Stropping on medium grit stones

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suntravel

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For me the best way to get rid of burrs ist to do light short strokes edge leading, like sharpening about 45° to the edge. Gives a fine mikroserration and lots of bite.





In comparison stropped edge trailing along the edge you get an wire edge with almost no bite and min. 50% less time on the board for the next touchup...





With finer stones the difference ist not so huge, but if you are looking for a toothy edge i would go with an steep angle edge leading.

Regards

Uwe
 

miggus

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Hey Uwe,

thanks for the info! Could you please point out how you see that there is a wire edge in the second picture? I'm not seeing it, hence the question.
 

Matus

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Uwe, just a side note: while high resolution microscope images are often shared on KMS, they are new stuff here on KKF. We may need a little introduction to understand what we are looking at. Please be partient with us (that 100% includes me). Thank you :)
 

kayman67

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Edge leading is the method described in very old guides and the one I went for myself.
 

daveb

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Is that a gizmo pictured with a knife attached? Blasphemy!
 

suntravel

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The arrows are pointed to an very thin burr pulled out in the direction from the edge. Will maybe break away on the board or fold to one side and leaves a not so sharp edge after a few cuts.

Would be better visible with an REM, but have not one handy :)

Regards

Uwe
 

stringer

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Uwe,
On this one we agree on everything. Well almost everything. Except I would never have time for a gizmo. And my freehand may not be able to beat it, well that's not true. My freehand is better because I thin and convex as I go. But, the important part, that we can agree on is:
Edge leading high angle low pressure passes is the best practice to remove final residual burr.
I have believed this to be fact for quite some time and my own empirical research corroborates the theory. Your photos are fantastic. I agree with you that it doesn't matter as much for finer stones, or Jnats, because there is less risk of a wire edge because there isn't as much burr forming potential. But for finishing on medium grit synthetics, it's best to finish with the 45 degree edge leading nanobevel. This ensures the best burr removal without risk of wire/foil edge. And still gives great bite.
Failure to do this results in much quicker rate of edge failure and more slippery edges that lose their teeth quick. Even on much finer stones, finishing on this manner gives a better lasting and feeling edge. Sharp and toothy at very high grits.
 

Garm

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I'm a little confused. Are you guys(Uwe and Stringer) talking about the same thing when you mention 45 degrees, or is one the angle of approach to the stone and the other the sharpening/deburring angle?
 

suntravel

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maybe a drawing would make better clear what I meant.



with a jig for deburring strokes, i do not chage the grinding angle, because every movent hits the edge, for deburring freehand i would lift the blade to an higher angle to make sure the few movements are hitting the egde.

Main benefit with jig is pressure control (less pressure = less burr) and precision, so you need less strokes to sharpen, less steel lost. So for me it is actually faster than freehand.

The way from stringer with a bit thinning while sharpening works also, but the blade will be worn out faster.

One of my pro chefs friends, brought me every 3 months his blades for thinning, after he started using a jig with pressure control i see him only once a year to thin out his knifes ;)

If you are having Gizmo in the house dont feed after midnight :D

Regards

Uwe
 

Garm

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I thought that's what you meant.
I'm going to experiment a bit with my angle of approach and see if it makes a discernable(to me) difference with regards to bite.
I never go as parallel as <20 degrees, but I think around 30-35 feels the most natural for me when sharpening the right side of the blade(holding in my right hand, edge facing me). I could see some body mechanics issues making your approach a bit of a challenge when freehand sharpening, making wobbling more likely, but I'm gonna give it a go.
It's very interesting to hear about your technique regardless:)
 

kayman67

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Uwe,
On this one we agree on everything. Well almost everything. Except I would never have time for a gizmo. And my freehand may not be able to beat it, well that's not true. My freehand is better because I thin and convex as I go. But, the important part, that we can agree on is:
Edge leading high angle low pressure passes is the best practice to remove final residual burr.
I have believed this to be fact for quite some time and my own empirical research corroborates the theory. Your photos are fantastic. I agree with you that it doesn't matter as much for finer stones, or Jnats, because there is less risk of a wire edge because there isn't as much burr forming potential. But for finishing on medium grit synthetics, it's best to finish with the 45 degree edge leading nanobevel. This ensures the best burr removal without risk of wire/foil edge. And still gives great bite.
Failure to do this results in much quicker rate of edge failure and more slippery edges that lose their teeth quick. Even on much finer stones, finishing on this manner gives a better lasting and feeling edge. Sharp and toothy at very high grits.
I think more and more that we see sharpening and even cutting quite similar. And we got there maybe the same way, doing own test and trial with stuff.
 

kayman67

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The way from stringer with a bit thinning while sharpening works also, but the blade will be worn out faster.

