What two secrets do you need to know about knapping in order to create stone tools?

Hertzian Cone

Knapping can be an incredibly complex art that can require years of experience to create beautiful and functional tools. But knapping, in its simplest form, is banging two stones together causing one to fracture and create a sharp edge. That edge could be used as a crude tool as it is. Probably 80% of the tasks you would need to tackle could be done with that edge. The next 15% of refinement would probably take weeks or a few months to learn and the last 5% of refinement may take years. So for simplicity, let’s focus on what you need to know to create a tool that would do 80% or more of what you need done. If you were to bang enough stones together, you would eventually figure out the two most important things about creating a predictable flake:The Cone and The Platform.

The Cone:  The type of stones used in knapping have a conchoidal fracture. (If you aren’t sure what types of stones make good tools, read this entry) Conchoidal fracture means that the instant the blow strikes the surface it is transmitted into a cone radiating at about 100 degrees.This cone (also called a Hertzian Cone) determines at what angle you must strike a blow to remove a particular chunk of stone. Hertzian Cone

If you only had to know one thing about knapping this would be it. The images show a stone core being struck at the correct angle to produce the desired flake and at an incorrect angle in which the cone radiates too deeply into the core.


Striking the blow correctly (as shown at left) aligns the edge of the cone with the flake you want to remove. The chances you will get the desired flake are good. 







Striking the blow at the wrong angle(as shown below) causes the cone to penetrate too deeply into the core.  The chances you will get the desired flake are very poor.










The platform:The platform is the point of impact on the core stone. What is important is that the platform allows the shockwave to travel along the stone and create a fracture in the direction that you want.You are going to hit the stone somewhere and you just want to make sure that the somewhere is going to be conducive to transferring the energy in a direction that you want. That may mean shaping the platform by chipping or grinding so that you have a suitable point of impact. The image below shows a poor (non-existant) platform. The blow will just glance off the core because the platform doesn't exist.





Is a great primer on the subject and a good place to start for the beginning knapper.

"Flintknapping – the art of making stone tools" by Paul Hellwig.

Is one of the best books out there but it has so much depth that it will probably just frustrate the beginning knapper.

"The Art of Flintknapping" by D.C. Waldorf


Video Resources:

This is a great series that should help you get started.  







You want to make a stone tool. What type of stone should you look for?

Examples of Chert
Chert formations, Pindus mountains Greece(source: candiru)
Examples of Chert

Our ancestors discovered that certain stones were very hard and, when broken, they formed very sharp edges.   These were logically used to produce cutting tools such as knife blades, arrowheads, axe heads and scrapers.  Geologists have refined classification of these various stones into categories such as flints, cherts, jaspers, chalcedonies, agates, quartz, obsidian, etc.  For the purposes of simplicity it is easy to lump them into two broad categories: Flint-like and obsidian. 

Flint-like stones all have a microcrystalline structure that breaks with a conchoidal fracture.  They are very hard (about a 7 on the Mohs Scale).  Their hardness and fracture qualities make them ideal for creating a durable cutting edge.   If you need a durable cutting tool, a flint-like stone would be your best bet.

Obsidian is natural glass that was made by volcanic action.  It also breaks in a conchoidal fracture and has a hardness of about 5.5 on the Mohs scale.   Since it was formed by quickly cooling, it does not have a crystalline structure.  Obsidian fractures to form an edge even sharper than the flint-like stones. Fractured obsidian can form an edge sharper than high-quality steel scalpels.  Since it is essentially glass it is more fragile than the flint-like stones.  If you needed to create a scalpel, then obsidian would be your best bet. That’s not to say that you can’t still make a fine tool from it.  It is just softer and more brittle than the flint-like stones. Obsidian can also be polished to form a mirror.






What is the most effective way to kill pathogens in drinking water?

Boiling: Handy to know the answer if you are out backpacking or taking a trip to the less civilized parts of the world. Common options are to use chlorine, a ceramic filter, iodine tablets or to boil the water to treat it. Boiling water is the only known method that is 100% effective in destroying pathogens known to cause sickness. The Centers for Disease Control have a very handy chart comparing the effectiveness of various water treatments. It may not be as convenient as the other methods but it works and is effective.

True or False: Bees and flies can help you find surface water?

True. Bees don’t usually fly more than 3 miles from their nests and must have a constant water source. So watching the direction they fly when leaving the nest can be a valuable tool for locating water. Flies stay even closer to water – about 100m or so. Paying attention to insects and vegetation can be very important to finding water.  According to The Backyard Beekeeper by Kim Flottum, bees seek water sources that are scented.  They smell the water and they fly to it.  That’s why you see bees at swimming pools or stagnant puddles vs. fresh water sources.  Once they find a source they mark it with a pheromone so the other bees in the hive will find it.  My grandfather could locate a wild bee hive by sitting in a field of flowers and watching which direction the bees flew when they left.  He would then walk that direction and repeat the process until he pin pointed the hive.  Seems reasonable that you could do the same thing for water.  

The exception to this might be flies in the desert.  Those little buggers seem to come out of nowhere. Not a drop of water for miles but the flies still seem to survive.