The Veyron uses all metric, but the tire size is written in width/diameter and wheel diameter. Oh, and if wheels were all in metric, would Dub have even existed? Do Veyron owners brag about "rollin on 540's"?

Amen brotha. Don't forget the increasingly often 2mm pitch spacing for PCBs and vector boards. Or, yes, maybe forget that. That said, all our PCBs are done in metric, with an often intervention of 0.1" headers.

I do always get a chuckle when someone actually asks what "SMT0402" means, and you have to explain the measurement confusion.

 

At the company that I work for all the engineers think in metric. Distance is usually um because we make small scale stuff. The weird thing is that our machinist is a stubborn **** and will only work in inches. We design everything in metric, put equivalent dimensions on the drawing in inches as a courtesy, then the machinist promptly crosses out everything in metric. His machines all have digital readouts that can switch back and forth between inches and millimeters, he just refuses to get used to metric after all these years. (It sounds horrible, but he's very good at his job so we tolerate it. If we didn't tolerate quirkiness then we'd have to fire most of the employees including me.)

Interesting note #2: we are currently designing a device for a certain military contractor. The device is clearly military in function. Most of the written specifications are in inches, ounces, etc (though there is some metric mixed in.) The engineers at that company all think in those units. They're willing to talk metric but you can tell it takes effort on their part.

 

The '99 Mars Climate Orbiter. And it wasn't supposed to land. That was the problem.

Background on failure:

Lockheed Martin, who build the spacecraft and its launching system, did everything in SAE units.

NASA JPL, like all right-thinking organizations, works in SI units.

Two different pieces of software, running on the ground, were used to compute thruster firings during the leadup to orbital insertion around Mars. One used SI units (newton-seconds), the other SAE units (pound-seconds) in specifying the required thrust to achieve the desired attitude and trajectory corrections.

Needless to say, data was transcribed directly from one system into the other without the required correction, and then uploaded to the spacecraft, leading to an improper thruster firing which caused the probe to plunge directly into the Martian atmosphere rather than achieving a stable orbit.


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