Basal thinning

[Sparrow]

Basal thinning is kind of a bugaboo for me. I think I probably mess up at this point more than any other stage except percussion preforming. I have been using light percussion to whack out these basal flakes and often it works good,but sometimes......(yeah, far as I can throw it) I just really like a point to taper from back to ensure a great transition when hafting into the shaft. I think there must be a better way. I have never learned how to use an ishi stick properly and wonder if maybe that would be the way.
I don't be knowing. It is usually the last stage I do before I do the final pressure flaking of the edge to sharpen the point.  This similar to how anyone else does it ?   (I need to sit-in with some good knappers)  '  Frank

[Bevan R.]

I feel your pain sir. I use an Ishi stick almost exclusively and still have that issue. I am researching on how to do a Clovis type flute to see if that is an option.

[Will H]

I know what you mean sparrow. This used to really mess me up until Jesse showed me the trick. The key is to start basal thinning early on. Run basal flakes before you run your thinning flakes so the side flakes cover your basal flakes alot of times the basal flakes will run up and step so when you run your regular thinning flakes they will usually take out those little hinges. By the time you get to final shaping/sharpening you will have the desired thickness profile for easy hafting Hope this helps! That's my 2 cents

[iowabow]

Will is right on target! As I finish the biface I move to the end and isolate the median ridge with kind of a nipple and drive a nice flute down the center.  Then I prep the two ridges on each side and drive two more off and then soft hammer flake 4 and 5 so not to take an edge off.  I have been also fluting just before final pass of flakes but you should wait before doing that because it requires certain elements to hard to explain with out writting a whole paper on nipple prep and proper holding.  I am still not real good at it but I am getting much better.  The pictures seen below are an early, middle and late stage reduction examples.  The white one is my final step before driving off the flute.  If you look close on the first to bifaces you can see flute running in and stepping like Will stated in his post. 

[JackCrafty]

Thinning from the base is like playing a game of catch with a raw egg.

Don't be aggressive.  Take several small, long flakes instead of a few large ones.  Eventually you will be able to take fewer and fewer flakes but it takes practice, practice, practice.

Will's advice is very good.

[iowabow]

I ran out and knocked this out to show that long thin works can be hit but you really have to have a good platform.  Here the preform was basal thinned last twice on the same side with good platforms and thin flakes.  You can see the remains of the two prep flakes and the center flake.  I only made one pass with the flakes starting base to tip and already the center flakes are merging with the first pattern of flakes.  I would next finish the right side then thin the base and finish the flaking pattern.  When hitting the base it is not good enough to have a good platform but you need a break flake first.  A break flake creates a place where the harder hit flake can snap from.  So I make a real soft tap or to play it safe with a pressure flaker then I can start reducing without as much worry about shock to the stone.  If I am in a hurry I use a small copper bopper and knock a flake off then go back to a larger one to drive a flake.  I learned this the hard way with the 80 obsidian points I made last month. Don't forget the relief break flake first.

[iowabow]

I have been getting ready for an event so I need a couple bifaces.  Anyway here is another biface with some agressive basal thinning flake work.  I twice drove flakse form the base here is a photo of a nice flake.  I have to do a lot of thinning from the base because many of the stones I use are very small.

[Sparrow]

Thanks alot. (Man, pictures save a thousand words) I am trying to take off too much at once.  '  Frank

[iowabow]

Just remember that there are many different ways to do it and there is not just one way to do it.  Me Will, Scott, Jackcrafty and other will all have just a little variation on the same theme

[StevenT]

This is some good stuff! Your explanation of taking off the two prep flakes before taking the center flake along with the great picture showing it was fantastic. Thanks mucho!

[cowboy]

All good advice! early on is the optimum time to take thinning flakes from the base unless you are setting up a nipple for a flute later. I've always used what i call a spider grip on the bi-face while hitting the basal platforms. You have to support your bi-face from all sides while striking it or your two peices will fly through the air just after you experience end snap . I have my thumb on one side opposing the three fingers on the other side while pinky finger is on the tip. squeeze in from those three side while hitting and it "usually" won't break..
 Later on i use the ishi for final thinning and always start a series of flakes from the base. as already stated you can clean all those steps up from the sides on the same pass.

[Bevan R.]

I understand the process if you are percussing the stone, but I mostly knapp slabs. Is there a trick to running flakes like that using an Ishi stick?

[iowabow]

I think I am going to let Will ring in on this because he is going to teach me about the ishi stick this weekend (I am using wood he is using a plastic of some kind). I do almost all thinning with percussion then switch to the ishi. I am using a Tower/Shannon/John Bybee technique. So I don't do a lot of ishi but Will explained on the phone a real cool process that I hope he will share with you all.

[gstoneberg]

Good thread, I struggle with this too.  I'm usually working on smaller spalls so I'm worried about losing length.  Consequently, I try to do most of the thinning at the base end from the sides.  Lots of times I don't do very well.  This is helpful.

George

[David_Daugherty]

Sparrow, thanks for starting this thead.  This is one of the best threads I have followed on any of the forums. very good instructions on basal work.  I followed the advice on the thread today and have had really good success with it so far.  Thanks to all the good tips on here as well, this is what makes this site fun.  We get the opportunity to share and to learn.  Really great stuff again, thanks to everyone involved.
David