In this article I will try to explain how Bill Earnhardt does his edge to edge flaking. This type of flaking is fairly complex so I hope I can explain it in a way that makes sense.
The biggest challenge with edge to edge flaking is that you are in a constant state of adjustment for the width of the blade. If just one flake comes up short, the whole piece is ruined and you must start all over.
The two main concerns with edge to edge flaking is the platform angle and the degree of bevel on the face side of the blade where the flake is being removed from. The problem is, as I mentioned, is both of these angles are constantly changing as the blade width changes. I will have pictures to accompany this article showing the difference in degrees of the angle for the longest flake at the widest part of the blade to the shortest flake at the narrow part of the blade.
The angles being shown are for obsidian, keep in mind different materials will change these angles so you will be have to adjust accordingly.
I would estimate the angle of platform at between 95-100 degrees for the longest flakes at the widest part of the blade.(picture 1) The degree of the angle decreases to around 85 for the shorter flakes. (picture 2) So throughout the length of this demonstration piece, we can see a variance in the angle of the platforms by 10-15 degrees. The degree difference could also vary depending on the width and length of the blade, seeing a larger variance with longer wider blades.
The other angle you must adjust is the bevel on the face of the blade where the flake is being removed. For the longest flakes at the widest part of the blade the degree of angle is around 170 degrees.(in relation to the blade being at 180 at straight up). The majority of this angle is formed in the bottom 1/4 of the blade face which corresponds with the end of the flake so you are actually removing less material at that point to keep the flake from stopping short.(picture 3) The bevel angle will increase up to 180 degrees as the blade width narrows and the flakes become shorter.(picture 4). So here again, we are seeing around a 10 degree difference which could also vary depending on the length and width of the blade.
For the flakes in between the widest and shortest widths of the blade, both of these angles for the platform and bevel will be some where in between the degrees given above. I can't give you exact angles for each, because they will change for each individual flake, so it will be up to the flintknapper to adjust for each flake. But atleast in this article, I have given you the parameters to work within.
Picture 5, shows the face of this demo piece and the lengths of flakes as they get longer. This piece is for demostration purposes only, it was not intended to be an actual blade. The last flake was not removed so you could still see the actual angle.
I hope this article and pictures have helped and it makes some sort of sense of what I am trying to relay to the reader.
I have made a video to accompany this article where I show the angles shown in the pictures and I discuss what I am trying to show in the pictures. That video can be viewed on our YouTube channel and it titled "Edge to Edge Angles". A direct link to the video is http://www.youtube.com/watch?v=GAmFpSBJLvk&feature=c4-overview&list=UUkAae6MidBwAAzR9GCnprNg
Or watch it here.
There are also two other videos of Bill doing edge to edge flaking on the YouTube channel at http://www.youtube.com/BillEarnhardtKnappin
Picture 1
Picture 2
Picture 3
Picture 4
Picture 5
