Diamond stone Grit & Strop Progression -- Basic German steel kitchen knives

[glasswave]

Hello,
I am wondering what might be the best grit progression to use on basic German steel kitchen knives.

The knives are lightly used, but I will be re-profiling them since they have been sharpened with a pull through sharpener. Just once or twice through the coarser metal V notch and then maintained several times via the carbon fine V notch. I don't know the exact steel, but I'd presume something like "X50 Cr Mo v15" 56+/-1 rockwell.

The knives are used for slicing, and are seldom ever used in a chopping/pressure cutting style. The foods sliced cut are seldom harder than shallots or onions.

I am using a fixed angle system (sorry) and have many grits to choose from 80 to 3000. I have a new strop, but haven't put any diamond compound, yet..
What grit progression (dry diamond stone) would you suggest? What micron stropping compound would you suggest for finishing/final burr removal?
Also, what sharpening angle?

I want them to slice food as effortlessly as possible. I have heard a lower "toothy" grit might be better than a fine polished edge for slicing.

Finally, once I get them sharpened as slicie as I can, What process/frequency would you suggest for edge maintenance to keep them slicing their best?

Thanks


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[Dwergi]

Something along the lines of 400 and then 1000. No point going much higher on soft stainless. 1500 tops, in which case 400/800/1500.

Sharpening angle is 25-30ish.

You don't necessarily need to strop it, just deburr on the highest grit stone with the Kippington method for example: https://www.kitchenknifeforums.com/threads/kippington-deburring-video.44003/

 

[glasswave]

Something along the lines of 400 and then 1000. No point going much higher on soft stainless. 1500 tops, in which case 400/800/1500.

Sharpening angle is 25-30ish.

You don't necessarily need to strop it, just deburr on the highest grit stone with the Kippington method for example: https://www.kitchenknifeforums.com/threads/kippington-deburring-video.44003/

Thanks for your reply.
My understanding is that most German kitchen knives ship with 20 to 15 edge degree per side. I never see 25 to 30 degree per side suggested for kitchen knives, only for utilitarian pock knives, machetes and such. Do you mean 25-30 inclusive? Or are you recommending as much since German steel simply cannot hold an edge.



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[Nemo]

I assume these knives are stainless?

Do you have a picture of the knives? Many German knives have a beefy finger guard that makes reprofiling difficult. These are often best dealt with by a file. Or power tools if you have enough experience to use them safely and without overheating the steel (if you're not sure, then you probably don't). If you are doing major metal removal, you may want to consider bluntening the knife before starting. especially if using a file or power tools. If you do use a file, a vice (with some kind of soft jaws, even if only makeshift) is sensible.

I don't use diamonds on this kind of steel. I often use a silicon carbide stone or sandpaper for big thinning jobs and for repairing a damaged edge. Although you can get a decent edge on SiC co bo stones, fo sharpening I mostly use a 500ish grit water stone, and a 1000ish grit stone for the final stages of deburring. In general, do not go finer than 1500 for these steels.

 

[Nemo]

I generally go 20 degrees per side.

I don't actually measure the angle, I estimate it using trigonometry. Approx 20 degrees will occur if you lay the blade flat on the stone then lift the spine up until til it is a third of the height of the blade.

 

[Dwergi]

Thanks for your reply.
My understanding is that most German kitchen knives ship with 20 to 15 edge degree per side. I never see 25 to 30 degree per side suggested for kitchen knives, only for utilitarian pock knives, machetes and such. Do you mean 25-30 inclusive? Or are you recommending as much since German steel simply cannot hold an edge.

I mean, edge angle is just whatever you feel like it can sustain.

I have no idea what I'm at really, just that it's probably around 20ish. I just checked with my angle gauge, and yeah 30 is probably too much. 15 feels too low though.

 

[glasswave]

I assume these knives are stainless?

Do you have a picture of the knives? Many German knives have a beefy finger guard that makes reprofiling difficult. These are often best dealt with by a file. Or power tools if you have enough experience to use them safely and without overheating the steel (if you're not sure, then you probably don't). If you are doing major metal removal, you may want to consider bluntening the knife before starting. especially if using a file or power tools. If you do use a file, a vice (with some kind of soft jaws, even if only makeshift) is sensible.

