Sharpening problem

P

pas3n7

Joined
Jan 10, 2010
Messages
14
Also hi, I'm new.

So I have this problem where I sharpen a knife, it's hair popping sharp, then I put it away and the next time I use it, it's not nearly as sharp.

I'm using a gatco rod system. I don't feel any burr when I'm on my finest two stones, and I use very light pressure.

Any idea what's going on, or what I'm doing wrong?

This happens on both my spyderco tenacious and my becker bk11 (The becker is 1095, and was oiled immediately after sharpening)
 
pas3n7 said:
Also hi, I'm new.

So I have this problem where I sharpen a knife, it's hair popping sharp, then I put it away and the next time I use it, it's not nearly as sharp.

I'm using a gatco rod system. I don't feel any burr when I'm on my finest two stones, and I use very light pressure.

Any idea what's going on, or what I'm doing wrong?

This happens on both my spyderco tenacious and my becker bk11 (The becker is 1095, and was oiled immediately after sharpening)
Click to expand...

I think you just happened onto one of life's little mysteries that no one can satisfactorily explain, using the laws of physics as we understand them today! :p
 
Thanks for the replies!

I guess I'll go on the assumption that it's corrosion, I'll oil a little more liberally and see what happens.
 
pas3n7 said:
Also hi, I'm new.

So I have this problem where I sharpen a knife, it's hair popping sharp, then I put it away and the next time I use it, it's not nearly as sharp.

I'm using a gatco rod system. I don't feel any burr when I'm on my finest two stones, and I use very light pressure.

Any idea what's going on, or what I'm doing wrong?

This happens on both my spyderco tenacious and my becker bk11 (The becker is 1095, and was oiled immediately after sharpening)
Click to expand...

I've noticed occasionally, that even when I can't see or feel a burr on my blade after sharpening, sometimes there's still a hint of a burr on the edge. It reveals itself when I strop the edge on leather after sharpening on the hones (I also use both Gatco and Lansky rod-guided systems). The burr will 'shave' little bits of leather and/or stropping compound off of the strop. And the stropping compound will even 'collect' underneath the burr on the edge (like it would collect under your fingernails if you were to scratch the surface of the strop with them). This makes it obvious as to where the burr is on the edge. When I see this happening, I use a ceramic stone with a stropping stroke (edge trailing) to straighten and/or remove the burr. Just make one or two light strokes on the stone, then strop on leather again to see if the burr is still there. Keep alternating in this manner until there's no evidence of a burr when stropping. In my experience, when I do this, I no longer have any issues with my fresh, hair-popping edge 'going away' when I put the knife away for a while. After I make it sharp, it stays sharp (at least until I actually put some USE on it ;) ).
 
Obsessed with Edges said:
I've noticed occasionally, that even when I can't see or feel a burr on my blade after sharpening, sometimes there's still a hint of a burr on the edge. It reveals itself when I strop the edge on leather after sharpening on the hones (I also use both Gatco and Lansky rod-guided systems). The burr will 'shave' little bits of leather and/or stropping compound off of the strop. And the stropping compound will even 'collect' underneath the burr on the edge (like it would collect under your fingernails if you were to scratch the surface of the strop with them). This makes it obvious as to where the burr is on the edge. When I see this happening, I use a ceramic stone with a stropping stroke (edge trailing) to straighten and/or remove the burr. Just make one or two light strokes on the stone, then strop on leather again to see if the burr is still there. Keep alternating in this manner until there's no evidence of a burr when stropping. In my experience, when I do this, I no longer have any issues with my fresh, hair-popping edge 'going away' when I put the knife away for a while. After I make it sharp, it stays sharp (at least until I actually put some USE on it ;) ).
Click to expand...


Thanks for the advice.

When you go back to the ceramic stone, do you use the same angle as when sharpening?
I've had some success using my finest stone by hand on a slightly higher angle than sharpening to touch up after it gets dull.

I was also under the impression that stropping was only for convex edges. If it's helpful in getting a more prefect edge, I may have to make that my next purchase (along with another knife, for scientific inquiry only :D).
 
You might have a small burr which ends up either unstraightening itself out or corroding a little bit.
 
pas3n7 said:
Thanks for the advice.

When you go back to the ceramic stone, do you use the same angle as when sharpening?
I've had some success using my finest stone by hand on a slightly higher angle than sharpening to touch up after it gets dull.

I was also under the impression that stropping was only for convex edges. If it's helpful in getting a more prefect edge, I may have to make that my next purchase (along with another knife, for scientific inquiry only :D).
Click to expand...

With regard to the angle on the ceramic stone, the important thing is to make sure that it's no larger (more obtuse) than the original angle you sharpened at. As I mentioned, I also use rod-guided systems to do the initial re-profiling/sharpening. After that, if I do notice a significant burr, I use the ceramic stone free-hand. But, I just make sure that I don't lift the spine of the blade too high when using the stone or strop. The beauty of stropping is in the fact that the soft leather will immediately reveal the burrs, nicks or other imperfections in the edge. Strop lightly on leather first, and if you do see evidence of a burr, duplicate the exact stropping motion on the ceramic stone (at the same angle as on the strop). Do it LIGHTLY, only a stroke or two at a time.

I don't know if you've already done this, but it's a great help to use a fairly strong magnifier (at least 5X - 10X) when inspecting your edge after sharpening. That also helps quite a bit in finding/removing burrs, even before going to the strop.

I don't have any experience with convex edges (don't have any), but I am a firm believer in stropping any edge, whatever the profile (and I believe you'll find many others here on the forum who feel the same way). In fact, almost all of my light touch-ups on my knives are done only on a strop. Once you've got a precise, even bevel on your edge, it's pleasantly surprising how easy it is to maintain it with light touch-ups on a strop after each use. Again, and I can't emphasize it enough, make sure you strop at the LOWEST angle possible, so you won't 'round over' your new edge.

Hope this helps, good luck! :)
 
@pas3n7

I strop all my edge types: convex, flat, hollow, zero...etc
When I was exclusively using a gatco system, I always ended up with kind of a burr which I would knock off by stropping on my belt (the one on my pants). One way to remedy this without stropping, is to get it shaving sharp with the course stone (if it needed that abrasive of a grit) it'll prob still be pulling the hairs a little at that point, but it should shave. That noticeable of a burr after the last step, usually in my experience meant that both sides of the edge were not ground until they met, the two sides of the edge probably didn't come completely together until the last step, which would leave a long and deep burr.
 
I know I'm reviving a dated thread here, but I wanted to add that I figured out what the problem(s) was (were) so that if anyone finds this thread via search, they will have an answer.

The problem with the spyderco was indeed poor sharpening technique. However, the problem with the BK-11 was with the sheath. It's made of a fiberglass reinforced plastic, and the edge was rubbing up against the sheath. The contact with the fiberglass dulled the blade. My temporary solution was to run some superglue down into the sheath to form a protective layer, and that seems to have worked out ok. Longer term solution is to replace the sheath.

Anyway, hope that helps anyone with the same mysterious dulling problem.
 
Thanks for the update! I had the same issue with my BK11 - the sheath is glass filled nylon, if you take a sharp knife and cut into it you'll see light thrown back within two or three cuts. Just for kicks I put a good working edge on my BK11, drew the edge across the sheath a few times till it was dulling the blade, then used the sheath for a strop - it actually restored the edge somewhat. The factory sheath is a menace.
 
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