I strongly suspect that it was anything but "accidental", but was rather related to just how much you could draw down the diameter of a wire in one step without breaking it.
If you can make a B&S Gauge X+1 wire from a B&S Gauge X wire in one drawing step, while making a metric size N wire from a size M wire requires two drawing steps, that actually matters.
The article alludes to this, but doesn't actually explicitly state it.
If you can make a B&S Gauge X+1 wire from a B&S Gauge X wire in one drawing step, while making a metric size N wire from a size M wire requires two drawing steps, that actually matters.
The article alludes to this, but doesn't actually explicitly state it.