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Converting microinches AA Ra to micrometers Ra

Can some one tell me how to convert Ra microinches AA to micrometers. I have already figured out it is not as simple as using 25.4 mm = 1 inch because it is an arithmetic average. An equation of sorts would help me out heaps.

M Hogan
- Melbourne
2002

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First of two simultaneous responses --

Converting an average is no different than converting a measurement. Just divide microinches by 40 and you obtain the micrometers.

Giovanni M. Ciriani
- Altavilla, VI, Italy
2002

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Second of two simultaneous responses --

Dear Mr Hogan,

Perhaps this can help you: Ra in micrometers = 1/40 Ra in microinches.

Kind regards,

Sjamp van Esch
- Eindhoven, The Netherlands
2002

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2002

MR.HOGAN

CONSIDER 39.37 (40.00) INCH = 1 METER

40 MICRO INCHES = 1 MICROMETER.

IF Ra VALUE IS 100 MICRO INCHES 100/40 =2.5 IN MICROMETER.

M.MUTHU RAMALINGAM
- Bangalore - INDIA