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Need help on Metric vs English conversion

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  • #51500

    Janney
    Participant

    Anyone has experience on how to validate the measurement that use different unit. In US we use English unit, but in Asia they use Metric. the supplier in Asia areas are often convert our prints to Metric for production and convert back to English to report the results. I experienced a lot of gage correlation issues because they use Metric gage and not English gage. if there is no option that they can get an English gage, what is the best way to solve the gage correlation issue? there are rounding error and gage variation.
    Thanks
     
     

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    #178617

    MrMHead
    Participant

    Would you not want to ask (tell) your supplier to use a gage / measurement whose resolution is well below your tolerances?
    For instance: If your Widget needs to be 50ft long, +/- 1ft, they should be measuring in centimeters and not meters.  Then the gage variation and conversion rounding on centimeters should be “invisible” to the +/- 1ft tolerance.
    Just make sure everyone converts in the right direction.  NASA has a pile of rubble in a crater on Mars as an example if you don’t!

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    #178619

    RC
    Participant

    Oh that brings back memories of making sure you’ve remembered to convert the g constant!

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    #178623

    Taylor
    Participant

    Best way to handle is convert your prints to Metric Tolerance.

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    #178624

    Janney
    Participant

    Then, how about the gage correlations? how can we compare the gages if they use different units?

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    #178630

    tcm
    Member

    Juz take a scrape part , place in to soak in a controlled temp environment for ~ 24 hrs. And measure it several times using the gage in question.
    Nxt, send the part over to your supplier 0.o… Have your supplier measure the part in the same kind of environment…. And compare both of the results?

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    #178670

    Janney
    Participant

    Supplier told me that they will use 1/10 of the tolerance as resolution. I don’t think it is correct. but they do not agree. for example, we have spec is ..015-.025in, when they convert to Metric, they use .38-.63 mm. they told me the different is at .(63-.38 )which is .25 and divided by 10, then it is .025, so the resolution of the gage is .01. is that right? I think the resolution of the gage should be.001.

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    #178673

    GB
    Participant

    “Supplier told you..” ???
    You should be telling the Supplier to meet your needs as the Customer in your measurement schema.
    Barring that, As another poster suggested, you change your measurment schema and dictate the appropriate metric measure.

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