[nbadg]

That's also what I was taught as a best practice, but it's not always possible. Otherwise, best practice is to index the gears (ie mark a specific tooth on each). That way, when you disassemble the gearbox (it's bound to happen sometime for maintenance), you can make sure it's reassembled so that the same teeth will continue to mesh, preserving the wear pattern. Otherwise, wear is substantially increased.

[fermenflo]

  That's also what I was taught as a best practice, but it's not always possible.

Well of course it's possible -there are infinitely many sets of coprime numbers! Silly engineers

[D_Alex]

Good luck for when you need exactly 2:1 ratio, like eg in clocks.

[Dylan16807]

Just add more gears in between.

[IMTDb]

So it's a bit like violence.

Gears: If it's not solving all your problems, you simply aren't using enough of it.

[_jal]

I look forward to trying out your infinite gearbox implementation.