Anyone know original angles on Konosuke?

[Edgy Guy]

Help. I've been bad.
3.5 years ago I bought a Konosuke 240mm Hitachi White #2 steel Wa-Gyuto, and a matching 120mm Petty.

They've had light use in a home but I have never sharpened them on a stone.
I have only touched them up on a round ceramic rod.

I want to restore the edges to the original angles, whatever those were.
The usual advice of finding the correct sharpening angle by painting the edge with a Sharpie won't cut it here because the original angles are loooong gone.

I know developing the skill of hand sharpening on a stone is preferred.
Forgive me, but I bought an Edge Pro and have one of those angle-measuring cubes.

What were the original angles?
Did they have a 2-step beveled edge on each side or just one? (Sorry if I'm using the wrong terminology.)
Were the angles symmetric or different on each of the blade?
If different, which side has what angle for a right-handed person? ... as show in my pic the engraved side of the blade is away from my body when cutting.

Thanks.

 

[EdipisReks]

I'd be surprised if there was a consistent angle.

 

[Timthebeaver]

Agreed.

You won't get a result which is faithful to the original edge geometry with a jig, in my opinion. If your Konosuke was anything like the other Sakai lasers I have handled, the bevel will be extremely small.

 

[Edgy Guy]

I'd be surprised if there was a consistent angle.

Thanks, you're probably right.

But I'm looking for the original angles (or angles that experts here recommend for such knives) to give these knives a fresh start after being neglected.
I think copying/preserving whatever wonky angles these knives have now is a mistake.

When new they were lasers.
Tomatoes practically cut themselves before the knife got near them.

 

[EdipisReks]

You don't seem to get it. The proper angle changes as blade thickness and edge curve changes, along the length of the knife. This means that the angle is not consistent.

 

[Keith Sinclair]

Never used a jig only freehand. Used the white steel Konosuke quite a bit at work. Even though it is a rather thin blade it is I would guess 70/30.

It is not the edge bevel that is assem. , it is up the face of the blade. If you look at the choil against a white wall, a trained eye can see that the backside is more flat & the cutting side more of an angle.

I use what you call a two step beveled edge. Back bevel (thinning) at 3-5% off the stone, then final bevel 10-15% on both sides. Some say sharpen more strokes on one side than the other.

On a trained blade like my Konosuke do finger progression from heel to tip once on each side thinning & again once on each side final. The final bevel has an even burr heel to tip. remove burr with very light touch lateral sweep. Can strop on newspaper to get rid of any residual burr.

Another technique is to do the low thinning bevel on both sides & the higher final bevel on just the cutting side & remove burr from backside. Some people like to do single bevel on gyuto's, not advisable as the edge can be quite fragile.

 

[mhpr262]

It is not the edge bevel that is assem. , it is up the face of the blade. If you look at the choil against a white wall, a trained eye can see that the backside is more flat & the cutting side more of an angle.

I use what you call a two step beveled edge. Back bevel (thinning) at 3-5% off the stone, then final bevel 10-15% on both sides.

I read that three times but I have no idea what you are talking about here ...

OP, there is no need for an "original" angle. Many, if not most, high-end knives come with only a rudimentary edge because the owners are expected to put their own preferred angles and degree of asymmetry on it. Just experiment a bit and use kind of the edge you prefer.

A good starting point is 70/30 asymmetry (meaning for a righthanded user, when viewed from the handle, the apex of the edge is to the left of the imaginary line that constitutes the middle of the blade). Also, the left hand bevel is usually at an higher angle than the one on the right. Like, 12°-20°on the left hand bevel and 10°-15° on the right hand bevel. Both factors let the bevel on the right hand side appear much wider than the one on the left.

If you have only sharpened with a ceramic rod so far I doubt you will need to do much thinning.

 

[daveb]

If you want to re-baseline the knife to "as new" condition the easy answer is to put it in a mailing tube and send it to one of the vendors here. Describe what you want.

 

[chinacats]

If you want to re-baseline the knife to "as new" condition the easy answer is to put it in a mailing tube and send it to one of the vendors here. Describe what you want.

+1

Send it to a pro, buy a stone and when you receive the knife back you will have bevels made to follow as you learn the process. You'll thank you, and your knife will thank you.

 

[CoqaVin]

I have the white #2 Konosuke, and there are barely any bevels at all, if any, I sharpen on JNS, and it works very very WELL

 

[Pensacola Tiger]

To answer your questions:

What were the original angles?

The factory edge was likely sharpened by hand, and would have been between 13 and 18 degrees on the convex side of the blade and 16 to 21 degrees on the flat side to accommodate the asymmetry. The angle increases as you approach the tip.

