Sharpening critique
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I want to offer my recent sharpening for critique. Maybe this will help, not only for myself but others. I have a beater knife, practice knife if you will that I have put to the clamp 3x and the sharpness is not quite there yet. It’s a tanto style knife.
The recent sharpening revealed a 3 deg difference (24-21). So I took my 100 D and moved the left side to 21. Proceeded to the 200 and worked the burr on both sides.
Critique and suggestions?
William, I’m not understanding this part, the “recent sharpening revealed a 3 deg difference (24-21)”. Where is the angle difference? Is it a side to side bevel angle difference, left side VS right side or is it the flat blade portion and tip portion bevels differ by 3 degree bevel angles. Are you clamping the knife in precisely the same position each attempt? Are you setting your guide rod angles with a digital cube, (i.e., profile the bevels to that cube angle setting)? Or are you matching a pre-existing bevel angle using a sharpie and determined the bevel angles at 24 and 21 degrees, hence the difference?
Sorry to bombard you with questions. It can be difficult to put into words a clear picture or description of what your running up against.
Just so you know your bevels are quite shinny and polished, indicating to me, your stone technique is good. If it isn’t as sharp as expected I can only surmise the bevels are not apexed keenly at the knife edge, all along the entire length of the sharpened bevels.
Marc
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Hi Marc! First, thank you! Please ask all the questions you feel the need to. I have not been saving my clamping data until this last sharpening. I wanted to learn how to find “The Sweet Spot”. Practice by repetition I guess.
Used my Sharpie on the right. Put the cube on it, 21 degrees. Sharpied the left, cube said 24. I’m not sure if my next move was correct or not. I set my left side rod to 21 with the cube. Sharpied it. Proceeded to use the 100. Carefully taking off all the Sharpie but right to the apex without rolling it over. I double checked by coloring it again at 21 deg and using my 1500. All color was removed right to the tip.
As far as my progression, it felt,like I was losing some sharpness somewhere after the 1000/1500. Best I can describe, it can shave paper but not cleanly. Hopefully that makes sense.
Here is a shot of my bevel using the USB microscope. I apologize if the clarity isn’t there. Still learning how to properly light the bevel to maximize detail. This is all the way to the 0.5 micron strop. It was kind of a pain because freshly applied emulsion likes to come off on the bevel and I had to wipe it clean every few strokes. Each pass left less and less residue.
William
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I’m kind of surprised how scratched the bevels look under magnification after that progression. I think you’ll see a big improvement when the stones wear in more.
Have you been checking your angles with each grit change and verifying that you have reached the apex by examining the bevels with your scope and some sharpie? How have you been deciding when to change grits?
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Wiiliam,
Wow those are some deep scratches, and i believe some chipping also. How much pressure are you using while sharpening, (i use very light pressure). Also are you making sure you are removing previous hones scratch pattern before moving onto next grit?
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Thanks, that clears up a lot. The facets, if you will, on the blade make for some difficulty to find a, proper placed, flat spot, to clamp the tanto while maintaining the “sweet spot” positioning. With a blade edge profile as flat as it is I’d sacrifice “the sweet spot” position for a stable, repeatable, clamping position. I’ve only had the opportunity to sharpen a couple tanto grinds. Both of these I sharpen in two steps, one phase for the blade flat and the next phase for the tip flat. I did reclamp/reposition the blade to accomplish this.
Now that you have the knife positioned and clamped and the guide rod angles, left and right, set at 21º with the angle cube all you need to do is insure your bevel is straight, even and continuous from the shoulder up to the apex of the knife edge. Feeling the burr is the best and surest way to know you have physically achieved this. Just because you think you are resetting only the one side bevel from 24º to 21º doesn’t preclude you from doing the same steps on both knife sides, in my book. I would repeat the progression including drawing the burr, again, to both sides. Ending each grit with left-right-left -right alternating side strokes. Then feel for sharpness.
