 80s

 

---------------------------------------

 

I almost asked a question in the forums about the thickness of the cladding! My impression, from measuring photos and from the various drawings  I found in the literature, is that it doesn't add quite as much as you indicate.  I was going to put calipers around some of my rtr models, but the handrails get in the way!  If anyone has some relevant dimensions, I'll be interested.

 

Mike

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................

 

Can I ask how you did the folding and rolling on this one?

I was really pleased with your comments,Mikkel, as I really wanted to demonstrate that scratch-building with metal sheet can be very straightforward! 

 

The way I do it is just like using card but brass is much nicer to work with, because it is tough, retains its shape when bent and can be re-worked if/when you make a mistake!  It also opens up the possibility of soldering,for a really strong result, although glue works well too.

 

I suspect a lot depends on the grade of brass - I use the Albion Metals sheets, which are pretty flexible.  It work hardens when folded so, as I have found, a joint will crack it you do too much re-working.  I guess it could be re-annealed with a small torch if necessary.

 

On the specific point of boiler rolling, I use a length of silver steel rod as a 'rolling pin' and a mouse mat as a soft surface.  I use fingers and thumbs to get the metal curving in the right direction and keep teasing the shape manually as I work along the sheet.  I bind it with another layer of masking tape plus a few rubber bands to hold the shape while soldering the seam from the inside, after running in some phosphoric acid flux.  Again I use my fingers (protected with a small wad of tissue) to hold things precisely in shape, while applying the iron.

 

For the right-angle folds, I score the brass with a 1/2carat diamond dressing tool run along a steel rule on the inside of the proposed fold.  This can cut quite deeply, so don't overdo it.  I then make the bend,initially by hand, over some aluminium angle held in my soft-jawed vice, and smooth it down with the rubber handles of a pair of pliers.

 

A lot of 'hands on' and 'suck it and see' but I find it is good fun :)

 

 

.....................

HAve you thought of using NS sheet instead of brass?

 

Yes!  I am using brass at the moment but that's because it was the first metal I tried and it seems to work.  If you think there are advantages to NS, I'll be interested in your thoughts.

 

I expect you know that I investigated 'Wolverhampton' livery in a forum thread.  I think It looks better in the darker tones of the photograph I worked from, for No.184.

 

 

Excellent stuff Mike, you've captured the proportions of number 184 beautifully! as Don says "I wouldn't mind one of these in 0 gauge" I'm looking forward to seeing this progress to the next stage.

I'm pleased you approve.  Of course it is nothing like the standard of your beautiful models but I like to feel that it is possible to make something attractive with relatively simple tools and facilities.  One can 'get way with' a lot more in 4mm than in '0' :)

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Hi Mike,

 

Looks like I missed the 1893 Wolverhampton rebuild!

 

As it happens, I have a copy of Swindon drawing No 11130 of 1893 sitting in front of me. This relates to alterations to the trailing end of a 517, but it shows the outlines of both the boiler and the cladding. The dimensions are unfortunately unreadable, but given the usual boiler diameter of 3'6 7/8", a quick measurement and arithmetic suggest about 3' 11 1/2" for the outside of the cladding (for what it's worth, my Mitchell kit came out at fractionally over four feet).

 

There are plenty of images online that may help to convince you - try a google image search on 'boiler cladding'. Here's one example, the length of the handrail knobs and the gap between top feed piping and boiler should give a clue.

 

Nick

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Thank you again,Nick.  I particularly enjoyed browsing on the South Devon Railway website - http://www.5542.co.uk/boiler.html

 

One photo, in particular shows some cladding on GWR No.5542 very well : http://www.5542.co.uk/images/2012_03_24/2012_03_24-5542-18.jpg

 

I'm not sure exactly what I'm looking at - I assume it is for the front ring ahead of the tanks - but it seems remarkably thin!  Perhaps there is more insulation between this and the boiler itself?

 

Compared with the 6" fibreglass  in our loft, the insulation around the boiler seems rather sparse!

 

Mike.

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Following a different tack on boiler cladding, I looked at a drawing in Russell's Pictorial Record - Part One of a GWR '439' class, as re-built at Wolverhampton.  According to RCTS Part 4,  these had the 'usual' goods-type boiler, measuring 11' 0" x 4' 2".  Russell's Fig.138, stated to be 'Diagram A' shows dotted lines, which I assume represent the boiler itself and solid lines, which assume represent the outside casing.

 

The drawing is not printed to exactly 4mm :1ft scale but, checking the quoted overall length (over buffers) of 49' 0 3/4" against measurement off the figure (210mm), yields a scale of 4.28mm :1ft.  The dimension on the printed drawing between the dotted lines is 17.5mm and between the solid lines 18.2mm (as near as I can judge).  On the scale of the drawing, these correspond to diameters of 4' 1" and 4' 3" respectively.

