[resonator]

> What's wrong with 9.5 mm?

As a number, well nothing. I'm not saying there are anything wrong with the numbers, I'm saying that with a standard set of imperial or metric tools, you're more likely to find your imperial tools working with with you.

> And what's going to happen when you divide by three, not two?

Well dividing by three will be 1/4". That's another common imperial size. But to answer the point I think you were trying to make, there are sometimes cases where it isn't natural — like dividing 3/4 by 5. In those cases you need to measure or pull out of divider. Your problems don't all disappear when using imperial but I find that more often the perfect dimension happens to be that of a commonly size tool.

> Don't see anything natural in one compared to the other.

I think you're arguing from the perspective of pure numbers verses the practicality of making something with tools that I own. If I was using CAD, it metric or imperial would make zero difference.

[moogly]

> with a standard set of imperial or metric tools, you're more likely to find your imperial tools working with with you

... when working with imperial, you mean? Or do you mean regardless if you target metric or imperial?

[resonator]

Actually, I take it back. As I said earlier, I mostly use vintage imperical hand tools. I've just been looking into modern metric tools and I'm finding that they're actually imperial, as in they come in sizes like 0.25"/3.2mm. So long as they're not rounding them to whole millimeters, they'll have the same ratio as the imperical tools.

I guess you can use whatever number system you care for.

Thank you for making me think about this.