III. The nib already has a slit usually about 14 inch long. This is sufficient in a fairly pliant pen; in a very stiff pen (see p. [60]) the slit may be lengthened to 38 inch. This may be done with care by holding a half-nib between the forefinger [p056] and thumb of each hand, but the safest way is to twitch the slit open (fig. [27]), using the end of another pen (or a brush-handle) as explained under Reed, V. (see p. [53]).
IV. The sides of the nib are pared till the width across the tip is rather less than the width desired[12] (fig. [28]).
V. The nib is laid, back up, on the glass slab, and the extreme tip is cut off obliquely to the slit, the knife blade being slightly sloped, and its edge forming an angle of about 70° with the line of the shaft (fig. [29]; see also fig. [36]). [p057]
The shaft rests lightly in the left hand (not gripped and not pressed down on slab at all), and the knife blade is entered with a steady pressure.
If the nib is then not wide enough it may be cut again; if too wide, the sides may be pared down.
Cut very little at a time off the tip of the nib; a heavy cut is apt to force the pen out of shape and spoil the edge of the nib.