Did they have a 2-step beveled edge on each side or just one? (Sorry if I'm using the wrong terminology.)

The factory edge (on mine at least) was a very narrow single bevel.

Were the angles symmetric or different on each of the blade?

Asymmetric.

If different, which side has what angle for a right-handed person? ... as show in my pic the engraved side of the blade is away from my body when cutting.

Unless you have a Konosuke that was purposely ground as a left hand knife, the side with the kanji is the convex side and has the lower angle.

Note that if you don't adjust the sharpening angle as you approach the tip, you will produce a thinner tip than optimum, weaker than the factory one, as shown in this pic:



Rick

 

[Edgy Guy]

You don't seem to get it. The proper angle changes as blade thickness and edge curve changes, along the length of the knife. This means that the angle is not consistent.

Thank you.
I didn't know that.

 

[EdipisReks]

Look at Rick's post at the top of this second page.

 

[ThEoRy]

You don't wan't to restore the original angle anyway as that wouldn't address the geometry behind the edge as you abrade steel and move up into the thicker part of the knife. What you want to do is sharpen from the top of the bevel abrading the steel behind the edge first, then work your way down to the edge. This will keep the blade thin as you go over time preventing any wedging issues.

 

[Keith Sinclair]

You don't wan't to restore the original angle anyway as that wouldn't address the geometry behind the edge as you abrade steel and move up into the thicker part of the knife. What you want to do is sharpen from the top of the bevel abrading the steel behind the edge first, then work your way down to the edge. This will keep the blade thin as you go over time preventing any wedging issues.

This is pretty much what I was trying to say, guilty of using my own terms maybe confusing. Have thinned behind the edge and raised the spine for second angle which creates a burr along the edge. Done this for years on my Konosuke taken some steel off of it over time still a great cutter.

 

[Tall Dark and Swarfy]

All good answers, especially Pensacola Tiger because he has had EP experience.

My immediate recommendation, and only for this 'initial' sharpening (assuming you haven't removed too much steel with that damned hone) is to set the EP at 15 dps and sharpen the gyuto in 2 sections, heel and tip. Start at no lower a grit than 1K Shapton. It shouldn't take much to put an edge on that thin grind. It will be more than sufficiently sharp. It will not be ideal.

An unmodified EP adds its own wonky asymmetry as PT described. You will get left edge bias at the tip and right edge bias at the heel whether you want it or not. You either learn to live with it, go to great lengths to null it out, modify the EP, or learn to freehand.

Investigate strops vs that ceramic hone.

Cheers,

Rick

 

[Zwiefel]

Note that if you don't adjust the sharpening angle as you approach the tip, you will produce a thinner tip than optimum, weaker than the factory one, as shown in this pic:

View attachment 25625

Rick

Thanks for this Rick! I have received 2 knives with this symptom, and created it a couple of times on my own and never understood why it happened. As I was learning how to sharpen, it went away at some point and I don't see it on my knives anymore...but good to know what was going on.

 

[gadgetguy9000]

Note that if you don't adjust the sharpening angle as you approach the tip, you will produce a thinner tip than optimum, weaker than the factory one, as shown in this pic:

View attachment 25625

Rick

A few points here.

When I use my EdgePro I rotate the handle away from me as I move along the curve to keep the tangent of the mid-point of the curve as close to perpendicular to the stone as possible. While this doesn't create a perfectly even bevel I believe you will get better results than adjusting the sharpening angle. Of course freehanding introduces its own set of errors, i.e. thinning the tip, convexing the bevel, etc. I think either approach is fine but as a home cook who doesn't need to do a great deal of sharpening I am more comfortable with the EdgePro. Finally, I don't use my tip that often - I am not a "rocker", so I am okay if the tip isn't as quite strong as the rest of the bevel - it is probably closer to optimal for me if it has a steeper bevel for the times I use it.

To the OP, I would use a single angle for both sides of the blade with a pretty acute included angle. If it gets chippy, back up and put a more obtuse micro bevel on it.

John

 

[chinacats]

So from the last post I gather that if you use an EP that you completely give up the original geometry and then never thin the knife at all? Seems like two out three sharpenings and you'll have to send the knife in for thinning? I actually enjoy my wobbly bevels (and it sounds like they may be as consistent as the EP as you keep turning the knife?)--at least my knives are thin and damn close to their original geometry

Not so much a knock on ep users as a total lack of understanding of why people choose them as opposed to free hand...to each his own.

Cheers

 

[gadgetguy9000]

So from the last post I gather that if you use an EP that you completely give up the original geometry and then never thin the knife at all?

On what basis did you draw these conclusions?

