Hi,
I had a similar experience as RAFLAUNCHES.
I spent my apprenticeship in an old power station where the boilers, being British, were imperial, but the 30MW turbines, being Swiss, were metric.
Every day, when jobs were being issued by the foreman, the mechanics would have to sort out their metric/imperial tools to take out on the job depending whether they were working on the turbine or boiler.
I always remember the confusion one day having taken the wrong feeler gauges to work on the turbine - another job for the "gopfer" (go for this/go for that) to return to the workshop for the correct set.
Another time, at an archaeological dig, the director instructed me to dig a 1 metre 6 inch wide trench!
Ian