I am one of the WE sharpeners that believe it is prudent to set your guide rod angles with a digital cube for each and every grit change, throughout the entire progression. I do not double check my angles between the leather strop progressions after lowering the initial 1-1/2º or 2º that’s recommended. One reason is there is “give” in the compressible leather so the angle setting has a built-in flexibility or variability and more importantly is to prevent cross contamination of abrasives between leather strops.
After I am sure I have apexed the edge on both sides at 21º by feeling a burr on both sides, with only the coarsest grit you’re using, I would complete the entire progression, once again up through 1500 grit. You may achieve this less time and effort since you’re maybe really doing a touch-up. But do as much effort and time as is necessary to get the sharp feel each grit. If you don’t achieve the results with a coarse grit it’s may be harder to make up for it with the next finer grit. When I’m in doubt I always step back down a grit or two and get the edge to where it feels right before progressing on again.
After you have established your profile, with your clamping position and your bevel angles, each step or grit in the sharpening progression, for me, is a repetitious mechanical progression of motion, light pressure, angle and position. Everything is the same till I change to another medium, be it DLF or Strops. For some of us WE sharpeners the “tell-tail” to knowing it’s time to move on up a grit is when the scratch pattern left from the previous grit is obliterated and completely replaced by the new scratch pattern left by the latest grit. To simplify discerning one scratch pattern from the next it is recommended that the stroke angle be reversed each grit change, (i.e., heel to tip, >> tip to heel>>heel to tip). So besides the size, depth and spacing of the scratch pattern getting smaller with finer grits the direction is across the last grit’s pattern.
BTW: The next time you use your strops the emulsion will have dried into the leather and it’ll stay put.
Marc
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I’m kind of surprised how scratched the bevels look under magnification after that progression. I think you’ll see a big improvement when the stones wear in more. Have you been checking your angles with each grit change and verifying that you have reached the apex by examining the bevels with your scope and some sharpie? How have you been deciding when to change grits?
Hi Organic,
Thank you for chiming in! I appreciate it. I must admit that I was not checking the angles with each grit change. Or at least as thorough as I should’ve been. I’m embarrassed to say that I winged it. Checked the edge, felt sharp. Looked under the 10x loupe for a quick scan and the scratch patterns appeared to be consistent. I’m still learning to decipher the patterns
Besides the loupe and USB microscope, is using the Sharpie a method to determine that you hit the apex at each grit? In other words, paint both sides. Alternating strokes until Sharpie is gone?
William
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Hi Pink Floyd,
Thank you! I thought I was using gentle pressure. But perhaps not light enough? I’m hoping scratch patterns will be easier to decipher after gaining some more experience.
In my post, I mentioned about the strops leaving behind residue on the bevel. Would hitting that residue with the strop paddle again, without cleaning it, cause some scratches?
