# Secondary edge on western-style knives  angle?



## Kamelion (May 30, 2017)

Dear Forum,

after reading an awful lot on sharpening, I am still a bit confused regarding secondary edge. It seems clear for me how it works on japanese knives, and I often also clearly see a secondary edge, going up a centimeter or more. On a western style knife though, if it has an edge with 20+20°, it is my impresson that the secondary edge ist maybe 15°, going up no more than 12 mm on the blade side. This is also how I tried to sharpen myself. Here is a picture of three of my western-style (and/or hybrid) knives:






_From the left: Misen, E. Dehillerin 23cm couteau de cuisine, Victorinox 28 cm couteau de cuisine._

The two on the right, I have tried to sharpen this way, approximately 1015° secondary edge, and a 20° edge that I mostly do with my Sharpmaker. Is this at all a good method you think?

Here a detail of the Dehillerin:





_E. Dehillerin 23 cm. The secondary edge is around 1,5 mm, and the primary edge just 0,15 mm or so._

Now, my big question here is how to sharpen the secondary edge in japanesewestern hybrid blades that are harder, and intended to have a 15° primary edge? For example, on knives like Hattori, JCK, Misono, Akifusa etc, I have never seen the kind of secondary e that seems to go 12 centimeters up the blade, but rather 12 mm. Now, I cannot judge if this is the only edge, or if it is a small, say, 10° secondary edge, and a 15° primary edge there. 

So, should it also go just 12 mm up the blade, thus being 810° or so?

Take the Misen as an example here. (Lets not have a big discussion about this knife here, I got it for fun, and am just trying it out). The edge it came with looks like this:





_Misen. Only one edge._

This is just a single edge, around 16°, and it itself already goes 1,3 mm up the blade side. It feels as if its not very thin behind the blade, so therefore I would like to make a secondary edge. What are your recommendations here, approx. angle, how far up the blade should it stretch etc?


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## foody518 (May 30, 2017)

There's no set rule for the secondary bevel. It helps you have a guideline for where or how to thin over time. Usually at 2-5 degrees if we're really talking about a thinning bevel. You go until the knife performs to your liking


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## Ruso (May 30, 2017)

If it's not a wide bevel knife thining will create a primary bevel, that will eventually alter the initial geometry. The consensus seems to be that it's an acceptable tradeoff that benefits the cutting ability in the long run.

P.S. Primary and Secondary bevels are quite interchangeable terms. But I belive the correct way in metallurgy is to call the "edge" a scondary bevel and the release bevel a primary bevel.


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## Kamelion (May 30, 2017)

Edit: updated the post with this info: Now, my big question here is how to sharpen the secondary bevel in japanesewestern hybrid blades that are harder, and intended to have a 15° primary edge? For example, on knives like Hattori, JCK, Misono, Akifusa etc, I have never seen the kind of secondary bevel that seems to go 12 centimeters up the blade, but rather 12 mm. Now, I cannot judge if this is the only edge, or if it is a small, say, 10° bevel, and a 15° cutting edge there. 

So, should it also go just 12 mm up the blade, thus being 810° or so?


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## Benuser (May 30, 2017)

+1.
In addition: start by easing the bevel's shoulder. Go on until you've reached the very edge. Verify with the marker trick or by looking at the scratch pattern.


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## Kamelion (May 30, 2017)

Benuser said:


> +1.
> In addition: start by easing the bevel's shoulder. Go on until you've reached the very edge. Verify with the marker trick or by looking at the scratch pattern.



Thank you. But approx. what angleand as a result, how far up the bladewould you recommend? As I said above, I have rarely seen a very high secondary edge on this kind of knife(?).


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## foody518 (May 30, 2017)

Kamelion said:


> Edit: updated the post with this info: Now, my big question here is how to sharpen the secondary bevel in japanesewestern hybrid blades that are harder, and intended to have a 15° primary edge? For example, on knives like Hattori, JCK, Misono, Akifusa etc, I have never seen the kind of secondary bevel that seems to go 12 centimeters up the blade, but rather 12 mm. Now, I cannot judge if this is the only edge, or if it is a small, say, 10° bevel, and a 15° cutting edge there.
> 
> So, should it also go just 12 mm up the blade, thus being 810° or so?



I think you're still thinking of this too prescriptively. As people use such knives over time they will end up with some sort of thinning bevel unless they don't care to maintain knife performance over time. Depending on how you sharpen, it may start as just looking like a longer convex edge bevel through continually easing the shoulder, but at some point you're going to have thinning marks more in the 5-10mm or more up the blade. All about how you're wanting the knives to cut. 
And your edge bevel size and angles is just going to be what fits your performance and durability needs as well.


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## Kamelion (May 30, 2017)

foody518 said:


> I think you're still thinking of this too prescriptively. As people use such knives over time they will end up with some sort of thinning bevel unless they don't care to maintain knife performance over time. Depending on how you sharpen, it may start as just looking like a longer convex edge bevel through continually easing the shoulder, but at some point you're going to have thinning marks more in the 5-10mm or more up the blade. All about how you're wanting the knives to cut.
> And your edge bevel size and angles is just going to be what fits your performance and durability needs as well.



Ok, you are probably right. But my feeling now is:

 It is a bit thick behind the edge, therefore a bit of thinning out would probably make it cut more elegantly.

