I recently purchased Japanese Knife. Unlike western knives, it has a grind so the two sides aren't parallel so I can't just half the edge angle to find the edge angle. See the side view of the blade in the photo below.
The edge is also very small, less than 1mm, so difficult to align the angle master with the actual edge
Any suggestions on how to find the correct edge angle?
(https://i.imgur.com/b2Ugj2i.jpg)
This seems like one for a black marker.
Rick
Quote from: RickKrung on November 22, 2018, 01:27:46 AM
This seems like one for a black marker.
Rick
That was typed entirely by my granddaughter, so I kept it short. That is assuming you don't have any fancy angle measuring tools. But, if you had one, you could use a laser protractor which can measure just one side. But, when a knife like that has been steeled a lot, you may not be able to accurately detect the correct angle.
If the bevel is really narrow, the black marker may be hard to see and harder to see where on the bevel it has been removed, so I would use magnification to examine it. And adjust the angle, by raising or lowering the USB, to where marker is being removed across the entire bevel.
Another response might be "who cares". Just decide what angle you want and turn the knife over so the flat side is up and use the Angle Master (AM). Then, there is just using the angle master on the bevel side and not worrying about any error the very shallow blade angle might cause.
Or, if it is a brand that posts the angles of its knives on their web site, go there and figure out what angle to use, but adjust the AM for the bevel angle plus the blade angle.
Rick (for real, it is me this time ;)
I would add a note to Rick's advice about determining the existing bevel angles. Using one of the techniques Rick describes, I can get pretty close to the existing bevel angle(s), but I don't obsess about it because I know that, try as I might, I am going to end up changing the angle(s) a bit when I sharpen. For this reason, for me the marker method is pretty much always going to be "close enough"; that is, even if I tried to be more exact in determining the existing bevel angle(s), I know that I am not able to replicate them exactly. This is especially true along the curved portion of the blade, where much will depend on what equipment was used by the last person to sharpen the blade. (I have a laser protractor, but I know that both measuring and replicating are going to become a less precise when I get to the curved portion of the blade, so the marker is usually just as reliable an indicator.)
More experienced users might be able to measure an 18.5º angle and then produce an 18.5º angle, but if that will ever be possible for me, I am not there yet. And no one who uses the knives I sharpen is going to notice a degree on either side.
What is as important to me (as determining the existing bevel) is documenting the way that I sharpen the blade so that, the next time I sharpen it, I can get close to what I did the last time. I have to write this down in a little book I keep: whenever I tell myself that I will remember, I forget. In this task, I find that an important point (crucial for blades with curved portions) is to fasten the knife jig at the same place along the length of the blade each time I sharpen. I am already challenged to keep my lifting (or pivoting) movement consistent between sharpenings, so I don't want to compound this variable by changing the fulcrum of those movements with different jig fastening positions. So, my little book records the bevel angle(s) and the distance of the edge of the jig from the tip of the blade (and stuff like USB height and jig projection, stones used etc.).
Gord
Do you know the steel type and hardness of your knife ?
I would use the method described by RickKung and his grand daughter, the marker pen. Adjust the tooling till you hit the spot and then go.
Identify the angle, as long as it lands between 10-15 degrees i'ts fine otherwise I would adjust it to somewhere there around and regrind it to a V shape with mirrored edges. As long as you don't have to remove too much material I don't think you will notice much of the changed angles of the cutting edge.
About the cutting edge being ground more on one of the sides comes from the knife maker or their master sharpener.
Mostly, if not always, their dominant hand is the right one and therefore sharpened more on the right side. This helps you as a knife wielder in terms of tipping over the produce you are cutting, potatoes, cucumber and what not.
With this slightly shifted edge to the right often comes that the edge on the left side can be of some what higher degree, as in more blunt angle, so when you use the sharpie trick you might find that it differs.
This again comes from the right-handedness of the sharpening master and the kind of machine they use in the factory.
The machine used is often a similar one that the link points at.
https://goo.gl/images/jzxBSp (https://goo.gl/images/jzxBSp)
Best of luck!
Thank you for your reply, Magnus. For those of you who are not yet familiar with Magnus, he is one of our top tier knife experts in both formal trainng and experience. He and Stig are friends, as well as professional acquaintances. I occasionally ask Magnus to comment, and he always delivers in depth, practical replies.