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Thanks, that clears up a lot. The facets, if you will, on the blade make for some difficulty to find a, proper placed, flat spot, to clamp the tanto while maintaining the “sweet spot” positioning. With a blade edge profile as flat as it is I’d sacrifice “the sweet spot” position for a stable, repeatable, clamping position. I’ve only had the opportunity to sharpen a couple tanto grinds. Both of these I sharpen in two steps, one phase for the blade flat and the next phase for the tip flat. I did reclamp/reposition the blade to accomplish this. Now that you have the knife positioned and clamped and the guide rod angles, left and right, set at 21º with the angle cube all you need to do is insure your bevel is straight, even and continuous from the shoulder up to the apex of the knife edge. Feeling the burr is the best and surest way to know you have physically achieved this. Just because you think you are resetting only the one side bevel from 24º to 21º doesn’t preclude you from doing the same steps on both knife sides, in my book. I would repeat the progression including drawing the burr, again, to both sides. Ending each grit with left-right-left -right alternating side strokes. Then feel for sharpness. I am one of the WE sharpeners that believe it is prudent to set your guide rod angles with a digital cube for each and every grit change, throughout the entire progression. I do not double check my angles between the leather strop progressions after lowering the initial 1-1/2º or 2º that’s recommended. One reason is there is “give” in the compressible leather so the angle setting has a built-in flexibility or variability and more importantly is to prevent cross contamination of abrasives between leather strops. After I am sure I have apexed the edge on both sides at 21º by feeling a burr on both sides, with only the coarsest grit you’re using, I would complete the entire progression, once again up through 1500 grit. You may achieve this less time and effort since you’re maybe really doing a touch-up. But do as much effort and time as is necessary to get the sharp feel each grit. If you don’t achieve the results with a coarse grit it’s may be harder to make up for it with the next finer grit. When I’m in doubt I always step back down a grit or two and get the edge to where it feels right before progressing on again. After you have established your profile, with your clamping position and your bevel angles, each step or grit in the sharpening progression, for me, is a repetitious mechanical progression of motion, light pressure, angle and position. Everything is the same till I change to another medium, be it DLF or Strops. For some of us WE sharpeners the “tell-tail” to knowing it’s time to move on up a grit is when the scratch pattern left from the previous grit is obliterated and completely replaced by the new scratch pattern left by the latest grit. To simplify discerning one scratch pattern from the next it is recommended that the stroke angle be reversed each grit change, (i.e., heel to tip, >> tip to heel>>heel to tip). So besides the size, depth and spacing of the scratch pattern getting smaller with finer grits the direction is across the last grit’s pattern. BTW: The next time you use your strops the emulsion will have dried into the leather and it’ll stay put.
Marc,
Thank you! I see several things right off the bat that I can improve upon with my technique. In my other responses, I believe the biggest culprit is <i>knowing</i> <i>when to change grits. </i>After reading yours and the other responses, I am better informed on how to proceed in that progression. Now it’s putting it to practice. Each sharpening gets better
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Learning how to know when to change grits is one of the most important aspects of sharpening. The method where you change stroke direction that Mark mentioned is going to be the most reliable, but when you have more experience you will be able to tell by the feel and sound of the stones on the blade. When it looks like it is time to change grits, do another 10-20 light passes. More strokes won’t hurt.
“Besides the loupe and USB microscope, is using the Sharpie a method to determine that you hit the apex at each grit? In other words, paint both sides. Alternating strokes until Sharpie is gone?”
Yes, a good way to make sure that you are getting all the way to the apex is to put on some sharpie, do a few strokes, and then look at the edge with your scope / magnifier. If you see any sharpie that has not been removed from the bevels then you are not at the same angle as before and you need to check again with the angle cube. I like to do this several times throughout the sharpening process.
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Organic’s points are excellent. To the question of when to change grits, I’ll add my vote that changing direction with each grit change is a huge help. Continue with the current grit until all scratches from the previous grit are erased. Consider that the “breakouts” at the apex are going to be deeper than the scratches left on the bevel. If you are really serious about getting the optimum edge, do like Organic says and take more strokes. I usually go twice as many strokes as it took to erase the scratches. You’re not removing scratches at that point – you’re refining the edge.
I did a couple of really dull filet knives for a friend tonight and reprofiled them from the factory edge to a 17 dps bevel with a 20 dps micro bevel. Both knives were of some sort of stainless that took a long time at 200 grit to even approach the apex. I used a Sharpie as Organic describes, but I never would have seen how far I was from the apex without some form of a magnifier. The thin line of black Sharpie ink was almost invisible to my old eyes. Then, I didn’t push the stones all the way to the apex, thinking that my 1000-grit micro bevel would take care of it. Mistake. By the time I’d achieved a sweet apex, it wasn’t a micro bevel anymore.
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Speaking of angles. Is it basically Dealer’s Choice in deciding angles? Say you have knife with factory 20 deg on one side and 19 on the other. Keep the same factory angle? Take it to 20? 19? Or whatever angle you wish? My OCD would want matching angles.
