Thursday, May 23, 2013

FAIL Knaping

atlatl dart for soil abrasion test
I’ve been putting a few test together over the course of the last couple of weeks with varying levels of success.  Most of the tests have ended in broken arrows, split atlatl shafts, squirting blood and shattered projectile points…so I'm pretty pleased.  Since the recent round of tests fell a little flat I’ll lump them together and chat about them all briefly.  Still, I learned a few valuable lessons and have a few ideas for future directions.
split foreshaft and cut sinew from impact on root

The first test was set up to get a better understanding of the shape differences created through point breakage and recycling versus knife dulling and re-sharpening on obsidian artifacts.  As it goes, we rarely encounter stone tools still in the hafting element and as such must infer the use as either a knife, a projectile point or both.  This little test came about as I wondered how many times projectile points needed to be re sharpened due to dulling from soil abrasion or breakage by impact.  This question came up the other day in a conversation about whether an artifact was a knife that had been flaked to re-sharpen it or a large extensively re-shaped point. 
tip damage from impact on tree root

 For a quick (and inconclusive) test I armed a dart with an obsidian point and shot it in to a sandy loam soil until it either shattered or became too dull to cut anything.  The test needs more controls and projectile points, but I was able to get eight shots into the ground with only minimal dulling of the cutting edge.  The point broke against a tree root on the ninth shot and created a fantastic example of an impact fracture. With my luck (or rather, lack of skill) I would break a dart point against a random hard object well before I had shot it so many times to warrant a resharpening flake pass.  Of course the most likely scenario would be a mixture of snapping and recycling alongside dulling and re-sharpening over the course of a hunting season depending on the hardness of the ground, hafting strength and the number of shots missed.  I’d like to revamp the test with a hundred darts or so to get a better picture of dulling versus breakage rates.  For instance, how many missed shots does it take to create an edge too dull to pierce hide and warrant retouch?  We’ll have to see.  I've never found a fragment large enough to re-sharpen after hitting a rock at 30 miles an hour so it seems that the local soil matrix will have a big effect on my breakage and re-sharpening ratios.  

reproduced crescent for hafting test 

The second test ended with me destroying the haft element two shots into the gig so I had to pack it up for another day.  I was (still am) interested in the prehistoric use of obsidian crescent tools.  This tool type is often encountered within Paleoindian assemblages, especially at sites located near relic shorelines of marsh environments.  These tool types have been tested for blood residue and appear to have come in contact with waterfowl, deer and human tissue.  Some have suggested that the more ornate shapes may represent prestige items or pendants.  Either way, I was going to haft the thing and launch it at meat to check out what type of damage pattern the system would deliver.  Well, the hafting element broke after two shots and the whole thing fell apart.  The wide surface area of the weapon seems to have shocked the haft and the whole mess became unusable.  I expect that this combination could do some serious damage, but unfortunately this is a test for another time.

pendant or projectile?
The Third test was a relative success. I was hoping to find out the smallest of river cane for use in my 45lb bow.  I have a stand of cane behind the house and have been trying to find an ideal length/diameter combination for this particular type of cane.  This cane needs heat treatment and straightening, as it tends to split due to flex otherwise.  Heating the shaft under low 
indirect heat helps to strengthen the arrow and makes thin river cane quite robust if done correctly.  The last cane arrow that worked well was used for the Foreshafts of Doom test.  That was about as large of a diameter as I could imagine working well.  Turns out that the wiggle room for the diameter and length combination is actually pretty small. Like my other tests, the twist of the feathers in flight sends lightweight shafts floating off to the top left.  In this test I had equipped the arrow with a heavier projectile point to compensate for the lightweight shaft.  This combination worked a little better but still wasn’t as accurate and hard-hitting as it should be.  The 45lb bow seems to want a slightly larger arrow diameter, medium flex and a projectile point that makes the arrow’s center of balance just forward of the middle.  I’ll keep refining the test.

don't worry it came that way

here's a point made on obsidian from Turkey, thanks John!

1a) poor isolation and bad angle took too much off from the platform

1b) removed flake showing the faulty platform