Gibson LMS Compound

John Palmer
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Re: Gibson LMS Compound

Postby John Palmer » Fri Jan 24, 2020 2:24 am

That ejector looks to have turned out well, Julian, and I see you've managed to incorporate what I take to be an oil pot at the front of the steam admission valve. That's something I've never yet managed to accomplish; looks like a challenge I must face on my next effort on one of these. For the control arm on the steam valve I have been preparing some artwork with a view to having some of these etched; not sure whether the design will work, but since it's part of a much larger bit of artwork for the upperworks of a 2228 Class I can afford the risk of failure - picture should speak for itself:
Ejector steam control arm artwork.jpg
Ejector steam control arm artwork.jpg (67.46 KiB) Viewed 693 times

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Le Corbusier
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Re: Gibson LMS Compound

Postby Le Corbusier » Fri Jan 24, 2020 9:46 am

Inspirational stuff Julian ... great to see the scratch built elements coming together :thumb

Where did you get your drills from?
Tim Lee

Julian Roberts
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Re: Gibson LMS Compound - Wakefield lubricator detailing

Postby Julian Roberts » Fri Jan 24, 2020 10:05 am

Thanks John (apologies for calling you Jeremy before this edit!) - great that you're making an etch. Below I'll put all the remaining photos of that part that I took in case it's useful. I've been thinking all the way along, surely it must be possible to get castings or etchings made for this assembly, as there seem to be lots of LMS (and GWR?) engines with some variation of these arrangements. But all that comes up on the Wizard and Brassmasters sites doesn't take one very far, and I still fail to see how the Gibson casting relates to any of the components. The oil pot (?) is just a truncated bit of broken boiler knob! The control lever going down to the main ejector casting actually finishes up in a hole I'd made in the boiler for a boiler knob and I see now the cheat isn't quite good enough, as it ends too far back relative to the main ejector casting. That might be alterable without too much anguish. The pipe coming down from the admission valve ends too far back too, but correcting that might unsolder too many things to be worth it.

Next issue, the Wakefield lubricators. How far does one go for realism? The smaller something is the more time it takes and the less difference it makes! The lubricator has 6 pipes coming out of it each side. That might be feasible. On the preserved Compound the pipes conveniently disappear over the edge of the footplate
Midland Compound 003.jpg

but in photos of the locos in BR times, where such detail can be seen at all, something more like this seems to be the case.

But there isn't anywhere near enough clarity to see how to start to model this. I wonder if anyone has any ideas/photos?

But then again, life is short...will it be worth it :( !

For what it's worth, here is a photo of what's inside underneath the lubricator on the preserved loco. Could some of all this have been put outside to ease maintenance in more cash strapped BR times?
Midland Compound 014a.jpg

(ON the RHS of 40938 the photo I posted earlier seems to show the simple disappearing pipes, but the LHS seems to suggest something more complicated as above.)

Here are further pix of the admission valve
Midland Compound 113.jpg
That little chain might be problematic!
Midland Compound 112.jpg
Midland Compound 111.jpg
Midland Compound 110.jpg
Midland Compound 109.jpg
Midland Compound 109.jpg
Midland Compound 108.jpg
Last edited by Julian Roberts on Sat Jan 25, 2020 8:50 am, edited 2 times in total.

Julian Roberts
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Re: Gibson LMS Compound

Postby Julian Roberts » Fri Jan 24, 2020 10:31 am

Thanks Tim! - RS Components

Julian Roberts
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Re: Gibson LMS Compound

Postby Julian Roberts » Fri Jan 31, 2020 3:04 pm

Parking the lubricator question for the time being (the pipework on the left of it is apparently the atomiser) I got on with the front steps. When I acquired the semi-built kit these were already attached but vulnerable and I removed them. The two holes for the footstep handrail were drilled each side - though whether they were pre-located in the kit design I don't know. Whatever, on reattaching the steps using the holes as a guide it was apparent they fouled the crosshead.

My first thought was annoyance that I'd forgotten the issue when I replaced the wheels with ones that had the correct throw. Had I got wrong information?

It was also now evident why the nut on the crosshead had been filed down. I had not been happy with this very overscale nut (visible in previous posts). Some weeks ago I had filed it down as far as possible and glued on a finicky representation of what is really there made from a piece of 5 thou phosphor bronze folded over at each end to represent what I assume are oil boxes, with a 16BA nut soldered in the middle. Once the 24hr Araldite had cured thoroughly (48 hrs) I filed them down to something nearer scale thickness in depth. Photo shows it before filing down.

Now it looked as though these were going to have to come off but fortunately I found photographic proof that on the prototype the steps were behind the crosshead at its rearmost position.

The steps located as per the kit looked wrong in relation to the front driving wheel too - slightly too much space between.

Steps located as per kit design

The steps needed to move only 1mm or so backwards to clear the crosshead even with the increased throw. New holes were drilled for the handrails.

