Building a Robinson 4-6-0

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John Bateson
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Building a Robinson 4-6-0

Postby John Bateson » Sat Jan 29, 2011 2:18 pm

It took me a long time to get my head around the way the Adams style bogie works on these locomotives but I think I may understand it now. I am quietly pleased with the results shown in the attached picture but as usual the camera does not lie and exaggerates the truth.
The only component missing is the hex bolt head on the pivot head (Eileen's may expect an order soon).
The equalising bars do not pivot as in the prototype, which was a step too far, and springing and side control will be by the traditional 0.3 mm wire.
IMG_0811.JPG
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Re: Building a Robinson 4-6-0

Postby John Bateson » Sun Jan 30, 2011 7:31 pm

IMG_0816.JPG
IMG_0817.JPG
The inside valve gear caused some problems - the almost final version is shown in the two pictures. With a bit of oil this seems to work as expected.
There is supposed to be a 6 degree lead, but in this case I have not quite got it all right!
16 BA Bolts are very fiddly in use as well, but the one on the axle will be hidden by the outer axle tubing.
John
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Re: Building a Robinson 4-6-0

Postby iak » Sun Jan 30, 2011 10:08 pm

Very nice John
Can we start drooling yet :D
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John Bateson
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Re: Building a Robinson 4-6-0

Postby John Bateson » Sat Feb 05, 2011 1:22 pm

Well, I finally got the second test etch off to PPD - they do a pretty good service.
Lots of changes made, to be frank I wasn't too happy with the way things fitted, so a few options have been added in.
However, the inside Stephenson's valve gear seems to be good-to-go. I'm sure this has been done before in 4mm scale, but I have not seen it except in static form.
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grovenor-2685
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Re: Building a Robinson 4-6-0

Postby grovenor-2685 » Sat Feb 05, 2011 1:59 pm

Etch drawing does look rather nice.
However, the inside Stephenson's valve gear seems to be good-to-go. I'm sure this has been done before in 4mm scale, but I have not seen it except in static form.

Refer to Tony Miles' various articles on his locos for Adavoyle, and more recently the Brassmasters 4F.
(Silly question deleted, of course these are probably outside cylinder locos)
Regards
Keith
Last edited by grovenor-2685 on Sat Feb 05, 2011 5:07 pm, edited 2 times in total.
Reason: To delete question re crank axles. KN
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Jol Wilkinson
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Re: Building a Robinson 4-6-0

Postby Jol Wilkinson » Sat Feb 05, 2011 2:35 pm

John,

you've got two sets of chassis spacers by the looks of it. If you are going to offer it for EM (or OO), you might want to think about some blanking plates for the hornblock cut-outs. That will enable those modellers, such as Roy Jackson, who might want the model but can't bring themselves to spring/CSB/compensate it.

They are just a small etched plate, with a full thickness section to fit in the cut-out with a hole for a top hat bearing and half etched outer edges that fit behind the frames.
There looks like enough space on the artwork to include them.

Jol

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Re: Building a Robinson 4-6-0

Postby John Bateson » Sun Feb 06, 2011 9:59 am

Jol,
The blank spaces on the fret are covered in text identifying the separate sheets so there is not really enough space.
However, I plan to add these blanking plates in another etch which should be generic. Thanks for the suggestion though, since I hope that by including the EM bits it will make it more interesting to modellers. My original idea was simply to solder the supplied axle boxes in place using etched marks on the chassis as a guide!

Keith,
I've just had a look at the inside gear you suggested, the Brassmasters 4F. Impressive and very complicated. My problem is somewhat simpler since the cylinders are outside the frame and the solution is shown in my earlier post on 30 Jan - this is a pre-production version, there is a drilling template on the etch which should make life simpler for the assembler and the brass plates are supplied already turned on my new toy.

