Centerline

[toms22]

A question, Just getting started in knapping. How do you raise the centerline on a piece of flint, Would someone please try and expain to me how? In order to get the flakes to go past halfway in pressure flaking. I have watch a bunch of video on you tube. boy the knappers make it look easy.

[knap_123]

ok, let me give it a go. so you no were the center line is right. well you can use a pressure flacker or hammer stone or ishi stick to raise the edes. i like the side of my bopper.  i hold it were its straight up and down and lightly brush the edges so small flake removal raises the edge.  the grind it good. instead of going side to side with your grinder sort of grind so you bevel the edge you  raised.  hope this helps, happy knapping john.
 

[billy]

John,

Everytime you knock a flake off a piece of stone, you remove material underneath.  That means if you are striking downward (or pressure flaking downward), each flake removal will move the edge upward (toward you).  When raising the edge toward you, only take small, short flakes.  Like knap said, just short brushing of your tool along the edge will do that.  Pressure flaking will require straight down pressure.  Sometimes you'll have to do that several times in order to move your edge the desired amount.  Once your edge is moved enough, then you grind the edge with a pebble or coarse stone.  Now, flip the point over and the edge will be below centerline.  You should notice a steep bevel on that edge.  You will strike (or pressure flake) more straight-in to that bevel.  Pressure flaking will require you to push straight in, then while maintaining that inward pressure you quickly change your angle downward.  That should drive much longer pressure flakes.  Percussing flaking will require you to strike more straight in, that will also drive longer flakes. 

 

[toms22]

Thanks to all that answered ny question. I understand a lot better and will put this information to use.

[D. Tiller]

I use the side of my copper bopper and push down while using a twisting motion. Seems to sheer just fine leaving a nice platform ready for me to smack or pressure flake.