 With some kind of secondary edge/thinning out, the sharpening will be easier, since I will not have to remove so much material.

With that in mind, what is a good starting point, angle-wise, you think?


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## Benuser (May 30, 2017)

The lowest angle you're comfortable with. Make sure to go almost to the very edge. Or less adventurous: start with the shoulders.


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## foody518 (May 30, 2017)

Kamelion said:


> Ok, you are probably right. But my feeling now is:
> 
>  It is a bit thick behind the edge, therefore a bit of thinning out would probably make it cut more elegantly.
> 
> ...



Benuser's comment above nails it. If you want numbers, again, in the 2-5 degrees ballpark. Make sure you've nearly erased your existing (likely overly large) edge bevel through the thinning process


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## Kamelion (May 30, 2017)

Benuser said:


> The lowest angle you're comfortable with. Make sure to go almost to the very edge. Or less adventurous: start with the shoulders.



I see. But any angle higher than 0° to the blade side would be the shoulders, since there is only the side of the blade, and then the edge.


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## Kamelion (May 30, 2017)

foody518 said:


> Benuser's comment above nails it. If you want numbers, again, in the 2-5 degrees ballpark. Make sure you've nearly erased your existing (likely overly large) edge bevel through the thinning process



Thanks for the help, its very helpful.


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## foody518 (May 30, 2017)

Kamelion said:


> I see. But any angle higher than 0° to the blade side would be the shoulders, since there is only the side of the blade, and then the edge.



Kind of, it depends on how much convex there is on the blade face. You can *just* hit the shoulder if you go at a higher angle but not so high to be the primary bevel, or you can hit some of the blade face and the very top of the shoulder, or after you ease the shoulder a bit you could very well find yourself contacting more of the lower part of the blade face. Just depends on the geometry in question


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## Ruso (May 30, 2017)

Kamelion said:


> I see. But any angle higher than 0° to the blade side would be the shoulders, since there is only the side of the blade, and then the edge.



Please read my comment on the 1st page. That's a tradeoff of thinning non wide bevel knives.


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## Benuser (May 30, 2017)

For further thinning behind the edge exercise serious pressure on the opposite side, at let's say 1cm from the very edge. Expect scratches from the stone slurry. Can go up to some 2cm.
Works only when the blade hasn't gone too thick...


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## Kamelion (May 30, 2017)

Thanks all for your helpful answers. I think I will try thinning out the shoulders first, starting with just 810° or so, getting my confidence and technique up a bit before doing some serious bevelling. Sounds reasonable?

Also, I have a follow-up, regarding a Chinese cleaver from CCK (1302). This one has several stages where it gets thinner. Look here:






Still, I was unsure about whether to sharpen an edge dirctly, so I put it on the whetstone, maybe 78° angle, creating the 2mm edge that is visible in the photo.






The very cutting edge is not visable, made at 15° (maybe what one would call a microbevel?)

Now I got a bit of angst regarding this though; was this a bad idea? Have I screwed up something, the blade geometry or so? Could I have made the edge to fragile? (I mean, the thing is preddy darn thin anyway.) Was it completely unnecessary? Or is it maybe even better this way?

Would love your input on this, since I am a bit worried I did something stupid


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## Benuser (May 30, 2017)

If you press with the half of your finger on the opposite side, you'll surely hit the shoulder of your bevel without touching the very edge. Verify with the marker trick.


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## rick alen (Jun 9, 2017)

In general: Lead-in angle from 1.75 to 2.5 degrees, depending on the "weight". A double secondary of 5/side then 10, then microbevel to suite the work. I prefer symmetric grinds because I am asymmetric-challenged, ie, always get the sides mixed up. ;-)~ I find that a symmetric edge done right works as well as asymmetric.


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## foody518 (Jun 9, 2017)

Kamelion said:


> Thanks all for your helpful answers. I think I will try thinning out the shoulders first, starting with just 810° or so, getting my confidence and technique up a bit before doing some serious bevelling. Sounds reasonable?
> 
> Also, I have a follow-up, regarding a Chinese cleaver from CCK (1302). This one has several stages where it gets thinner. Look here:
> 
> ...



Hard to say since I don't know the edge retention characteristics of CCK, but to my eye that would even look reasonable on a decent hardness J-knife, so check to see if this is holding up or if your edge is folding. 
It's trial and error anyways, hope you are enjoying your new knives


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## rick alen (Jun 9, 2017)

I'll add that a wide-bevel gyuto should simply have a lead-in angle of 3-5deg/side, no other taper from the spine.

In all cases you need to pick your edge thicknesses also, this of course depends on hardness of steel (softer steels take a bend-set if you go too thin) and the kind of work you are going to do.


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## Matus (Jun 9, 2017)

Listen to Ben  

My approach would be - thin the knife as much as possible (step by step - thin some, sharpen, test - repeat until happy), and apply a micro/mini bevel under much larger angle, so that you get better edge holding and edge stability without making the blade thick behind the edge. If I would do that kind of thinning I would go up some 2 cm from the edge - maybe even more (depending on the geometry of the knife). I have never even tried to measure my sharpening or thinning angles - in spite of the fact that I am a physicist ... :scratchhead:


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