Quote Originally Posted by Steve Peterson View Post
It seems like I am often scaling between cm and mm. Sure, the conversion is easy, but it is also easy to forget and end up with a size that is 10X larger or smaller than expected. This error rarely occurs with imperial measurements. Construction is always in feet and everything else is always in inches.
If you end up with something that is 10x too big or small it would indicate that you don't have a basic feel for the size of the piece you are making. I'm old enough to have used a slide rule early in my career. If you misplaced the decimal point it meant you didn't have a good feel for what the answer should be. Last time I checked, stud spacing in construction was in inches not fractions of feet.
The only reason most people prefer the imperial system is that they grew up with it. Canada went metric a long time ago but I grew up with imperial so I am still more comfortable with it, I have nephews who grew up with metric and guess what? Even for me, driving distances are much easier to picture in metric despite my preference for imperial for woodworking. Why you ask? I can picture the length of a football field which is, approximately 100 metres long so a kilometer is about 10 football fields, Much easier to picture than 17.6 football fields.
The real source of errors is when converting between the two systems, to see a great example of this check out the Gimli glider, the pilot would give Sully a run for his money when it comes to extreme landings.
https://en.wikipedia.org/wiki/Gimli_Glider