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The recent discussion re steeling with Stitchawl spurred me to take another look at this practice. Until now my experience with this activity has been largely limited to kitchen knives using a groved steel and a "smooth" one that had become discolored and somewhat abrasive. I've gotten poor performance when using the smooth one on the harder steels found in most pocket/hunting cutlery, even though I still use them on my softer kitchen knives with good results. Having taken a close look at many fresh and worn knife edges, I have never been comfortable with the "re-alignment" theory that is most often applied to the practice, so what is happening?
I realize Verhoeven among many others have covered this topic already, but I have not. Here goes. Based on the micrographs and cutting tests I have a couple of observations. My test knife is a EKA H8 in 12C27 Sandvik. It was sharpened up to the fine side of a Norton Crystalon stone and deburred with the oil and swarf from the stone applied to newspaper (the best wayI know of to do a thorough deburring and not affect the grind structure). Test knife could shave arm hair and just dry shave facial stubble, though not clean to the skin. Could easily crosscut newspaper with a push cut, though sounded quite abrasive when doing so.
The steel is smooth, though not mirror smooth. I cleaned it up thoroughly and polished it with white compound - very shiny and feels very slick when steeling. Pressure was very light, just enough to maintain contact.
Pictures are at 160x and 640x
First two are fresh off the stone and paper:
Next two are after 5 passes on the smooth steel, increasing the angle only a degree or two. The edge exhibited a modest but obvious improvement on the stated tests relative to the starting edge - most notably the pitch of the sound it made going through newspaper became higher and more uniform.
Last two are after 45 passes, some of the conventional wisdom suggests this could harm the edge. Testing showed a large improvement in cutting characteristics - dry facial stubble flew off my cheek without irritation and I was able to rapidly slice 1/4" strips from the crossgrain newspaper. Still no real evidence of burr or wire edge creation, though there appears to be something sporadic - visible lower right in the 160x pic that makes me think they're starting up in some spots...
It is my opinion based on this test that steeling is in fact a form of sharpening (I have come to think of it as the opposite of stropping but achieving a similar outcome, and it quite possibly is realigning the edge, but I have to think this effect is minor compared to the "smoothing" effect I'm observing) using plastic flow instead of grinding to accomplish its goal. I can come up with no other explanation for what I'm seeing. The steel is not removed, but smeared/pressed/squashed, something that Verhoeven among others has already observed to some extent - unlike Verhoeven I observed no breakout of the apex and even after 45 passes I do not see any apex deformity that cannot be traced back the original grinding - this was a surprising find. I do suspect I could have stopped at 10-15 passes and perhaps gotten the best result I was going to get, but wanted to see the effect of too many passes. Clearly too much pressure would be devastating, esp combined with too many passes.
Done carefully it appears capable of significantly improving a lightly worn edge or coarsely sharpened one. I'll have to do some more work on this using a more refined edge and see what the effect is. It may be (and makes perfect sense) that the more refined the edge the more important it becomes to use a glass steel, or one with very exacting surface treatment (has anyone tried chrome?)
This is fast and effective - I'll be giving it a try on some of my larger knives next.
I realize Verhoeven among many others have covered this topic already, but I have not. Here goes. Based on the micrographs and cutting tests I have a couple of observations. My test knife is a EKA H8 in 12C27 Sandvik. It was sharpened up to the fine side of a Norton Crystalon stone and deburred with the oil and swarf from the stone applied to newspaper (the best wayI know of to do a thorough deburring and not affect the grind structure). Test knife could shave arm hair and just dry shave facial stubble, though not clean to the skin. Could easily crosscut newspaper with a push cut, though sounded quite abrasive when doing so.
The steel is smooth, though not mirror smooth. I cleaned it up thoroughly and polished it with white compound - very shiny and feels very slick when steeling. Pressure was very light, just enough to maintain contact.
Pictures are at 160x and 640x
First two are fresh off the stone and paper:
Next two are after 5 passes on the smooth steel, increasing the angle only a degree or two. The edge exhibited a modest but obvious improvement on the stated tests relative to the starting edge - most notably the pitch of the sound it made going through newspaper became higher and more uniform.
Last two are after 45 passes, some of the conventional wisdom suggests this could harm the edge. Testing showed a large improvement in cutting characteristics - dry facial stubble flew off my cheek without irritation and I was able to rapidly slice 1/4" strips from the crossgrain newspaper. Still no real evidence of burr or wire edge creation, though there appears to be something sporadic - visible lower right in the 160x pic that makes me think they're starting up in some spots...
It is my opinion based on this test that steeling is in fact a form of sharpening (I have come to think of it as the opposite of stropping but achieving a similar outcome, and it quite possibly is realigning the edge, but I have to think this effect is minor compared to the "smoothing" effect I'm observing) using plastic flow instead of grinding to accomplish its goal. I can come up with no other explanation for what I'm seeing. The steel is not removed, but smeared/pressed/squashed, something that Verhoeven among others has already observed to some extent - unlike Verhoeven I observed no breakout of the apex and even after 45 passes I do not see any apex deformity that cannot be traced back the original grinding - this was a surprising find. I do suspect I could have stopped at 10-15 passes and perhaps gotten the best result I was going to get, but wanted to see the effect of too many passes. Clearly too much pressure would be devastating, esp combined with too many passes.
Done carefully it appears capable of significantly improving a lightly worn edge or coarsely sharpened one. I'll have to do some more work on this using a more refined edge and see what the effect is. It may be (and makes perfect sense) that the more refined the edge the more important it becomes to use a glass steel, or one with very exacting surface treatment (has anyone tried chrome?)
This is fast and effective - I'll be giving it a try on some of my larger knives next.
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