If necessary, draw a new line "B" all around the guitar
block at the point where the transition to the peghead starts; also
mark a centerline on the guitar block and draw one line at a
distance of 3/4" (20mm) on either side of it on the top-side
of the peghead.
Mark the peghead taper as shown in the drawing above. Holding the
Ryoba saw at a tight angle, cut out the peghead close to the final
shape.
Smooth the surface with a block plane until you approach the line
marking the peghead shape line. Because of the grain you must
always work towards the end of the peghead.