For those who are interested, knife sharpening can become more subtle than just sharp. I am grateful for members like Magnus who can help lead us into very interesting paths.
Ken
Quote from: Heli_Guy on November 21, 2018, 11:56:59 PM
I recently purchased Japanese Knife. Unlike western knives, it has a grind so the two sides aren't parallel so I can't just half the edge angle to find the edge angle. See the side view of the blade in the photo below.
The edge is also very small, less than 1mm, so difficult to align the angle master with the actual edge
Any suggestions on how to find the correct edge angle?
...
To me, your post is like saying... I just bought a car, how do I work the radio? There are many types/styles of Japanese knives... what exactly did you get?
Gotta be honest though... most Japanese style knives are better sharpened on a waterstone... ::)
Quote from: Magnus Sundqvist on November 22, 2018, 02:31:11 PM
I would use the method described by RickKung and his grand daughter, the marker pen. Adjust the tooling till you hit the spot and then go.
Identify the angle, as long as it lands between 10-15 degrees i'ts fine otherwise I would adjust it to somewhere there around and regrind it to a V shape with mirrored edges. As long as you don't have to remove too much material I don't think you will notice much of the changed angles of the cutting edge.
About the cutting edge being ground more on one of the sides comes from the knife maker or their master sharpener.
Mostly, if not always, their dominant hand is the right one and therefore sharpened more on the right side. This helps you as a knife wielder in terms of tipping over the produce you are cutting, potatoes, cucumber and what not.
With this slightly shifted edge to the right often comes that the edge on the left side can be of some what higher degree, as in more blunt angle, so when you use the sharpie trick you might find that it differs.
This again comes from the right-handedness of the sharpening master and the kind of machine they use in the factory.
The machine used is often a similar one that the link points at.
https://goo.gl/images/jzxBSp (https://goo.gl/images/jzxBSp)
Best of luck!
Perhaps, I'm not understanding your post, but my understanding is most Japanese knives are purposely sharpened asymmetrically... not just a byproduct of being sharpened with a "dominant hand"... ???
I am a believer in sharpening for the dominant hand. In my case, I am left handed. I have two identical santuko knives. One is sharpened with the tradional (western style) double bevel. I reshaped the second knife with a single bevel on the left side of the knife. I can make thinner slices of apple and cheese with my left hand knife.
I agree with Rick and Magnus about using the black marker. Frankly, I think the Anglemaster works better with larger bevels and flat surfaces.
I do not presently own any expensive Japanese knives. I regard them as very fine tools, but beyond my budget. If I ever purchase such a knife, I would reluctantly sharpen it very carefully. I would not sharpen such a knife for other people. Call me overcautious; that's just how I feel.
Ken
Quote from: Ken S on November 24, 2018, 01:28:33 AM
I am a believer in sharpening for the dominant hand. In my case, I am left handed. I have two identical santuko knives. One is sharpened with the tradional (western style) double bevel. I reshaped the second knife with a single bevel on the left side of the knife. I can make thinner slices of apple and cheese with my left hand knife.
I agree with Rick and Magnus about using the black marker. Frankly, I think the Anglemaster works better with larger bevels and flat surfaces.
I do not presently own any expensive Japanese knives. I regard them as very fine tools, but beyond my budget. If I ever purchase such a knife, I would reluctantly sharpen it very carefully. I would not sharpen such a knife for other people. Call me overcautious; that's just how I feel.
Ken
Like I said, I can't tell if he's saying it's sharpened that way on purpose, (for a dominant hand)... or just because the sharpener favors one side over the other when sharpening (because the sharpener just sharpens one side more). In reality, it's usually two different angles, so I'm guessing it's the former.
Hopefully he will clarify. ;)
Around the 6:30 mark in the video below they show a machine and the technique i'm trying to describe.
Fun fact; I've visited the Yaxell factory twice, their master sharpeners are really nice guys and incredibly good at their craft.
https://www.youtube.com/watch?v=nqKoAaMxy3U
About if the different angles actually have specific purpose or if it's all in the hands of the maker I would answer; both.
