Experimental Archaeology: Flint Knapping

As many of you may have heard by now, this season at the Kaims, on the Sunday of each week, we’re running a programme of experimental archaeology sessions, the first of which was Flint Knapping.

During the day students and local volunteers had the opportunity to learn the basics of knapping practices, and were able to try their hand at creating usable pieces of worked stone.

To start with, here are a few knapping terms which may be unfamiliar:


A hard tool (usually cobbles of very hard stone) used to strike flint/obsidian cores to form flakes & usable pieces.


Also a tool used to strike stone, softhammers are often made of bone or antler. In our experiments we used soft hammers made of elk antler. Using a different hammer material allows for different levels of accuracy as well as producing different shaped flake pieces.

Bulb of percussion:

A feature of stone flakes produced by a hard hammer impacting the flint/obsidian. It appears as a ‘swelling’ or ‘bulb’ at the point of impact below the platform.

Img 0690

The bulb of percussion on an obsidian flake – the rounded protrusion to the right.


The edge of the stone being knapped where the strike occurs.


The blow or force of impact.

Pressure Flaking:

Pressing rather than striking with a soft hammer in order to sharpen/resharpen the flake edges. This removes a series of micro-flakes.

Paul holding flake.jpg

A flake with a retouched edge.


When certain types of raw material are struck with a hard hammer, the impact creates a force which travels through the stone. Known as conchoidal fracturing, the force of pressure creates a bulb of percussion and can then go on to create ripples, which are readily apparent in obsidian though not so much in flint.


Img 0692.jpg

Lines of percussion on an obsidian flake.


Where the strike occurs is crucial to whether or not a flake is created. If struck on the edge of the platform, a flake will usually break off. Sometimes the pressure will continue through the stone, hit an impurity naturally occurring within the stone and break away which creates a blunt edge (not ideal).


Img 0691.jpg

A step fracture (blunt edge) on the left side of a flint flake.


Using our tools, we flaked pieces off of flint from southern England and obsidian from the western United States. After we all had a go, we tried pressure flaking which was more difficult. This involves abrading the surface (crushing/sanding down the inconsistent edges to create a stable edge for sharpening) and then applying pressure directly onto the flake edge with the softhammer, pulling down with the antler tine.


Ian knapping.jpg

Student Ian knapping obsidian.


Students got to see the differences between flint & obsidian in texture, consistency & ease of use. Obsidian was definitely easier.


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An obsidian nodule core vs. a flint nodule core.


We hope to have another round of knapping when our schedule permits! In the mean time, stay tuned for the next experimental session – prehistoric brewing.

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