Turtle Backs

[iowabow]

Ok last two pictures but thats kinda how I handle turtle backs with junk in the trunk. I don't work them normally because they are hard. I started this at 8am and it is 4pm now I took a 2 hour break.

[Timo]

Great job on a tough piece. Some of those long flakes would make good gun flints.

[iowabow]

I I have not seen any gun flints.  Do they break them in half and the flake one end?

[JackCrafty]

Here's how I do it. 

http://www.youtube.com/watch?v=5P-1edaal18

http://www.youtube.com/watch?v=EUcm8lD0Rm4

[iowabow]

That is to cool that you can knap like that jack.

[JackCrafty]

Thanks Iowa.  My flintknapping buddies out here gave me some funny looks at first but they are used to seeing it now.   

[iowabow]

I just doesn't look like it should work. I tried one day to do it after watching your video and it was a nogo for me.  I think I am going to have to see it in person.  You however make it work amazingly well.

[JackCrafty]

Watch my video "A Different Perspective" to get a view of my technique from a distance.

[aaron]

i want to chime in on strategy for turtlebacks- preforms with one flatter side and one humped side. The humped side is difficult to thin. conventional wisdom says that this is a problem of centerline- it's hard to thin the humpped side because the edge is so far "above" center ( a "high" edge, when viewed with the humpped side facing down). therefore you could move the edge toward center , letting you get at the humped side. (others above suggested this) BUT- this sacrifices length and width fast. Therefore, I try to use massive percussion flakes to thin the hump with only one or two flakes which come off this "high" edge. It's kinda like a deep overshot flake. you have to set up steep strong platforms and give them a mighty whack- hard to do on smaller pieces, but i work in easy obsidian. I think this is illustrated by the pic above in timo's post where he drew a platform on that artifact photo.
to state this another way- I just ignore the rule which says platforms should be near or below the centerline. The flake wants to hinge as it dives into the hump, but with enough oomph and support, it can lead to some nice rapid thinning.
i didn't watch jackcraftys whole vid, so sorry if this is covered there...(cool technique, though !)

[bushman]

Thanks for all of the help everyone, it has helped a lot. Thank you iowabow for taking the time to take all of them pictures to show the process and for posting them, was that a piece of coral? 
Bushman

[iowabow]

No it was a piece of flint burlington.

[gstoneberg]

I just doesn't look like it should work. I tried one day to do it after watching your video and it was a nogo for me.  I think I am going to have to see it in person.  You however make it work amazingly well.

I learned from Patrick so I use his indirect percussion method too.  Even sitting with him, I really struggled with the technique at first.  It took the better part of 2 days to begin to "get it" so to speak.  The hardest thing for me was understanding how hard I needed to hit that thing to run a long flake.  I've finally ordered some plastic bars to make duplicates of his.  Hardwood just will not take the bashing.  Since I have a small wire in one end of the tool I do almost no pressure flaking except to sharpen and notch the point.  That's the next thing I need to learn.  I think my problem with turtle backs is that I don't do enough platform prep, especially abraiding, so I get the big flake when I go for it.  If the preform is relatively small, and most of mine are, I only get a couple of attempts at knocking the hump off before the point is too narrow or too short.  It is definitely easier to do with direct percussion, but if I miss a little bit I sometimes ruin the point.  I hate it when that happens.

Good thread.

George

[iowabow]

I think working a turtle back takes time and material.  The more you work at it the better you get.  Everyday I get better because of what I learn from the last point.