Hair splitting sharpness.
- Thread starter Wei Jun Lee
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Michi
I dislike attempts to rewrite history
Yes. I think it's somewhere around 14,000 grit equivalent.
I have no idea what actually happens at the apex. I suspect that it just ends up getting rounded off from board contact, possibly by rolling a little, or by bits of carbides flaking off.
What I've noticed is that all my Wüsthofs seem to settle in to the same sharpness in short order, no matter whether I finish them on a 1000-grit stone or a 5000-grit stone. Seeing that it doesn't seem to make any real difference, I've stopped taking them beyond 1000.
i'm another disbeliever in the theory that higher grit edges don't last as long on any given steel (softer or harder). if anything, they should be stronger than a lower grit edge, because the edge will have smaller valleys between peaks, meaning less chance for the peaks to get torn off.
the important thing to remember when sharpening a softer steels is to use a more obtuse angle, which is easier said than done if you've developed muscle memory from sharpening a lot of harder steels at very acute angles. this is where micro bevels can really come to the rescue.
the important thing to remember when sharpening a softer steels is to use a more obtuse angle, which is easier said than done if you've developed muscle memory from sharpening a lot of harder steels at very acute angles. this is where micro bevels can really come to the rescue.
kannamaster
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Sharpness is a very subjective thing and practical sharpness as compared to ultimate sharpness can not be defined without taking many factors into consideration. And in a work context you have to ask is a sharper edge actually a better edge than a slightly less sharp edge that is much easier to maintain and achieve? Most of the time we think of a more acute angled edge as being more sharp but if taken to the extreme you could creat an edge that was sharp for a very short time and would then start to break down after a few stokes and is that really useful?
I don’t find splitting a hair to be a practical sharpening goal and I would suggest that you measure sharpness by what you plan to cut with the knife. If that is fish then you should - imo - be looking to creat an edge that cuts fish with control, minimal effort, leaves a beautiful surface, is reasonably durable and is easy to recreate and maintain.
In other words you can not define sharpness outside of a set of goals for the tool you are using, the materials you will be cutting, and ratio of time and effort it takes to maintain an edge vs. the time that edge can be used. Would you spend 15 mins to sharpen a knife that would need to be resharpened after 5 mins of use?
Many people have mentioned light pressure in the final stage of sharpening and the importance of careful burr removal but what is also important is that your final burrs need to be the smallest possible burrs you can make. You must learn to create and recognize a burr along the full length of your blade that is so small that you are almost not sure it exists. Anything bigger will usually break off while you are removing the burr and you won’t know it - but your edges will show inconsistent durability. I recommend removing your final burrs by using only forward strokes at a skew angle and lifting in between strokes rather than the normal back and forth sharpening motion. This helps to more carefully “cut off” the burr instead of bending it forward and backward, breaking it off, and leaving behind a jagged edge. I’d also recommend starting with freshly flattened stones and using a nagura stone or even rubbing two finish stones together to help create mud on your finish stones before the final sharpening stage. Think of the mud as a sharpening paste and try to float your blade on top of the mud when you remove the burr. When you get to the finish stone start with the back side or flat side down first - while the stone is still as flat as possible - and polish the flat side until it is completely shiny and flat out to the edge. Starting on the flat side will also make it easier to feel any burr you create when working the bevel side. Next sharpen on the bevel side and focus on the wrought iron or soft steel of the bevel at first. You should be able to do this without making a burr while you will notice the color of the mud darkening and thickening and the bevel becoming polished. Control the consistency of the mud with a few drops of water at a time but don’t rinse the mud off the finish stone. When you are nearly done allow the mud to dry a bit and thicken and raise the sharpening angle a few degrees and use very light pressure and slow strokes until you create a shallow micro-bevel and very small burr. You’ll need to rinse the blade with water in order to carefully feel for a properly small burr. Carefully remove the burr with slow forward-only strokes. Repeat once or twice until you get a really small uniform burr, followed by a flawless burr removal. Stropping will usually not be needed but some of the modern steels especially benefit from a stropping.
I don’t find splitting a hair to be a practical sharpening goal and I would suggest that you measure sharpness by what you plan to cut with the knife. If that is fish then you should - imo - be looking to creat an edge that cuts fish with control, minimal effort, leaves a beautiful surface, is reasonably durable and is easy to recreate and maintain.
In other words you can not define sharpness outside of a set of goals for the tool you are using, the materials you will be cutting, and ratio of time and effort it takes to maintain an edge vs. the time that edge can be used. Would you spend 15 mins to sharpen a knife that would need to be resharpened after 5 mins of use?
Many people have mentioned light pressure in the final stage of sharpening and the importance of careful burr removal but what is also important is that your final burrs need to be the smallest possible burrs you can make. You must learn to create and recognize a burr along the full length of your blade that is so small that you are almost not sure it exists. Anything bigger will usually break off while you are removing the burr and you won’t know it - but your edges will show inconsistent durability. I recommend removing your final burrs by using only forward strokes at a skew angle and lifting in between strokes rather than the normal back and forth sharpening motion. This helps to more carefully “cut off” the burr instead of bending it forward and backward, breaking it off, and leaving behind a jagged edge. I’d also recommend starting with freshly flattened stones and using a nagura stone or even rubbing two finish stones together to help create mud on your finish stones before the final sharpening stage. Think of the mud as a sharpening paste and try to float your blade on top of the mud when you remove the burr. When you get to the finish stone start with the back side or flat side down first - while the stone is still as flat as possible - and polish the flat side until it is completely shiny and flat out to the edge. Starting on the flat side will also make it easier to feel any burr you create when working the bevel side. Next sharpen on the bevel side and focus on the wrought iron or soft steel of the bevel at first. You should be able to do this without making a burr while you will notice the color of the mud darkening and thickening and the bevel becoming polished. Control the consistency of the mud with a few drops of water at a time but don’t rinse the mud off the finish stone. When you are nearly done allow the mud to dry a bit and thicken and raise the sharpening angle a few degrees and use very light pressure and slow strokes until you create a shallow micro-bevel and very small burr. You’ll need to rinse the blade with water in order to carefully feel for a properly small burr. Carefully remove the burr with slow forward-only strokes. Repeat once or twice until you get a really small uniform burr, followed by a flawless burr removal. Stropping will usually not be needed but some of the modern steels especially benefit from a stropping.
Some folks like to sharpen and some like to cut. There's a happy medium there somewhere but you just have to find that for yourself as it varies. I'm certain that the matter could be shown by a bell curve. I'm on said curve really close to Michi but possibly not as good at sharpening. In fact, I've got a couple of knives that need sharpening right now and I think I'm gonna do it...right now!
