# How to correct edge profile?



## crlums (Feb 27, 2018)

Im a relative newbie and Ive been using my Miyabi artisan to practice thinning for the first time and to improve my sharpening skills overall. Its performing better after some modest thinning, but I think it could benefit from more thinning than Ive done so far. 

Ive noticed an issue though. Im not sure on the precise terminology but Ill do my best. Im noticing that I have a slight concavity thats developing about a third of the way up from the heel of the knife. Instead of a true flat spot theres a section that doesnt actually contact the board. What causes this? It seems like I took too much steel off the edge in that section (or maybe I didnt take enough off the heel portion). 

More importantly, how do I fix it? Its minor now but I dont want to make it worse and this feels like an opportunity to learn how to adjust the profile of the knife. (This miyabi could use a larger flat spot IMO). When I have the knife on a stone it seems like the concave section is usually on the stone, and its hard to focus on just the heel portion of the edge without bumping up against the bolster. 

Ill try to follow up with some pics tonight.


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## chinacats (Feb 27, 2018)

The quickest way is to breadknife it. Mobile right now but try searching site:kitchenknifeforums.com breadknifing


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## crlums (Feb 27, 2018)

Thanks for the input. Im currently reading through this thread and finding it helpful (http://www.kitchenknifeforums.com/showthread.php/21738-Fixing-hole-in-edge). My edge hole is much less severe though.

I took some pics to show my issue. I added an arrow on the pic, and later a sharpie mark on the knife itself to indicate the troublesome area. Please forgive the shot with the blade directly on the counter top. Its due for a sharpening and that shot and flash was the best way I could really get the edge hole to be obvious. Im also trying to figure out the correct way to position it on the stone so as to not take more metal off the area that's already an issue. 

https://drive.google.com/open?id=1Ei1VNzaf2cSWIwoavTXr5KkcTU0swuxu

I can go the breadknifing route if needed, but I'm wondering if this is minor enough that I can just focus on the heel and belly to even things out.


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## chiffonodd (Feb 27, 2018)

crlums said:


> I can go the breadknifing route if needed, but I'm wondering if this is minor enough that I can just focus on the heel and belly to even things out.



Yeah it's so minor I wonder if breadknifing is necessary. Is it noticeably affecting the way the knife's performance? Are you getting "accordion cuts"? If not, I would maybe just leave it and concentrate more on the non-"reverse belly" sections in future sharpening sessions.

Breadknifing is the best way to ensure that you reprofile the knife correctly. The problem is that you'll have to thin it out afterward, and if you don't do that correctly, you could end up right back here again!


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## HRC_64 (Feb 27, 2018)

If you bread-knife a hollow, you will get a dead-flat immediately after, and you want this (new) angle of flat/attack to be correct or very close to correct. No big deal but keep an eye on the profile before and after so you don't make more of a problem.


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## chinacats (Feb 27, 2018)

I agree that if it doesn't affect performance I'd just work on sharpening it out over time. Of note, I'm not a huge fan of using a sharpie but do when I do a major adjustment to the profile or as stated you can have more problems. Doesn't look too major but a minor issue in a crucial area of the blade (wherever it is you tend to use most) can be worth fixing.

As to pics, if you put the blade flat and aim a light from behind, the light will shine through and give the best shot of how big the problem is.


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## unprofessional_chef (Feb 27, 2018)

Miabi knives are already very thin to begin with. There are other things you can do to maximize your edge's performance. Like optimizing the edge's bite and burr removal.


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## crlums (Feb 27, 2018)

Thanks for the advice everyone. This honestly wasn't effecting performance or causing accordion cuts. I'm viewing this knife as a learning experience though. I decided to try my hand at fixing it so I just took out the stones and gave it a shot. I initially just tried to take steel off the heel portion without breadknifing. It wasn't really working super well, and was arguably making it worse. I tried some relatively gentle breadknifing and that fixed it really well and really quickly. Preliminarily, I think I may have even managed to improved flat spot relative to when this knife was new (thats my goal at least)

I moved on to thinning and seem to have been able to keep the flat spot intact without causing another hollow to form. The heel portion is still super dull though. I need to go back at it tomorrow to thin some more and then get a better edge on the heel portion. I'll post follow up picks when once I'm done.


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## Kippington (Feb 27, 2018)

Good to hear it is working out.
Bread-knifing works extremely well if you do it properly in conjunction with sharpening.

On a side note, it looks like you'll have you modify your normal sharpening technique to prevent this from happening again.


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## Benuser (Feb 28, 2018)

A thicker heel is quite common and should get some more time with every sharpening. I agree that breadknifing is rather drastic in this case. 
Make sure to end every stage in the sharpening with stropping -- i.e. edge trailing strokes. Not only to reduce the burr but to even out the profile as well.


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## rick alen (Mar 4, 2018)

Even after looking it up I'm not certain what "breadknifing" is. Quick explanation?


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## HRC_64 (Mar 4, 2018)

rick alen said:


> Even after looking it up I'm not certain what "breadknifing" is. Quick explanation?




'saw back and forth onto a flat surface'

like what you do to your cutting board
with a bread-knife.


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## ian (Mar 4, 2018)

Yea, that confused me for a while too. At some point I was certain it meant to wrap sandpaper around a dowel or something and focus on sharpening a small part of the knife at a time, as one could to sharpen a serrated knife.

Its weird: I had a hard time adjusting knife profiles with this method.