Most knives I buy, I find upon inspection have unmatched bevels, side to side. I buy mostly hand forged/hand made kitchen knives so that’s to be expected since they’re hand sharpened. As long as the bevels apex the knife edge and meet at a very precise keen line the knives usually will perform very well.
Most knives I buy are specified as “even bevels, (50/50)” to denote the angle is supposed to be close to the same side to side.
Other knives I buy, less frequently, are specified as “asymmetrical bevels (e.g., (70/30) or (90/10)” to denote they were intentional ground or sharpened with the actual knife grind or the sharpened bevels, different from left to right side. The general reasons for this can be for specificity of tasks the knife is made for, (in the case of the grind) or to steer the cut for finer slicing, (in the case of the bevel).
Some of the determiners for setting the bevel angles are, what the knife will be used for and how hard or durable the steel is. This is the “art” part of knife sharpening based on experience from past sharpening results and the “science” part from metallurgy.
Finally to answer your question, I would start by matching the bevels with the purpose in mind to determine how well this knife as designed and ground, at this bevel angle setting, cuts when it is sharpened well and correctly. I would be inclined to try to move the bevels toward a same angle setting side to side. This is mostly for aesthetics so the bevel appear uniform, visually. Also, I believe it is easier to sharpen a centered bevel of the same height when using the same angle settings side to side, for the beginner to WE sharpening.
The wider bevel angles tend to cut fairly or moderately well and are more durable over the long run. This is a good angle for ever day use. The narrower bevel angles tend to cut or slice better and easier but wear out faster. There are no set in stone guide lines but there are general rules we have learned and shared through experience. 20º dps is a good general angle to start with to see how well your knife cuts and the steel holds up. Higher or more obtuse is for rougher work and possibly more chopping action. Finer or more acute angled bevel like 17º dps >>>15º dps are usually employed for fine cutting and slicing with usually harder steels. These narrow angle need the hard steel to stand up to the narrowness of the edge so they cut and slice rather then the edge bending or rolling over.
There is not much difference between 19 and 20 degrees so that choice is yours. Even if you choose to stay or match the bevels the first sharpening for any knife with the wicked edge always profiles the bevels to a more precise and even level then the edge ever had due to the precision and design of the WEPS.
Marc
(MarcH's Rack-Its)I’m not sure if I clearly understand Marc’s comment. I’m quite sure that when a knife is designated as having a 70/30 bevel, it means that the apex is off-center by that ratio, but the angles are still assumed to be equal. The effect of the off-center edge causes it to cut toward the narrow side, as the wider bevel causes the edge to be “pushed” toward the narrow bevel side. A chisel edge, which is essentially a “100/0” bevel ratio, will cut dead straight vertical along the zero face of the knife. I have sharpened several knives with off-center apexes to improve the slicing performance. The narrow bevel is on the side opposite the user’s hand. For a right handed user, I sharpen the narrow bevel to be on the right side of the blade (as viewed in the vise).
My sister recently gifted a Japanese knife to her daughter-in-law. That knife has a chisel grind, with the flat side on the left, as viewed by the user while cutting. I’m a lefty, so that knife would be a real problem for me. I suspect that in Japan, lefties are probably pressured early in their lives to switch hands. The nail that stands out gets pounded down.
Tom, we are both right. It can mean exactly what you are saying where the % designation relates to the physical grind and the apex is offset. It can also mean that the angle is the same but 70% of the sharpening time and effort is spent on one side and 30% is spent to the other side. Here is an explanation made to me by a professional knife importer and knife sharpener specializing in Japanese style knives. I asked him about this subject when I posted questions on another knife forum. when I was trying to understand the meaning of the designations. That’s when I originally posted this thread to the WE forum.
