Sharpening vs. stropping vs. REsharpening vs. REstropping

[captaincaed]

This is all about woodworking tools, but I think this was an excellent experiment. It discusses initial sharpening, initial sharpening + stropping, and then the benefits of successive RE stropping or RE sharpening at a finishing grit (4-8k). At the end of the day, he's taking tool steel, sharpening it, then dulling it on wood. Sounds analogous to using a kitchen knife to me.

One of the best features of these tests are the clear display of experimental scatter, which folks like @Larrin are always banging on about, trying to make you knuckleheads understand. It's not always about a direct comparison of single numeric values - it's about seeing trends, and especially about comparing trends between groups.

I have some opinions about how this might affect my own practice, but ... I'll hold off until folks discuss

and

go

 

[cotedupy]

I'm going to have to be a lot more sober before I can deal with sentences like these:

One of the best features of these tests are the clear display of experimental scatter, [...] It's not always about a direct comparison of single numeric values - it's about seeing trends, and especially about comparing trends between groups.

(Will reply properly in a couple of days... )

 

[captaincaed]

I'm going to have to be a lot more sober before I can deal with sentences like these:




(Will reply properly in a couple of days... )

Just type now. It’ll be hilarious!

 

[Delat]

This maps with my experience. Stropping w/compound helps a little bit once or twice but that’s about it. I can stick with my highest grit stone for “touch ups” for ages though. I’m not a heavy user at all though, so ymmv.

 

[M1k3]

This maps with my experience. Stropping w/compound helps a little bit once or twice but that’s about it. I can stick with my highest grit stone for “touch ups” for ages though. I’m not a heavy user at all though, so ymmv.

Same experience I have with knives.

 

[ptolemy]

This is all about woodworking tools, but I think this was an excellent experiment. It discusses initial sharpening, initial sharpening + stropping, and then the benefits of successive RE stropping or RE sharpening at a finishing grit (4-8k). At the end of the day, he's taking tool steel, sharpening it, then dulling it on wood. Sounds analogous to using a kitchen knife to me.

One of the best features of these tests are the clear display of experimental scatter, which folks like @Larrin are always banging on about, trying to make you knuckleheads understand. It's not always about a direct comparison of single numeric values - it's about seeing trends, and especially about comparing trends between groups.

I have some opinions about how this might affect my own practice, but ... I'll hold off until folks discuss

and

go

cool video.

i guess my only q is... i would never consider using a strop if I have 5k or 8k stone.. I more look at strop for 20k+ i.e last possible ending sharpness and on working tools or knives, I'd prob never go into strip at all... unless it's a razor

 

[Kawa]

This maps with my experience. Stropping w/compound helps a little bit once or twice but that’s about it. I can stick with my highest grit stone for “touch ups” for ages though. I’m not a heavy user at all though, so ymmv.

+1

 

[big D]

I view this as pretty decisive information. It also implies (IMO), that stropping may actually be detrimental in the long run to newcomers to sharpening. It has been stated numerous times that for beginner's, while making the edge sharper, stropping masks errors in holding a consistent angle. If one should strop often attempting to save metal, it produces a rounded edge bevel. This would eliminate the flat spot, which is key to finding the proper angle for someone newer to sharpening. --------------- just a thought.
Thanks for the video.
D.

 

[Kawa]

Even when not rounding of the edge,
I think that after some minor wear sets it, a strop just can't 'repair' the edge anymore.

i'm not talking 2+ micron (that is grinding or removing metal), but cardboard, denim or 1micron (or lower) loaded strops.

 

[miggus]

Hmm I don't know if I'm fooling myself, but to me, stropping seems to improve my results quite a bit (I'm not a good or versatile sharpener, but I think I get results that are perfectly acceptable for kitchen use).
But I never considered stropping to be a replacement for sharpening. Hadn't even occurred to me. Instead I use it as a very light touch-up in order to bring back a still pretty good edge or finalize a sharpening session. I'm talking like 5 - 7 passes on each side, nothing more.

Do you think stropping is valid for that? It sure is plausible that it's masking inconsistencies in my sharpening.

