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).