Electrocuted Ditmar Maximette 581

Discussion in 'Fettling Forum' started by Martin K., May 12, 2016.

  1. Martin K.

    Martin K. Subscriber

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    No! What you removed is not the graphite packing, which is now still in place. It is only a piece of metal which is pressed on the packing by screwing in the nut. The packing actually is hardened and prevents the excenter shaft from being pulled out.
    As Nicola said, remove the Aluminium seal for the vaporizer, the needle rod, the handwheel and then try to pull out the excenter shaft gently. A little heat applied to the threaded piece will probably help. Behind the packing there is still a small metal disc which serves as a stopper for the packing. All is accessible from the excenter shaft side.
     
  2. Henry Plews

    Henry Plews Subscriber

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    Here are two images of the valve from a Ditmar 506, the valve is the same as on your lantern.

    Valve stem 01.JPG Valve stem 02.JPG

    You can see the graphite packing between the two brass pieces.
    I did not remove the valve wheel because it was very tight and I did not want to break it.

    Henry.
     
  3. Martin K.

    Martin K. Subscriber

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    @Henry Plews ,
    these are good photos to show what I meant to explain. You were lucky to be able to remove it all. The inner brass piece sometimes could be only a small flat washer.
    Your example is from the later era (post war). The flat hex nut on the shaft must be loosened first towards the packing in order to release a driving plate whose teeth grip into the Bakelite wheel. After that the Bakelite wheel can be unscrewed from the shaft. Then the driving plate can be removed, and finally the inner hex nut can be unscrewed in order to release the box nut and packing from the stem.
     
    Last edited: Mar 15, 2018
  4. Henry Plews

    Henry Plews Subscriber

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    @Martin K.

    Thank you Martin. I already have the lantern in pieces for fettling and, lucky for me, it wasn't difficult to remove.
    I had undone the small hex nut behind the wheel but I must not have pulled the driving plate back far enough.
    Thanks also for confirming that my example is post war. Apart from the Bakelite wheel, are there any other significant differences? I have soldered a split in the base plate and lined the tank with POR15 tank sealer. I'm just waiting for the sealer to cure before I re-build the lantern.

    Henry.
     
  5. WimVe

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    Before doing what should be done REMOVE the fibre hand wheel !
    If that breaks, there is no replacement.
     
  6. Kit

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    I get the 581 last week. However the tank is leaked and the needle is broken. I have to solder it first.


    IMG_9138.jpg

    IMG_9155.jpg

    IMG_9156.jpg
     
  7. Kit

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    I have soldered the tank, but the nrv seams to have some problem.

    I test the pressure of the tank with water. The water will leak from the pump after pumping. What should I do? Thank you!

    6091133A-9C1F-4053-85AE-91F97469591B.jpeg
     
  8. Martin K.

    Martin K. Subscriber

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    Hello @Kit ,
    have you replaced the rubber seal in the pip? Best to use Viton because that's soft enough and will withstand petrol.
    And is the seal set evenly inside the pip?
    And can the pip move freely inside the sleeve?
    And is the rim of the valve without any damage / scratches?
    And have you used a new lead washer? When mounting add a bit of grease/oil which will allow better screwing.
    If all that is OK then it should work properly. If not, then there could be a more serious problem: The bottom or wall of the pump tube could be cracked. You can try to find that out by pressurizing the empty tank and pouring some paraffin (or water) into the pump tube. The bubbles will show where the leak is.
    6091133A-9C1F-4053-85AE-91F97469591C.jpeg
     
    Last edited: Mar 18, 2018
  9. Kit

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    Thanks Martin.

    I have not remove the rubber seal in the pip because I have no parts.

    The pip move freely. The rim is no damage.

    I have no new lead washer. So I try a DIY rubber oring just now and the situation is much better. But it still leak very very little water. I worry it is dangerous if it is gasoline or kerosine.

    it is scary for me if the bottom or wall of the pump tube may be cracked. I hardly solder it. I will try it torromow.

    Thanks very much.
     
  10. Tony Press

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    @Kit

    Try taking the rubber pip put and turning it around so that the other end is making the seal.

    Cheers

    Tony
     
  11. Kit

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    I have repaired it. It works now. Thanks all

    B430FE25-6837-43D4-A590-AE16F9167CB8.jpeg
     
  12. Martin K.

    Martin K. Subscriber

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    ...good job! :clap:
    And it looks really nice with the brass finish.
     
  13. Tony Press

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    Good work, @Kit.

    Cheers

    Tony
     
  14. Kit

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    I get the 593 yesterday. It dont have the needle and the ceramic burner.

    I insert the 581 needle in the 593. The gasoline is flowed from the jet even I close the valve.

    I find the jet hole of my 593 is much larger than my 581 so the 581 needle cannot stop the gasoline flowing.

    Is the needle of 581(kerosene) actually the same as 593(gasline)?

    thank you

    IMG_9811.jpg
     
  15. Martin K.

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    The petrol (gasoline) lamps could possibly use larger jet diameter than those running on paraffin (kerosene). However, I never tried to measure and compare them. The needle in general is not meant to act as a valve, so it will not stop the fuel flow. The petrol lamps have a positive fuel shutoff valve operated with the handwheel.
    If the jet is worn you will notice it by a rich mixture (halo around the mantle) when operating.
     
  16. Kit

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    The gasoline is still flowed even I turn off the handwheel.

    Your Ditmar gasoline lamp can shut the valve off?
     
  17. Martin K.

    Martin K. Subscriber

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    Yes, the handwheel has not an excenter, but uses a threaded spindle which acts as a shutoff valve. The valve spindle has also a cam and the needle rod is pushed down towards it by a small spring which sits below the aluminium gasket.
     
  18. MYN

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    Good fettle and sounds exciting, especially with the fabrication works of a new vaporizer on Martin's lantern.

    Kit, the valve could not shut off the fuel possibly due to the above needle rod-cam assembly's preventing the pointed end of the valve stem from reaching its seat/full-shut position.
    You have to dis-assemble the above to fix that. Do not attempt to force turn the valve or it might create an unwanted indentation at the wrong part.
    A cross-sectional drawing or illustration of your Ditmar would be helpful if you could find it.
     
  19. Martin K.

    Martin K. Subscriber

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    maybe you get an idea how it works when you look at this page. Look for the parts #732, 733, 734, 745, 753, 711.
     
  20. vonat35

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    Hi Martin!
    You did a very fine job with this lamp wreck!!
    I recently purchased this little lamp, with the missing inner upper part: hood, j-pipe, burner, etc.
    Does these parts from HK150 fit for the Maximette, or you had to make a lot of changes?
    Thank you for your answer!
    Best regards:
    Georg
     

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  21. Martin K.

    Martin K. Subscriber

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    Hi Georg,
    usually the mixing tube does not fit under the hood and must therefore be shortened. If you are lucky you will find a hood with a mixing tube where the threads are cut long enough, but mostly they aren't. In this case you will need a M11x1 die to cut the threads longer. Take care that the burner is sitting high enough. The upper brim of the ceramic burner should be located ca. 10mm below the underside of the preston loop.
    Besides from that there are no changes necessary.
    Regards, Martin
     

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