Thanks for the link
Bernd,
Changing to 20tpi makes perfect sense, the only thing that confuses me is:
"...MiniMill comes with 16TPI lead screws. One turn of the dial moves the table .063". So for 16 turns of the dial your table will travel 1.008"..."
If it is indeed 16tpi thread, than one turn of the dial moves the table .0625", and for 16 turns of the dial
the table will travel 1"On the other hand (I guess because the dial is rounded up to .063" per turn?) 1" of table travel will show on the dial as 16x.063"=1.008" - but it will still be 1" of table travel...?
You could mark the dial in 1/16" or 1/32" or 1/64" and there would be no error in display

- just your mental arithmetic would get a bit more complicated
So, it's a good idea to use 20tpi simply because one turn of the dial moves the table .050" and it is easy to mark the dial in 50 divisions.
The problem with 16tpi is not the table travel, but the difficulty of marking the dial with 62,5 divisions.
Chris