Bow drill
From Wikipedia, the free encyclopedia
The bow drill is an ancient tool. While it was usually used to make fire, it was also used for primitive woodworking and dentistry. It consists of a bearing block or handhold, a spindle or drill, a hearth or fireboard, and a simple bow.
The spindle, carved to reduce friction at one end and maximise it at the other, is held at one end by the bearing block, and at the other by the hearth. The string of the bow is wrapped once around it, so that it is taught enough not to slip during operation. A variation on this called the Egyptian Bow Drill attaches the string in a slightly different way.
The usual position that a person assumes whilst operating the bow drill is as follows: the right knee is placed on the ground (assuming a right-handed operator) and the arch of the left foot is on the board, pinning it in place. The left wrist, holding the handhold, is hooked around the left shin so it can generate enough downward pressure and speed; achieved is done by pushing down with the handhold and spinning the drill. The heat of the friction between the hearth and the spindle both creates charred, fuzzy dust and causes it to ignite - forming a coal or ember. The handhold is lubricated and the spindle is carved to about thumb thickness, usually six to eight inches long.
An indentation and a "v" notch into the center of the dent is made into the fireboard and the spindle is placed on it. The notch allows a place for the dust collect while it is being abraded off the spindle and the hearth. Eventually, the friction generates heat to ignite the dust, which can be used to light tinder.
Whilst a "v" is most common, other methods to create a cavity to contain the dust whilst it is being ignited can be used. For example: drilling part-way into a hearth made by lashing two sticks together from one side, and then drilling from the other side to meet this hole; or using the area where two branches separate.
The hearth and spindle can both be soft woods, yucca, aspen, cedar, and most willows all work very well. Combinations such as hazel and poplar also work well. The bow should be stiff - but slightly limber - and around the length of the elbow to fingertip. The bearing block can be made of anything; but bone, antler, and stone work the best as they can be easily greased, do not create as much friction, and do not burn.
However, it should be noted that many people perfer personal variations; such as a straight bow as opposed to a long one, or a long spindle as opposed to a short one, and so a large degree of practise and experimentation is required to master this skill for oneself.
[edit] Hand Drill
The Hand Drill is a similar method: but uses a longer, thinner spindle; and instead of a bearing block and bow combination, the downward pressure and spinning is achieved by rubbing the hands together around the spindle. As the hands move downward to the base, they are quickly moved back up to the top. However, skilled operators can either maintain pressure with their hands almost stationary vertically; or, in a movement comparable to floating, gliding and sliding, can "float" their hands back to the top of the drill. There is a more limited choice of materials to use with this method.
