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Thread gauge calibration/verification

Discussion in 'Gage Calibration and Uncertainty' started by shndcb, Apr 15, 2016.

  1. shndcb

    shndcb New Member

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    Can I use the shadowgraph and Mylar to calibrate the thread gauge?
    I think this is much easier and faster than 3 wire method.
     
  2. equilibrium

    equilibrium Member

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    Could you provide some information on your application/industry? Without more information, this would be difficult to answer.
     
  3. shndcb

    shndcb New Member

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    Automotive seating industry. using some thread gauges to check nuts and stud thread. Like M6X1 M8X1.25 M10X1.5 and 7/16 20 standard threads.
     
  4. Andy Nichols

    Andy Nichols Moderator Staff Member

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    Can I ask why you're doing this?
     
  5. shndcb

    shndcb New Member

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    all our gauges have a calibration frequency and need to be calibrated like once a year.
     
  6. Andy Nichols

    Andy Nichols Moderator Staff Member

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    This is a common practice. The OP is asking about a specific method of calibration.
     
  7. equilibrium

    equilibrium Member

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    I'm not in automotive, or very familiar with their requirements. From my perspective, the three-wire method is still preferred. That way an actual number can be derived, rather than a go/no go result from an overlay. While we've never used the data extensively, it has helped with inventory control and indicated where more gaging was needed, based on wear.

    As to the calibration frequency, we base that on usage. Thread gages are sealed after calibration and are returned after 3 days of use. This actually began as a somewhat arbitrary selection (before my time here), but we now have about seven years of data to support that decision. Threaded ring gages and specialty thread measuring gages still go to outside calibration services because we're not equipped to measure those in-house.
     
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  8. QMSmaster

    QMSmaster Active Member

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    have you ever seen how a plug thread gage is calibrated? You probably do not have the correct equipment for that either.
     
  9. RoxaneB

    RoxaneB Moderator Staff Member

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    That was the OP responding to your question about why s/he is doing this. ;)
     
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  10. Andy Nichols

    Andy Nichols Moderator Staff Member

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    OOOppps! But really I was asking why studs and nuts are being checked...:D
     
    Last edited: May 10, 2016
  11. RoxaneB

    RoxaneB Moderator Staff Member

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    Who was this directed towards, QMSmaster?
     
  12. QMSmaster

    QMSmaster Active Member

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    The OP. You need more than a micrometer and a 3-wire kit.
     
  13. Andy Nichols

    Andy Nichols Moderator Staff Member

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    Before anyone decides which is the best method, shouldn't we be asking what the gauge is being used for and then, does it need to be calibrated? Since the OP hasn't replied other than to say their procedures require calibration, I'd suggest that if the gauge is being used:

    • to identify if the thread size is correct, then no calibration is required (it's just being used as a nut, in effect) or
    • to identify the class of thread, then calibration is probably a good idea.
    Without answers, we can debate all day and get wrapped around the axle about calibration, equipment and methods, with the result that, potentially, vast sums of money are wasted on something which may be brought into question later (hopefully by management)
     
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  14. QMSmaster

    QMSmaster Active Member

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    fair comment
     
  15. gaugestools

    gaugestools Member

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  16. Andy Nichols

    Andy Nichols Moderator Staff Member

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    Still haven't figured why nuts and studs are being checked...
     
  17. gaugestools

    gaugestools Member

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    No, I think it is better use 3 wire method