It feels sharper on the 6000... but I'm mostly testing cutting paper and not really putting the knives to their actual use. So maybe it doesn't feel so sharp cutting paper but it might work better for its intended purposes?
Paper cutting tests a few things. One of the big ones is burr removal. If your edge still has burr on it, paper tells you because it hangs, catches, and tears the paper. If your edge is dull, paper tells you because the blade will not initiate the cut. In fact it can tell you some relative sharpness depending upon the exact cut. But let me get back to that in a minute.
You are probably making better paper cutting edges from the 6000 stone for two reasons:
1. A fine stone is much easier to deburr with. The finer you go, the easier it is to deburr. The more coarse the stone, the more difficult it is to deburr. You are probably removing the burr really nicely with the 6k.
2. A finer (more polished) edge does better in paper. The edge will be thinner, smoother, and (as above) more completely deburred.
A more coarse edge will really "hook into" what it is cutting. Which makes cutting slick materials (like soft tomatoes) easier. Really polished edges can slide off of slick material.
Back to paper for a moment. Try these exercises:
1. Cut paper along one of the factory edges. Notice how it cuts.
2. Turn the paper 90 degrees and cut along a different factory edge. Do you notice a difference? You should because the grain of the paper runs through it and going with the grain is easier and against the grain is harder.
3. Get a fresh sheet and start with the "easy" side (with the grain). Line your blade up with the paper. Now notice that there are 3 axis that you can move the blade relative to the paper:
A. You can lean it over and cut a triangle off of the paper. Keep it as straight up and down as you can, so it cuts a rectangle. This is harder than an angled cut.
B. Start again and notice that you can rotate the knife so that it is straight like in (A) above, but the blade is angled with the *edge* of the paper. Make that angle 90 degrees. This is harder.
C. Start again. Line up like in (A) and (B) above. Notice that you can tilt the back of the blade up or down, which makes yet another angled cut into the edge of the paper. Make this 90 degrees also. So 90 degrees in all three dimensions directly into the edge of the paper. This is the most "pure" push cut you can make and is the most difficult.
Many very sharp edges can't really start a push cut into phonebook paper with a pure 90 degree cut in all dimensions.
Try this with the grain *and* against the grain. Against the grain is quite difficult. My super polished edges from the Spyderco UF could push cut, against the grain, with a 90 degree angle in all 3 dimensions. Less polished edges will struggle to do it.
Some of this is just messing around. Real world sharpness is defined by the user. I find that a coarse edge, which is completely deburred, performs really well for me in real world tasks. Like cutting meat and vegetables. Like cutting open plastic "blister packs", or opening boxes. Try both and see what you like: Polished and coarse.
Brian.
