Any one use metric in your kilt making ?

[MichiganKyle]

I'm at an age where, during my schooling, Metric was "the way of the future" and very strongly pushed for both math and science education. But outside of the textbook, there were so many things that were still in Imperial (or, as ThistleDown mentioned, US customary units - there is a difference) that you ended up doing schoolwork in Metric and everything else in your life in Imperial. I still do to this day:

• Body measurements (height, weight, clothing) are measured in Imperial.
• Anything large or related to building is Imperial (dimensional lumber, pipe sizes, wire gauge, vehicle wheelbase and often engine displacement, etc.).
• Distances and speeds are measured in Imperial. This means that when I want to run a "5K" on a treadmill, I know I need to run for 3.11mi and set the machine accordingly. Running at 6.7MPH gets me to a 5km in under 30 minutes with a few minutes for cooldown.
• Printing and paper are all in Imperial - 8.5"x11" is standard "letter" size, and resolution is measured in DPI (dots per inch).
• Food items are a combination of both systems - nutrients in grams for food quantities measured in ounces. Volumes are usually in US customary units except when they're not - a cup of sugar, a 5lb bag of sugar, a gallon of milk, but a 2-liter bottle of soda pop.
• Temperatures are pretty much always in Fahrenheit, except for in a scientific or manufacturing realm (3D printing is always Metric, materials are generally characterized in Metric, temperature limits for sensors are usually given in both systems but always at least in Metric).
• When 3D printing parts, I nearly always work in Metric except if I'm trying to match something else that was originally designed in Imperial. When designing parts, it strongly depends on the application.
• When woodworking, I nearly always use inches because (a) it's easy to divide into known fractions, (b) most dimensional lumber comes measured in nominal inches, and (c) you're likely not going to get everything terribly precise anyway. A foot can be easily divided into 1/2, 1/3, 1/4, and 1/6 without fractions or if you want to use simple fractional inches there are many more very simple multiples and fractions you can choose from.
• When machining, I usually use 1/1,000 or 1/10,000 of an inch ("thou" or "tenths"), because that's what my machining tools use (40's era lathe, 60's era mill, etc.) and is very traditional and ingrained in all kinds of handed-down knowledge from expert old-timers. But sometimes I will measure in Metric when working with other Metric things and do conversions only as needed.

I think a lot of it just comes down to the amount of investment the USA has in older standards and equipment. The cost to change everything to Metric overnight is just too great, so it's been done gradually for decades, and that leaves us somewhere in the middle. You just become used to using both systems situationally and converting as needed.

Getting pedantic, neither system is "more accurate", considering there are fixed conversion factors between them with a fixed number of significant digits. You could precisely and accurately measure in football fields, smoots, or attoparsecs. SI units are certainly more logical, but they're still just two different ways of measuring the exact same thing, and you can be as precise or as sloppy with either system. Centimeters and millimeters are certainly smaller delineations than inches, but thou are smaller than millimeters, and microns are smaller still. From an American perspective, it comes off like if someone said that the Spanish language is better than French because the pronunciation rules are more concrete and consistent - the same thing can be represented in either, and it's a little unfair to both. When you're raised on both, conversions just end up becoming second nature. My calipers for machining measure in Imperial decimal, Imperial fractional, and Metric and can be toggled back and forth for the same measurement, and that's kind of how I tend to think of measurements - a number based on an arbitrary unit that only exists because some people agreed to use it. The meter was originally based on the size of the planet and isn't anymore, the inch was probably based on human thumbs and certainly isn't anymore. Both systems are so old that it just comes down to which group of arguing dead people you happen to agree with.