I've just ordered my first CNC machine from a Chinese manufacturer and the only experience I've got is theoretical, by playing with CAM software and reading a lot, so please, excuse my ignorance.
The Chinese use the metric system, and the machine I'm buying comes with an HSD spindle and a few metric collets. I know I will need collets of different sizes so am planning to buy a few. In my understanding, I can fit a metric bit in an imperial-size collet, as long as it fits, so, the questions are:
Is the type of collet, in metric or imperial sizes, just a matter of preference? Or are there technical aspects I should consider when buying one or another? Which bits are more commonly available from US suppliers (m or i)? In other words, should I buy imperial collets if I am to use imperial bits? Is it just a matter of common sense and less work trying to figure out conversions, or are there any technical issues or other factors to consider with mixing metric bits with imperial collets or viceversa?
I am assuming that you are using an ER collet type system or you would not be talking about interchanging cutters metric to imperial.
Anyway the point is that will not be a problem putting your metric cutters in an imperial collet or vice versa.