Scattergun 3.5” King Arthur ‘Sir Sagramore’

[Tim Watson]

Inside every lump of metal there is a shape trying to come out - actually two in this case.

The cab roof handles would probably have helped positioning when the rear was removed for maintenance purposes ( on the prototype).

The metal strip was bent to shape, drilled 0.8mm x 4 and then sliced into two handles. These were tapped 14BA and held in place with bolts whilst soldering.

That’s the roof done.

Tim

 

[Tim Watson]

Maunsell cabs did have a slightly ‘hang dog’ look to the front spectacle plate. This wasn’t quite correct on Sir Percivale, with the windows being parallel-sided.
I therefore used a piercing saw to make space to enlarge the window a bit.


The window frame was then swaged into the correct shape.

The end result is subtly different and probably worth the effort.

There are a whole load of rivets / bolts needed in this area.

Just need to find where I put that tobacco tin…

Tim

 

[michael mott]

ust need to find where I put that tobacco tin…

My Mum used to say that but she was looking for the "golden virginia" inside not rivets.

 

[Tim Watson]

I found the tin, which was Golden Virginia, but they were smaller than I remembered them; so rivet bolts on order.

Tim

 

[Tim Watson]

Today was the day of the rivet / bolt for Sir Percivale. On the prototype, the top of the cab was designed to be removable for improved access during heavy shoppings. Most of the bolts representing the fixings are round headed 10BA, permanently fixed and dummy, but some are slotted to allow dismantling the cab.

It will make lining out a bit more challenging but shouldn’t be too bad, considering the fairly large scale.

Tim

 

[Tim Watson]

I have re-united the cab with the rest of the loco, returning to the rather cooler big workshop to do so. It still fits!




Tim

 

[mickoo]

I have re-united the cab with the rest of the loco, returning to the rather cooler big workshop to do so. It still fits!




Tim

Impressive

 

[Tom Insole]

Oooof! This just gets better and better every time I see updates!
Keep ‘em coming..
It’s looking fantastic

Tom

 

[Tim Watson]

Sir Percivale is no more, he’s changing name to Sir Sagramore. The only surviving engine of the class, Sir Lamiel, is undergoing a major restoration.

777 Sir Lamiel Progress Report - Sir Lamiel

We’ve made good progress on Sir Lamiel’s overhaul. Our target is to return Sir Lamiel to working order in time to celebrate its 100th birthday in 2025.

www.sirlamiel.org.uk

I therefore thought it a very good cause to help a little, so I’ve joined the funding round table. This has meant that the engine has changed name, Sir Sagramore being an available name that I could use and an engine that was photographed many times when new.




The engine is looking quite racy with the full cab. In true Stalinesque form, I have airbrushed out the old name In previous posts…

Tim

 

[oldravendale]

I'm following this with some considerable pleasure, Tim, as it's a favourite class and also as an original member of the enthusiasts who created the GCR (membership No 5). Here's Sir Sagramore right at end of life, outside Eastleigh Works, on 5th April 1961.



Brian

 

[Tim Watson]

Thanks Brian. There will now be a shortish interlude back to CF to get some lift shafts modelled for York Road tube.

Tim

 

[Tim Watson]

After a bit of a diversion to other bigger and smaller projects, I have returned to the NBL works.
Sir Sagramore has a hydrostatic lubricator, which needed a 180 deg (in line) globe valve to isolate the steam feed when required. Commercial examples are rather crude. Ian Jaycroft had made the top half of a valve but I couldn’t find the globe itself in any of the bits bags.

The bottom half was turned up in the lathe with a small hole for the valve seat and a larger tapped hole for the valve spindle body.


This was set up in the drill, having filed two flats on the sides of the valve body. The angled holes were drilled by eye.


The gods were being benevolent as both holes ended up in the correct place.


Two pipes, threaded 3/32” 60ME, with a flared base were made. The openings to the valve chamber were also increased in size with a dental bur. These were then blocked off with Tippex and the assembly clamped together.


