The Boiler: Construction

NB: This really is getting very 'Deja Vu' as it wasn't that long ago that I gave these details on this page. However, it needs recording on the blog and therefore I'll keep posting the entries here. We are getting very close to being 'up to date' now...I will need to start cutting metal again soon so I have something to post. I seem to struggle to get in the workshop during this lockdown, spending most of my time outside enjoying the weather while working on my classic Porsche... It just has to be done.... hopefully, I'll get back in action soon. Ok, so onto the log of the boiler, a truly wonderful piece of work by Paul. Not so much text in this entry as it's really just me sharing the progress updates as supplied by Paul, lots of pictures though.

Today was a very important day and that was due to the boiler shell being test fitted to 4472's frames for the first time. It was a great day, Paul (Southern Boilers) spent a good few hours with me discussing the various requirements for the boiler and checking for it's fit which I have to say is very good. I do have a couple of pictures to show how things look. I believe that she's finally looking like a steam locomotive and with Paul's boiler she is not only going to look the part but will steam like the prototype too. Even without the cleading she looks like a Gresley locomotive, yes I am a very happy man and getting very excited about receiving the finished boiler in due course. The rear splasher has been removed as I still need to cut out a segment to clear the boiler barrel and I also need to remove a little material from the running board inner edge around the firebox, both of these were a known fact and have been mentioned in previous updates.

The first picture show's her from the rear quarter, or at least as close as I could get to the rear.

And here's a view from the front, doesn't she look the part?.. ok I'm a little bias, or perhaps a lot?..

So there she is, I hope to get back on her very soon. For anyone out there who's in the market for a boiler, I can highly recommend Paul Tompkins of Southern Boilers, IMHO, the best out there, both in quality and customer service.., it was great seeing you again sir....

I'm busy doing some DIY but want to keep you guys in touch with what's going on behind the scenes and so I have asked Paul and have been granted permission to show some of the progress being made on the boiler. No pictures for tonight but I can share a modified drawing showing the planned layout for the crown stays. For those familiar with Don's design, you'll know that there are 4 rows of crown stays, Paul will be fitting 6 into 4472's boiler as can be seen here.

There will be a number of changes to the design as I'm sure was clear to some with the barrel shell, other visible differences will mostly be on the backhead and these will be explained later. To begin with, the two holes low down in the throat plate corners are wash out plugs to remove scale from the lowest points in the boiler.

Paul sent me some photo's tonight, I have to say this is going to be one superbly made boiler, hope they whet your appetite, they certainly did mine..

Backhead

Dome bush (modified)

View inside to show the main steam pipe support and that of the two injector steam valve pipes too

A view from the firebox

Another view from the rear taken at a different angle

I don't think that I need to say anything else, the pictures speak for themselves... truly excellent work...

Good afternoon everyone

Hot of the press we have two photo's direct from Southern Boilers showing the excellent work on the combustion chamber tubes, Paul has been a busy man...Paul has installed larger pipes for a better tube/grate ratio, more details later.

And we have another picture to look at folks, this time the front tube plate....

A have a few more pictures from Paul, these are the crown stays for you all to enjoy...

Paul informs me that the throat and side stays are also done along with those for the arch support, pictures to follow.

Now this is one picture that I have been eagerly awaiting, doesn't it look superb.....first class in every sense of the word...

Paul has just sent me these latest pictures which show the stay and Firehole door penetration, all looking excellent...not long now before completion....

Just one photo for tonight, these are the manifold and regulator bushes, machined from PB102 with M2 threads for studs. Manifold will have an 'O' ring for sealing..

Two pictures for today showing the penetration of the foundation ring, you can just see one of the blind bushes in the ring which are for holding the ashpan and associated damper operating mechanism.

Here you go, guys,

One exceptionally well built near finished Gresley A1 boiler in 5" gauge from Southern Boiler works, I take my hat off to it's creator Paul Tompkins and very much look forward to collecting it in person from his works end of next week.

Not much left to do, the stay ends will be trimmed, the boiler will be given a good clean and then tested at twice it's working pressure for two hours. Let's just say that I'm very excited about seeing it in the flesh...

The boiler has just passed it's twice working pressure test and Paul has kindly given me 3 pictures to share. When the boiler is fully completed I'll post some more pictures with more details on the boiler. I must say that I have been very impressed with Paul's work, not only the quality of the build and his knowledge in all things boiler making but also the info passed back to me at each stage and total communication throughout. For anyone wanting a professional boiler made or repaired, he's your man...