It included this: Jon Broida of Japanese Knife Imports gave me permission to share his posted reply:
Sharpening angles are one of the most common things I am asked about. I find it’s often important to talk about them together with asymmetry, but let me address the sharpening angles first. In general, there is not going to be an exact angle that is correct, but rather a range of angles that works. For instance, most double bevel Japanese knives will work well with angles somewhere between 10-15 degrees per side. The closer you are to the 10-degree side of things, the sharper the knife will feel, but it will also be more fragile, brittle, and may not hold its edge as long. The closer you are to the 15-degree side of things, the more tough and durable the knife will be, though it won’t feel quite as sharp. It’s also ok to go even lower or higher than this, depending on your personal preference, though I often recommend staying within this range until you have a better understanding of how things work for you. For what its worth, Japanese craftsmen aren’t measuring the angles when they make or sharpen the knives either. Lastly, it’s important to keep in mind that you don’t have to always use the exact same angle. If you want your knife to feel a bit sharper, go a bit lower. If you need a more tough and durable edge, go a bit higher.
As for asymmetry, it seems that this is a rather confusing issue for many. Part of the confusion stems from the fact that many of the ways that we describe these asymmetries are gross oversimplifications. For example, the ratios like 50/50 or 60/40 don’t really describe anything of substance. Is it the ratio of the percentage of sharpening on each side? Is it a ratio of the angles on each side? In reality, it’s neither. No craftsman in Japan it’s there and measures angles or ratios. What really matters is the way that the knife cuts. The asymmetry deals with two main issues-thinness behind the edge and steering. The more asymmetrical a knife is, assuming the angles are equal, the thinner the knife is behind the edge. However, the more asymmetrical the knife is, the more likely it is to steer. It’s also important to keep in mind that the angles are not always equal. When figuring out asymmetry for any given knife, the first thing that you want to do is cut with the knife. When you cut with a knife, you want to assess whether it is steering to the right or to the left, and how easily it moves through the food. If you notice that your knife is steering to one direction or the other, you want to create more surface area on the side that it is steering towards, so that the knife cuts straight. This can be done by adjusting the angle (either more or less acute) and/or adjusting the amount of time spent sharpening on each side. If you notice that the knife is wedging in food as it goes through, this may mean that you need to sharpen at a more acute angle, or that you need to thin behind the edge. Some of this can also be dealt with through adjusting asymmetry, as previously mentioned. Does that make sense?
When I asked the same question of the knife importer, where I just bought an asymmetrical ground knife, (i.e., 70/30) , his explanation was essentially the same. It’s not a description of the bevel angle or grind offset but an indication of the percentage of time spent sharpening one side VS the other, to help steer the direction the knife cuts. Here is the pasted copy f his email response to me when I questioned him on the method to employ to sharpen my new purchase:
Dear Marc
Thank you very much for shopping with us and your confirmation.
For sharpening your new knives (Double bevel edge 70/30). We recommend the sharpening angle approximate 12’ for sharpening face side of blade edge. We recommend the sharpening angle for sharpening opposite side of blade edge 15’.
You sharpen face side of blade edge more than opposite side edge. If total sharpening strokes are considered as 100%, you sharpen the face side of blade edge for 70%, you sharpen the opposite side of blade edge for 30%.
We hope you will enjoy sharpening time and enjoy sharp edge blade of kitchen knives
In here, we have sharpening movie with Master Nagao, we hope it will also help for your sharpening process at https://japanesechefsknife.com/pages/how-to-sharpen
Thank you very much again for shopping with us and your new inquiry.
Best Regards
Koki Iwahara
JapaneseChefsKnife.Com
Tom you did use the nomenclature 70/30 bevel. I’m using the nomenclature 70/30 asymmetrical bevel. Maybe the difference is more than semantics?
Here is how a knife I had purchased was described (read under “specifications tab”). It is confusing and I don’t believe either explanation is incorrect. As long as it’s clear what were referring to. I believe I made reference to both associations in my post above, that Tom is referring to, trying to explain them both in general terms.
Marc
(MarcH's Rack-Its)
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