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 iamanbk |
What happened? |
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Posts: 84 (03/28/09 3:22 PM) |
This was a nice 7" Keokuk spall. I was trying for a long thinning flake. It ran to 1/2" from the end of the spall, which would have been great,
except for the "waves". I was using a 1" weighted copper billet. The platform was solid and ground. The ridge ran almost to the end of the
spall. Any thoughts why the divots appeared? My next hit snapped it in the divot closest to the middlr.
Thanks, Jeff 
"If you haven't found something strange during the day, it hasn't been much of a day." |
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knapperbob |
rebound | ||
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Posts: 39 (03/28/09 3:46 PM) |
Jeff,
The divots appear because the billet bounces. Copper does that because of its hardness. Antler has less of a tendency to bounce but too much muscle can do the same trick. There is a limit to how far you can run a flake of a given thickness with copper before it hinges, because of the bounce. Bob |
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aztecstoneandflint |
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Posts: 231 (03/28/09 5:15 PM) |
I agree with Bob and to expand a little, you were on the verge of an overshot, where the flake wants to curve into the rock. From what it seems like you said is that you took a second stike from the same end which (if you did) would follow that first curve into the rock and, unfortunatley, complete the mission. Softer stike and or less depth/angle would prevent this. Any time you stike a wedge shaped piece ( and you did strike in the right location) the force is more chaneled, it is even worse when the wedge is wider at the opposite end. Once you get into this mess you should consider working back into the waves from the other end or from the sides.
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 clamdigger |
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Posts: 52 (03/28/09 5:18 PM) |
i agree with bob, this has happened to me many times. you took to big a bite. also that seems to happen more often with
heated stone . IMO the energy starts to dissapate at that first ripple, it doesnt terminate in a hinge because the stone is heated, the flake continues but the path of the flake is interupted. leaving you with ripples as opposed to a hinge fracture. |
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BOHUNTER |
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Posts: 858 (03/28/09 5:28 PM) |
Your strike was heavy to remove the ridge, the deep start only left it one place to go and that was downward. As it ran out it started down as ANY flake will
do and ran out of energy. As it slowed rapidly it rippled. So just clip the other end and make one towards it and this will clean it off or feather it out!
Long piece, should be a killer inside. Try and remove as much thickness from the ends before you attack the sides. Ive seen the technique in a lot of videos so there has to be something to it! Attack mass, from ends and keep it balanced out! Nice rock! We wanna see the final piece!!! |
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BOHUNTER |
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Posts: 858 (03/28/09 5:29 PM) |
Your strike was heavy to remove the ridge, the deep start only left it one place to go and that was downward. As it ran out it started down as ANY flake will
do and ran out of energy. As it slowed rapidly it rippled. So just clip the other end and make one towards it and this will clean it off or feather it out!
Long piece, should be a killer inside. Try and remove as much thickness from the ends before you attack the sides. Ive seen the technique in a lot of videos so there has to be something to it! Attack mass, from ends and keep it balanced out! Nice rock! We wanna see the final piece!!! |
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sandhillcowboy1 |
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Posts: 1228 (03/28/09 5:44 PM) Administrator |
Jeff,
How were you holding the spall on your first strike? Rick |
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iamanbk |
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Posts: 86 (03/28/09 5:50 PM) |
I was holding it on the outside of my thigh with my leg pad curled around the far end. This was only one strike. I made a lot of gravel today!
Jeff
"Reality is something you rise above."
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flint hills50 |
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Posts: 41 (03/28/09 5:58 PM) |
I've had the same results happen to me, holding it just as you described. That would be a fun shot on the "Time Warp" show! Craig
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aztecstoneandflint |
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Posts: 232 (03/28/09 6:17 PM) |
Jeff, you said your second stike snapped it at the first ripple. Did you stike it from the same place as the first? Joe
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iamanbk |
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Posts: 87 (03/28/09 6:23 PM) |
Same side - I tried to follow the ridge on the left side. The flake was good, and I had the end supported, but it still snapped.
Thanks, Jeff
"Reality is something you rise above."
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