John
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Re: Building a Robinson 4-6-0

Postby grovenor-2685 » Sun Feb 06, 2011 10:36 am

My problem is somewhat simpler since the cylinders are outside the frame
Yes, and your solution looks fine in the pics, of course this is only the beginning, you have inside cylinder and 4 cylinder versions to contend with before you finish the GCR 4-6-0s and by all accounts Robinson had trouble fitting adequate bearings on his crank axles.
But one step at a time eh.
Regards
Keith
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John Bateson
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Re: Building a Robinson 4-6-0

Postby John Bateson » Thu Feb 17, 2011 11:15 am

Glad to say I have now finished the first drawings for the upper bodywork after a lot of changes to the original intentions. The fret will include some assembly aids and a few outlines to assist production of the furniture. As before there should be enough parts for an EM version . A scaled version will be off to Scotland this afternoon unless I have any last minute thoughts (usually phrased around the words 'Oh Sugar' (expletive deleted).
Also just received late yesterday the second test etch for the chassis and other underpinnings. Looks good - now I have to build it and write the instructions...
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Re: Building a Robinson 4-6-0

Postby iak » Thu Feb 17, 2011 3:00 pm

Very nice looking John.
The artwork is art in its own right 8-)
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Re: Building a Robinson 4-6-0

Postby John Bateson » Wed Feb 23, 2011 2:59 pm

Construction of the second test etch is proceeding apace. The chassis frames are ready to connect having pre-fitted the frame stiffeners and the removable springs seem to have come out quite well. These can be made either as a single layer or to scale width, which is something I prefer.
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Re: Building a Robinson 4-6-0

Postby John Bateson » Tue Mar 01, 2011 10:30 am

I have the first results for the GCR style cast number plates, on the face of it they look rather nice.
I am a little worried about the '1' character though. Although I believe this has etched to scale it does look rather a little thin - but that may just be my perception.
These were produced by tracing a number of pictures plus the helpful drawings in Johnson, plus some advise from Great Central Railway Society and Morgan G. I think the font set I have produced will make it easy now to produced the full set of GCR number plates should there be a market for them and of course if these are acceptable then they are easily scaled for other groups such as 'S' or '3mm'
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Re: Building a Robinson 4-6-0

Postby John Bateson » Thu Mar 17, 2011 4:29 pm

At last the thing is beginning to look like a steam engine. There is a lot to do yet but so far so good ...
Time to produce some chimneys I think.
John
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iak
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Re: Building a Robinson 4-6-0

Postby iak » Thu Mar 17, 2011 4:31 pm

Dribble.... Image
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Re: Building a Robinson 4-6-0

Postby Horsetan » Tue Mar 22, 2011 12:19 pm

grovenor-2685 wrote:Etch drawing does look rather nice.
However, the inside Stephenson's valve gear seems to be good-to-go. I'm sure this has been done before in 4mm scale, but I have not seen it except in static form.

Refer to Tony Miles' various articles on his locos for Adavoyle, and more recently the Brassmasters 4F.....


Also Martin Finney provides etches for working inside Stephenson's in some of his kits as a matter of course.
That would be an ecumenical matter.

simonmoore

Re: Building a Robinson 4-6-0

Postby simonmoore » Wed Mar 23, 2011 10:55 pm

Beautiful work so far. :D

Simon

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John Bateson
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Re: Building a Robinson 4-6-0

Postby John Bateson » Mon May 16, 2011 10:54 am

Finally getting around to producing some masters for the castings. After a little trial and tribulation with the smokebox door I plucked up the courage to try the original dome fitted to the Robinson locomotives.
2011-05-16 11-43-02.523.jpg

The main problem with the smokebox was the problem with parting off, I found it very hard to get a flat cut on the back of the smokebox so that it would sit flat on the boiler. The door is only 1.4 mm deep and probably a little too flexible, and with the parting off blade only the same width I could see everything flexing.
Got around this by doing the thing back to front, flat cut across the 19 mm rod but leaving a 6 mm spigot 30 mm long to fit into the chuck to hold it firmly, then turn the thing round and do the front face. Expensive in brass but seemed to work.
I know Terry will say I should have some collets ...
The dome looks about right but I am open to correction as always, the measurements were take off the GA.
John
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Re: Building a Robinson 4-6-0