Two large endodontic files were used to open out the feed and delivery channels, visible above and below one another.


The sub assemblies can now be seen. After silver soldering the shape of the valve was established using burs, stones and abrasive rubbers.


The delivery hole can be seen at the top of the pipe.


There may be ‘proper’ ways of making globe valves, but this one passes the ‘puff’ test.


Tim

 

[Tim Watson]

It’s quite difficult to work out how someone else intended to make an incomplete model. The livesteam manifold on Sir Sagramore clearly needed two plugs at each end but it was only fairly thin copper pipe that they could fix into. Using silver solder at this late stage would have been much too risky for the assembly.

Consensus at the NLSME was that if a high temp soft solder was to be used then a screw thread would be advisable to give auxiliary retention to hold the plug.



The pipe just about took a 7/32” 40 TPI ME thread, but a plug made to that size was much too loose (A 1/4” 40 ME tap would have been much too big for the wall thickness). The solution was to make a 1/4” 40 ME plug with the die tightened up and wind it in with force using a large pin chuck. This swaged the copper pipe, increasing its size for the plug which was then soft soldered in place with Comsol.



The expanded pipe size is just discernible on the RHS



Bit naughty really, but there is no way those plugs are coming out any time soon.

Tim

 

[Tim Watson]

The original injector steam feed pipes had an un-prototypicalr swan neck exit from the boiler valve.

I therefore made a right angle fitting to neaten up the plumbing.

Original valve at the top. The right angle extension was threaded 3/16” 60 TPI ME at each end. A 90 degree chunk of metal was removed with a diamond slitting disc. It was bent to shape with frequent annealing and then silver soldered.

Still not strictly correct, but Ian’s original valves are a work of art which I wanted to keep.


Apologies for the bombardment of posts, but I thought it might be a good way of catching up on this project.

Tim

 

[michael mott]

Nice work Tim, those small fitting can be a bit of a challenge.

Michael

 

[garethashenden]

What are ME threads? Its not a standard I'm familiar with.

 

[michael mott]

A set of threads developed for Model engineering, mostly 40TPI

Michael

 

[Tim Watson]

What are ME threads? Its not a standard I'm familiar with.

Sorry Gareth, my bad form, should have specified the full name ‘Model Engineer’ before using the abbreviation. Sixty TPI is a very fine thread that Ian Jaycroft used quite frequently: I just managed to locate some taps & dies for a couple of sizes.

Tim

 

[Tim Watson]

The injectors on Sir Sagramore were originally partially made by Ian Jaycroft. Unfortunately, both were incomplete and a challenge to finish.
On the RHS I have therefore fitted a ’Chiverton’ 16oz injector from Paul Pavier. The water feed pipe to the boiler clack had a right angle fitting made, a requirement of having limited space. The internal passage is polished to aid water flow.
The injector has fairly large fixings so it is placed low down (as per prototype) and has a simplified water supply. The bottom water feed pipe again has a bespoke 90degree fitting to keep the plumbing neat.
The moth-eaten steam supply pipe at the top is just a placeholder: I’m awaiting some more 1/8” pipe to reinstate this.
There will be a discrete accessible water control valve fitted in the tender giving a well streamlined water flow.
Ian’s original set up with the incomplete miniature injector had plumbing that was a bit of a snakes wedding, with generally rather small bore pipes for the water feed. The handle for the water control valve was very small and quite inaccessible within the cab. I may, however, try Ian’s arrangement (duplicated) on the LHS, where access to the water valve is better, as the engine only needs one reliable working injector, there also being hand and axle driven pumps to get water in the boiler. Reverse engineering the injector could be very challenging, but probably worth a go.

Apologies if this is all a bit off-topic for railway modelling!

Tim

 

[michael mott]

Hi Tim do you have D.A.G. Brown's book Miniature injectors inside and out? It really is a great treatise on model injectors.

Michael