We happen to be BOTH at this time. What a confusing mess. You go to do work on your car and never know whether the nut is going to be metric or English? Even our model airplanes, have metric engines with English fasteners.

Metric is so nice.... Except when you need a 8M X 1.25 and all they have is 8M X 1. Or the 4mm screws are no longer than 15mm.

There's even a mess-up in our system with the #12 crews. Some young engineer will invaribly spec #12's for an application but no one stocks them. To get a few is special order and ten prices. Our system normally jumps from #10 to 1/4" leaving a gap.

Another problem is trying to figure whether it's 5/16" X 24 or 8M X 1?

Eventually you learn instant conversions from MM to decimal and fractional inches?

Enjoy,

Jim