I can't stand bendy footsteps and always solder a strengthening layer behind them. They should be located inwards from the footplate (or 'platform') edge so that the steps themselves are within the overall width profile of the locomotive. Fortunately it wasn't necessary to compromise either of these considerations. All I had to alter was the front fixing of the chassis which locates under a tab, which I shortened. To remove the chassis there is a screw at the back to remove, then lift and slide the chassis back then lift out. Murphy's Law dictates that, with the wheels fixed to the gear and no way of turning the motor by hand, someday the chassis will have to be removed when one crosshead is at the rear position. So the backwards sliding movement needed was minimised as far as possible. With the cosmetic oil boxes filed down it is possible to remove the chassis, with care, even if the crosshead is at the rear position.

Below proof it works, so far at least. Tender steps need to be straightened

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Will L
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Re: Gibson LMS Compound

Postby Will L » Fri Jan 31, 2020 3:44 pm

Julian Roberts wrote:...

Its certainly coming along nicely Julian, but if you want a reason why I prefer springing to compensation see the body lurches at seconds 12, 18, 21 and 25.

Julian Roberts
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Re: Gibson LMS Compound

Postby Julian Roberts » Sat Feb 01, 2020 3:24 pm

Yes Will (thank you! - my progress may bring shudders to those of equine saddlery sensibilities but I do this to encourage others of my unashamedly amateur standard to similarly have a go) and for the reason you pointed to I won't build anything more with a fixed axle. (Both loco and tender of the Compound have a fixed rear axle.) While this dip is a gross exaggeration, with a fixed axle any track blip, even a crossing V, shows up as an unprototypical lurch. This loco was started six or seven years ago and was second hand. With the recent re-wheeling I could have taken the frame apart even further, and I could have made a new tender frame, but the loco has inherent problems everywhere and did already basically actually work, so I think my time is better spent finishing this off making the best I can of it and getting on with whatever comes next. That will probably be the CSB-only J50 from High Level if it's out as promised soon. And I have a Dave Bradwell loco to make so in due time I will show how a sprung chassis copes with this dip.

An equally strong reason I'll never have fixed bearings again is that assembling a pair of wheels with its hornblock bearings (and gearbox as appropriate) is so much easier as a separate activity. The front pair of new wheels for the Compound went together perfectly in the GW press, but I had a nightmare with the rear pair, as I always have had trying to do this process with the frame attached and getting in the way.

But just for the record, as some people don't seem to understand this, with compensation no axle needs to be fixed (except one on a 4 wheel vehicle). The last two locos I have made both have the front axle rocking on a central beam, and a longitudinal beam on each side linking the rear two wheels. The pivot of the two longitudinal beams is asymmetrically placed approx one third of the distance from the outer wheels to improve roadholding as I wrote in Snooze 199.

Here is the Barclay Tank on the same piece of track, and the Crab, where the front pony wheel has a central roller supporting much of the loco weight, the front driving wheels are simply sprung. The tender is a separate vehicle unlike with the Compound and has a fixed axle at the rear

Any tender I make from now will have a twin beam arrangement.

Below a couple of pictures of the real crosshead.
Midland Compound 012.jpg
Midland Compound 118.jpg

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Re: Gibson LMS Compound

Postby Horsetan » Sat Feb 01, 2020 9:44 pm

Julian Roberts wrote:.... my progress may bring shudders to those of equine saddlery sensibilities.....

Not as much shuddering compared to today's bill for updated safety kit.
That would be an ecumenical matter.

Julian Roberts
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Re: Gibson LMS Compound

Postby Julian Roberts » Sun Feb 02, 2020 10:46 am

Just as I thought I was nearly through with only a few small details left to fix on I realised the reverser isn't on yet. And that took me to a load of photos I took - many more than these. Some of this must be represented. Lots of scratchbuilding? least I've got plenty of information, but I wonder how much of this detail is available to buy if I knew where to look. Of course I'm going to have to guess what else goes the other way round with the reverser being on the left hand side in BR times, if it's worth getting that bothered about detail - doubtful.
Midland Compound 093.jpg

Midland Compound 096.jpg

Midland Compound 002.jpg

The next picture shows the link between the reverser and the lubricator from the other side. Does this mean the amount of oil supplied varies with the amount of cut off I wonder...not that it matters on the model. The picture also shows the pipes coming from the lubricator that I surmise go to the atomiser which in later times (again surmise) went up on the platform next to the lubricator.
Midland Compound 014.jpg

I've found a photo that shows a possibly easier atomiser to represent albeit from loco 41071

Julian Roberts
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Re: Gibson LMS Compound

Postby Julian Roberts » Sat Feb 08, 2020 10:02 am

Basic effort confected from some spare valve gear etch. When it's painted a darkish colour it'll look better...



The connection to the lubricator presently fixed to the pipe will look OK when the lubricator is there. The other connecting lever in the prototype pictures goes to the assisting steam reverser but I'm not bothering with it as it's hardly visible and according to the book was removed. Though I'm not sure if I have understood that correctly as it is visibly still there on the picture of 41071 in the previous post.

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