 

[chinacats]

Same angle on both sides of the blade and inconsistent bevels from flipping the knife around whatever center of axis thing you had going...?

Plus, if you don't thin, then you blow the geometry as the angle changes as you move up the blade face.

Edit to say that I'm really not trying to be a jerk (sorry) but you're having to do more work than I do on something that is supposed to make this process simple (and in the way I read and understand what you are saying you are ruining your knife). I just have to try to maintain an angle and thin as I go...plus the cost of all your goods is more than required to have a nice set of stones--not more than some foolish people (looking in mirror) can spend on waterstones.

 

[gadgetguy9000]

Same angle on both sides of the blade and inconsistent bevels from flipping the knife around whatever center of axis thing you had going...?

Plus, if you don't thin, then you blow the geometry as the angle changes as you move up the blade face.

The bevel will be very consistent along both edges, though not perfectly so. If the blade was 50/50 to start with, you can get pretty much exactly that when sharpening. It seems that you might not understand how the EdgePro works. If you can perfectly freehand an asymmetric bevel to a 1 or 2 degree tolerance on each side, kudos.

I didn't address thinning at all. Though it could be used to thin, the EP is probably not the best tool for the job. I try to minimize the amount of material I remove when I sharpen, so I don't need to thin my knives as frequently as once every two or three sharpenings.

 

[chinacats]

The bevel will be very consistent along both edges, though not perfectly so. If the blade was 50/50 to start with, you can get pretty much exactly that when sharpening. It seems that you might not understand how the EdgePro works. If you can perfectly freehand an asymmetric bevel to a 1 or 2 degree tolerance on each side, kudos.

I didn't address thinning at all. Though it could be used to thin, the EP is probably not the best tool for the job. I try to minimize the amount of material I remove when I sharpen, so I don't need to thin my knives as frequently as once every two or three sharpenings.

No I'm not that consistent--really more concerned with maintaining geometry to keep the blade cutting at least as well if not better than new. As to understanding the ep, I know enough to know it won't work for my use Ultimately if you're happy with your edges that's all that counts.

I should link this thread for those who haven't had a chance to read it.

 

[gadgetguy9000]

No I'm not that consistent--really more concerned with maintaining geometry to keep the blade cutting at least as well if not better than new. As to understanding the ep, I know enough to know it won't work for my use Ultimately if you're happy with your edges that's all that counts.

I should link this thread for those who haven't had a chance to read it.

This seems a pointless discussion because you seem more interested in ad hominem attacks and pushing your view than helping the OP, but that seems to be your style, followed by some sort of disclaimer.

As to the post that states "All Japanese knives are asymmetric", this is simply counter-factual, unless one is discussing single bevel knives only.

I would be interested in seeing a physics-based elucidation of the advantages of asymmetric blades in the kitchen, free of simple assertion and cultural mysticism.

 

[chinacats]

whatever...it's obvious that you're happy with what you do, it's just that some people may be trying to make up their own minds. If you don't believe J-knives are asymmetric by design then there is no use discussing any of this...since your knives are no longer asymmetric

People should be aware that the double bevel knives they purchase are asymmetric from the maker--your misguided thoughts do not change this.

I'm done, except to say that the OP is the one looking to find out how his blade was made (asymmetric) and you are not helping if you don't know how his knife or other gyutos are ground from the maker. How you maintain your knives is up to you, but repeating bad information does nothing to further your cause or to help the OP.

Cheers

 

[Zwiefel]

This seems a pointless discussion because you seem more interested in ad hominem attacks and pushing your view than helping the OP, but that seems to be your style, followed by some sort of disclaimer.

I don't see any ad hominem attack in the preceding posts.

As to the post that states "All Japanese knives are asymmetric", this is simply counter-factual, unless one is discussing single bevel knives only.

I would be interested in seeing a physics-based elucidation of the advantages of asymmetric blades in the kitchen, free of simple assertion and cultural mysticism.

I would suggest that you purchase a straight-edge/right-angle tool and carefully examine your blades. If you find that they are symmetrical, there are a lot of folks here that would be interested in seeing photos demonstrating that.

Perhaps you mean "asymmetrical edges" though? That's quite a lot harder to demonstrate. However, an asymmetrical blade would need an asymmetrical edge, n'es pas?

There is also this thread: http://www.kitchenknifeforums.com/showthread.php/5656-Asymmetry-–-The-REAL-DEAL

 

[Geo87]

Gadgetguy: Remember asymmetry is not just edge geometry but the way the entire blade is ground. Just because your edge may be 50/50 doesn't mean the blade is ground evenly behind it.

Do you experience any wedging or steering issues ? (Serious question I'm not attacking you here just to be clear )