Making a Bow Drill “Notch” With The Spindle

Another alternative bow drill technique. I have made a few videos featuring what I like to call a tunnel or side-hole hearth, but I have been wanting to make one showing a variation on that for a while. The basic idea here is that you can drill the tunnel with the spindle, rather than carve it out with a knife.

Instead of using up energy and material driving a full thickness spindle through the wood, I thinned it out into a drill bit tip with a taper so that it could slowly widen out the hole into a cone shaped tunnel.
The main advantage to the tunnel hearth is that it can be used on a stick or piece of wood that might not be wide enough to accommodate both the divot and a notch. It also seems to make for easier embers with soft material; possibly because heat is being trapped in the tunnel and bringing the dust up to a higher temperature.

Edit: Gary Minick was insightful enough to notice another advantage that I forgot to bring up here. The fact that the hearth is getting cut via friction could potentially serve to dry out and preheat the material even before the main drilling begins; which could be very helpful with damp wood.

This could also be very useful if you wanted to try a “no-knife” bow drill set; though you would probably be more efficient using two spindles made from round sticks; with a thin one for the tunnel and a thicker one to go for the ember.

However, I always like to mention that the classic v-notch is by far the most reliable method for me, but a tunnel hearth seems to be a close second; and I am much more likely to be successful with it than other alternative approaches like the key-hole or two-stick methods.

The first time I tried doing this was a couple of years ago with the hand drill, and for some strange reason I ended up with an ember when I was drilling the tunnel. This has never been repeated, so I think it was just strange fluke, but keep your eye out for that and don’t dump the dust around the rim if it’s still smoking.

I actually had to film this video twice, as the first time I apparently didn’t hit record when drilling the tunnel, so I had to reshoot the whole thing, but I included the drilling footage from the first shoot at the end of the video; just because it is so fun to watch those embers squirm out of the tunnel.

The set and curls were made from Western Red Cedar, with a Douglas fir bearing block, and #36 bank line on a vine maple bow.

Credit to Arleigh on BCUSA for introducing me to the idea of the tunnel hearth.

Questions, comments, and suggestions are always welcome and appreciated.