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Flintknapping
is the making of flaked or chipped stone tools. This technology
was used in historic times to manufacture gun flints and in prehistoric
times to make spear and dart points, arrow heads, knives, scrapers,
blades, gravers, perforators, and many other tools.
Flintknapping requires the ability
to control the way rocks break when they are struck. The best rock
is somewhat brittle and uniform in texture and structure, lacking
frost fractures, inclusions, or other flaws. This type of rock is
very fine grained or non-grained. The best rocks for flint-knapping
are chert, flint, chalcedony, quartzite, jasper, and obsidian. Chert
and flint are silica-rich rocks found throughout the Midwest in
limestone and dolomite deposits. These rock types, when struck with
another rock, piece of antler, or bone, will fracture or break in
a characteristic pattern called a conchoidal fracture. This
creates a rock fragment called a flake.
Flakes
have specific features identifying them as the result of human hands
rather than natural processes. All flakes typically have a striking
platform (A), bulb of percussion (B), eraillure (C), radial fissures
(D), ripple marks (E), and negative flake scars on the dorsal side
from earlier flake removals (F). You can think of these features
in terms of dropping a rock in a still pond: the rock hitting the
water (A), the splash (B), the drops that fly away from the splash
(C), the drops that fall back near the splash (D), and the concentric
waves moving outward (E). Naturally broken rocks usually do not
exhibit these features.
The production process begins with
a piece of raw material, called a core. Flakes are removed
by striking the edge of the core with a sharp, forceful blow, in
what is called percussion flaking.
Percussion flakes are
removed using a hard hammer or soft hammer. Hard hammers
are typically made of igneous or metamorphic rocks such as granite,
quartz, basalt, or gneiss. Hard hammers tend to pass most of their
energy to the core without absorbing much of the force, so they
are used to flake large cores of hard materials. A carefully controlled
strike is always more important than a hard strike when using a
hard hammer. |
A soft hammer is made of
a piece of antler, although bone and some very hard woods can be
used. Moose, deer, elk, and caribou antler are all usable soft hammers.
Soft hammers are used when flaking very brittle material such as
obsidian or when greater control is needed. Soft hammers will not
pass as much energy to the core and will absorb some of the force,
affording greater control of the size and shape of the removed flake.
Edges being worked must be ground dull prior to flake removal. This
dulling helps prevent edge collapse. A piece of sandstone, very
soft limestone, or other soft rock may be used to dull the edge.
Indirect percussion flaking
is a process where some device holds the core or flake being worked,
leaving both hands free to drive off flakes with greater force or
precision. One hand holds a punch-like piece of antler or bone against
the core while the other holds a hammer and strikes the punch to
drive off flakes. This combines the accuracy of pressure flaking
with the force of percussion flaking.
Another method of flake removal
is pressure flaking.
The knapper detaches
flakes by applying leverage (pressure) to an edge. An antler tine,
piece of bone, or hard wood sharpened for accurate application of
force is needed for flake removal. Downward and
outward pressure pops the flakes off. This method can straighten
and sharpen edges of a finished tool or shape a tool from flake
to final form.
Flakes can be used for simple tasks
or can be further reduced to make various types of tools. A small
amount of shaping can turn a flake into a knife, scraper, or other
useful implement. |
A biface
is any chipped tool produced by flaking of both surfaces. Bifaces
are typically formed in the following reduction sequence:
Each stage reflects progressive
reduction of a core or large flake. The desired product might be
a projectile point, knife, or drill. Bifaces and other tools were
usually repaired and resharpened frequently, extending their use-lives
but reducing their sizes until they were discarded.
Heat treatment improves the
knapping quality of some raw materials. It requires gradual application
of high heat. The color and luster of the rock often change noticeably,
and the flaking quality of the rock improves because its texture
becomes smoother and less grainy. Heat treatment is usually applied
to small and medium cores, flakes, or bifaces; larger pieces are
difficult to heat evenly and thoroughly. To begin the process, a
good sized fire is burned down to glowing coals and hot sand. A
pit is excavated and the remains of the old fire placed into it
(A and B). Already warmed chert pieces are placed into the pit (C)
and covered with sand. A new fire is built and allowed to burn out
over a 24 hour period before digging up the heat treated pieces.
Care must be taken, for heat treatment can cause rocks to fracture
explosively.
Flintknapping
is a fun and interesting hobby which can provide considerable
insight into the lives of prehistoric peoples. Chert, flint, and
other rocks usable for flint-knapping can be acquired from local
quarry operators, rock shops, stream beds, and other gravels,
or by knowing your local geology. Antler and bone for hammers
can be obtained from 
your local meat locker or butcher.
Flintknapping is very dangerous.
Cuts are common and can be severe. Always wear safety glasses, knap
outside, and make it easy to clean up by using a tarp. Work where
your flakes will not be mistaken for a real archaeological site,
because the methods described here can produce flakes identical
to prehistoric flakes. Try using your flaked stone tools in your
garden or kitchen to see how well they work and learn more about
the lifeways of stone age peoples.
Recommended reading:
Don E. Crabtree, 1972. An Introduction
to Flintworking. Occasional Papers No. 28. Idaho State University
Museum, Pocatello.
John C. Whittaker, 1994. Flintknapping:
Making and Understanding Stone Tools. University of Texas Press,
Austin. |
