#pressure flaking

Here's the dacite flake with very little serious flaking done:

And here's the finished lanceolate point it became:

I cleaned up the platform a bit with hard hammer percussion, but the rest was done with an antler pressure flaker.

Turned out pretty good, actually. At 1 1/4 inch it's a bit small for the (theoretical at this point) atlatl, but still functional.

I'm trying to teach myself to think about projectile points the way people who actually used them archaeologically did, which involves a lot of making points out of whatever stone I have, packing them around in my pocket, using them for random tasks they weren't necessarily meant for, and breaking or losing them occasionally.

My brain immediately files them under "treasure", but I need it to start putting them somewhere near "box cutter blade".

Flakes from Flat Surfaces (Winn 2003)

I did some more test flaking on obsidian slabs to observe the shape of the flakes removed. Flakes were removed with pressure using an Ishi stick with a copper tip and another with an antler tip on the 1st test [Photo 1]. And a 2nd test was performed with percussion using both copper and antler [Photo 2]. All of the slabs were photographed afterward showing the slabs as well as the tools used.

OK, so what does all this prove? Well, it seems that the type of tool used (copper or antler) as well as the method of removal (percussion or antler) have little impact on the shape of the flake removed! There may be some minor differences that I could not detect, but they are insignificant. Of course, this only applies to a flat surface which provides ideal conditions and repeatability. Is this knowledge of value when removing flakes from an irregular surface, such as a biface? I think it is. That is just my opinion, but the whole purpose of performing a test like this is to gain insight into what can be expected under typical conditions that are not perfect (the surfaces we encounter in bi-facial reduction). I'm going to make the assumption that the shape of a flake removed from any surface has little to do with the type of tool used (copper or antler) or the method of removal (percussion or pressure). Instead, I believe that the primary determining factors in the shape of any flake removed from any surface are primarily a result of the following.

The shape of the surface where the flake is to be removed. The flake will follow ridges if they exist and it will fan out on flat surfaces.

The point at which the pressure is applied (when pressure flaking) or the point of impact (when percussion flaking). This will determine the initial thickness of the flake as it begins its travel.

The amount of applied force. This factor affects the mass and shape of the flake removed. More force is required to initiate fracture as the platform depth is increased (or the depth below the surface at which the pressure flaker makes contact).