^^^^
i have used them before and made a mistake of
using them on rough surfaces mutilple times and
they still write fine.....the tips get a little messed up
but i am not a dumbass to push super hard on a
rough surface were the nib completely rips off.
they are fine when i use them on rough surfaces.
if the spring is out of them on a rough suface it will
still affect the nib no matter what.
i might try to make them a little thick.
but they work fine for me and will continue to
work fine.