 

I realise that I'm not using the drawing for the purpose intended but, at least, it leaves me feeling reasonably comfortable that my model, which measures at 17mm OD (before painting) is a fair representation of the prototype.

 

This is a problem of scratch-building - if you use RTR or build a kit, you take what is given but, with scratch-building, it is as easy to get it 'right' as not, if you have the relevant facts :)

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Oh come on, Mike, you're being really selective there. Just look at the other two drawings on that page or on any of the next few pages. In each case there's around a mm or more between the solid and dashed lines. Whilst these are far from accurate drawings most do show room for a good 2-3 inches of lagging. The 439 drawing hardly has room for the cladding to clear any rivets joining the boiler rings!

 

Nick

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Oh come on, Mike, you're being really selective there. Just look at the other two drawings on that page or on any of the next few pages. In each case there's around a mm or more between the solid and dashed lines. Whilst these are far from accurate drawings most do show room for a good 2-3 inches of lagging. The 439 drawing hardly has room for the cladding to clear any rivets joining the boiler rings!

 

Nick

:) I just wanted to feel that I was in the right ball-park for the OD and didn't scrutinise the whole page - just took the 'Bicycle' because it was an early Wolverhampton re-build.  I really don't think those dotted lines are meant to be accurate but the OD shown seemed around the value I've chosen.  After scanning and re-scaling the drawing on the computer, I can get the OD up to around 4' 4" but we're into line-thickness on the drawing now.  I will keep looking for more information, though, and I do value your input.

 

EDIT I can confirm your observations on 517-type boilers. As it happens, i have been scanning some drawings recently and the one of a Collett 14XX measures as 4' 3" against a 3' 10" specification for boiler diameter - 5" difference, as you suggest.

 

I wonder if older boilers had less lagging. Dean's 4' 3" boilers would be perilously close to the drivers, if they had an extra 5" of cladding.   I think I'll start a thread in the forums to solicit more thoughts.

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Thanks for the info on the folding and rolling, Mike, I'm taking notes. Nickel Silver sounds like an option too. It will be a while before I get around to something like this (next challenge on the list is to build my own points), but I can now start looking at odd GWR locos with a modeller's eyes.

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Hi Mikkel - building points sounds very serious to me!  I'd tackle an engine far more willingly!  At the moment, Nick is doing a good job in persuading me to raise my sights in the matter of accurate dimensions.  From what I read, pointwork becomes critical down to the 'thou' level :)

 

Mike

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Hi Mike,

 

Remember 5-6" overall is only 2.5-3.inches per side.

 

I've just been looking through Ahrons' Development of British Locomotive Design, no GWR examples but a couple of fold-out dimensioned drawings may surprise you:

 

An NER 4-4-4T, boiler 4'9", cladding 5' 8 1/4"

 

A MR 4-4-0, boiler 4' 7 7/8", cladding 5'3".

 

Maybe the GWR was rather stingy with its insulation?

 

Nick

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Hi Mikkel - building points sounds very serious to me!  I'd tackle an engine far more willingly!  At the moment, Nick is doing a good job in persuading me to raise my sights in the matter of accurate dimensions.  From what I read, pointwork becomes critical down to the 'thou' level :)

 

Mike

 

I only meant a point kit, not scratchbuilt.

 

A question out of interest: If there had been an expensive kit available for the 184, would you have used that? Or do you see an advantage in making your own parts?

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......................

 

A question out of interest: If there had been an expensive kit available for the 184, would you have used that? Or do you see an advantage in making your own parts?

 

I scratch-build for my own pleasure, mainly!  I can fiddle about and try different things, and I suppose I like the feeling of 'mine, all mine'  As I'm sure is apparent from my posts, I go for 'atmosphere' rather than strict accuracy, though I don't like getting things wrong, knowingly.

 

Kits can teach a lot about the details of railway stock.  For example, before I built the Wizard Models/51L etched brass kit of the GWR N6 horse-box, I knew very little about brake gear. 

 

I can't get over-excited about all those details that are hardly noticeable when a train is running and sometimes re-assure myself that, once I have built the basic 'shell', I can add details later, whenever I feel like it (though I usually start something else before reaching that point)

 

When/if I feel that I've acquired the skills to do justice to an expensive kit, I may well have a go, just to see what I'm missing at present

 

Mike

 

p.s. scratch-building can get expensive, too - mainly from sourcing the detailing parts!  I'd like an affordable3D printer so I could keep everything in my own hands  :)

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