GWR no 34

[trelawney]

This is my first project.  As received for completion.   GWR no 34 as designed by William Dean .

This has been scratch built from drawings from the NRM.  5 inch gauge and approx 36 inches long.

Picture to follow with sincere thanks to Wilf for his patience and help on this part.

[uuu]

IMG_3079 by Wilf, on Flickr

[trelawney]

Many thanks Wilf.

Brief History .. Built 1890 under William Dean.  Two built, no 34 and 35 and shedded at Helston for working the St Ives branch line.

In 1895 they were altered to the form shown as in picture, with a water tank in the bunker as well as the short side tanks. In this form they served for a few more years. The second, no 35, was condemned in 1906, whilst No 34, which had acquired a fully enclosed cab along the way, was sold to the army in 1908 and spent the next few years at the Longmoor Military Railway until condemned in 1921.

Stems from my interest in the Heston branch whilst being stationed at RNAS Culdrose, many moons ago.

[uuu]

I'd come across the name "Dean" before in the context of the Dean goods loco that Julian (jma1009) had years ago. I had to look this one up. If it goes half as well as Julian's , it will be a good loco. If you can match it, then it will be fantastic.

Wilf

[trelawney]

Pleased you posted that, Wilf.
This came without any drawings so had 4 round eccentric? things on an axle.
A visit to SRS and looking up Dean brought up the Dean Goods.
Fortunately a very similar set up to mine, so it seems these all four are attached to the valve gear.
This is going to be a challenging build, as now have to determine lengths of the rods that connect them.
Just been messaged to say worth asking the NRM for drawings,  so will do that.

[uuu]

You have a whole world of pain ahead of you in determining the dimensions of the valvegear components. Read up all you can about Stephenson's valvegear.

Here's a starter piece by Don Ashton: www.donashton.co.uk/html/stephenson_s_gear.html

The eccentrics will have arms running forwards to a curved link. Two eccentrics for each cylinder. One eccentric is for forward motion and the other for reverse, so raising or lowering the curved link selects which one is dominant. But then it gets a whole lot more subtle and tiny differences in geometry introduce desirable (or adverse) extra movements.

Wilf

[trelawney]

You have a whole world of pain ahead of you in determining the dimensions of the valvegear components. Thanks for the starter piece.

I have a feeling you may be right Wilf. I will give it my best shot and if it defeats me then I will happily pass it on to a member who is capable of sorting and using it, rather than just sitting here. 

The Hunslet laser cut frames arrived, so with the Don Young notes, I can have a go at that.

[weary]

Hello,

Looks like you have got yourself an interesting project.

Tricky to tell from your picture but it looks like you may have a couple of valve-gear components front far left of pic. If so, these may give you an idea of some of the component dimensions. Inside or between the frames you may have some features that similarly will give indications of valve-gear component positioning and dimensions. For instance, is that the (location of the) pivot hole for the lifting links that I can see in amongst the scratch marks on the inside right frame just ahead of the rear driving wheel? If the steam ports on the valve faces to the cylinders have been machined, similarly they will give you good indications of travel etc. and can be combined with the eccentric offsets that you already know to discern other design dimensions. If you can obtain the works drawings from NRM then of of course you have a good basis for development. The original builder may have increased valve stroke rather than sticking to the the 'scaled' dimensions so you can check that first!

Patience and application combined with careful reading of Don Ashton's work as recommended by Wilf should allow you to develop something suitable.

Good luck,

Phil

[trelawney]

Thanks Phil

The thread is causing some off forum messages of support which is encoraging plus raising further questions.

I have been told that a somewhat yellowed drawing of the mainframe of no35 loco will be sent to me. 34 and 35 were identical.

Drg info label reads :- WM DEAN 0-4-4T Wolverhampton.
No35. 1890 Scale :- 1.088 - 1ft.

Also, the builder was a Vicktor Daniel from Rickmansworth.  This is still being investigated.

[trelawney]

Phil

I have the two connecting rods and now 4 eccentrics complete with arms had surfaced so beginning to come together.
The two curved links will need to be worked out.

[weary]

Excellent news there.

Should be relatively easy to come-up with (the curved) expansion links!
Don Ashton's work referenced above should assist greatly.
You will also have to establish the dimensions of the lifting-links to lift (and lower) them and the associated arm if those parts are not in your collection of fittings.
In any event, if components are missing you should be able to start drawing-out the fixed points of the gear when you are ready using the components that you have to hand and calculate from there.
A bit of patience and consideration, even 'experimenting using something approximate' if that is your preferred way of working, should resolve any issues. Though bear in mind that you may have to make some compromises to suit the extremely short distances involved in your axle to cylinder-chest distance.

It looks like your (cab) reversing handle works a thread (looks like it maybe in your photo above, far left, just beneath the buffers?). Is so then you will have to construct a stand for that if not present 'somewhere', but your general arrangement drawing, or failing that some construction inspired from similar locomotives should sort that for you.

Phil

[trelawney]

Admitting defeat on this one as beyond my capabilities to sort.

So if anyone can take it on board and complete then send PM. Would exchange for a smaller 3.5 inch model for which drawings are available.

Not interested in selling, only exchange.

Thanks.

[weary]

Deleted.