bambuko loco works 0-6-2 (Fowler)

[bambuko]

Yes indeed ttg,
but CAD is cruel mistress as well - it doesn't tolerate "near enough"
What is taking all this time, is that I am not "modelling" in CAD, I am designing in "CAD",
so... if there was an existing design on paper, it would take no time to create the model (assuming that paper design "added up" in the first place - a lot of them don't )
Because I am designing "my own", often I end up, in some direction, only to find that something interferes or doesn't work for practical reasons,
so back one goes and things get re-arranged (only to find another problem... )
All great fun

[Hydrostatic Dazza]

Yes indeed ttg,
but CAD is cruel mistress as well - it doesn't tolerate "near enough"
What is taking all this time, is that I am not "modelling" in CAD, I am designing in "CAD",
so... if there was an existing design on paper, it would take no time to create the model (assuming that paper design "added up" in the first place - a lot of them don't )
Because I am designing "my own", often I end up, in some direction, only to find that something interferes or doesn't work for practical reasons,
so back one goes and things get re-arranged (only to find another problem... )
All great fun

Hear Hear

[bambuko]

At long last... bit of an update.
As mentioned before I wasn't all that happy with the first attempt.
My brazing was dodgy, frame ended up a bit wonky and having real thing in front of me (rather than CAD image) made me change some of my ideas.
So everything you've seen so far ended up in a scrap bin and I started again.
This time I have used SIFBRONZE No101 (instead of No1) - added managanese makes it flow better, especially in the kind of joints I am using.
I have also decided not to braze all frame stretchers, only brazing front and rear buffer beams (as per original LBSC advice).
This is the result:



All the stretchers are secured with bolts.
I have decided to move to metric - selection available from https://ghw-modellbau.de was just what I wanted.
I have used mostly 1.4mm 2mm hex bolts and some 1.6mm 2.5mm hex.
The only possible problem going forward is the exchange rate...



Next was the new smokebox design, to allow coal firing.
Here I am making bottom part of the somekobox, which will fit between the frames:


and here it is ready for fitting of the top/proper smokebox:



and viewed from the bottom:



it's all fabricated/brazed from sheet and than milled to size to fit tightly in between the frames.
Bottom will eventually be closed to make it into airtight box.

Smokebox proper is another fabrication from steel:



Front door and chimney to follow...
In the meantime, that's how the whole caboodle looks like:



TBC

[IanC]

Superb workmanship.

[Hydrostatic Dazza]

I have been pondering the fabrication of my smoke box, you have given me some leads and ideas.
I reckon I will use silver brazing (56% Harris, I use it daily in my work) for my fabrications.

[bambuko]

Smokebox assembly temporarily test fitted to the frame:



and from below, showing bottom closing plate fitted as well:



and with all the frame stretchers in place:



In this view, you can see the two temporary bolts/nuts securing smokebox to the frames (eventually they will be replaced by bolts securing cylinders).
Above them two (larger) holes for steam and exhaust piping:



Also the brass angle for securing/supporting cab floor.
The two CSK slot screws between front and middle axle will be (eventually) hidden behind motion bracket.

Another view from below:

[bambuko]

... I reckon I will use silver brazing (56% Harris, I use it daily in my work) for my fabrications.

Not an attempt to teach grandmother to suck eggs

The two reasons I am persisting with Sifbronze are:
cost - silver solder is so ***** expensive (so where I can get away without using silver solder I will not use it)
and because I can braze in two or three stages without the whole thing falling apart (I haven't used any screws to hold bits together before brazing).

[FWLR]

Nice bit of brazing there and some very nice machine work also.
Shame you had to throw the first attempt away. Did you salvage any of it. You put a lot of very good time and effort into it.....

[bambuko]

Nice bit of brazing there...

I would call it tolerable rather than nice
need to practice more

...Shame you had to throw the first attempt away. Did you salvage any of it. You put a lot of very good time and effort into it....

No didn't salvage anything.
Job worth doing is worth doing well, so no regrets

[dewintondave]

It's lovely to see so much steel being used

[FWLR]

Nice bit of brazing there...

I would call it tolerable rather than nice
need to practice more


Still it's better than mine...

...Shame you had to throw the first attempt away. Did you salvage any of it. You put a lot of very good time and effort into it....

