Geoscience Reference
In-Depth Information
Figure 7-4. Fire bow and drill.
Bow
Use any stick, preferably curved, and roughly ½- to ¾-inch thick by 30 inches long. With your
knife, make a shallow groove around each end (about an inch from the ends) to make a spot to
tie your bowstring. Use a hefty, strong string or leather thong (not rope) to tie the bow. Braided
leather thongs or 1/8- to ¼-inch nylon cord work well as bowstring. Typically, plant fiber cord-
age must be doubled back on itself and corded a second time to make it strong enough for the
bowstring on a fire-drill bow. The string may stretch as you work the bow. Tie the bowstring
with a little slack to allow for the string to wrap around the drill. Experiment with different
string tensions and with using your fingers to tweak the string for more or less tension while
using the bow.
Drill
Usually the drill and the fireboard will be made from the same material, though the choice of
wood for the fireboard (also known as hearth board) is most critical. For a fire drill and hearth
board to make fire, they must be very dry and they must generate an extremely fine powder
when spun together. Try to pick freestanding wood with the bark weathered away, because
wood lying on the ground usually picks up ground moisture. If your pieces of wood generate
coarse, gritty wood shavings, you should find another chunk of wood. The best woods are usu-
ally softwoods that are not very resinous. Resins such as those found in most pines, spruce, and
firs tend to act like a grease, making it difficult or impossible to get enough friction going to