I don't use diamonds on this kind of steel. I often use a silicon carbide stone or sandpaper for big thinning jobs and for repairing a damaged edge. Although you can get a decent edge on SiC co bo stones, fo sharpening I mostly use a 500ish grit water stone, and a 1000ish grit stone for the final stages of deburring. In general, do not go finer than 1500 for these steels.

Thank you for your kind reply.
Yes, stainless. There is no bolster to get in the way of sharpening. When I say "re-profile" I mean the reprofile the edge, not the blade..

All I have is diamond stones. And I am just doing the edge, not the blade. They don't have chips of edge damage other than being pulled through a V notch pull-through sharpener.



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[HumbleHomeCook]

Drop down to your 80 and set your bevel. The 80 grit makes me wonder if you're using a KME? Doesn't matter, just curious.

Then work up, no need to go over 1k and lower is better in my opinion. No need for polishing or any of that.

Focus on finish de-burring.

 

[Mr.Wizard]

Since you are not chopping I believe you can get away with a fairly acute edge, down to maybe 15 degrees per side. You may wish to experiment with even lower, around 13, and micro bevel of 17 degrees done coarse. For example polish the bevel up to 800 and debur, then apply the micro bevel with the 200 or 400 plate.

 

[M1k3]

Reprofiling? Start as coarse as you have available, 50-200ish grit.

 

[Nemo]

Now I’m not quite sure what you mean by “reprofiling”.

Are you changing the blade’s profile or just giving it a new edge?

 

[glasswave]

I mean, edge angle is just whatever you feel like it can sustain.

I have no idea what I'm at really, just that it's probably around 20ish. I just checked with my angle gauge, and yeah 30 is probably too much. 15 feels too low though.

I don't know what the edge can sustain, but it seems that most people seem to be sharpening their German Stainless knives with 15 to 20 degrees per side.

 

[glasswave]

Now I’m not quite sure what you mean by “reprofiling”.

Are you changing the blade’s profile or just giving it a new edge?

Sorry, I guess I used the wrong terminology, what I meant was changing the sharpening angle of the new edge. Like from 20 degrees per side to 17 degrees per side.

 

[Mr.Wizard]

Sorry, I guess I used the wrong terminology,

Not wrong, just a different circle. In guided sharpening circles reprofiling often means changing the bevel angle and conforming the edge geometry to that fixed by the jig. More broadly profile refers to the outline or silhouette of an object and "re profiling" might mean something like restoring belly to a blade that has been flattened, correcting an unintentional recurve, or changing the shape of the tip like adding a clip point. "Rebevel" is I believe more idiomatic here for what you are doing.

 

[Benuser]

I like them with a convexed edge. First task is in removing the shoulders — where bevels and faces meet. Makes a huge difference in performance while in no way making the edge any fragile. In the contrary: as less force is required to get the knife through food, the contact with the board is less violent.

To remove the shoulders you may look for the exact angle with a fine stone. I wouldn't be surprised if it were under 10°. Perform the abrading itself with a coarse stone. Continue if you want to get it thin behind the edge.
You want the face and bevel to form a continuous arc, up to the very edge, which will end around 17° per side. I'm used to make them different on both sides, but there is absolutely no need to follow this habit.

I have tried diamond stones with them. The Naniwa Diamond 1k is evidently too fine: the Wüsthoff — Rc 58 — edge folded within two meals, the Global crumbled. Belgian Blue — 4k: immediate crumbling with a Burgvogel / Messermeister — 56Rc.
To explain what's happening here: it's a bit controversial, but in my experience it has to do with the steel's structure: relatively large chromium carbides in a weak matrix. A fine stone is supposed to abrade the matrix and not the carbides, which would explain the carbides breaking out. However, this doesn't fit with the NP1k experience: the stone most be expected to abrade very well chromium carbides. That was exactly why I did give it a try. So, no satisfactory explanation why Krupp's ubiquitous 4116 doesn't hold any refinement — even if very relative. @stringer uses ND600 with his co-workers' soft stainless.

I have best results in performing all work and finishing deburring by alternating edge leading strokes on a Shapton Glass 500. Make sure to clean the stone prior to the last phase.

 

[glasswave]

Drop down to your 80 and set your bevel The 80 grit makes me wonder if you're using a KME? Doesn't matter, just curious.

Then work up, no need to go over 1k and lower is better in my opinion. No need for polishing or any of that.

Focus on finish de-burring.

