MRC
·What? Never heard of this. I just divide by 2.54.
When I was in skule it was 25.4 plus some small change. Forgive me, skule was many, many years ago, I forget the amount of change. Then it was normalised to 25.40000 by fiat (not the car manufacturer). Although I worked in the USA for some years supporting our British CAD/CAM programs I don't remember this turning up, but in the 1980s we got complaints that over long distances our software came up with wrong dimensions. By then I was the backstop on anything our field people couldn't solve and that was when I found out about the "Survey Foot". But the NIST would like to bring the USA into the 19th C and make the Survey Foot equal to the regular foot. https://www.nist.gov/pml/us-surveyfoot
Good luck with that gals & guys at NIST. Now how is it going about going metric???