How to tell difference between 250CP and 350CP jet needles?

Discussion in 'Fettling Forum' started by Lars Høyrup Jensen, Aug 7, 2019.

  1. Lars Høyrup Jensen Denmark

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    I recently bought some new jets and jet needles for my Primus model 1094 lantern. Originally the lantern was 300CP. Now I have bought both a 250CP jet and a 350CP jet. I also bought three 250CP jet needles and three 350CP jet needles.

    Is it possible to tell the difference between the 250CP and the 350CP jet needles? I am not able to distinguish between them. See attached photos.

    jet needles.jpg
     
    Last edited by a moderator: Aug 7, 2019
  2. george

    george United States Subscriber

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    For me, it is very hard to tell unless it is stamped on the needle. Someone here I am sure can help you with this and perhaps I can learn something, too.
     
  3. Mackburner

    Mackburner United Kingdom Founder Member Subscriber

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    Simple enough. Just measure the needle Dia with a vernier caliper and the smaller one will be the 250cp. ::Neil::
     
  4. AussiePete

    AussiePete Australia Subscriber

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  5. WimVe

    WimVe Subscriber

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    As neil wrote is the best way but I also seem to see that the ones in the picture are marked with two stripes.
    Do you also have some with three stripes ?
     
  6. Salar and Stove

    Salar and Stove Denmark Subscriber

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    250 = 0,16 mm
    350 = 0,19 mm
     
  7. Lars Høyrup Jensen Denmark

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    Hi everyone,

    The jet needles in the picture all have two stripes. But two of them af 250CP and three are 350CP (or vice versa). So the stripes don't seem to help me.

    I hadn't imagined that a caliper would be accurate enough for this task. But excellent that it can do the job. I will buy one. I suppose that a standard one like the one in the attached picture is sufficient.

    Thanks for the help!

    Anmærkning 2019-08-11 114317.jpg
     
    Last edited by a moderator: Aug 11, 2019
  8. AussiePete

    AussiePete Australia Subscriber

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    I think, for this measurement, that a micrometer would be better than vernier calliper.
    Cheers
    Pete
     
  9. cmb56

    cmb56 Sweden Subscriber

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    @Lars Høyrup Jensen
    I agree, a micrometer will be better.

    1D75F3C8-71D3-4B42-A08C-E7BEA727E2F4.jpeg

    A vernier caliper is good to own in any case but a good micrometer will give you a better reading on smaller dimensions.
    They are little more expensive but is well worth it.

    Personally I believe that the two stripes on the needles are only marks from the manufacturing process.

    Michael
     
    Last edited: Aug 11, 2019
  10. Lars Høyrup Jensen Denmark

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    Hmm, they are a bit expensive, those micrometers. Around 50 euro as far as I can see.

    I think I will go for the vernier caliper and hope that it does the trick. If not, it is good to have in any case, as Michael points out.

    What happens if you install a 250CP jet needle in a 350 CP jet?

    And vice versa (if possible)?

    BR
    Lars
     
  11. cmb56

    cmb56 Sweden Subscriber

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    @Lars Høyrup Jensen
    The 250 needle will go through the hole in the 350 nipple/jet and clean as much it can but not completely.
    The 350 needle will most probably bend or get stuck in the hole of the 250 nipple/jet.

    I write nipple/jet because in some parts of the world it is nipple and in some jet.
    Sometimes jet means only the hole.

    Have you tried manually to see which needle goes into the holes?

    All needles will go through the holes in the 350 nipple/jet but only the 250 needle will go through the 250 nipple/jet.

    Michael
     
    Last edited: Aug 11, 2019
  12. JonD

    JonD Subscriber

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    A modern digital caliper would be perfectly good enough for this. Pictured was an analogue one - properly a vernier which the digital ones are not. They are much cheaper than a micrometer.
     
  13. cmb56

    cmb56 Sweden Subscriber

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    @Lars Høyrup Jensen
    Biltema has one micrometer for 115SEK but I do not know where you have the closest store to where you live in Norway.

    It cost less than the vernier calipers that Biltema sell.
    Analogue - 149SEK
    Digital - 229SEK

    Precision of the micrometer: 0,01.
    Precision of the calipers:
    Analogue - 0,02.
    Digital - 0,03.

    Michael
     
  14. AussiePete

    AussiePete Australia Subscriber

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    There is the measuring error to consider when using a vernier calliper.
    The vernier calliper, on such a smaller diameter wire has the potential to be slightly at an angle, that is not measuring at 90deg to the wire being measured thereby measuring slightly more. The micrometer, because of the clamping between the spindle and it’s anvil, will be automatically measuring the true diameter of the wire.
    Just my experience speaking.
    Cheers
    Pete
     
  15. Lars Høyrup Jensen Denmark

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    I bought a vernier caliper. I was not able to measure any difference between the different needles. Then I tried putting the needles through the hole of the CP250 jet (good idea, Michael!). They all went through without problems.

    I am beginning to suspect that the needles are all the same size (and probably CP250).

    Not the biggest problem in the world. My lamp seems to work with the needles even though the jet I have installed is 350CP.
     
  16. WimVe

    WimVe Subscriber

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    All your needles are marked with two stripes .....
     

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