I picked up a XARILK I saw in classified, which came with a bundle of 11 never used Sy Tools diamond stones in grits from ranging from 80 to 3000, plus 3 more metal backed stones that aren't used either. They are suppose to be decent for what they are. Not bad for $60 and essentially never used. He had sharpened about 2 knives with the crappy plastic back stones that also came bundled with it, before deciding it wasn't for him. I also got a cheap little amazon angle finder with it.

I added a leather strop from Grit-o-matic and picked up a small bottle of Jende 4 micron strop compound.

That's my setup for now. I am probably going to add an entry level Japanese VG10 Gyuto to the collection pretty soon though.


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[Benuser]

Entry level VG-10? I hope it comes with a decent Heat Treatment. With conventional stones, the art in sharpening good VG-10 is in carefully abrading the burr in a tight progression. SG500, NP800, NP2k, SG4kHR, you get the idea. Not letting the burr flipping over and over: abrading, with the lightest touch. The same technique will hugely improve your sharpening in general.
With diamond stones, as far as I have tried, there is no need for a tight progression. Got a Hattori OK with deburring as far as possible on a SG500, only followed by ND6k.

If the 'entry level' VG-10 comes with a poor or average Heat Treatment, prepare for hell. That said, the affordable Tojiro DP come these days with excellent VG-10.

 

[Mr.Wizard]

@Benuser Would this steel that "doesn't hold any refinement" be used in this Henckels product?

 

[glasswave]

Thanks for your help.

Entry level VG-10? I hope it comes with a decent Heat Treatment.
If the 'entry level' VG-10 comes with a poor or average Heat Treatment, prepare for hell. That said, the affordable Tojiro DP come these days with excellent VG-10.

I am looking at the Tojiro DP, Tojiro Basic, and some others.

With conventional stones, the art in sharpening good VG-10 is in carefully abrading the burr in a tight progression. SG500, NP800, NP2k, SG4kHR, you get the idea. Not letting the burr flipping over and over: abrading, with the lightest touch. The same technique will hugely improve your sharpening in general.
With diamond stones, as far as I have tried, there is no need for a tight progression. Got a Hattori OK with deburring as far as possible on a SG500, only followed by ND6k.

It seems like +/- doubling makes a pretty good progression for vg10, I assume. It also seems to benefit from a finer finish. 200 → 400 → 800 →1500 → 3000 → 4 μ strop?
or would 200 → 600 → 2000 → 4 μ strop be better?


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[Benuser]

@Benuser Would this steel that "doesn't hold any refinement" be used in this Henckels product?

View attachment 388694

They use like all other brands Krupp 4116, with all the marketing nonsense about 'specially formulated proprietary steel' we know from Zwilling / Henckels. So I wouldn't expect any benefit from a polished edge. I don't expect it to hold.

 

[Mr.Wizard]

They use like all other brands Krupp 4116, with all the marketing nonsense about 'specially formulated proprietary steel' we know from Zwilling / Henckels. So I wouldn't expect any benefit from a polished edge. I don't expect it to hold.

That's perfect. I remember you writing about this before but at the time I didn't have a knife to test with.

 

[Benuser]

Thanks for your help.

I am looking at the Tojiro DP, Tojiro Basic, and some others.


It seems like +/- doubling makes a pretty good progression for vg10, I assume. It also seems to benefit from a finer finish. 200 → 400 → 800 →1500 → 3000 → 4 μ strop?
or would 200 → 600 → 2000 → 4 μ strop be better?


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What about these strops? Just curious. It's a steel where it's hard to get rid of a burr without raising a new one, on the other side. It's no fine grained Swedish carbon steel. I guess stropping here is asking for troubles. What are you going to do when halfway your stropping a burr appears? Hoping to strop it away? Forget it. A VG-10 burr is tenacious. Do you have such a fine stone to gently abrade it?
Why no set of very light alternating edge leading strokes on your finest stone?

 

[Benuser]

Thanks for your help.

I am looking at the Tojiro DP, Tojiro Basic, and some others.


It seems like +/- doubling makes a pretty good progression for vg10, I assume. It also seems to benefit from a finer finish. 200 → 400 → 800 →1500 → 3000 → 4 μ strop?
or would 200 → 600 → 2000 → 4 μ strop be better?