My guess is that you probably won't notice any difference other than convenience in maintaining the edge if you reshape the edge to a symmetrical one.
Unless a costumer specifies how they wish for it to be resharpened I almost always sharpen it symmetrical.
If it's a deba shaped knife then of course it's a whole different story when it comes to resharpening.
Thank you, Magnus. Excellent information.
Ken
Quote from: Magnus Sundqvist on December 05, 2018, 11:51:24 AM
Around the 6:30 mark in the video below they show a machine and the technique i'm trying to describe.
Fun fact; I've visited the Yaxell factory twice, their master sharpeners are really nice guys and incredibly good at their craft.
https://www.youtube.com/watch?v=nqKoAaMxy3U
About if the different angles actually have specific purpose or if it's all in the hands of the maker I would answer; both.
My guess is that you probably won't notice any difference other than convenience in maintaining the edge if you reshape the edge to a symmetrical one.
Unless a costumer specifies how they wish for it to be resharpened I almost always sharpen it symmetrical.
If it's a deba shaped knife then of course it's a whole different story when it comes to resharpening.
I didn't spend a lot of time looking, but it appears that Yaxell knives are more along the line of what some call "Western style Japanese knives"... these are typically sharpened the same on both sides (symmetrical). As evidence... the sharpener they sell... :o
(https://forum.tormek.com/index.php?action=dlattach;topic=3817.0;attach=2949)
(Not a recommendation btw)...More "traditional" style are sharpened asymmetrically because they're shaped that way to begin with. So, maybe it's a bit of an "apples to oranges" comparison?
Quite recently I stumbled over this very good explanation of what I think was your first question.
The reason for the shape of the cutting edge:
https://www.kitchenknifeforums.com/threads/a-basic-explanation-of-asymmetry.33951/
So, by sharpen the knife in such way you will get a more long lasting edge.
But you have a Tormek so why not sharpen it symmetrical and straight? - It won't last as long, but it's a quicker method for resharpening and it will have superior cutting abilities.
I hope this cleared some and didn't make it messier in the lovely jungle of master sharpening.
Best regards
Magnus
+1 for asymmetry and water stones. The water stones will give the traditional convex bevel that these Japanese knives are designed around. The rounded bevel is why you can't see it.
Heli-Guy. It looks from the photo that you have an asymmetric knife. As you may have figured out, these knives are ground for use with one hand and not the other. As you hold the knife and look down on it, if the bevel is on the right side, it is a right handed knife. It will push the sliced material to the right.
As others have mentioned, many of these knives were meant to be sharpened on true, flat water stones. The angle when using water stones varies but most are 11 to 15 degrees per side. Shun knives are 16 degrees.
Recommend that you do yourself a favor and find out how the knife was sharpened. If it was a very low angle, like 11 degrees, learn how to sharpen with it with water stones. It's fun and you will get a wonderful edge. Please don't screw up your knife by trying to grind a bevel on it. I see this all the time.
A Japanese knife with asymmetric grind sharpened on Tormek by our customer Kent (Sweden) sharper than a razor.
YouTube Video
https://www.youtube.com/watch?v=iQ9OQepVlR0 (https://www.youtube.com/watch?v=iQ9OQepVlR0)
Looks like the knife has bitten his left index finger :)
Kent's sharpening routine is Tormek SG wheel or a pair of CBN wheels to #1000 - Tormek SJ wheel (# 4000) - Paper Wheels with fine diamonds - and finishing on Tormek leather wheel with Chromox (using FVB for angle control).
Kent determined edge angle on each blade side with a CATRA laser protractor, and maintained the correct grinding and honing angle for each side on all these wheels using our computer software.
Superb result! - but most importantly is that for him it is a repeatable technology, a routine. Quality Japanese knives Kent sharpens within 30-37 BESS, sharper than the Gillette razor.
Our video about the CATRA laser protractor: https://youtu.be/rv2ulY6Less (https://youtu.be/rv2ulY6Less)
.
Quote from: wootz on February 27, 2019, 11:36:22 PM
A Japanese knife with asymmetric grind sharpened on Tormek by our customer Kent (Sweden) sharper than a razor.
