• Abrading...
The process of polishing the edge of a preform's platform to
strengthen the it in preparation for flake removal by percussion
or pressure flaking.
• Biface...
A spall or piece of flint that has been flaked on both sides.
• Bulb...
Often called "The bulb of percussion" it is the area
very close to the edge or margin of the biface where the flake
originates due to pressure or percussion work. It can sometimes
be deep and cause significant concavities along the edge. The
bulb should be kept at a minimum.
See drawing
• Center
Line...This term is used to describe
the imaginary centerline of a preform as viewed from the blade
edge. See
drawing
• Cobble...Some
flints occur in cobble form. These are irregular shaped but
smooth, and are formed in various sizes averaging from one to
5 pounds and are generally covered with a cortex.
• Concave...
A"cupped" area on the face of a preform or nodule.
This should be avoided until the material around it has been
removed thus raising this "negative" area to match
the contour of the rest of the Blade or core.
• Convex...
The opposite of concaved. It is a rounded raised area. A lens
shape is a good example. This is the foundation for good successful
flaking!
• Core...
The "mother stone" or nodule which spalls are removed
from. Also a carefully prepared worked piece of flint that Sharp
useable blades are removed from.
• Cortex...
The outer "skin" of a flint nodule or spall. Usually
a chalky white or brown material ranging from 1" to 1/4"
thick.
• Flake...
A thin, sometimes broad and sharp piece of stone chipped from
a larger biface or preform.
• Flake
Scar... This is the
"scar" left
behind where a flake has been removed.
• Flute
Flake... A special flake removed
from the base of a blade or preform that travels up the face
towards the tip. The purpose of this flake was to create a concaved
channel to aid in the special hafting technique of Paleo era
points.
• Heat
Treating... Flint was often heat
treated by North American peoples. Things are no different today!
The flint is very slowly heated and cooled to temperatures ranging
from 350-700 F, depending on the material quality and type.
Not all flints benefit from heat treating. Heat treating gives
the flint a glass like attribute making it easier to chip.
• Hinge
Fracture... This is an undesirable
flake that falls short of it's mark by " rolling"
out. See image.
• Isolated
Platform... This is a platform that
has been "isolated"
from the material around it. This is done
by carefully chipping the stone away from either side of it.
This leaves the platform sticking out a bit. The energy is transfered
much farther "down range" using isolations.
• Knapping...
The skillful act of chipping flint or making gun flints.
• Margin...
The edge or circumference of the biface or
preform.
• Nodule...
A large to very large smooth or irregular piece of flint.
• Overshot
Flake... The affect of a flake that
travels from one margin to the other and "clipping"
the opposite edge.
• Platform...
A platform has 3 main components,
this is discussed in "platforms".
A carefully prepared area on the edge of a preform to be struck
to create the desired flake. Or A naturally occurring area on
a rough spall or nodule that would produce a desired flake or
spall. Platforms are the key to good knapping.
• Platform
Bevel... This is the part of the
platform that is actually struck.
• Platform
Support... This is the underside
of the "bevel". It gives support to the platform at
the time of strike.
• Platform
deltas... These are the results
of flake removal. See
drawing
• Preform...
A bifaced blade in various stages of reduction.
• Pressure
Flaking... The act of removing flakes
by pressure using an "Ishi
Stick" or flaker.
• Percussion
Flaking... Removing flakes by directly
striking the stone with a billet.
• Raking
and Shearing... Raking is the action
of carefully dragging a course abrader or other device to remove
"micro" flakes from the edge of a biface or preform
to change it's shape or give support to an edge before actual
abrading is done prior to percussion or pressure work.
• Spalling...
The act of breaking up a nodule or cobble into workable and
desirable sized pieces.
• Spalls...
The finished untrimmed large flake removed from a larger "mother"
stone.
• Stack...
Another BAD thing. A series flakes that fall short of a single
specific objective. Resulting in multiple failed attempts to
remove a specific problem area. Read"Platforms"
for preventative measures.
• Step
Fracture... A single flake falling
short of it's mark by creating a
"step" on
the surface of the Blade. The thinner you get the more this
demon haunts you.
