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iD's 3 Axle GWR Siphon: Now Fully Completed


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Impressed by all those brave souls who are building rolling stock for the 2012 challenge, I thought that I'd go out on a limb and have a go at scratchbuilding a GWR 3-Axle Siphon - although I'm not sure which diagram I'll end up building. I hope the use of a simple 3-Axle underframe kit (which will be further developed and built up) will meet with AndyY's OK.

 

Off to plunder my assorted Russell volumes...

 

F

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This will be interesting as it's something I've long intended doing. However, as I've acquired a number of old K's kits and a D&S brass one, the idea has slipped down my list of priorities.

 

Russel will help, but you really need G W Siphons by Jack Slinn and Bernard Clarke, ISBN 0-906899-60-5, as it contains drawings and details of all the six-wheel types. It is an old HMRS book, but copies can sometimes be found on line at reasonable prices.

 

Nick

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Having had one of my periodic episodes of insomnia, I used the "stay-awake" time to create my plans.

  • I scanned the appropriate page from Russel, extracted the diagramme for the O4 Siphon and resized the image until it was exactly 4mm/foot (as the Russell had dimensions of the Siphon on the diagramme, I made an approriate length "size bar" bar and manipulated the image to match the size bar.
  • Using straightforward rectangles in powerpoint I resized the rectangles until they overlaid the appropriate part of the diagramme.
  • The resized and resited rectangles were then colour-coded to indicate the necessary width of Evergreen strip to be used (05mm thick x 0.5 - 2.5mm wide - depending upon location of beam/bar)
  • Once the basic plans were made, I then added both cutting and alignment lines, grouped the disparate parts into objects and deleted the scanned Russell diagramme

The resulting print out will allow me to build the sides and ends using plastic strip with minimal need to hack at sheets of plasticard. Below is the resulting plan/printout

 

post-123-0-16790100-1334321363.jpg

 

Will be fun to do and will fit in nicely in between waiting for various bits of pub and goods shed to dry.

 

F

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As Mrs iD is in Italy for a holiday with an old girfriend of hers, the iD had time to work on all 3 competition projects :imsohappy:

 

First done today was building one of the Siphon sides. I started by using a steel ruler and a pritt stick to lay the plastic strip onto the scale plan for the horizontal planks. Cross beams were added and allowed to dry.

post-123-0-06412300-1334508281.jpg

This was trimmed and the other bars added. A time consuming and fiddly job. Although I had made a minor miscalculation a few slivers of strip set me right. After letting dry I peeled the paper away from the side (very little paper stuck to the plastic, presumably because the plastic touching the paper, the horizontal planks, had been sealed to a degree by the pritt stick)

post-123-0-88468300-1334508375.jpg

It will need some preliminary cleanup once every thing is dry and set, but the high quality finish will be done once I have assembled the body in its entirety.

Against the drawings and photos it looks acceptable.

post-123-0-09631500-1334508619.jpg post-123-0-80441000-1334508742.jpg

It's not particularly difficult, just tedious and time consuming and definitely a Sunday job (the side took me about 3 - 4 hours to build, including waiting time)

 

F

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What is this "dark side" that people seem fond of mentioning? I thought it was when photographers change from film to digital but you; dear iD, have used it in this context as well as in connection with changing to EM gauge. I'm confused!

 

Chris

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What is this "dark side" that people seem fond of mentioning?

Chris

I was being ironic, as the GWR is perceived by those benighted souls who have yet to see the glory that was Swindon as being "the dark side"

 

Anyway, it's all model railways, innit?

 

F

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I saw somewhere for 3 axled wagons and coaches, it was to remove the centre wheels from their axle and mount them on a tube, then fit a suitable rod through the tube. This is then fitted into the bearings. The wheels and tube would then be able to slide from side to side. It seems that this wouis more than enough movement and more prototypical. I am going to do this on my next 6 wheel brake. It seems far easier than all the faffing around with Clemensons.