No didn't salvage anything.
Job worth doing is worth doing well, so no regrets

Pity that, it's possible to remove brazing isn't. You could have used it for something. But you are correct though, you do a brilliant job at what ever you do.

[bambuko]

It's lovely to see so much steel being used

Indeed, that's one of my objectives in this project.

btw - how did you secure the rivets in the smokebox in your Wild Rose?
Brian Wilson's book is talking about using superglue for dummy/non-functional rivets but I am not convinced that it is good idea for coal fired smokebox?

[GTB]

Brian Wilson's book is talking about using superglue for dummy/non-functional rivets but I am not convinced that it is good idea for coal fired smokebox?

The simplest option is not to fit rivets, as a lot of late build Fowlers had flush riveted smokeboxes. My late '20s Fowler 0-4-2T was one of them, which saved me a lot of fiddly work. Possibly the smokeboxes were welded, but I'm not sure Fowler were that adventurous back then.

Anyway......

I wouldn't use superglue myself, but Brian points out the smokebox paint will hold them in the longer term, so a blob of smokebox paint applied to the rivet from inside the smokebox would probably work.

When I built my Baldwin it needed a row of rivets at each end of the smokebox. I pressed the ones at the front into the wrapper before I rolled it, as my rolls have a groove which would clear the rivets. The larger rear ones were added after rolling using individual brass rivets and I couldn't get a straight whack at the rivet to close it in the normal way.

The rivets weren't structural so I made up a simple L-shaped dolly that could be given a whack from outside the smokebox and have sufficient leverage to burr the rivet over enough to keep it in place. Don't have a photo of the work in progress, but hope that gives you the idea.

Regards,
Graeme

[dewintondave]

btw - how did you secure the rivets in the smokebox in your Wild Rose?

I used slotted 8BA brass round head screws.

[bambuko]

Thank you for your suggestions.
I will have to make few tests and ponder my options...
btw there are also brass threaded roundhead screws with no slots

[bambuko]

...The simplest option is not to fit rivets, as a lot of late build Fowlers had flush riveted smokeboxes. My late '20s Fowler 0-4-2T was one of them, which saved me a lot of fiddly work. Possibly the smokeboxes were welded, but I'm not sure Fowler were that adventurous back then...

Spot on Graeme
Thank you for this suggestion.
Did a bit more homework and indeed the prototype for my model doesn't have any rivets, instead front face of smokebox appears to be bolted to the round body.
Here a photo of sad remains in a museum in Australia link:



Couple of things that might interest some of you

It appears to be one the last few steam locomotives to be built by Fowler in UK (in 1935).
It was this design that formed the basis of Bundaberg locos build In Australia around 15 years later.

It was (unusually) equipped with draw gear permitting operation on both 2ft and 3ft 6inch gauge.
This was acomplished by laying a third rail adjacent to the 2ft track to 3ft 6inch gauge.
Centre buffer and draw gear is symmetrical with 2ft gauge track, but the three link coupling and hook and steel face buffing blocks are assymetrical,
to accomodate 3ft 6inch rolling stock.

[tom_tom_go]

Poor thing, those tanks don't look like they will hold water anymore!

I like the look of it though, would be good to get hold of a plastic looking model and weather appropriately to have the loco stored in a yard.

[bambuko]

I can see the attraction ttg

For balance - there is works photo of the same loco (Airdmillan) here

Michael R. Lane Collection (from negatives in the Museum of English Rural Life)

[bambuko]

Bit more progress to report
Started on the cab floor:


Brass angle is soldered and riveted to the floor and the whole thing is then "bolted" to loco frame:



and, viewed from below:



I tried riveting alone but wasn't happy with result, so ended up using rivets to locate the brass angle and soldered the whole thing together.
Started by using silver solder, but the heat needed was distoring the floor and any excess solder (difficult to avoid... at least with my skills) was diificult to clean up neatly.
Ended up using high temp soft solder (known as Comsol or 5/S alloy according to BS) - lovely to work with and easy to clean.
It needed pre-tinning particularly on steel but that was easy with Baker's fluid as flux and home made silicone brush.

[tom_tom_go]

Lovely work, I find soft soldering so much easier!