Postby John Bateson » Tue May 24, 2011 12:55 pm

Just received the first of the production etches - things are getting quite interesting. Plus there is a separate 'filler' etch for those of the EM persuasion which is also in Nickel Silver. Although I gather some EM modellers do fit springing and/or compensation.
John
Sheet 1 Small.jpg
Sheet 2 Small.jpg
Sheet 3 Small.jpg
Sheet 4 Small.jpg
Sheet 5 Small.jpg
Sheet 6 Small.jpg
Sheet 7 Small.jpg
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Re: Building a Robinson 4-6-0

Postby DougN » Wed May 25, 2011 12:33 pm

All I can say is Wow. I hope that it goes together as well as those etches look. Having looked at the Dave Bradwell Etchs for the Q6 in ever reducing numbers and started playing with a high level Black Hawthorn. There seems to be better etching than others. This is no crititisms of the kits design but of the "cooking" of the brass in the etchant... The DB is better than the HL kit from these points and if the design is great and the etching done well things are a joy to build! the others have a slightly larger challange!
Doug
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John Bateson
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Re: Building a Robinson 4-6-0

Postby John Bateson » Fri Aug 05, 2011 12:30 pm

Been a bit quiet on here recently but here is something different.
I have been trying to finish off the castings for the locomotive (got 10 boxes of etches under the bench!) so thought I would try a different tack.
The pictures are from a couple of tender parts that a company in Holland have made up for me using litho printing, a new technique that will expand a lot in the next few years.
Both pictures show one of the flaws in this method, the surface is not too clean, but almost impossible to see this without a magnifier.
IMG_0946.JPG
IMG_0947.JPG
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Re: Building a Robinson 4-6-0

Postby 45609 » Fri Aug 05, 2011 2:14 pm

Hi John,

Presumably these are parts done by Shapeways? Is this the "Strong White & Flexible" (SWF) material? I am waiting for some parts from Shapeways but I ordered mine in the "Frosted Ultra Detail" (FUD) material. Detail rendition of FUD is claimed to be down to 0.2mm but it is not as strong as SWF. However this may not be a problem if the parts are intended for casting masters.

There is a lot more on 3D printing, techniques and others projects here....

http://www.rmweb.co.uk/community/index. ... cad-group/

Cheers....Morgan

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John Bateson
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Re: Building a Robinson 4-6-0

Postby John Bateson » Fri Aug 05, 2011 4:00 pm

Shapeways is indeed the source and SWF the material. FUD sounds better for detail and I have a few pieces to try, but not too sure if they will survive the preparation of the moulds.
I also have a stainless steel thing on order, looking forward to that.

I have spent a while (including on RMWEB) before I tried this, it may be the way to go for all small parts in the future, although a parcels van is not that small. Again the scaling facility with CAD makes such a project very nice indeed.

Just wish they could do domes and chimneys but it is the bottom edge of the flare that is the problem it seems.

John
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DougN
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Re: Building a Robinson 4-6-0

Postby DougN » Sat Aug 06, 2011 11:23 am

John, the way that Dave Bradwell deals with the handle to the top of the brake standard is to have a cut to the top of the standard and you are to solder in a handle from l shaped wire. I think this might solve your problem above?

I still have to do this to my NER tender forthe Q6.
Doug
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John Bateson
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Re: Building a Robinson 4-6-0

Postby John Bateson » Sat Aug 06, 2011 2:24 pm

Hi Doug,
The material, SWF, is a heat resistant plastic. Soldering is not really an option in this case.
It would have been nice if the stainless steel was capable of this sort of resolution though, although I think the FUD (fine ultra detail plastic) should be able to model the handle as well.
John
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Re: Building a Robinson 4-6-0

Postby DougN » Sun Aug 07, 2011 4:11 am

Oh I have the wrong end of the stick. I thought that these were the masters for the LWC brass. There by just leaving a slot for the modeller to install the handle.
Doug
Still not doing enough modelling


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