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Whilst there is undeniable satisfaction in building a Cleminson chassis and getting it to work, and the Brassmasters kit makes this easier, it must rate as one of the most over-engineered solutions of all time. If four wheel stock of the same wheelbase will get round your curves, then the steerable outer axles are really not needed. I've just used the solution mentioned by Peter on my D&S Siphon and it works well though, admittedly, the minimum radius I've tried so far is only about one metre. It's a solution that Bill Bedford has mentioned before and I also have some Roco HO German six wheelers that do something similar. For a 4mm vehicle, mount the wheels on a length of 2mm outside diameter tube with an inside diameter of 1mm (I used brass from Eileen's). This is trimmed to length so that it does not extend beyond the wheel faces. The tube is then slipped over a 1mm diameter Exactoscale pinpoint steel axle which is inserted between normal bearings in the centre W irons. The wheels on their tubular axle then have freedom to move sideways as needed.

 

Nick

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Gentlemen, thank you for the tips regarding the third axle. Being somewhat of a hair shirt & self-flagellation disposition (no sniggering in the back...), I shall first attempt the Brassmaster Cleminson 3 Axle etch (which the esteemed Mr F kindly obtained for me).

 

Should it fail, I will then fall back on the methods suggested by Mark, Peter and Nick - although being somewhat hard of thinking as of late, a "how to" set of photos would be helpful (and for the Brassmaster etch should anyone have such piccies [or be able to point me in the right direction]).

 

F

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I have used a similar chassis kit by Ian Macormac, it is based on the

Cleminsons but is less complicated [in both construction and the way

it works]

It has a sheet of brass as a base with one axle set twisting, the next

set sliding and the last pivoting. There is one piece of flexible brass

wire joining all three.

It works well, I have just used one under an approximation of a K16

[GWR short, full brake] that I picked up at a toy fair for practice.

Jeff

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  • 3 weeks later...

Well progress has been made :sungum:

I completed the second side last week, cut out the ends and floor yesterday and glued it all together today....

post-123-0-57141500-1336333643.jpg

The partition (of which there are two - to support the roof) has yet to be hollowed out and trimmed to fit.

post-123-0-77971100-1336333715.jpg

I'm not sure how accurate it is, given that despite my plans (which do help) my plastic hacking is not as precise as I'd like it to be (I'm aiming for quite fine tolerances here, [about ± 0.1mm], but I can only manage ± 0.5mm), but with one eye shut, without my glasses and at 50 paces it does resemble a Siphon :read:

post-123-0-04226000-1336334162.jpg

I've also added internal bracing (only partly complete in this photo) to stop the sides from bowing and I'm thinking of doing an end-to-end spar to prevent the ends from bowing as well...

post-123-0-72781900-1336334254.jpg

There's still a lot of further finishing to do (e.g. completion of buffer beams and adding framing to the ends) plus one hell of a lot of making good... and that's before I start on the underframe...

 

Strangely enough I'm fairly pleased about this effort (so far), so I'll need to be much more self critical if I'm going to stand a chance in the scratch built challenge....

 

F

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I'm wondering how you are proposing to fashion the roof. If it fits between the sides that wil help to stop them bowing inwards - that's the theory, anyway! Are you proposing to make the partition permanent as I don't think the prototype had them.

 

Consider yourself deserving of a bravery award for tackling this type of vehicle! I'm so glad they had all gone by 1961.

 

Chris

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Hi ChrisF

 

The partition will be trimmed so that the roof arc is supported by two thin pillars which will be pretty much hard to see from outside and thus keep the see-though look so typical of the Siphons.

 

I have not yet decided how to do the roof, probably thin plastic card layers (5 thou???) cut to size and glued over the formers (i.e. the ends and the partitions).

 

Stay tuned...

 

F

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I'd be tempted to fit a false ceiling full width and length (with some holes drilled in it to allow any solvent vapours to escape when the roof proper is added). This with a floor would probably prevent the side from bowing. (But quote me on it!) :nono:

 

Got to say though that the model is really coming on and does look like a siphon (even with my glasses on :no: )

 

Ian

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I'd be tempted to fit a false ceiling full width and length (with some holes drilled in it to allow any solvent vapours to escape when the roof proper is added). This with a floor would probably prevent the side from bowing.

That's an idea, I hadn't given the idea of a false ceiling much thought. I could cut a false ceiling and fit plastic rod to it so that the whole assembly clips into place

Got to say though that the model is really coming on and does look like a siphon (even with my glasses on :no: ) Ian

Thank you, glad to see that I'm going in the right direction. However, after yesterday's euphoria about making true progress on the Siphon has waned, I've found some glaring errors to "make good" - but still, it is moving forward.

 

F

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