How to convert Ra readings

[Brian Hackett]

Hello,
I have a machining surface finish requirement of 125 and my surface finish tester only reads in Ra or Rz.
Is there a conversion from Ra? My tester states the finish is .225Ra is this equal to or better than 125?
Is there a website or conversion formula? Can you show me how?

Please help.

You can contact me at --- removed email

[Kelly_Bramble]

Welcome to Engineers Edge!

See:

Surface finish review

and

Surface Roughness Conversion - towards the bottom.

[PinkertonD]

Betcha he does not come back to see that assistance Kelly. If they leave an email the lazy sods expect us to follow up with them for their work. Good luck with that lazy-people.

I worry about the quality of Engineering people the Colleges are turning out these days. Bad enough we have few to none of the artisan-type machinists that can actually use a manual lathe or mill.