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Are these those diamond stones? What the hell are you expecting to be doing with a 200 stone and then getting a stable final edge??
Take into account the nature of the steel. It's basically unstable. It's no simple carbon of AEB-L. Have a look at micrographs of it. You change anything in place A and everything will change in place B.
When thinning this stuff I wait a day before going on. A perfectly deburred with a conventional 320. Next day: a fat burr on one side. And you're willing to start with a diamond 200??
The tight progression I suggested was with conventional stones, and with a very light touch. No edge trailing.
You may try on your 600, deburr only edge leading, and go on on your 3k. Alternating edge leading strokes, as light as you can.
A permanent marker (sharpie) and a loupe (triplet, 10x) are very helpful to make sure you have clean bevels, without paint or swarf on top. As long as there is, the bevels don't meet. You're just accumulating debris on top of your previous edge, likely to form a wire edge. Very common with VG-10 and jig users.

 

[glasswave]

Are these those diamond stones?

Yes, diamond stones.

What the hell are you expecting to be doing with a 200 stone and then getting a stable final edge??

I do not know what the hell I am doing. I thought that much was obvious.

Take into account the nature of the steel. It's basically unstable. It's no simple carbon of AEB-L. Have a look at micrographs of it. You change anything in place A and everything will change in place B.
When thinning this stuff I wait a day before going on. A perfectly deburred with a conventional 320. Next day: a fat burr on one side. And you're willing to start with a diamond 200??
The tight progression I suggested was with conventional stones, and with a very light touch. No edge trailing.
You may try on your 600, deburr only edge leading, and go on on your 3k. Alternating edge leading strokes, as light as you can.

I know little about metallurgy besides the basics. Gold is heavy and malleable. Titanium is light and stiff. That kind of stuff, I don't know what micro-graphs are or how to read them. I gained the impression that if you are "re-beveling" you should start fairly coarse.

Tonight I took one of my walmart practice knives and used a 200 to replace the previous edge. I had a massive burr worked up in about 2 minutes. I then went to 500 → 1000 → 2000 → 4 micron strop. At 2000 I finished with alternate side feather weight strokes away from the edge as I saw in a vid on burr minimization with fixed angle systems. I then stropped three light touch strokes a side pulling away, followed by 2 per side, then one.

It was my best result yet. An Italian dry salami was slightly stiffer than butter. Lazer printer paper could be sliced with zig zags. It'd glide through magazine paper if you got started right. Paper towels, not so much.

A permanent marker (sharpie) and a loupe (triplet, 10x) are very helpful to make sure you have clean bevels, without paint or swarf on top. As long as there is, the bevels don't meet. You're just accumulating debris on top of your previous edge, likely to form a wire edge. Very common with VG-10 and jig users.

I tried to get a decent loupe, but it didn't work worth a darn, so I've been using this 30x Magnifying glass, which seems under powered but OKish. I've use the sharpie pen trick on occasion. I hope to learn enough not to ruin a VG10 knife by the time my upcoming Tojiro or similar needs a sharpen.

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[Benuser]

Yes, diamond stones.


I do not know what the hell I am doing. I thought that much was obvious.


I know little about metallurgy besides the basics. Gold is heavy and malleable. Titanium is light and stiff. That kind of stuff, I don't know what micro-graphs are or how to read them. I gained the impression that if you are "re-beveling" you should start fairly coarse.

Tonight I took one of my walmart practice knives and used a 200 to replace the previous edge. I had a massive burr worked up in about 2 minutes. I then went to 500 → 1000 → 2000 → 4 micron strop. At 2000 I finished with alternate side feather weight strokes away from the edge as I saw in a vid on burr minimization with fixed angle systems. I then stropped three light touch strokes a side pulling away, followed by 2 per side, then one.

It was my best result yet. An Italian dry salami was slightly stiffer than butter. Lazer printer paper could be sliced with zig zags. It'd glide through magazine paper if you got started right. Paper towels, not so much.


I tried to get a decent loupe, but it didn't work worth a darn, so I've been using this 30x Magnifying glass, which seems under powered but OKish. I've use the sharpie pen trick on occasion. I hope to learn enough not to ruin a VG10 knife by the time my upcoming Tojiro or similar needs a sharpen.

