Thursday, 21 December 2006

Drill Update

Being able to drill holes is not neccesarily essential in primitive skills, but it makes life a lot easier. The drill bit can mounted on a hand drill, bow drill or pump drill. The hand drill is the simplest and to me seems easier on the bits than bow drill since there isn't as much sideways torque. The bit can be a simple pointed stone or even bone or antler, but I feel knapped stone has a better combination between stability and hardness than the other alternatives. Storm uses quartz chrystals, which are potentially an even better material, but I unfortunately don't have any available to me at this time.

Knapping the bit

To understand knapping, you need to understand how stone breaks. The force of the blow is distrbuted in a conical shape beneath the blow. A cone itself isn't very useful, but when you understand that this is the way the force from the hammer (either stone, antler or hard wood) goes you know that you will need to tilt the core away from the direction of the blow to achieve a flake instead. The angle is different for the different hammer materials used. The drawing shows hammerstone striking off a flake at left, in the middle working the flake with an antler billet, upper right shows the principle of abrading the edges, lower right shows pressure flaking.

This is the principle of all knapping, but with fine pressure flaking you need to press more in the direction of the flake because the force is less sudden and the force travels in a more delayed fashion. This is a function both of the material used (antler) and the speed of application. Below I am using an elk (moose) antler billet to strike off a flake.

If the force isn't sufficient to fully free the flake from the core, you will end up with step fractures. They are abrupt changes in direction of the break and chances are, unless you strike off a very thick flake and thereby removing the step, every succeeding flake will end in that step, in effect reinforcing the step in every removal. The easiest remedy for a serious step is usually to attack it from a different angle, either from the the opposite end or from one of the sides.

When knapping, thinking in stages is quite recommendable, but I often mix them a little as suits me best. The first stage after the flake removal is to make the flake regular and thin it. This is usually done by using a soft hammer, like an antler billet. On smaller pieces you may do it by pressure flaking. Below: Pressure flaking in my own hazardous way.

When the perform is finished, you can start shaping the piece by pressure flaking. By putting a lot of pressure on the edge quite parallell to the flake itself, you will further thin the blank. This is not always what is wanted however, especially in the last phases of the knapping where you may want to strenghten the edge instead of thinning it. To achieve that use more sideways instead of parallell pressure. To be able to apply enough pressure to press off good sized flakes and to have strong enough platforms for striking of blades you will often need to abrade the edges to strengthen them.

Safety isn't my strong point to be honest, but since the flakes are horribly sharp it should be taken into consideration. I don't use googles, where would I get those in the wild? But by pressure flaking towards your palm (pad it with leather) or a hard surface the flakes will more than likely not hit your eyes. Being of a rather lazy nature, I often take a shortcut on this and pressure flake with my index finger and thumb pinch. If you don't take care that can cause flakes to fly in your face. If you get a small flake in you eye, it can usually be removed by blinking under water. But by all means, be careful. The photo shows the safer way of pressure flaking.

This drill bit is now finished and ready to be hafted. These instructions can be applied to most knapping and certainly arrowheads. Sorry the poor quality of the photo.