BR Standard class 6 No. 72010 'Hengist' and Clan Discussion Thread

I must hasten to mention that, to my knowledge, I had no part in this at all!
But it must be great news, congratulations to those who gave the invitation.
You must have really made his visit a very good experience for all his party.

 

Latest News shows the modified rear cylinder covers all machined up. I hope they don't find any mistakes on them, it looks a lot of work and effort, not to mention the cost!

 

We are reasonably confident as Pattinsons took quite a bit of care on them. Next week we will get them onto the surface table to check key dimensions

 

Surface table... don't you mean surface plate (calibrated) ? ...not being critical btw.

 

It perhaps rather depends on the size of it? In my day a surface plate was portable, a surface table needed a 25ton o/h crane to shift it!

 

This one was moved with the overhead crane. It was far too heavy for 2 of us to lift

 

Have I~ missed something here, and the cylinders have already been cast and machined? If they haven't, making the covers first seems (to, admittedly, a non-engineer) and back to front way of doing things!

 

No you haven't missed anything and yes the covers have been made before the cylinders.

Front covers

A long, long time ago (before my time) the project obtained a couple of front cylinder cover castings with no paperwork. Recently we tested these and found a crack in one of the castings. This has had to be scrapped. The other cover is OK and can be machined. We have borrowed the pattern for the cylinder cover and are currently seeking quotations for casting a cover to replace the scrapped cover.

Hind Covers

At last years Open Day, we had a couple of visitors from the Ironmongers' Company who were very interested in our project. They offered to provide a grant for us to manufacture a cast iron component. We decided to use that grant to manufacture the hind covers. It would be an interesting project as we modified the design to provide the support to the front of the slidebars. The grant covered the casting of the covers and part of the cost of machining.

The project aims to collect parts so that when the cylinders have been cast and machined, we can start assembly without waiting for parts.

Hope that helps!

Ian

 

Ian
I assume from this that on the Clans originally (like the Brits) the slide bars were solely supported with the bracket on the frames?
Is is a known issue that you're trying to eliminate or was it considered a better way to do it?

 

Bryan

Yes you are correct. This was a known weakness. If you go to this news page

https://www.theclanproject.org/build/Clan_BuildDiaryMonth.php?buildyear=2024&buildmonth=12

Bottom photo

and here

https://www.theclanproject.org/build/Clan_BuildDiaryMonth.php?buildyear=2025&buildmonth=09

Technical details can be found here

https://www.theclanproject.org/design/Clan_Design_Clip.php

Section 7

This type of hind cover was fitted to the Caprotti Class 5 and our design is similar

 

Ian
Thank you very much for the reply, very interested in the CLIP report and the points it raises.

 

Today saw the 2025 AGM held on site in the fab shop at CTL Seal in Ecclesfield nr Sheffield. All very positive and great to see the progress made over the last year (I missed the open day in April).
The near complete bogie looks fantastic and progress continues on the frames.
The likely next big purchase will be the coupled wheel axles, bearings and canon boxes, plus boiler design.
Not bad for a membership of c. 270!
Why not join us and help to speed up progress even further?
https://www.theclanproject.org/Clan_JoinUs.php

 

Orders have now been placed for the axles, tyres and roller bearings. We should get the bearings around Xmas but they will need to stay in their preservative wrappings until we are ready to use them. We also have a request for quote out for crank pin material, this is the same grade of steel as axles. The CAD model for the cannon axle boxes is close to completion. Our Timken drawing specifies a longer sump than the cannon boxes fitted to 70013.

We have started, hopefully, the final strip of the bogie. John has spent the last few weeks measuring the clearances between the cannon axleboxes and the axlebox guides. This will give him the data to determine the machining required on the liners.

Work has been progressing on the bogie side control springs. We want to be certain on what material we should specify so we have used CTL Seal's hardness tester to measure the side control springs on 70013 at Loughborough and 70000/71000 at Crewe. This has provided another set of data so that we can specify the correct grade of steel.

 

Along with all the major items which are progressing it is good to see that even the smaller items get their full attention and documentation on this project.
Check out the latest news page. https://www.theclanproject.org/Clan_News.php
These lads are really learning about how to build a new steam locomotive!
The apprentices at CTL Seal have a wonderful opportunity to see a major engineering project being built, and to help with it.

 

One thing I love about the Clan Project is the way that joy of making bits large and small comes accross. Whether it's a driving wheel or a drivers sandwich holder plate, it's all made with care and attention.

Must be great for the apprentices as there are so many bits (and corresponding techniques to master)

 

Have they changed their minds about the inner firebox material? The last time I looked it was to be steel but now it seems less certain.

https://www.theclanproject.org/build/Clan_Build.php

 

In this update they repeat the old saying that: "There is an issue with steel fireboxes in that steel has only 30% of the heat conductivity of copper."
There is absolutely no such issue! The plates are so thin that the temperature drop across the plates is less than 2 °C, irrespectively of what material you chose. While the difference between fire and water is around 1000 °C.
The issue regarding heat transfer is solely that scaling adheres firmly to steel (like rebar to concrete) while it is more easily washed out from a copper firebox. Thus if water treatment can be used (as it should), steel is much better.

 

Most german Baureihe 50/52 (More than 11000 boilers) had steel fireboxes of nearly same dimensions as the proposed Clan thing.

 

Definitely a steel inner firebox with comprehensive water treatment

Ian

 

Having read this post, it occurs to me that copper clad steel is widely used for electrical earthing conductors, mainly to deter metal theft as it has negligible scrap value. Apparantly, you can't electroplate copper directly onto steel, so a thin layer of nickel is electroplated onto the steel, then copper is electroplated onto the nickel. As a leftfield thought, could this be done for fireboxes, which ought to help with the scaling problem?