M-1941 Dated 1941 - With F/A Tube Fettle

Discussion in 'Military' started by idahostoveguy, Jun 18, 2014.

  1. idahostoveguy

    idahostoveguy R.I.P.

    Jun 15, 2009
    Here's an M-1941 Military single burner dated 1941, most likely built by AGM. The burner knob, pump, and check valve are indicators of this.

    The first pic shows the stove all done up and ready to fire, but it had to go through some changes to get to this point. The stove came without the F/A tube so I stole one off of a dead lantern I have. Being too long, I had to perform a little bit of surgery to make it work since the M-1941's F/A tube is a lot shorter, but performs the same function.


    Here are a couple of more profiles of the stove. Colors are a little off because the paint matches exactly to Olive Drab on my other 1944 version, which is in excellent condition.

    1403062693-M1941_016.jpg 1403062706-M1941_023.jpg

    The following pic shows how the fuel tank looked before and how the new (old) F/A tube is just a bit too long to torque the burner down on to the tank. Surgery follows. I was amazed that the F/A tubes can be salvaged from so many different years and from a different manufacturer and still work. I believe the F/A tube was from a Coleman 220 from the 70s.

    Also, as another point, I think the stove was having issues with the F/A tube anyway. There's a small dent in the center of the bottom of the tank where what looks like the original F/A tube was trying to poke the bottom. I've seen the condition on several of these old M-1941s and Coleman 530s. If you tighten the main valve down too tight and one or two too many turns the F/A tube will hit bottom and put a dent on the inside of the tank that shows. Not good. I've performed the following surgery on 3 or 4 of these for the exact same reason.


    I made a few measurements and marked the tube to where I would cut it. I had to cut it several times since my measurements were a bit off of what I should have cut it to the first time. I gave the F/A tube about 2mm off the bottom of the fuel tank. The measurement above is not accurate, it is there for illustrative purposes only. You'll have to make your own measurements.


    I attached a locking forcep to the end of the F/A tube. It's just soft soldered on and easy to remove with a little bit of heat. Don't put your forceps on too tight because as soon as the brass gets a little warm and you pull it off, the small cup will deform and get out-of-round.


    I took my small butane torch and applied heat to the end of the tube. I gently twist on the cup until the solder softens enough for the cup to come off.


    Here it is off of the end of the both tubes. There's an inner tube for the fuel and the outer tube is the air tube, which has a hole near the top of the that tube (not shown) for air to escape through when lighting the stove. This is the main concept for instant lighting on this stove, other like it, and lanterns of the Coleman variety. When the rod is down and plugging the hole, mostly air is forced through with little fuel. After lighting the rod recesses into the tube and more fuel runs up the tube rather than air.


    The following is the cutting sequence of the tube. I used a dremel to cut the tubes, which is a lot cleaner and easier to do the cut with. Using a hacksaw causes the tube to get bent while in the vice and the cut isn't as clean, which requires a lot more sanding to clean up. Click on the thumbnails to get a better look at the inner and outer tube. The inner is the fuel tube, the outer is the air inlet tube.

    1403062961-xM1941_009.jpg 1403062979-xM1941_010.jpg 1403062992-xM1941_011.jpg

    Here's the cup sweat soldered back on. You don't want to apply too much solder since it may fill the hole that is in the bottom of the cup. Just enough around the perimeter will do.


    Now I have to cut the rod off to the right length as well. I actually installed the F/A tube back onto the burner and turn the main valve all the way off so that the rod is extended to its maximum length. Once there I mark it, remove the rod, and then cut with dremel again for a nice clean right angle cut. I use a little bit of 600-grit paper to smooth it out perfectly, testing its functionality in the tube until it works through smoothly without any catches or snags.


    Here's another view of the tip in its finished state. The solder looks quite solid and air-tight. The solder must go all the way around otherwise you'll get leaks, which may cause less air to be taken in when instant lighting is begun.


    Now back to our regularly scheduled program. This is the stove all done up. I went ahead and sanded down the frame since it was quite ratty looking and had layers of rust and gunk on it. I used VHT silver and baked in the oven to turn the paint into ceramic. I also replaced all of the cotter pins that hold the stove grates. A couple of them had fallen off while cleaning. I actually had to cut those from larger pins to match the size of the originals.


