For those who use a bow drill or an Archimedes drill to be more
accurate. Try making your own drill bits. When I was an apprentice I
was taught to make drill bits using sewing needles, one of my
apprentice jobs was to hand grind tailors needles into drills. The
method was to hold the needle in a pair of pin tongs, with the
needles eye exposed, then using a pair of pliers I would snap the
the needle across the thread eye of the needle. Then I would rub each
side of the snapped needle eye across an oilstone making the broken
needle eye the shape of a watchmakers screwdriver. Finally I would
hold the needle in the pin tongs square to the stone, then slightly
angle the top and grind a shallow point on the end, at a slight
cutting angle when the drill was for a regular flex drill or without
a cutting angle when used with a bow drill. One of the elder
craftsmen in the workshop used to make various size drills for use
in his bow drill and he used to grind the opposite end of regular
drills in the same way as I described, so that he had drills of
various sizes that he could use in his bow drill as well as having
the regular drills for a normal drill. This method of grinding drill
shanks is ideal for making drills for cutting half pearl settings if
you do not have the ideal size pearl drill.
Peace and good health to all
James Miller FIPG