YouTube Video
https://www.youtube.com/watch?v=iQ9OQepVlR0 (https://www.youtube.com/watch?v=iQ9OQepVlR0)
Looks like the knife has bitten his left index finger :)
Kent's sharpening routine is Tormek SG wheel or a pair of CBN wheels to #1000 - Tormek SJ wheel (# 4000) - Paper Wheels with fine diamonds - and finishing on Tormek leather wheel with Chromox (using FVB for angle control).
Kent determined edge angle on each blade side with a CATRA laser protractor, and maintained the correct grinding and honing angle for each side on all these wheels using our computer software.
...
Actually, more questions than answers...
Is it an "asymmetric grind' knife, or a symmetric knife with an asymmetric edge? (There's a difference (https://www.kitchenknifeforums.com/threads/asymmetry-%C2%96-the-real-deal.5656/)).
Is the asymmetric edge intentional, or as discussed earlier, the result of being hand sharpened? And should this asymmetry be maintained or "corrected"? Was it a customer request, and/or would the customer know the difference? Etc....
Most of the earlier discussion and info on the web discussed earlier suggests Yaxell knives, like the one in the video are, or at least suggested to be, sharpened at 12° per side (https://youtu.be/ydFZ6LKQfk0)... and the hand sharpening might produce the unequal bevels... doesn't necessarily mean it's "correct" and should be followed.
Quote from: cbwx34 on February 28, 2019, 02:44:44 PM
Actually, more questions than answers...
Is it an "asymmetric grind' knife, or a symmetric knife with an asymmetric edge? (There's a difference (https://www.kitchenknifeforums.com/threads/asymmetry-%C2%96-the-real-deal.5656/)).
Is the asymmetric edge intentional, or as discussed earlier, the result of being hand sharpened? And should this asymmetry be maintained or "corrected"? Was it a customer request, and/or would the customer know the difference? Etc....
Most of the earlier discussion and info on the web discussed earlier suggests Yaxell knives, like the one in the video are, or at least suggested to be, sharpened at 12° per side (https://youtu.be/ydFZ6LKQfk0)... and the hand sharpening might produce the unequal bevels... doesn't necessarily mean it's "correct" and should be followed.
If only the Japanese were interested in Westerners' opinions of the Japanese sharpening tradition... they would not appreciate them "correcting" it.
Even though studies have shown that double-bevel edge outperforms single-bevel, we do not double-bevel every single Japanese knife, the same with asymmetric - understand the givens, follow them and put the sharpest edge the steel allows.
http://knifegrinders.com.au/SET/Double-bevel_outperform_Single.pdf (http://knifegrinders.com.au/SET/Double-bevel_outperform_Single.pdf)
On quite a number of occasions I was asked to restore original edge profile on a Japanese knife botchery-sharpened "European way".
You can keep questioning while we keep sharpening.
Quote from: wootz on March 01, 2019, 10:10:35 AM
If only the Japanese were interested in Westerners' opinions of the Japanese sharpening tradition... they would not appreciate them "correcting" it.
Even though studies have shown that double-bevel edge outperforms single-bevel, we do not double-bevel every single Japanese knife, the same with asymmetric - understand the givens, follow them and put the sharpest edge the steel allows.
http://knifegrinders.com.au/SET/Double-bevel_outperform_Single.pdf (http://knifegrinders.com.au/SET/Double-bevel_outperform_Single.pdf)
On quite a number of occasions I was asked to restore original edge profile on a Japanese knife botchery-sharpened "European way".
You can keep questioning while we keep sharpening.
Thanks for the compliment. "Questioning"="learning" (as opposed to, I dunno, repetitive motion?) ::)
I'm not sure why you introduced a "Double bevel" vs. "Single bevel" study into this... not really the issue here. (Your study, from what I can tell only looked at single bevel knives, which, while asymmetric, doesn't mean it will apply). Maybe take another look at the questions?
More and more knives labeled "Japanese" are not ground nor inteneded to be sharpened asymmetric. Another thought, most that are, are labeled for right or left handed use... another point I don't see on the knife shown in the video, or in their advertising. It's why I asked, I don't have one to look at.
A
lot of knives, both Japanese and Western come with asymmetric edges... doesn't mean they were intended to be that way, nor should they necessarily be maintained or resharpened that way, is what I'm saying/asking here.