"no bulp of percussion" thinning

[iowabow]

The bulb is very flat anyways. I have been trying to explain mid stage thinning with percussion since I had that awaking a couple weeks ago and posted thinning pictures. Tower also described flakes he found with little bulb of percussion. So I stated looking at my flakes more closely and worked on perfecting a technique that could be easy explained. I took many pictures of the end of mid stage thinning. The center is thinner than the magins no edge. Also almost no flake scares from thinning as the merge. It very interesting because if you can do this over the stone then it is fog. Without the grind this is me dreaming about a perfect point.

[iowabow]

This picture is of the flake

[iowabow]

Thes pictures show how nice they blend

[iowabow]

These two flakes cut stone in half almost.

[iowabow]

This picture shows the heavy bite on a strong platform. This is the mid stage secret.

[iowabow]

Maybe I am a little past mid stage but ya get the idea I hope.

[caveman2533]

Look like you are ripping the platform edge off, or lipping. The flake should have a tiny lip where it was torn from the edge. If you can control that it can leave a wicked edge. But it is also very risky because the very thin edge is also very fragile. I try to avoid lipping on flint. On argillite and rhyolite and quartzite this common and is a normal flaking signature of wood struck flakes.

[Hummingbird Point]

iowabow,

You talking about pressure or percussion flakes?  On percussion flakes, you can get very little to no bulb by using elk anler.  It is "springier" or some say "softer" than whitetail so you can get away with less (sometimes no) abrading and the antler will dig into the edge and pull the flake off.    I do this sometimes kind of just by feel in late stage work using a hafted antler which allows me to kind of swing the antler into the edge and pull down on the tool's handle at the same time, basically making a big presure flake.  I don't really know how to explain it.  I just do it and don't really understand it.  Anyway, point is, when I see people talking about no bulb, or flakes that show no abrading, I think of elk antler, although with my whitetail "antler hammers" it works to an extent too.

Keith

[caveman2533]

One step away from a perverse fracture

[iowabow]

iowabow,

You talking about pressure or percussion flakes?  On percussion flakes, you can get very little to no bulb by using elk anler.  It is "springier" or some say "softer" than whitetail so you can get away with less (sometimes no) abrading and the antler will dig into the edge and pull the flake off.    I do this sometimes kind of just by feel in late stage work using a hafted antler which allows me to kind of swing the antler into the edge and pull down on the tool's handle at the same time, basically making a big presure flake.  I don't really know how to explain it.  I just do it and don't really understand it.  Anyway, point is, when I see people talking about no bulb, or flakes that show no abrading, I think of elk antler, although with my whitetail "antler hammers" it works to an extent too.

Keith

shown was a percussion flake

[JackCrafty]

Yep, that's pushing the material to the limit...  with good results.  I see that on artifacts.  Broken or whole, he old knappers pushed the envelop. 

[iowabow]

One step away from a perverse fracture

I don't think I have heard that term used on this site. Could you define it for me. I think you mean snapping in half.

[caveman2533]

Yes usually cuts the point off at an angle, it when the crack rolls and goes vertical and cuts across the piece usually with a twist like shape to the crack. I know I sound negative about it not trying to be, just be aware like Patrick says you are pushing the limit.  The thin edge is a place cracks to initiate from bending stress. This edge ripping can be done when pressure flaking also, by placing the tip above center line. Will leave a wicked sharp edge.

[iowabow]

Yes usually cuts the point off at an angle, it when the crack rolls and goes vertical and cuts across the piece usually with a twist like shape to the crack. I know I sound negative about it not trying to be, just be aware like Patrick says you are pushing the limit.  The thin edge is a place cracks to initiate from bending stress. This edge ripping can be done when pressure flaking also, by placing the tip above center line. Will leave a wicked sharp edge.

cool do you have a photo of this kind of fracture? I may have done that on a small scale once. Also I am seeing a new kind of flake failure. Just wondering if it is related. These failures are not altogether bad.

[iowabow]

Caveman don't worry about sounding negative when you are providing really good information. We need as much good information as we can get on this abo section. Also there are so few doing abo it's kind of a brotherhood. Keep it coming.
On that note I feel it is important to point out how much of an impact this site has had on my knapping. A lot of people had a profound impact on my development. The list is long and some no longer post on here anymore but without their help I would not be where I am.
Tower kinda jumped in early as he saw me developing and sent me rock and a set of the finest knapped thin points I have ever seen. He also sent preforms. Gundoc has talked to me for countless hours about knapping, Shannon and Jessie helped a lot, as I read through old post I saw outback Bob and Bonepile offering help and advice. I read a lot of Jamie's post about ABO. Talked on the phone a lot to Scott about Burlington heat treating and his results vs mind. Paul Wolfe "cowboy" sure helped a lot. Can't forget that JackCrafty and all the videos Patrick has made. And let's not forget the the one guy that will keep you humble and always reminds everyone why strong ABO Hunting points are necessary for a guy like me. I am sure I am leaving someone out.
Now only after years of knapping I finally have a technique to mid stage thin.  I only hope this thread helps others on this ABO path.