2. The KnifeAbove the crushed tube is my knife. It's a Benchmade 875 with the blue titanium liners that Trip gave to me for a birthday. It's the knife I use for pretty much all my quill cutting. It's got a 3.75 inch ATS-34 blade of 59-61 HRC hardness with a .12 inch thickness and a plain edge, no sawtooth. It fits my hand well and, surprisingly, does the fine detailed work very easily. The edge is magnificent and cuts very nicely without any slippage or misses.
I also bought one of the 330's, because I wanted something small, but it just doesn't have the stability the bigger knife has, the only differences are that it's .8 inches thick and far shorter. So I have no idea why it doesn't cut raw quill material as well. It does cut, but my control isn't as good with the smaller blade and with all the microscopic adjustments I like to make, I prefer using the larger knife. The 875 goes through the stuff easily, the 330 makes it a bit more work. I have some hope that the tempered tubes may make the 330 more useful.
I have used a little, tiny Swiss Army pen knife (funny how pen knives are good for cutting pens), you know, those tiny pocket knifes with a toothpick and tweezers that always get lost? I sharpened it with a diamond knife sharpening stone, and it's good for getting the membrane out. It even has a built-in scissors to start the shaping of the tines and to finish the tip with, so it's actually a fairly good thing to use if it can be sharpened enough to cut neatly. It is harder to use than either of the above knives; however, it is significantly cheaper.
The knife should be clean, extra sharp to prevent slippage and accidents, and have a flat, none-edged back near the handle for scraping certain bits clean. I'm fairly sure that even a good kitchen knife should be able to do the job, but make sure that it has smooth edges, not serrated. A XACTO knife, straight razor, or a scapel can also work; but they're all much harder to control because of the lack of control surface.
They say that in the old days, folks kept a penknife solely for the usage of cutting quills, and that it was kept wicked sharp and never used for anything else, even scraping parchment to erase a mistake. Some say that the curved tip is shaped to make cutting the curved edges of the tines more easily, but I've never used anything but the base of the edge because I've found the tube material too tough to just press and cut, I've mostly had to just carve the tips into the right shape.
3. Other StuffThe other two items are make the process much easier. I use the tweezers for pulling the dried membrane out of the center of the feather, and I use the scissors both to shape the nib and to finish the very tip. For the initial shaping, to make sure that I don't completely mess up the tines by pushing really hard on them with a knife, I have to have a pair of very sharp sewing scissors to snip away the worst of the extra material on either side of the tip.
Resharpening doesn't really need either of these additional tools, as the knife tip can take a bit of membrane out of the center and the knife edge is very good for doing the relatively small amount of material removal needed to just reshape the tip, rather than re-cutting it from scratch.