I've made up a wire rope to give a better hold rather than a smooth
wire. If your jeweler has the taps and dies, threading the wire
will also serve to create a better hold.
Even easier than threading, or making true two-wire twisted "rope"
is to draw the wire square (or for beads with a larger diameter hole,
just the square shape from a wire rolling mill works) so the corner
to corner dimension of the square wire is the right size for the
drill holes. Then anneal, chuck one end in your flex shaft handpiece,
hold the other end in pliers, pull taut, and hit the food pedal.
You’ll end up with a nice tight twisted square wire that looks much
like a threaded wire, and works just the same for nicely holding a
pearl. Stronger than a two-wire twisted rope, and faster to make that
either that or a threaded wire.
If you don’t have a square draw plate, you can even roll or hammer a
flat into round wire, or hammer it roughly square, and twist that. It
doesn’t give as much of a distinct groove to the twist, but it can be