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Almost any knife needs a sharpening fresh out of the box, unless we're dealing with (semi-)customs. And even when you get a stone sharpened knife, it's not necessarily right for you.
Most knives get in factory a minimal sharpening — three strokes or so, right, left, right — and a lot of buffing. It wil feal reasonably sharp but won't hold. With all the buffing steel gets fatigued and will rapidly fail.
The first thing I do with a new knife is giving it a good sharpening, making sure nothing is left from the original edge, and thinning a bit to at least compensate for the removed edge, as the new one comes a fraction closer to the spine in a thicker part of the blade. If the blade comes fat behind the edge, or there is a protruding shoulder, I will have to deal with as well.
My remark about the 200 diamond was out of concern about using it at the very edge. Perhaps great for thinning, but too coarse to work at the bevel, especially at the very edge. That can be done by much finer grits with far better results.
There is little you can do that can't be undone. Ruining a knife won't happen. Hard to imagine about how deliberately one must do to achieve such a result.
In general soft stainless don't hold a polished edge, so stop in time. A serious problem is in getting a burr completely at lower grits. No fun, but I have no solution.
Remember with better steel as well to deburr at every stage. You don't want failed steel to get incorporated in the new edge, and a burr is steel that has failed.
Have fun.

 

[glasswave]

What about these strops? Just curious. It's a steel where it's hard to get rid of a burr without raising a new one, on the other side. It's no fine grained Swedish carbon steel. I guess stropping here is asking for troubles. What are you going to do when halfway your stropping a burr appears? Hoping to strop it away? Forget it. A VG-10 burr is tenacious. Do you have such a fine stone to gently abrade it?
Why no set of very light alternating edge leading strokes on your finest stone?

I have come to understand that stropping as a final step it the best way to get rid of any remaining burr. At least the YouTube sharpening channels seem to support this. They say stropping is the key to burr removal and separates the strong, sharp, lasting edge from the quick to dull basic edge. Do some ultra light, away from edge, passes on your finishing stone, then strop.

I have 2000 grit and 3000 grit finishing stones. When finishing, I use light, away from the edge strokes on alternating sides which should help with the burr. Some say drag the edge across a hunk of wood.


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[Mr.Wizard]

Here are a few resources I think may be of help.

Since you are using diamond plates on a jig I suggest looking at Wicked Edge founder Clay Allison's videos.

Dr. Larrin Thomas is a leading voice and innovator in knife-specific metallurgy. He shares a wealth of information on KnifeSteelNerds.com, has published two books, and used to post on this forum.

The late Dr. Vadim Kraichuk did meticulous testing and development with angle-controlled powered sharpening. His site KnifeGrinders.com.au has quite a few resources of interest and his many videos are still up. He held the somewhat unusual opinion that a highly polished edge is better for butchery but backs it up with data. His inexpensive Knife Deburring ebook is still available and it is my understanding that proceeds support his family. I recommend it.

Dr. Todd Simpson does amazing electron microscopy of knife edges and explores different sharpening processes. You will see his work used by both authors above. His blog: ScienceOfSharp.com

 

[Benuser]

I have come to understand that stropping as a final step it the best way to get rid of any remaining burr. At least the YouTube sharpening channels seem to support this. They say stropping is the key to burr removal and separates the strong, sharp, lasting edge from the quick to dull basic edge. Do some ultra light, away from edge, passes on your finishing stone, then strop.

I have 2000 grit and 3000 grit finishing stones. When finishing, I use light, away from the edge strokes on alternating sides which should help with the burr. Some say drag the edge across a hunk of wood.


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With edge trailing moves as you describe you're sure to both abrade the burr and raise a new one on the opposite side. So, it's a never ending story. Better use edge leading strokes. Deburr on every stone. Not only on the last one. You may check whether the burr is gone by feeling with your nail along the edge from heel to tip and back, on both sides, who should both feel equally very smooth. If you feel any resistance on one side, e.g. at the belly, continue with the edge leading strokes.

 

[Mr.Wizard]

I do not wish to be confrontational but it is important to realize that things may work differently with different hands, tools, heat treatments, etc. Here's a quote from a highly skilled professional freehand sharpener on this forum. That whole thread is worth reviewing.

Certainly you will want a low grit stone (or sandpaper) if taking even small chips out of cheap stainless. A Crystolon or India Coarse n Fine is always a good investment.

You don't need to finish the edge lower than posher knives. Cheap stainless will take a high grit edge just fine, what it won't do often is take a low angle.

By far the most important thing though is: cheap stainless (in fact most stainless apart from the really good stuff) doesn't like to be finished/deburred edge-leading. Not one little bit. You want to end with repeated, light-pressure trailing strokes and then strop hard.

 

[sanmateo]

I sharpen everything edge-leading, decreasing pressure, and increasing angle slightly as I go.

"different strokes for different folks"