The thread issue that you are talking about is mixing between ISO, British and Italian threading. If you stick with one threading, even between brands, you should be fine...
Originally Posted by Baxtefer
Type Thread Equivalent
I.S.O. 1.375" x 24 tpi 34.92 x 1.048 mm
British 1.370" x 24 tpi 34.80 x 1.058 mm
French 34.7 x 1 mm 1.366" x 25.4 tpi
Italian 35 mm x 24 tpi 1.378" x 1.058 mm
and
ISO, English and Italian are all semi-interchangeable, but it you shouldn't go back and forth between different types of freewheels on the same hub repeatedly