Flintknapping Basics – Part 2

This is the second article in a two-part series on flint knapping basics. Click here to read flint knapping part one.

There are two major techniques in flint knapping: percussion flaking and pressure flaking. Both methods utilize a different set of tools, motions, and are used during different stages in the production of stone tools. Thus, both techniques must be mastered to be a well-rounded flintknapper.

Percussion Flaking Tools

Percussion flaking, as the name suggests, uses tools to strike the stone. There are two tools used in this method: the hammer stone and the billet. The hammer stone is a round, dense stone used to strike the surface of the flint knapping material. It’s important to find a round hammer stone: this guarantees only one point of contact with the flint knapping material, which enables the flintknapper to better predict the fracturing of the material. Choose the size of your stone based on the size and hardness of your flintknapping material. The bigger and heavier the hammer stone, the larger the flake removed. For more control and smaller flakes, the hammer stone can be downsized.


Billets, on the other hand, are elongated flintknapping tools made of stone, copper or antler. Their length allows more force to be applied to the strike. Billets can range from 4 inches or more, and also differ in weight, similar to hammer stones. Copper is an ideal material because of its softness, which helps to grip the edge of the stone and pull flakes away. It’s also more durable and longer-lasting than antler.


Using Percussion Flaking

Percussion flaking is used at the beginning of a flintknapping project. First, when presented with a raw cobble of stone, the amount of material must be reduced in size, or spalled. A spall is a large flake knocked off of a cobble, keeping in mind the proportions necessary to create the flintknapping tool. This spall undoubtedly is still thicker than needed, and has a rough and uneven surface. Percussion flaking is then used to thin and clean up the spall so that it begins to resemble the finished product more closely in length, width and thickness. Most often, percussion flaking is done on the outside of one’s thigh, which is covered with a protective leather pad. The cobble or spall is held on the outer thigh of the left leg with the left hand, and is struck with the hammer stone or billet with the right hand. Strikes are carefully positioned below the spall’s centerline, which is determined by imaging the spall half full of water. The centerline thus moves as the spall is repositioned. Strikes are kept below centerline so the force can pass partially through the material, removing only a flake and not breaking the stone into several pieces. The force travels as a cone, called the Hertzian cone. All stone breaks in this manner, and this phenomenon can be seen on a plate glass window when shot by a “BB.” The entry hole is smaller than the exit hole. As the spall gets smaller, the billet or hammer stone should be sized down appropriately.

Creating a Bi-Face

A spall is called a bi-face when it looks finished and is symmetrical. The bi-face can now be worked using pressure flaking. This technique is a more controlled way of applying force to the bi-face by pressing a copper nail or antler tine to its edge to the point of fracturing flakes from its face. If a copper nail is used, it should be set in a wooden handle about palm-width in length. If a nail is set in a longer handle the length of your arm, the tool becomes an “ishi” stick, and gives the user more leverage to work the bi-face. The bi-face is held in the non-dominant hand sandwiched between a folded-over pad of leather. The edge to be worked is placed at the base of the palm, and the side to have the flake removed is face down. This hand is placed against the inside of the knee of the same side. The pressure flaker is held in the dominant hand, butt to the inside of the knee of the same side. The point is placed on the edge of the bi-face and pressed in toward the center of the stone and flicked downward to remove the flake. The legs are used to apply this pressure.


As the edge of the bi-face is pressure flaked, it thins to the point that it can no longer receive force from the pressure flaker and must be strengthened. This is done by abrading. A rough stone such as sandstone is used to abrade the edge of the bi-face, wearing it down to a blunter and sturdier platform from which to receive to pressure. This step makes the difference between effective flaking and simply crushing a weak edge to dust. The edge is then alternately flaked and abraded until you have the finished product.

To produce a stone tool such as a knife, spearhead or arrow head, a progression of percussion flaking to pressure flaking is used to bring a cobble of stone to a tool fine enough to be an aerodynamic stone tip or a primitive ballistic weapon. Such tools traditionally were used to bring down large and dangerous mega-fauna from safe distances, or to defend friends and family from marauding tribes. With the right tools and sequence of using these tools, the development of technique is all you need to produce these amazing blades that were used by most cultures at one time or another all over the world.