Hand-Operated Bow Drills
Q: When I was traveling I bought a hand-pumped drill that looks like one of those things Indians used to start fires. Is it an antique? Does anybody still use them for making jewelry in the developed world?
A: Bow drills like that are fun, and indeed date way way back in their design. But whether yours is very old or not is hard to tell. You can still buy these newly manufactured, looking pretty much like yours, though of course of new clean wood and all. I don’t see them sold much in the U.S., though both Otto Frei and Allcraft have carried them at times, more as a curiosity I think than anything else. But I have met jewelers, usually European-trained, who actually prefer these for some work, and at one point, many years ago, I spent just enough time with one to figure it out, though not to develop great skill. They take a gentle touch, but once that’s figured out, they’re delicate and nimble tools capable of many of the same things a flex-shaft can do.
One key to their easy use, if you’re still trying to figure that out, is the drill bits themselves. While ordinary twist drills can work in a bow drill, they don’t work well. Better is to make your own bit from straight steel stock. Grind or forge the working end to a flat with a slight point in the middle, so you end up with a spade bit, not a twist. They are somewhat similar to commercially-made flat pearl drills; the tip has the same angled top and cutting edges as a twist drill with one exception: both cutting edges are relieved from the same side of the bit, so that one whole side of the bit cuts, while the other does not. What that means is that one edge (what would be a flute on a twist drill) cuts on the clockwise revolution, while the other one cuts on the counterclockwise revolution. Only one edge is cutting at a time, so they’re a bit slower than standard twist drills, but this way, at least one edge is cutting at all times. It works surprisingly well once you get the hang of it. The fellow I knew who enjoyed using these instead of his flex shaft generally made his own drills from sewing needles.
The back end of the spindle does not need to be held. Gravity holds the shaft down on the work whenever there’s some slack. Since you’re not pushing down on the rewind part of the cycle (the bar is moving back up), pressure on the bit is reduced, but the tip stays in the hole well enough. You “steer” the drill with the crossbar, not by holding the spindle in any way, at least so far as I recall.
by Peter W. Rowe M.F.A., G.G.