One of my pro chefs friends, brought me every 3 months his blades for thinning, after he started using a jig with pressure control i see him only once a year to thin out his knifes ;)
I believe he does it more like me or I do it more like him from a certain point. Technically it's thinning, but not as imagined. It's more of a realignment of the entire geometry as you would sharpen and it's really subtle, but on the long run makes a difference. Some proper thinning is required eventually, but not for a really long time. Having a good sense of building the edge matters greatly. The knives I work with lose height at an imperceptible rate over very long periods of time. And this gets me to the second part. I believe most people are unnecessary aggressive while sharpening thus the need for more observable thinning so often.

On the subject, my experience is that it's actually hard for most people to use this technique. You will find J-strops as most recommended alternative and honestly, not even an alternative, but first and only recommended approach. And this is why a fix system might help. I'm not sure how expensive it would be and just how many would want to use one anyway.
 

ian

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You know, sometimes when sharpening I find the blade is moving almost parallel to the edge. Like, I’ll have a 35 degree angle to the stone, but I won’t be pushing parallel to the stone, but rather parallel to the edge.

Are there actual downsides to this? Makes it easier to hold a consistent angle, since the stone is contacting a huge portion of the bevel.
 

suntravel

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You know, sometimes when sharpening I find the blade is moving almost parallel to the edge. Like, I’ll have a 35 degree angle to the stone, but I won’t be pushing parallel to the stone, but rather parallel to the edge.

Are there actual downsides to this? Makes it easier to hold a consistent angle, since the stone is contacting a huge portion of the bevel.
Yes the downside is to get an wire egde and loosing al the bite the scratches from the stone could make, also you make scratches along the edge, weaking the edge and make it more prone to chipping...

Regards

Uwe
 

ian

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Yes the downside is to get an wire egde and loosing al the bite the scratches from the stone could make, also you make scratches along the edge, weaking the edge and make it more prone to chipping...

Regards

Uwe
That all makes sense. I hadn’t noticed a decrease in performance the times I’d sharpened like that, though, so I didn’t know what to think.
 

HRC_64

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I have one series of questions...:D

if you draw the edge "parallel" (perfectly, let us assume) to the edge, how do you get a wire edge?

I would normally have to think for a wire edge you need plastic deformation (1) and
of the steel ORTHOGANAL to the edge (2),

to some degree (ie, literal degrees)

otherwise the motion would either plasticallpy deform along the edge itself (?),
or more likely simply shear off the edge or the wire edge (?).

although I suppose shearing off the edge could be its own problem (?)

One would thing this is something that would show up on these kind
of high resolution images?

OK that is all for my thought experiement for today :p
 

ian

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I have one series of questions...:D

if you draw the edge "parallel" (perfectly, let us assume) to the edge, how do you get a wire edge?

I would normally have to think for a wire edge you need plastic deformation (1) and
of the steel ORTHOGANAL to the edge (2),

to some degree (ie, literal degrees)

otherwise the motion would either plasticallpy deform along the edge itself (?),
or more likely simply shear off the edge or the wire edge (?).

although I suppose shearing off the edge could be its own problem (?)

One would thing this is something that would show up on these kind
of high resolution images?

OK that is all for my thought experiement for today :p
Yeah, a lot of things about this confuse me. E.g., if you look at the images here:

https://scienceofsharp.com/2014/04/16/the-honing-progression/

then it's not like the micro-serrations on the edge correspond to the grooves from the grit particles, so it's not completely obvious to me that sharpening more perpendicular to the edge will give you a toothier edge.

Anyway, most of the things Uwe said sound very reasonable (I also don't really know about the wire edge) but I never know what to think, really...
 

Foltest

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In my opinion what matters is the use of edge leading and edge trailing strokes. Edge trailing strokes tend to do more plastic deformation. You use edge leading strokes because you are more likely to shear off the wire edge.

As for the stroke angle, it doesn't matter. Edge of the blade is formed by two planes meeting together. When the metal on the edge gets too thin, grains of the steel fall out, as there is not enough material to hold them. And they fall out approximatelly in the directon of normals of those planes forming the edge. Therefore, when you combine those 2 normals, they form a plane. And unsuprisingly, intersection of this new plane with the edge is direction in which the teeth are formed. As @ian noted above, just look at the images and you will see it.

If you didnt understand what I just wrote, look at the image. Blade - black, normals and plane they form - red, teeth orientation - green.
Untitled.png


Photos from scienceofsharp, with different stroke angles and same teeth orientation:
 
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kayman67

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Well, yes and no, to some degree.
I'm going razors here since with them I did microscope extended testing over motion and this relates to something said above.

So, with razors, if I moved more towards the side of the stone (not quite xs, more like a smiling deburr motion), I could get a more even finish with less evident scratches or a mirror finish accordingly to the stone used. If I kept it at roughly 45, I could get a consistent scratch pattern or some scratches on stones capable of mirror finish, but not just as easy as others. And part of the reason for this above is how the edge will form microteeth in general and how they will perform. But it can develop into a bigger topic once we acknowledge that some abrasives will interact differently with some alloys, regardless of given grit.
With razors there is a debate regarding this, with some common ground over the fact that stones and alloys play a role together, again more or less.
 

