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Deciding Vernier Caliper verification tolerances

Discussion in 'Gage Calibration and Uncertainty' started by MonsterEnergy22, Sep 20, 2023.

  1. MonsterEnergy22

    MonsterEnergy22 Member

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    Good Morning,

    I'm hoping some one can be help me, this will be a very brief & basic question.

    We currently verify our Digital Vernier Calipers in house against a set of externally-calibratied slip gauge blocks.

    When writing the calibration/verification procedures, there was no original equipment manufacture's tolerances stated so we decided upon +/- 0.2mm (it was literally just decided) , we've been happy with this since then.

    However, a new mechanical engineer expressed his shock when he heard this and said it should be +/- 0.01mm , I didn't really have an answer for him as to why it should/shouldn't be as such.

    We have our material tolerances specified for all types of materials, for example, cutting lengths of steel material has a tolerance of +/-1mm,

    obviously if the vernier had a reading error of 0.2mm this could potentially result in non-conforming materials.

    Is/are there any resources available to better understand this process?

    I greatly appreciate any replies as always.

    Have a nice day.
     
  2. Andy Nichols

    Andy Nichols Moderator Staff Member

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    The general industry practice is a 10:1 ratio. Thus if measuring to 1mm, the equipment should read to 0.1mm and be verified/calibrated with something which is 0.01mm
     
  3. MonsterEnergy22

    MonsterEnergy22 Member

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    Thank you for your reply Andy & apologies for my question of a rudimentary nature. I appreciate your help as always.

    Whilst the concept of a 10:1 ratio and your explanation is perfect, are there any recognised documents that go into detail regarding the 10:1 rule?

    EDIT:

    as a thought,
    I've verified my Vernier that reads to 0.1mm with a calibrated item that reads to 0.01mm.

    How do I decide the acceptable tolerance limit? for example as I stated earlier, I allow for +/- 0.2mm deviation from the nominal value?
     
    Last edited: Sep 20, 2023
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  4. Andy Nichols

    Andy Nichols Moderator Staff Member

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  5. Md. Hasan Ibrahim

    Md. Hasan Ibrahim New Member

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    Selecting the right tolerance for caliper verification is crucial. While +/- 0.2mm may suit some applications, precision demands, especially in manufacturing, often require tighter tolerances like +/- 0.01mm. The choice depends on your specific use case and the acceptable margin of error. Consulting industry standards, collaborating with experts, or referring to equipment specifications could provide insights for a more informed decision. Best regards
     
  6. MonsterEnergy22

    MonsterEnergy22 Member

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    Hi Hasan,

    Fortunately, my organisation doesn't require anything extremely precise.

    Since posting this thread I discovered a R&D general tolerances for manufacture, to which many tolerances were "0.01mm", based upon that, I moved to 0.01mm :)
     
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