We don't normally see discussions of stub nibs here because they're not traditionally used in calligraphy except maybe for italic with the right nib. For those unfamiliar with them, stubs are a form of broad nib but the corners tend to be more rounded, less sharp, so you don't get quite the sharp hairlines and stroke endings that you get with a sharp italic or engrosser's nib.
Stubs were originally developed in the mid-19th-century in an attempt to make a nib that was easier to write with, especially easier with which to write quickly. They can give a similar modulation in line to a pointed pen but with less control. Spencerian looks funny with a stub nib.
Most stubs are fairly stiff, it's the bounce that can slow you down, after all. But there are some which have a degree of flex. The Spencerian Congressional is known as the stub with the most flex, and is really wild to write with. It's also a rather broad stub to begin with, so you combine that with the flex and it works best for larger writers.
I was writing a letter this morning with an Esterbrook 654 Barrister. I've only ever tried one once, quickly and then put it aside. Today when I tried it, I discovered that it had some spring to it, and was sharper than other stubs, so it was a kind of in-between pen between an italic and a stub, with some flex. It was fun! This prompted me to pull out some other unusual stub nibs and give them a spin. Since I had, I thought I'd share with y'all.
If you want to learn more about stubs, I have an entry on my website on the stub pen.
https://thesteelpen.com/the-steel-pen-table-of-contents/stub-pens/Andrew