Sharpchef

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The gizmo, jiigs or what ever you call it, that we use is basically benchstone sharpening, nothing else... Just imagine a golf or tennis teacher leading your movement while hitting the target/ball.

It`s not just like giving an exact angle, it can reduce the pressure brought to piece of steel that is at least 10 times slimer than aluminium foil ! Remember that... Don `t joke about it, it makes sence, and will improve everybody`s sharpening....

In my test runs, and i was an absolute hater of Jiigs like EP Wicked edge etc.... laughed loud about it ;) .. So no matter what you gonna say about such things "you never will touch" etc....
It works and it is faster then freehand, you get much sharper results (no problem to do a HHT-5 freehand, and i think some of you might get this too!) but the edge will fold roll and be unable to cut after a few cuts.... You know this problem... A Jiig like this solves this problem, and this is the cool thing about it... Take a good steel knife, sharper then a razor blade, and even sharper then most straight razors! (not a joke!) , and cut longer with it then with your best grind ever on medium stones.....

Back to topic, edge leading rulez! ask the Straight razor guys they know how to sharpen! Edge trailing is a waste of time...

Greets Sebastian.

Greets Sebastian.
 

HRC_64

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IMHO pressure is a huge "unkown" variable in sharpening methods be they hand or jig or whatever else.

I can see the idea that a "stabilizing element" could allow for lighte and lighter pressure without compromising "stability". So in theory this could let us deburr better, since using hand pressure you need some minimum amount of tension to keep the edge angle stable.

FWIW this semms to be completely different than the "angle is precisely x.yzx degrees" type discussions had previously....in the sense that its not a precise angle that is critical, but the general concept of minimal pressure on burr formation/removal...

Notwithstanding all of that, there is MUCH about "edge shaping" that I think is useful to LEARN/DO by free-hand in part because the method forces you to be closer to the work -- ie, hands the blade and contsantly feeling/and looking at your work.,,, so when it comes to re-profiling, convexing and generally testing the "cutting" response of your grind modifications etc...freehand is indisuputably at an advantage...at least in my perspective.

But this is an interesting discussion/conversation to think about differnt ways of doing things.
 

daveb

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Where's the "Don't Like" button for SOS?

He uses 43 pages to tell you what time it is......
 

Barmoley

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I think the issue is that the gizmo I assume is expensive and takes setup and planning. Moreover it sort of discourages building of the skill by suggesting that if you use it anyone can sharpen better than even people with years of sharpening experience. So if one uses the gizmo exclusively and then needs to sharpen a knife freehand, the results will be poor.
The other issues are more psychological, the gizmo is a "scientific" approach to sharpening, but many view sharpening as a skill and activity they spent years to learn. There is a romantic aspect to it that brings you closer to your knives because it makes knives almost alive since one has to take care of them. As such it upsets people that spent years building these skills and feel that they are in a special group.
The gizmo might be great and work amazingly well in many cases, it sounds like it does, but most here won't use it or give it a chance. For professional sharpeners though it probably makes a lot of sense, assuming it works as described and it seems to make sense that it works well.
 

suntravel

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With two left hands you will get poor results with an jig also, but it can speed up the learning curve for beginners.

Not everyone new to good knives wants to learn several years maybe full of frustration.

But being able to sharpen well freehand is the best starting point for a jig.

Regards

Uwe
 
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Sharpchef

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I think the issue is that the gizmo I assume is expensive and takes setup and planning. Moreover it sort of discourages building of the skill by suggesting that if you use it anyone can sharpen better than even people with years of sharpening experience. So if one uses the gizmo exclusively and then needs to sharpen a knife freehand, the results will be poor.
The other issues are more psychological, the gizmo is a "scientific" approach to sharpening, but many view sharpening as a skill and activity they spent years to learn. There is a romantic aspect to it that brings you closer to your knives because it makes knives almost alive since one has to take care of them. As such it upsets people that spent years building these skills and feel that they are in a special group.
The gizmo might be great and work amazingly well in many cases, it sounds like it does, but most here won't use it or give it a chance. For professional sharpeners though it probably makes a lot of sense, assuming it works as described and it seems to make sense that it works well.
I agree that you need sharpening experience for using a sharpening system (again nothing like EP! or WE!) like the shown above. But expensive ? It is much more expensive to spend too much money in useless high grit stones and even more on super duper fine naturals.... If you allready have spend this money a sharpening system like this is the best way to spend your money and are finally at the stage to use this high grit stones.... :) .

The benefits are for free in this way.

Greets Sebastian.
 
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