A Short Diatribe About The Metric System

So, I hate my job and haven't had the time or energy much to blog lately. I'd much rather tweet random statements and make snarky comments over at Hit & Run.

Anyhow, my ire was raised by the absolutely bastardized implementation of the metric system that exists in the US. Now, I'm not talking about the SI system of units, a lovely idea in theory that has failed to catch hold here in America. I'm discussing the ancillary bits and bobs of technology that are specified in metric units. Today's example will be bolts.

As I peruse my handbook of all things mechanical I note an M8 x 1.25 bolt has a head size of thirteen millimeters. This means one uses a 13 mm wrench to remove said bolt, right? Perhaps in a perfect world, such is the case. Here in ugly reality, oh, but hell no. I have before me two M8 bolts, which go in the same piece of equipment. One was removed with a 12mm wrench, the other with a 1/2 inch wrench. I mean seriously, people, WTF?. There is no system of bolts I am aware of where you use metric threads with inch heads.

On the other hand, if I go buy a 3/8 inch bolt anywhere in the country I have a close to 100% chance I will be able to use a 9/16 inch wrench to remove or install it. Metric? Luck of the draw. Somewhere close to the nominal size will be what you need.

This is why people who work with things in this country have a propensity to hate the metric system. We're just not very good at it.