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## HRC_64 (Mar 4, 2018)

ianbiringer said:


> I had a hard time adjusting knife profiles with this method.



especially why you have a fine apex
vs a coarse abrasive... 

I like to start with a fine abrasive to
better keep the profile
intact

... and then move down
to a rougher abrasive
vs. more substance

(=more balanced)

of course YMMV


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## Kippington (Mar 5, 2018)

Would you mind elaborating? I dont quite understand and can't visualize what you've said.

Are you saying you bread-knife on fine sandpaper before you do it on the coarse stuff?


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## HRC_64 (Mar 5, 2018)

Kippington said:


> Would you mind elaborating? I dont quite understand and can't visualize what you've said.
> 
> Are you saying you bread-knife on fine sandpaper before you do it on the coarse stuff?



Basically, that's the same idea. 
A dull edge is a thick edge. 
A thick edge is more stable edge.

A more stable edge can take a more 
abrasive power tangential to the curve 
without problems.


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## ian (Mar 5, 2018)

Im not certain that I understand what the merits of this approach are, either. I get that you are worried about a coarse abrasive wearing down a sharp edge unevenly. (Or are you worried about it grinding out the edge too fast, so than you cant control the profile?) Its not clear to me that any micro-unevenness wouldnt just work itself out during the rest of the sharpening.


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## Kippington (Mar 5, 2018)

Hmm, very interesting. I've just realized why I got confused.

What you've said here is completely correct: 'Bread-knifing' is to:



HRC_64 said:


> 'saw back and forth onto a flat surface' like what you do to your cutting board with a bread-knife.



I got confused because I haven't used the above method to fix a knife in years, but out of habit I still use the term 'bread-knifing' to describe any method that results in the same thing: a squared off edge to fix the profile.
There's a more efficient way of doing it where you don't need to start on finer abrasives before moving onto the coarse, but I can see why you might need to if you actually are doing the 'sawing' motion.

Once you think about it, trying to cut directly _into_ the abrasive is not a very good way of going about it. Far better is to scrape the knife side to side like a butter-knife on toast, holding the knife directly upright the whole time (at right angles to the abrasive). This way you use far more surface area on the stone/sandpaper, instead of a long and extremely thin portion of it. You can also start working on the coarse grits, rather than working your way down to them from fine. Each grit works more efficiently this way too.

There are better ways, but they're harder to explain.


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## HRC_64 (Mar 5, 2018)

ianbiringer said:


> Im not certain that I understand what the merits of this approach are, either. I get that you are worried about a coarse abrasive wearing down a sharp edge unevenly. (Or are you worried about it grinding out the edge too fast, so than you cant control the profile?) Its not clear to me that any micro-unevenness wouldnt just work itself out during the rest of the sharpening.



its a technique, its not anything more than that.

the more you approximate a curve with a series of flat spots,
the more you need to remove the flat spots,
which requires more technical skill.

If you are trying to simplify the technical skill,
or stretch your faithfulness to the original profile,
or deal with a problematic alloy, etc
more technique can be useful.


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## chinacats (Mar 5, 2018)

Kippington said:


> Hmm, very interesting. I've just realized why I got confused.
> 
> What you've said here is completely correct: 'Bread-knifing' is to:
> 
> ...



Yes, I agree as to method. When I say breadknife I don't exactly saw into the stone but hold the knife vertically and 'scrape'. It is quick and efficient. I'm also a bit confused by starting with a finer abrasive as I usually go to my most coarse stone to do the work and then follow up by a bit of thinning to balance the bevel.


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## HRC_64 (Mar 5, 2018)

Kippington said:


> I still use the term 'bread-knifing' to describe any method that results in the same thing: a squared off edge to fix the profile.



Yeah, seems legit...IMHO anything orthogonal to the edge profile ultimatley is 'breadknifing' in this sense 

trying to explain where a "figure of speech" comes from sometimes just needs the more literal explanation.


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## Kippington (Mar 5, 2018)

True. Makes me wonder how many people actually use the method as it's described...


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## ian (Mar 5, 2018)

One question: I get that in terms of speed, the perpendicular scrape is going to win. Sometimes, though, I may be wanting to create a pretty agressive curve in the edge (eg when shaping the tip) and then I find it easier to cut the stone (either with the edge or with the spine, when doing the tip) since I can create a continuous curve by lifting and dropping my elbow when I do that. I think itd be harder to create a continuous agressive curve with the perpendicular scrape method, since the motion would be less natural... ie youd have to be scraping towards yourself while lifting the handle in a different plane. What do you all do in this situation?


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## chinacats (Mar 5, 2018)

ianbiringer said:


> One question: I get that in terms of speed, the perpendicular scrape is going to win. Sometimes, though, I may be wanting to create a pretty agressive curve in the edge (eg when shaping the tip) and then I find it easier to cut the stone (either with the edge or with the spine, when doing the tip) since I can create a continuous curve by lifting and dropping my elbow when I do that. I think itd be harder to create a continuous agressive curve with the perpendicular scrape method, since the motion would be less natural... ie youd have to be scraping towards yourself while lifting the handle in a different plane. What do you all do in this situation?



Agree that there is some degree of finesse to get exactly to a working profile and this is the right way to go about it...the scrape works best for fast metal removal followed by some rocking motion...been a while since I've had to use this technique myself but definitely the quickest easiest way to get rid of a problem.


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