One thing I forgot to mention is the pen tips wear out after a year or so and you will need another one. I found you can't fix a bent tip or one you drop on the point that shows no damage, they just won't write correctly.
I knocked my pen off my work bench the other day, looked like it hit on the point but didn't show any damage but just wouldn't make a fine line.I put a new point in my pen and the difference was like daylight and dark. I could make the finest line easily.
I made a bow that was auctioned to raise money for the Alabama's Children's Hospital. The guy that won the bow bid very generously to win. The bow was a righty and Tim is a lefty. To cover up the old rest when I swapped it to the other side I inletted a disc of highly figured osage burl wood over the R/H rest and put Tim's name in the circle.
Tim's bid was really huge so I made his wife a BBO as a "thank-you" note. I couldn't personalize Tim's bow without giving his wife's bow the same treatment so I did the same inletting on hers.
Long, boring story but my point is you can do some mighty fine lettering with a calligraphy pen with a new, extra fine point. New points only cost about a buck fifty so there is no reason not to change them out on regular basis. Here is an example of my latest attempt with my thumb in the picture to give the lettering size some perspective.