Here are the pictures...

I'll be collecting the boiler on Friday, I can't wait...

That very special day has arrived and that's to pick up the completed boiler. I will share with you the pictures that Paul posted earlier on FB. Over the weekend I'll place the boiler on the chassis and add another picture or two. Can't do it now it's a bit too heavy for me to lift out of the car on my own, old age and all that..

The pictures....

I promised to show a few pictures with the boiler on the chassis and also give some more details about the boiler. Some details were told to me in confidence and not something Paul would wish to pass on to competitors so I'll keep quiet on any of those.

Ok, so the boiler is as you'd guess mainly to Don's design but is stronger and has a higher working pressure of 100 PSI vs Don's recommended 90 PSI. The shell is a work of art, with the parallel barrel blending in nicely with the taper and having no step thanks to 'Tig', it really does look like full size in shape and I can share a picture here of 1470 ( first of the class) when built in 1922 to show what I mean.

Backhead:

Now Don's is pretty good, very close to scale although fittings are slightly larger and spacing between the water gauge bushes is larger. I have kept the water gauge bushes as drawn as scale versions would give too small a window to view the water level. I will make the gauges as close to scale as possible, just with longer glass sections.

The steam valves will be to scale and I'll be using Adam's (Cro Fittings) castings to achieve this, the bore sizes for water and steam will follow the normal practice of 5/32 pipe for steam and 3/16 water to match the injectors planned for the model, I can't recall which sizes I have chosen just now but it's written down somewhere. Bore sizes for the mounting pads are 3.2 mm for steam and 3.8 mm for water. I'm undecided on whether to try for working clacks within the steam valves themselves or to fit them independently below the cab floor, I'll see if it's feasible to get the clacks working first.
Regulator bush is as drawn by Don.

Manifold bush is to scale, this is able to keep the bore size as drawn by Don. Manifold itself will again have castings supplied by Adam.

Paul has fitted 4 blind bushes into the backhead for me to secure the cladding when done, this will be very much to scale.

The everlasting blowdown valve is as drawn by Don.

There are two extra water feed bushes along the bottom of the backhead, one of which will be used to fill the boiler using a HP electric pump, this will be able to feed water against boiler pressure if ever required, something I doubt will ever be needed but it's nice to have a back up when there's no hand pump in the tender which according to Don would be undignified to have on this loco, I agree. I did mention these plans some time ago, some years in fact, think I was still building the tender?

There are also 4 washout plugs, 2 on the backhead lower corners and 2 on the front throatplate just above the foundation ring in each corner.

Paul has fitted larger tubes for a better tube/grate ratio, as drawn they are 1/2", they are now 9/16 18swg.

The steam header as drawn is threaded into a 3/4 x 26 tpi bush, Paul has modified this to have an 'O' ring with 8 mounting bolts to secure it. Also the dome bush has an added shelf with 2 holes for mounting the regulator body which otherwise would just be held by the steam pipe.

The Blower stay is what I would call a live stay, it's not a permanent fixture as drawn, Paul has followed full-size practice with a removable 1/4" tube that will be furled and beaded in to seal, I'll cover this better when I get around to making the two connections for blower valve and ring later.

The upper steam area follows OZ code with doubler plates, butt straps, whichever you prefer, this means rather than being 3 mm thick on the tube plates as drawn, it's, in fact, 6 mm thickness of material and no longitudinal stays, which do little in a boiler of this length.

Last (i think) but not least is the fusible plug bush fitted into the firebox crown.

3 pictures of the model, The boiler is more or less in place, might need to drop a fraction and move back a tad but I won't play around with anything until the chassis is properly sitting horizontal, it's about 2 degrees out in the pictures.

close up of the backhead...

front three quarter view

Lastly, I tried to take a picture square on to show the side profile, this gives a good view of the barrel especially the underside showing the taper below the running boards in to the firebox and then the top profile, parallel at the front, up from the domw and then back down to the cab. I can't fit the running boards as I can't get the splashers over the wheels as it hasn't had its rear section removed yet  to clear the boiler. I also still need to trim a little along the inner edge around the firebox. ox.

Next job is to dress the boiler into the frames.