I've been selling fountain pens for only a little while, but my experience so far is that Jowo and Bock nibs are far more variable and unreliable than one might expect. About half of the nibs need tuning to become acceptable and a lot need serious re-shaping. Some are so asymmetrical in tine widths that I do not know how to make them work.
So far I would say that the Bock nibs are more likely to have excessively tight tines than the Jowo, but no small pen maker could send either brand out without testing and adjusting as necessary. Are penmakers OK with that? Should I be sourcing a different brand of nib?
What about the nibs that I cannot use? Should I try to send them back to the supplier—fpnibs for the Jowo, and a local supplier [in Australia] for the Bocks—or to the manufacturers, or should I just take the failures as part of my costs?
I had a bad Conklin nib from Goulet pens a couple of years ago and they replaced it happily, but I wonder whether they were having to eat the cost.
Michael Lew, PlatypusPens.com