@Estefa When the nib dries up, the two tines pulls apart again. My guess is that I need not split it too long. As in Foster's manual, 1/4" (2.5mm) should suffice as the slit length for pointed pen. But for broad edged?
@jeanwilson Thank you. I am trying to use a quill as the only everyday writing tool in the future. As you can see my predicament, I need to learn how to cut a quill for both broad pen and pointed pen. Foster manual is useful. The use of the edge of the pen is very useful, I have made some use of it; Thanks. However, I am still not able to achieve a clean hairline with the full on-edge, except when the ink is about to used up on the quill. Perhaps it has to do with how much ink is on the nib? I do have the Wolffgang Fugger manual. I will look further on how to cut and achieve this. However, it is in Deutch, I have to resort to lots of translation and decipher from the illustrations.