British Military No.12 burner woes

The stove was cheap because of a missing pot rest, missing tank cap (Vapalux M320 lantern type is identical) and because of this ...





A work in progress, but I'll need to fabricate a new flame plate, fettle that 8mm fractured copper pipe and fix (or replace) the valve spindle, which is missing a tooth.

Initial thoughts. I'm uneasy about taking a brazing torch to the copper pipe, because I reckon that getting the silbraze to flow won't be far off the point at which the copper melts - well, maybe 250 degrees Celcius separates the two. I'm more inclined to install an 8mm compression fitting.

To be continued ...

John

 

Hi John, that copper pipe has been so abused that I think it should be scrapped rather than re-using any part of it. A new length of piping and a careful hand when brazing should do the trick.
Best Regards,
George.

 

Hi George. Sound reasoning from a metallurgist isn't something I'd take lightly! You're right of course. The stub of pipe can be drilled out of the burner base and the nipple on the tank end can surely be re-used.

I'm thinking of making the spreader plate out of a stainless steel kitchen ladle, though I'll no doubt get through a lot of Dremel grindstones in the process.

John

 

Hi John, the flame plate of the No.12 is the most complicated I have ever seen.
Have you thought of getting in contact with TOC for a spare part? There was someone who posted on CCS who said that he was a near neighbour to the factory and had spoken to them before.

Best Regards,
George.

 

I recall that post you're referring to, George, but not well enough to track it down (so far).

You'll remember that initially, when No.12's first came on the civilian market (via ebay, since I've never seen them from retail sources), the talk on CCS was that the manufacturer, TOC, was not best pleased about their falling in civilian hands [why? it's not a Stealth bomber when all's said and done!!!] and wouldn't supply spares.

Maybe we got that wrong or perhaps they've changed their stance on things, but I might just explore that possibility.

John

 

I talked to TOC years back & they were very cagey. Maybe a source close to Catterick Garrison explains there early appearance in the wild up in the North East.

 

Hi John, please see comments by K180:

https://classiccampstoves.com/threads/16802

Best Regards,
George.

 

Hi John, here is a link to the thread which discussed the features and operation of the complex flame-plate of the No.12 stove:


https://classiccampstoves.com/threads/14231

I believe it could be very difficult to produce the rectangular slots and associated tags of the flameplate, without special tooling and a heavy press.

See also the reference to Mike's No.12 burner which appears to be fitted with the plain flame-plate from British Army No.2 stove burner.

Best Regards,
George.

 

About the only way I can think of doing it as follows:

The starting assumption is that the small holes that produce the flamelets are rectangular because they are stamped out and as part of that process produce the tabs on the outer edge of the holes. I'm assuming here the actual shape doesn't matter and that the hole shape is determined by the manufacturing process rather than necessitated by design.

Assuming the above is correct (leap of faith required), then here's a method to recreate. Drill round holes in the same positions and of around the same area (meaning the same amount of retangular vs circle area). Underneath on the outer edge of the circle of holes weld (I don't believe brazing will be up to the job) a small ring of the height of the tabs on an original burner. Carefully file out the space on the ring between the holes and you should end up with something closely approximating the original ring.

Bit of a phaff I know, but is hopefully a workable solution.

Cheers, Graham.

 

Really useful stuff there, thank you George, Graham and Ross. I've read and even contributed a bit to one of those posts and still managed not do an adequate search!

Thanks too to the input from Gary (Bernie Dawg) for the insights he provided into the burner in his post and specific to my project for his offer of a new valve spindle!

I'd best get to work on an update ...

John

 

Hi
I may be wrong but isn't the spindle, needle and nipple the same as a 111.

 

Yeah, that's right. The jet and jet needle are ok, and the spindle from US Gary is for a 111.

John

 

It did cross my mind that the plate off a Karrimor Gosystem or Chinse Booster would mod. I'll have a look after.

 

Well, I struck a compromise. I scrapped the majority of the pipe, retaining the stub brazed into the burner base. Then putting a 90-degree angle (using a pipe spring tool) in a new length of 8mm copper pipe and utilising an 8mm 90-degree compression fitting, I arrived at this



I borrowed a replacement spindle from an Optimus 111 and installed it in the No.12's burner, then pressurised the tank and ensured there were no leaks. I've not yet made up a burner plate, but wanted to see flames!

Though not a permanent solution, a silent burner inner and outer cap could be perched on the burner ...





Primed and lit, a reasonably controllable flame resulted



A brass disc cut from the base of a mangled Primus No.5 tank, so slightly dished, will become the burner plate ... once I've decided how!



John

 

Impressive bit of fettling John, looks good and proffesional too! Does it still fit in the case in the proper position for the pot supports?

 

Nice work John, the 111T would have been a better option for the army I would have thought considering the bloody noise a 12 makes...no good for the SAS lol.

If you ever make a 111T conversion kit please put me down for one.

 

Very nice work John!!!

A fine British stove it is again.

Jeff

 

Worked on the burner plate. Took my brass disc and a marker pen ...



... and a pair of tin snips and a 3.5mm drill, getting a lot of offcuts in the process ...



... to arrive at this





Worked pretty well on full power



... and simmer too



Bit flimsy though, so with that reasonably successful prototype done I'll be using thicker brass sheet for the final version, or perhaps stainless steel.

John

 

Sorry, didn't reply earlier, Big BTU. Yes, the burner sits no higher in the case than it does with the original fuel pipe, and it was easy to ensure that the length of the new pipe placed the valve spindle in alignment with the hole in the case to take the control rod.

John

 

Hi John,

Looking good......

Cheers, Graham.