Measurement sensitivity - Rule of Ten

[kreg]

Does anyone know of a source document that designates the "Rule of Ten" whereby measusement instruments should be able to discriminate to one-tenth of the specification measure? Is this just a commonly held practice or is there an ISO or ANSI standard or similar document that specifies the Rule of Ten?

 

[randi]

It is probabbly from the time when the first Mil C-45662 concerning calibration control was written. Today the field measurement devices are becoming exceedingly accurate therefore the backwards traceability to the working standards, reference standards, and Master Stndards or National standards is not able to maintain this ratio of 1 to 10. Therefore in many of the new standard guides you will see a mention of a ratio of at least 3 to 4 times or better. It is for the user to decide. For a more thorough examination you may have to evaluate the system accuracy and the uncertainity aspects in line with the new standard guidlines mentioned in ISO 9001 and other associated calibration standards like ISO guide 170542. I am not sure of all the standard numbers, please check with any ISO reference table.

 

[Rexli]

QS9000 , Technical manal , MSA

 

[stephenh15]

The "Gage Mentor Workbook" from Resource Engineering in Tolland, CT.

http://www.reseng.com

 

[aamoroso]

I have been trying to convince management where I work to get to 4x. I feel comfortable with that number based on our tolerances (+/- .030 in most cases). When it gets down to the tighter work I think the number is still accecptable becasue the talent levels increase as does the proven ability to hold tighter tolerances with Mics and bore mics and high end hand measuring tools.

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