Britannia 5" to Norman Spinks design via Blackgates

[acctutor1946]

Hi everyone,

I have been building my Brit for about 15 years! and have now reached the ash pan and grate, not particularly fast, but hey ho.

My question, for starters, concerns the the ash pan.  The plans show three ports in the bottom of the ash pan, with a lever underneath to lift three panels for ventilation.  My thought is that it will not work, as the shaft simply rotates and the ports will not rise.

Any comments???

Bill

[ettingtonliam]

Are you sure those are not intended for dumping the ash at the end of a run, rather than ventilation? Draught is normally supplied by hinged plates at front, back or both ends of the ashpan. Holes in the bottom when running will dump ash and cinders on the track which might not make you too popular.

[dhamblin]

I agree with that - three doors at the bottom of the hopper with one between the frames and one on each side outside the frames. Damper doors should be positioned higher up at the top of the ashpan at front and rear.

Regards,

Dan

[Boadicea]

Sheet 14 shows both the grate actuator and the damper flaps and operator mechanism.

The 4 damper flaps (if they are dampers) are straightforward and are shown with a lever from the cab to operate.

The grate is shown as 3 sections across, with the middle section operated by an actuation rod from the side to allow the middle to drop.

As built to drawings you drop the middle section at the end of a session and the ash goes down into the bottom and poked out through the flaps.
This can be tedious but works.
Alternatively, you can just suck out all the ash with a powerful vacuum cleaner and blow out the ashpan with compressed air. I use this method on a loco inherited, but would improve if I had the time.
The width of the 3 grate sections allows you to (just) get each section out through the firehole door for replacement.
All this works but you are now at a stage where you can improve things for yourself, e.g. make the ashpan easily removable and just have the dampers if you think you need them.

There are other accounts here where people have improved on the grate arrangements greatly e.g. oldnorton and steve (springcrocus).
I think you should peruse these - it could be worth it later.

Edit ....
springcrocus tackles it here

[oldnorton]

Hello Bill

Welcome with your first posting.

There have been some good Britannia builds on here from Jim and then Steve and I added a few images of what I did. I have had a look to see if I could link to images of what I did to the ashpan, but I have not been successful at the moment. (If Boadicea found my images I am impressed!)

The Perrier linkage for opening those three doors is not the best, I changed it to a design of my own. Just ask if you want me to find something.

Those three doors need to be used for dumping ash at the end of a run, and the hot fire if you find a way of dropping that past the grate (another story). They are not there for providing air for combustion, but they will leak anyway.

You will need a whole series of holes drilled in the ashpan sides to provide ventilation for the fire. Perrier does not show any. You cannot over ventilate, the fire will draw what it wants. Some people talk about 'damping' the fire draw but I think that is a false wish with the type of driving and track use we experience.

Hurry up with the build 

Norm

[Jim]

Thanks Norm for the comments.

If you want to see my long rambling thread of building a Britannia to, in my case Jean Perrier's drawings, you'll find it here: modeleng.proboards.com/thread/6349/70036-boadicea

My personal philosophy is to keep the operating features such as the ash pan-grate assembly as simple as possible, so my fat fingers could do what in real life a shed worker could do from the ash pit. Plus should something go wrong, as it does from time to time, a fix can be achieved with out a major dismantling of the loco.

Norm makes some very valuable observations in his comments above that are well worth heeding.

Enjoy the build,
Jim

[Boadicea]

Nov 6, 2023 17:55:17 GMT oldnorton said:

(If Boadicea found my images I am impressed!)

Norm

As Bart Simpson would say - prepare to be dazzled!

Page 3, but a good discussion thread throughout

[oldnorton]

Thank you Boadicea! that link is to what was probably the best debate on what to do with a Britannia grate.

Yes you found two of my photos that I posted for Steve's help, but the one I was thinking of for the OP, Bill, I now realise was in ME magazine and not posted here.

Norm

[acctutor1946]

To everyone who answered my "stupid" query, many thanks, the replies have given m e a considerable start to finish off the grate.

Many thanks


Bill