• 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.
Have other Questions or
suggestions?
Let us know!
You
want to learn
more about modern knapping? Go to a
"Knap-In" near
you! Simply search this site or view the links
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