Black 5 loco boiler tubes

[colm57]

I am working from a drawing of the black 5 which is over 40 yrs old. On the drawing it states there are 18off 3/8”dia. and 4off 11/16” dia boiler tubes totalling 22 in number. The front view of the boiler shows 5 rows of said tubes, however, the section through the boiler barrel shows only 4 rows so there is a row missing. If it is correct that there are 5 rows of 22 tubes this would mean that the firebox would need to move upwards in Z direction reducing the height of the crown stays but for me the expensive problem is the firebox height would need to be increased to accommodate the move in Z.Any assistance would be gratefully received.

[uuu]

What gauge are you working in? If it's 5", there are some excellent pictures of a Black 5 under construction in this thread, pages 29 and 31.

Wilf

[coniston]

Jun 6, 2021 13:32:23 GMT colm57 said:

I am working from a drawing of the black 5 which is over 40 yrs old. On the drawing it states there are 18off 3/8”dia. and 4off 11/16” dia boiler tubes totalling 22 in number. The front view of the boiler shows 5 rows of said tubes, however, the section through the boiler barrel shows only 4 rows so there is a row missing. If it is correct that there are 5 rows of 22 tubes this would mean that the firebox would need to move upwards in Z direction reducing the height of the crown stays but for me the expensive problem is the firebox height would need to be increased to accommodate the move in Z.Any assistance would be gratefully received.

I assume this is the boiler for LBSC's Doris in 3 1/2" gauge. I have the drawing in front of me which states the exact tube layout you mention. I believe it is an error in the longitudinal section view, the lateral section through the firebox shows the correct tube layout which fits the as drawn firebox. Just ignore the number of tubes shown in the longitudinal section.

If you want any more confirmation I have a new boiler made by GB boilers in the workshop which I can check and photograph for you but not until later tomorrow at the earliest.

Chris D

[colm57]

Thanks Chris. A photo at your earliest convenience would be fantastic. Thanks for your help,much appreciated

[coniston]

Jun 7, 2021 12:51:01 GMT colm57 said:

Thanks Chris. A photo at your earliest convenience would be fantastic. Thanks for your help,much appreciated

Here are some photos of the boiler for Doris I have. 

This is the firebox tube plate showing the 4 rows of fire tubes and 1 row of super heater flues.




And here's the smokebox tube plate



This is the depth of the inside of the fire box at the tube plate end (front). The drawing shows a dimension 5 7/16" so this is pretty close.



Sorry for the poor drawing picture but the dimension is there.



Anyway I hope this helps and I am sure the drawing longitudinal section is incorrect and you can proceed with 4 rows as shown on both tube plates.

Chris

[colm57]

Thanks for the photos. That has confirmed I have the correct hole pattern. It also confirms my worst outcome.In order to align the tubes between the firebox through the boiler barrel into the end plate, I need to move the firebox up in Z direction. This means making the crown stays smaller in height and adding the distance the firebox moves in Z to the height of the firebox so it protrudes below the outer wrapper as to drawing. What surprises me is the l would have thought that there would be a mention of it on the forum because other builders of this model would have come across this problem. Anyway, thank you for your input.
Regards
Malc

[coniston]

Jun 10, 2021 10:16:33 GMT colm57 said:

Thanks for the photos. That has confirmed I have the correct hole pattern. It also confirms my worst outcome.In order to align the tubes between the firebox through the boiler barrel into the end plate, I need to move the firebox up in Z direction. This means making the crown stays smaller in height and adding the distance the firebox moves in Z to the height of the firebox so it protrudes below the outer wrapper as to drawing. What surprises me is the l would have thought that there would be a mention of it on the forum because other builders of this model would have come across this problem. Anyway, thank you for your input.
Regards
Malc

Hello Malc, I really do not see any need to move the firebox crown up. The section at the right of the drawing shows the correct layout and the top of the firebox as drawn lines up in the longitudinal section. The only problem is the longitudinal section is drawn incorrectly only showing three rows of tubes. If you draw a line from the centre of each row shown in the RH section across to the longitudinal section you will see the draughtsman's error. I am sure from the drawing that you can go ahead and make the firebox to drawing and it will all fit. Although typically with LBSC drawings there are not really enough dimensions to actually make the firebox tube plate . No location for the four super heater flues are shown, the only indication is the longitudinal section showing them placed touching the top flange

Chris

[colm57]

Hi Chris, your absolutely spot on correct. I think I was looking at it from a sense of panic. I had presumed that as there were was a line of holes missing @ 7/16” CTS in order to get the correct pattern in, I had to move the firebox up in Z. I interrogated the drawing and realised that the longitudinal section drawing the tube centres were incorrect. So all is good now. Thanks for the support.
Regards
Malc