Thursday, June 27, 2013

Ground Stone Workshop

Hi all,

The world of stone tools is of course so much larger than flaked projectile points.  Ground stone artifacts played a major role in processing food, making other tools, jewelry, house construction, warfare and a myriad of other uses.  The other day we were lucky enough to have Jenny Adams come out to the field school to give a ground stone artifact workshop.  Jenny is the author of “Ground stone Analysis: A Technological Approach”.  Her exceptional book details the use of stone tools that were shaped by grinding and pecking and illustrates the methods that archaeologists use to collect meaningful information about these kinds of items.  Here are a few highlights from the workshop!
Grinding corn with a mano (hand held grinder) and metate (large U-shaped basin) proved to be quite the task and showed how much effort really went in to creating a meal for hungry families.  These formal items are often found within prehistoric room blocks associated with mealing bins where corn flour was produced and collected.  

The groundstone axes and war clubs were amazing.  The effort to create these tools is astounding to think of.  If it took me an hour to cut through an atlatl blank with a stone saw, imagine the effort expended on the creation of these items!  The size of the artifacts were a little unsettling as well; I would not like to have this coming at me, nope, no thanks.

Stone drills were often used to hollow out pumice or other vesicular volcanic stone to create smoking pipes.  The stone drills performed fantastically and made relatively (as in it still takes a while) quick work of stone pipe bowls. 

The use of tabular stones for grinding small holes on shell for ornamentation was an interesting endeavor that illustrated the time investment locked up in a single necklace. 

The groundstone implement for straightening arrow shafts was also pretty fantastic to see in action.  I would like to have one of these little gadgets for sure.  By passing the arrow shaft back and forth the shaft becomes smoother and straighter, all the better for zipping though the air!

thanks for coming out Jenny!!

Wednesday, June 26, 2013

A Lesson in Diligence: Making an Atlatl with Stone Tools

Hi all,

undisclosed activities at undisclosed locations 
For the last few weeks I’ve been out in Mule Creek, NM working as staff for the fieldschool run by Archaeology Southwest.  Check out the field school blog here!

I didn’t bring an atlatl along for the project so I decided to make one.  Then of course I had to challenge myself to make it all with stone tools, hasty decision for sure.  Just to be up front with the conclusion to this whole thing…I broke down and did the finishing touches with a metal blade.  I know I know, but hey I made a functional weapon system and used stone tools for 95 percent of the labor so it’s a decent first try.  Next time will be 100 percent stone tool manufacture now that I have the techniques down a little better. 

original blank

Perishable implements: 

tree stump with a split in it
One halved segment of cottonwood limb that Rob Jones (hey bud!) and I had set aside to cure last summer
One Juniper limb segment for a hammer
Antler tines to retouch tools and help reach the stone wedge when it gets to the midpoint of the atlatl blank

Various stone tools:

Quartzite wood splitting wedge
Quartzite drawknife
Basalt drill
Basalt saw
Quartzite saw
Rhyolite saw

indirect antler method
direct hammer

I’ll say it straight up; this thing takes a heck of a lot of time and patience to complete.  But then the balance of value and disapproval one feels toward effort spent is a relative measure, isn’t it?  I chose to saw a piece of wood in half with a rock, someone else might not see the fun in that.  The end result worked out well though and I learned a lot.  I had to figure out a way to thin the atlatl blank in an efficient manner without spending a year whittling the thing with a stone flake.  So I devised a plan to split thin shavings along the grain of the blank with a wood hammer and stone wedge from the interior of the blank towards the rounded outside of the piece. 

I figured the convex outer edge would offer a little extra strength over a simple flat piece of wood but I’d have to test that to find out.           
The wood splitting endeavor actually worked really well.  I was surprised at how fast I was able to reduce the blank into a thinner piece.  The quartzite held up well and needed tweeking and edge sharpening now and then.  Usewear on the splitting tool came in the form of chipping on the working edge and polish on the high points across the ventral and dorsal faces. 

Most of the work came in the form of cutting the blank to size and shaving the contours of the atlatl with the stone drawknife.  One cut took me over an hour to complete and I went through four resharpening events on the basalt saw and two resharpening passes on the quartzite and rhyolite saw before I was able to cleanly snap the unwanted section from the blank.  I was also pretty surprised at the amount of debitage created from making the atlatl.  I will sift the debitage and broken tools to get a better understanding of material usage rates for the next blog post.

After a few retouch events the saw edge became too thick to fit into the cutting groove such that the tool faces were in contact with the wood but the working edge was not.  At that point the tool became useless as a saw and had to be replaced.  Think of the geometric index of reduction (GIR) for hide scrapers but translated to saw tools.  After a certain amount of re-sharpening a tool ceases to perform adequately and is either discarded outright or saved for future reduction and use.  This pattern was cool to see in operation.  Sturdy stone material such as basalt, quartzite or rhyolite is essential for this process as obsidian or chalcedony would break right away.   

Starting a split with the wedge
Ok so the atlatl came together well.  I thinned the piece to so it flexes slightly and drilled a hole with a basalt drill to insert an antler spur.  The antler spur was set into the atlatl with pine pitch glue and seems to work ok so far. I’m sure it will break and need replacing at some point soon. 

The dart is still under construction but all that remains to be completed is fletching with turkey feathers from the ranch next door.  The shaft is made from river willow taken from Mule Creek, the dart point is made from quartzite (unknown sort of local location?) and the point is set into the foreshaft with pine pitch and a fiber wrap.  Oh, and we have yucca cordage for the handle.  Soon this battle station will be fully operational! 

Cheers and happy hunting!   

edge damage and polish from friction on wood 

This quartzite saw was decent but not great, 6 out of 10. It dulled quickly and chipped easily

The quartzite saw seemed to work better as a drawknife rather than a back and forth type saw edge

original basalt saw flake blank
Basalt saw after two additional sharpening passes. Basalt saw won the day

river willow branches for dart shafts
Dart shafts pegged out to cure 

I'll show the completed project soon!

Thanks to Danny Beard for the great B&W photo