Bow drill

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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. Related drills include the pump drill and the hand drill.

Contents

History

39.28 ± 0.11 ka or older hand operated drill was used to perforate prismatic stone ornaments at Kostenki [1][2]

The bow drill appeared in Mehrgarh between the 4th and 5th millennium BCE.[3] This bow drill—used to drill holes into lapis lazuli and cornelian—was made of green jasper.[3] Similar drills were found in other parts of the Indus Valley Civilization and Iran one millennium later.[3]

Description

This is an ancient method of starting fire without matches. It uses friction to generate heat. The heat eventually produces an ember in the burnt sawdust. The ember is tiny, smaller than the head of a cigarette, and fragile. Once the ember is formed it is carefully placed into a "tinder bundle" (a bird's type nest of stringy, fluffy, and combustible material). Once the ember is in the tinder bundle it is then carefully nurtured and coaxed into flame. Once the tinder bundle bursts into flame, it is then placed into the fire lay.

The spindle, carved to reduce friction at one end and maximize 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 taut enough not to slip during operation. A variation on this called the "Egyptian Bow Drill" which attaches the string by wrapping it around multiple times, or actually tying it to the drill or through a hole through the drill shaft, then wrapping it. ("Egyptian Bow Drill" from link on main fire making article)

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 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 6 to 8 inches (150 to 200 mm) long. Another option to practice is to make the "handhold" into a "mouth-hold" piece, so it's held down by pressure from the chin/mouth, leaving both hands free.

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