Pressure Flaking

Elk River 1

Pressure flaking involved pressing a section of bone or antler against the platform edge and increasing the pressure until the crack initiated and a flake was removed.  The stoneworker could be very precise in the location where they set the tool and the direction of applied force.

The pressure flaking technique involved static loading of force onto the platform, in contrast to the dynamic loading seen in direct and indirect percussion.  Static loading resulted in a more stable crack path.  The pressure technique was usually applied by using the muscles and weight of the body to build up sufficient force for the flake to initiate.  It was possible to achieve very precise and aesthetically-pleasing effects using pressure flaking. 

In making bifacial tools, Native Americans held the core (a flake or biface) in the palm of their non-dominant hand and applied pressure with the flaker held in their dominant hand.  In Australia, flintknappers held the biface in their fingers with one edge supported on an anvil.  Pressure blade-making was achieved using a variety of complex techniques.  The pressure-flaking technique was used on fine-grained stones.

Collateral Pressure Flaking

Collateral pressure flakes were removed more or less parallel to each other.  The term ‘collateral pressure flaking’ refers to flakes oriented at right-angles to the platform edge. 

End scraper, North Carolina

End Scraper

Kimberley point, milk glass

Kimberley Point

Kimberley point, lithic casting lab

Kimberley Point

Pirri point SA

Pirri Point

Pressure flaking tool, Alaska

Pressure Flaking Tool

Dalton point casting lab

Sloan Dalton Point

Transverse-Parallel Pressure Flaking

Transverse-parallel pressure flaking scars are oriented at an oblique angle to the edge perimeter, rather than straight-in.  Transverse-parallel pressure flakes were usually removed in a sequence, creating two or more parallel flake scars.  Often the parallel scars cover both faces of the tool.  

Angostura point

Angostura Point

Elk River 1

Elk River Point

Arrowhead 8, UAE

Trihedral Arrowhead

Danish dagger type V mwm

Type V Dagger

Trifacial Pressure Flaking

The pressure technique was used to make triangular-sectioned tools in Denmark, Mali, and Oman.  The blanks were flaked on three faces from the three unifacial or bifacial edges that define the cross section.  The result was a ‘trifacial’ flaking pattern.

Trifacial point, Denmark

Trifacial Point

Pressure Blade Making

The pressure technique was used in many parts of the world from the Late Pleistocene to the recent past to make blades from fine-grained flint, chert, and obsidian.  The precision of pressure flaker placement combined with the static loading of the core platform meant that large numbers of uniform blades could be removed in series from one core.  

Blade from Pakistan

Blade

Obsidian Aztec blade

Blade

Aztec pressure blade core re-do 1

Blade Core

Microblade core Pakistan

Microblade Core

Microblade core North Africa

Microblade Core