Just can't get anything sharp…
- This topic has 13 replies, 8 voices, and was last updated 06/29/2016 at 11:21 am by
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Could be wrong, but just from your pictures, it doesn’t look like you’re hitting all the way to the edge…
… it looks like there’s a change in the grind at the very edge, especially as you near the tip. It could be, that, even though you created a burr with the first stone, the subsequent stones weren’t hitting the bevel at the same angle. You might try remarking your blade with a Sharpie between stones, and make sure each level is making contact in the same spot.
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600 grit should give you a very nice, toothy working edge, but it might seem a little coarse when trying to slice paper. I normally go to at least 1000 grit. If I’m really fussy about it, I’ll then polish it with 6 micron diamond film. For mirror edges, I’ll do the entire progression; 400, 600, 800, 1000, then 15, 9, 6, 3, 1,5, 1.0, 0.5 and 0.1 micron films. The 15 and 9 micron film is an equivalent to the 1200/1600 ceramics.
I think Cliff is spot-on about you’re not having reached the apex along the entire edge. If you fail to hit the apex with your 400 grit, you’ll waste a lot of time after that trying to make the edge sharp when in reality you haven’t yet made an edge. If you check with a loupe and are still unsure, go back to 400 grit and stone one side at a time until you can feel with your fingertips that there is a small burr on the opposite side and that it extends full length. A burr is the one sure tactile way of telling you that you’ve reached the edge. Do the same on the other side and when you know you’ve produced burrs on both sides, you know you have an edge and can move on to the next grit. You can follow the same procedure, or you can use the loupe to inspect the scratch pattern. Now you’re looking to see if the current grit’s scratch pattern extends to the top of the bevels. If you’re not sure, give your micro-adjusts a quarter turn CCW. A quarter-turn is roughly 0.1 degrees.
Usually, after having achieved an apex full length, I use five strokes per inch of blade length, which I’ve found will usually remove the scratches from the previous grit. Most of your time is spent on your lowest grit and things go pretty fast after that.
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Do you always need to strop after sharpening to get a well cutting blade? Should stropping always be the last step or can diamond film be the last step?
No… you should have a ‘well cutting blade’ prior to stropping. In fact, if you don’t have a decent cutting edge off the stones, I wouldn’t strop at all until you do. 600g should be easily cutting paper.
The rule of thumb generally agreed to on this forum is that you should increase the angle by 1.5 to 2 degrees when you go to soft strops. This is because the strops may roll over the apex and round off a perfectly good edge.
I thought it was the opposite… isn’t Clay lowering the angle a degree or two when stropping with leather? (Just to clarify, if he sharpens at 20 deg. he strops at 19?)
At any rate, tcmeyer’s post has some good info. My first thought is you’re using too much pressure… it doesn’t take a lot to sharpen, especially with the finer stones. Pay attention to this and the other points tcmeyer brought up.
My only other thought at this point is, if you do have a burr the entire length, the 2nd step is getting rid of it. Try this. Take the finest ceramic stone, raise the angle 3-4 deg. (so if you’re sharpening at 19 deg. raise it to 22 deg.), start at the heel of the blade with the bottom of the stone touching and make 2 very light, edge leading, alternating strokes, heel to tip. Very light… you’re not trying to create another bevel, just trying to remove any burr that might be there. Test the edge… if you don’t see any change try it one more time… if it doesn’t work, then stop (something else is wrong, and I don’t want you creating a new bevel you’ll have to sharpen out). Can’t emphasize VERY LIGHT enough.
Finally, don’t get frustrated, although the WE produces very sharp knives, the basics of sharpening still need to be learned to get there.
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Quote: “The rule of thumb generally agreed to on this forum is that you should increase the angle by 1.5 to 2 degrees when you go to soft strops. This is because the strops may roll over the apex and round off a perfectly good edge.”
Once I started doing this, I was on an entirely different level of sharpness. I didn’t realize that by stropping at the same angle I was sharpening I was removing my hair popping edge. I use a very very light touch when stropping so I go even less than 1.5 degrees. About .5 to 1 seems to do the trick for me. Or, I just go a half a turn on the adjusting screw.
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