 

[salparadise]

I view this as pretty decisive information. It also implies (IMO), that stropping may actually be detrimental in the long run to newcomers to sharpening. It has been stated numerous times that for beginner's, while making the edge sharper, stropping masks errors in holding a consistent angle. If one should strop often attempting to save metal, it produces a rounded edge bevel. This would eliminate the flat spot, which is key to finding the proper angle for someone newer to sharpening.

I’ve had this problem. I’ve been trying to sharpen kitchen knives on stones for about a year, and I’m just not getting a very sharp edge off the stone. A few stropping strokes on newspaper and it’s sharp-sharp. I pay attention to holding the angle, but apparently I’ve plateaued. I have the information, equipment, and a good amount of practice but keep hoping for the day when it just works like I know it should. I’m going to try again tomorrow- no stropping.

 

[bsfsu]

I think some of the results are applicable to knife sharpening but I don't think we can extrapolate all of the results in the vid for 'knife sharpening'.

I generally strop after sharpening but I don't strop too sharpen, it's part of the finishing process.

The experiment is good but it is relevant for woodworking tools, not the higher end kitchen cutlery we talk about.

 

[bsfsu]

I’ve had this problem. I’ve been trying to sharpen kitchen knives on stones for about a year, and I’m just not getting a very sharp edge off the stone. A few stropping strokes on newspaper and it’s sharp-sharp. I pay attention to holding the angle, but apparently I’ve plateaued. I have the information, equipment, and a good amount of practice but keep hoping for the day when it just works like I know it should. I’m going to try again tomorrow- no stropping.

Look into your burr removal before you hit the strop. You might find if you can refine your burr removal you will achieve that sharpness, a couple of strops will finish/refine/smooth the edge and give that extra sharpness though.

 

[enchappo]

Look into your burr removal before you hit the strop. You might find if you can refine your burr removal you will achieve that sharpness, a couple of strops will finish/refine/smooth the edge and give that extra sharpness though.

 

[MattPike4President]

Look into your burr removal before you hit the strop. You might find if you can refine your burr removal you will achieve that sharpness, a couple of strops will finish/refine/smooth the edge and give that extra sharpness though.

Focusing on burr removal helped me move past what felt like a plateau in my sharpening a while ago, my edges last a lot longer now as well. I don't strop but not for any particularly thought out reason

 

[captaincaed]

I generally strop after sharpening but I don't strop too sharpen, it's part of the finishing process.

The experiment is good but it is relevant for woodworking tools, not the higher end kitchen cutlery we talk about.

Laying my cards on the table here…

I’m curious why it wouldn’t be relevant. My takeaway idea was restropping may get you back to an apex, but will round out your sharpening angles, leaving a fatter convex bevel. (And over time that edge gets harder to refresh.) Knives go through dense food as planes travel through wood.

Diminishing returns from stropping without going back to stones.

One thing not discussed is how stropping removes bite/smooths the apex. Great for wood tools and razors, less so for cutlery. I will grant that’s one aspect of “sharpness” that woodworkers never really talk about.

 

[captaincaed]

I view this as pretty decisive information. It also implies (IMO), that stropping may actually be detrimental in the long run to newcomers to sharpening. It has been stated numerous times that for beginner's, while making the edge sharper, stropping masks errors in holding a consistent angle. If one should strop often attempting to save metal, it produces a rounded edge bevel. This would eliminate the flat spot, which is key to finding the proper angle for someone newer to sharpening. --------------- just a thought.
Thanks for the video.
D.

I think this is very well said. So well said I won’t add to it. Judicious application.

 

[esoo]

So my first thought was the grit range of the compound vs the stone. Now it looks like a SG8K which is 1.84u, vs 3u for the compound he is using so the compound is coarser, so should be "faster". After than, my thought it what is the grit density of the compound vs the stone could affect the speed.

For his case of using planes, it would be interesting if he'd used something like this honing plate instead of leather:
https://www.leevalley.com/en-ca/sho...69438-veritas-steel-honing-plate?item=05M4001
Would the removal of the flex of the leather make a difference?

I use stropping as my last step in sharpening as I can hear an audible difference in the cutting performance. But I go 1K or 3K to 1u diamond on leather to refine the edge. But once my edge is not acceptable to me, I return to the stone + strop combo, I never use the strop alone.

