Knapping in the Man Cave

     Home from the trip to Sunriver, I was eager to start working with the obsidian. First up, however, was to clean up Anne's CRV. It had treated us well while it slowly found the way to Little Glass Butte. To climb further to the top of Main Glass Butte would have required 4-wheel drive and a higher ground clearance. We'll need to save that for another day.

      Once I was cleared by the CRV boss, I hid myself in the man cave, fashioned a couple of knapping tools, donned my Bob apron and selected my first obsidian victim from one of the two bags we had filled.  

      The first thing that needs to be done with the stone is to attempt to create a usable flake. This normally means holding the stone firmly in one hand and whacking it severely with a hammer stone with the other hand. If you have selected a good spot on the stone's surface, then a piece(s) of obsidian will fall away. One needs to whack the stone at an angle which is away from the stone's center of mass. The angle is ~ 75 degrees. 

     Well, whack away I did. If I weren't such a newbie at this craft, I would suggest that it appeared many of the obsidian stones we had found at Glass Butte were defective, because all they did was crumble when struck. Of course, I was striking the piece incorrectly.  Alas, I finally managed to break off a usable flake.
      This first step is known as percussion knapping. This is often done with a river rock that is easily gripped and has a distinct striking edge. Using a percussion tool is often the easiest way to rid a flake of regions of excess stone.
     The next step is called pressure knapping. 
The lathe was handy to turn a couple of grips to hold small lengths of 3/16" brass rod. Metals such as copper, of which brass is primarily made, work well in holding firm on the edge of a flake of obsidian.
     When down and outward pressure is applied on the edge of the flake with the flaking tool, one wants to hear a snapping sound as the tip of the tool breaks past the edge. How the tool is positioned on the edge, at what angle of attack it is held, and how much thrusting pressure is applied all combine to determine the size and shape of the small flake which breaks away. A pointed antler has historically been favored as a pressure knapping tool.
      I used the drill press to center a hole in the end of the new handle. I then tapped a 2" length of brass rod into the end. I roughened the end of the rod with my hammer stone. The hammer stone can also be used to mildly abrade the edge of the obsidian stone you are flaking. This is important to repeatedly do, as flake removal leaves behind a shiny and slippery surface.       
     The surface one is working on is know as the platform. The platform must have an edge which is either flat, or slightly raised. If not, the flaking tool will just slide off. 
     I quickly learned that creating something like an arrowhead is not a very efficient use of an obsidian stone. It is my hope that my efficiency will improve rapidly so I do not cobble all of the stones into gravel and dust. 
     Within a few hours, and a couple of days, I had created a few arrowheads. A handful of them turned out to be very nicely proportioned; length, width, and thickness wise. I also created a significant pile of very sharp pieces of volcanic glass.     
                                               
                    
     As an archer, I was eager to try a few of the heads to see it they could withstand impact with my hay bale target butt. Over time many of my arrows receive some form of damage. I selected three which needed new points. 
     After carefully notching the tips, I used a waxed nylon string to bind the heads to the shafts. In the wild, one would use sinew to tie on the head and follow up with a pitch to take any small amount of wiggle out of the arrowhead. I chose to use a few drops of CA glue, aka, superglue. Those heads were locked in tight.
    It has been said that a fine flake of obsidian will create a cutting edge that is one molecule thick. This is compared to surgical steel which can be sharpened to within four molecules of thickness. The flaked edge of an arrowhead is much wider than one molecule, but it is still extremely sharp. I was impressed with the arrows' balance and how well they flew. All shot true and survived to be used again, and again, I hope.