Measuring Jet/Nipple Orifice size.

Discussion in 'Fettling Forum' started by Jones the lamp, Apr 27, 2019.

  1. Jones the lamp

    Jones the lamp Subscriber

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    A post from Alby regarding problems with a Korean manufactured generator prompted me to post this.
    It would appear that the orifice of the generator nipple could be oversize.
    If you are into fettling I think being able to measure the size of nipple orifices accurately is essential. Broach Set.jpg
    Broach Set.

    With the aid of a micrometer or a digital callipers and a set of watchmakers broaches, NOT brooches, it is easy to measure the size of an orifice to within 0.01mm.
    Broaches come in various sizes and they are used for resizing plates in watches and clocks.
    One set I have consists of 6 broaches for resizing holes from 0.15mm to 1.5mm diameter.
    The broach is inserted into the orifice and the diameter can then be measured. Note the broaches are not round but slightly oval. They also have a 1:100 taper. It is the combination of oval shape and taper that allows for the resizing of holes,
    Small Orifice.jpg
    Broach in small orifice
    Small Broach.jpg

    Micrometer showing 0.19mm orifice

    Large Orifice.jpg Broach in small orifice.

    Large Broach.jpg
    Enlarged 0.29mm orifice.
    If you are interested in the broaches a search of the web will return numerous hits. Go for the smallest available. Cousins UK have a variety to choose varying in price from ₤23.50 for a set from 0.05mm to 0.30mm.
     
  2. Tony Press

    Tony Press Australia Subscriber

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  3. MYN

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    That is very informative, @Jones the lamp .
    A quantitative measure of jet orifice diametres would come in handy.
     
  4. Digout

    Digout Australia Subscriber

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    Great Information.

    Thank You
     
  5. ROBBO55

    ROBBO55 Subscriber

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    A very useful set to have. :thumbup:
     
  6. phaedrus42

    phaedrus42 Subscriber

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    That is a very clever way of checking jets for wear and size!
     
  7. rollschmidts

    rollschmidts Subscriber

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    Danke dir !:Daumen hoch::klatschen:
     
  8. primaxel

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    :thumbup::thumbup::thumbup:
    A very good and simple way:thumbup::!:

    Regards Frank
     

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