Drill Standards

[MarkJoya]

I've searched the internet, but have found little about standards for drill sizes for various common parts, i.e.:
-resistors
-capacitors
-DIP ICs
-TO220 and similar cases
-TO92 / 39 and similar cases
etc.

Does anyone know if there have been standards set?

What's your opinion?

Is there a guide to calculate hole diameter from lead diameter???

Thanks & good day!