    The fuel cap chain was gone so I found a suitable replacement made out of brass. I also used high-tension wire for the ends. Very difficult to make those bends in the wire. I also added the funnel just to dress it up. It is certainly not original to the stove. I had a spare one so I threw that on to make it a little more authentic.


    Here's the main knob, which is not Coleman, but actually seen on AGM stoves.


    Another look at the new cotter pin replacements. Should last a little while. They're made of stainless steel and very rigid.


    Here's the stamp on the side of the fuel tank:


    I'm pretty sure 'American' is short for American Gas Machines. This is not a fact, just supposition on my part. It is appropriate though.


    And, this stove is a 3-legger.



    More to follow...
    Last edited by a moderator: Jul 1, 2015
  2. idahostoveguy

    idahostoveguy R.I.P.

    Jun 15, 2009
    Well, let's see if the F/A tube works this time. It didn't the first time I put everything back together. I had to smooth down the rod in the F/A a few times until it would come up and out of the small cup on the end. I finally achieved lift off in the following pics.

    Here it is ready to go with Coleman Fuel in its belly. I forgot to spread the feet out for the photo op.


    I love how these are started. You can just turn the knob and fire it up. I know that I could have done the prime the burner thing, but I never do on these. They are supposed to be instant lighting so that is how I light them. I turn the knob a 1/4 turn and light. Lots of yellow fire at first.


    Here's another shot of the startup sequence. Some people don't like this at all, especially, with a full tank of gasoline. It just looks like it is ready to blow.


    Of course it doesn't blow. I have a fire extinguisher on standby but it is not needed. Blue fire ensues just after about 1 minute of fire column burning.


    This is the burner after about 5 minutes or so. It's turning a little purplish/violet/yellow but hangs on. I finally decided to put the feet out. Did that while it was burning. I don't recommend that. Started to singe arm hair while doing that. Don't try this at home.


    Here's the stove with the test kettle on. I've boiled water in this stainless steel kettle for years now. It's still holding together. You can see part of the flame wrapped around the bottom of the kettle.


    It took 11 minutes to boil a 1.5 liters of tap water, which was at around 43F to start with. The ambient temperature was around 60F with altitude at 4700 ft. My time is based on when the kettle is placed on the stove and until the kettle begins its highest whistle, which I've done for all of my boil times so they are quite consisted on that part of the boiling component. I usually use 1-liter but decided to fill'er up and go for it.


    Last edited by a moderator: Jun 26, 2015
  3. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Aug 25, 2009
    Lancashire, United Kingdom
    Great work Sam.

  4. shagratork

    shagratork United Kingdom Moderator, R.I.P. Subscriber

    Aug 9, 2005
    Durham, N.E. England
    Sam, it is a good gallery item and fettle all in one! :D

    I loved the good explanation of the Fuel Air tube functioning and your fettle to make one.

    Like you say, as far as I know the 'American' on the tank indicates it is an American Gas Machines stove.
  5. Murph

    Murph United States Subscriber

    May 14, 2010
    Milwaukee WI, USA
    Hopefully, you've got a steel fount, the brass founts from AGM had more bad cracks than Benny Hill!!! :lol:

  6. lant-ern

    Jul 21, 2007
    Nova Scotia
    The surgery went well and the patient looks like it has a lot of years left in it. :thumbup:

  7. idahostoveguy

    idahostoveguy R.I.P.

    Jun 15, 2009
    All, thanks for the nice comments!

    Murph, it is definitely a steel tank. So, I trust that it will not get any stress cracks but it may rust through! They're just made that way. I'll try to make this one last until I can give it to my youngest grandchild when they get old enough. If not, I've got a few brassies that will fill the void.

  8. loco7stove

    loco7stove Subscriber

    Sep 30, 2010
    Excellent work Sam, well done :clap: :clap: :clap: 8) :thumbup:

    Stu :D :thumbup:
  9. Rick b

    Nov 20, 2008
    Nice work Sam. Its burning really well.