
HAMMER MODE
To detach a flake or a blade it necessary to use an implement
called a hammer or percussor. These can be harder or softer than
the material being flaked. Examples of materials used for hard
hammers are pebbles of dense stones such as quartzite or flint,
with soft hammers being made from antler, horn, bone, ivory or
wood.
Different stages in artifact manufacture can require several different
flaking tools and methods. Various experimental studies have shown
that the use of these different hammers can be identified (for
example, Bordes 1947, 1948; Bordes
& Crabtree 1969; Crabtree
1967; Newcomer 1971, 1975; Ohnuma
& Bergman 1983, Tixier
1980). Although it is fairly easy to distinguish hard hammer
from soft hammer it is more difficult to recognise percussors
of different materials (example, soft stone and antler) within
the same group (Ohnuma and Bergman 1983, 161-170).
direct percussion
Direct percussion or simple percussion takes place when the hammer,
which can be hard or soft, is applied directly to the piece being
worked. This does not necessarily result in rough or crude flaking.
As has been demonstrated by experimentation a skilled knapper
can produce well-formed and even elaborate artifacts using this
production technique (example, Newcomer
1975, 99-101).
index
indexindirect percussion
Indirect percussion is a technique which involves striking a punch-like
object with a hammer or percussor. The tip of the punch is rested
on the platform of the core at the point intended to receive the
blow. It is important to keep the core immobile during the striking
process. When using this technique it is also advisable to prepare
the core platform to prevent the punch from slipping.
"In indirect percussion a punch of antler or wood or other
hard material is placed on the platform and struck with a hammer,
instead of striking the stone directly with the hammer. This allows
the force to be directed very precisely, an important factor in
making blades, which require a carefully prepared core with an
even platform and regular ridges for the blades to follow."
Whittaker 1994., 33.

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hard hammer
"Hard hammer percussion - that is, striking the tool with
another stone to remove flakes." Whittaker
1994., 27
The following are indications of the use of a hard hammer or percussor:
-unlipped and often large butt and pronounced bulb of percussion.
-a clear cone and marked point of percussion.
-pronounced conchoidal fracture marks on the bulb.
-clear concentric percussion rings and fissures.
see Ohnuma & Bergman 1983
indexsoft hammer
The following are indications of the use of a soft hammer or percussor:
-vague cones of percussion and diffuse bulbs of percussion.
-narrow butts which are often punctiform or with a lip. Lipped
butts have a small overhang on the ventral surface at the edge
of the butt (Owen 1988, 218).
see Ohnuma & Bergman 1983
indexIt should also be noted that a hard hammer can become softened
from repeated use until it has the same qualities as a soft hammer.