 

[salparadise]

Focusing on burr removal helped me move past what felt like a plateau in my sharpening a while ago, my edges last a lot longer now as well. I don't strop but not for any particularly thought out reason

Yes, I’m aware of the importance of burr removal. There are really only a few key aspects to sharpening - consistent angle for a flat bevel, getting to the apex, and removing the burr using progressively lighter pressure. Everything else is just learning to do these well, and visualizing the state of the edge without being able to actually see it as you work it.

We’ve all seen videos of the masters going from bricked to sharp-sharp with about twenty passes in less than four minutes. It has to be the angle—everything else is doable by being aware of it.

I sharpened this morning and did better than before by concentrating more on the angle, staying on the SG500 longer, then finishing on the SG2k and using a magnifier to check for any sign of a burr. It was definitely sharp enough to use off the stone, but then two strokes per side on newspaper made it feel twice as sharp.

I’m not sure if I’m missing something, or if I just need to hold the angle better.

 

[Barmoley]

There has to be some convexity in any free hand sharpening of knives, especially knives with curved edges. Without a guided system it is virtually impossible to create a truly V shaped, angle consistent edge over the length of the whole blade. With chisels where edges are straight and very short and the shape of the chisel providing an angle guide it should be doable on stones. Yet we can clearly create durable and sharp edges on knives while free handing and if anything convex edges should be more durable if not technically as sharp as V edges. So I am not sure flatness of the bevel is the ultimate goal or that it is even achievable using our methods. Some swear by stropping and others swear against it, so I wonder if compound, and stropping medium make a large difference, as well as just how long one does it. I‘ve seen some of the best sharpeners do Final few passes on a strop, loaded or otherwise and they get excellent results. In my understanding stropping is not for sharpening, but for refinement and final deburring, it is also used a bit to refresh the edge when very slightly dulled., but only very slightly.

 

[enchappo]

There has to be some convexity in any free hand sharpening of knives, especially knives with curved edges. Without a guided system it is virtually impossible to create a truly V shaped, angle consistent edge over the length of the whole blade. With chisels where edges are straight and very short and the shape of the chisel providing an angle guide it should be doable on stones. Yet we can clearly create durable and sharp edges on knives while free handing and if anything convex edges should be more durable if not technically as sharp as V edges. So I am not sure flatness of the bevel is the ultimate goal or that it is even achievable using our methods. Some swear by stropping and others swear against it, so I wonder if compound, and stropping medium make a large difference, as well as just how long one does it. I‘ve seen some of the best sharpeners do Final few passes on a strop, loaded or otherwise and they get excellent results. In my understanding stropping is not for sharpening, but for refinement and final deburring, it is also used a bit to refresh the edge when very slightly dulled., but only very slightly.

Very good points.

And while getting down to fundamental principles is great, even for straight edged tools saying that it is only about flat bevels, apexing, and deburring is overly reductive.

And on the specific wording in the earlier post, that it is about “removing the burr using progressively lighter pressure”, this to me is either just incorrect, or elides so much detail as to be misleading, depending on how you want to characterise it. Science of Sharp (I think) showed pretty conclusively IMO that even with less pressure than the weight of the blade, edge trailing on even high grit stones will never fully remove a burr.

 

[bsfsu]

Laying my cards on the table here…

I’m curious why it wouldn’t be relevant. My takeaway idea was restropping may get you back to an apex, but will round out your sharpening angles, leaving a fatter convex bevel. (And over time that edge gets harder to refresh.) Knives go through dense food as planes travel through wood.

Diminishing returns from stropping without going back to stones.

One thing not discussed is how stropping removes bite/smooths the apex. Great for wood tools and razors, less so for cutlery. I will grant that’s one aspect of “sharpness” that woodworkers never really talk about.

Maybe I was a bit flippant with the "relevant", the whole stropping to sharpen is not something I do, I know the razor sharpeners strop into the 10's -100's passes but sharpening just on the strop as they do in the vid is not something I've come across. So for me, some of the data wasn't as relevant.

I think along the same lines as you, I think over stropping removes the bite from a knife but I like to do a few passes to "refine" the edge, I find I get better sharpness after a strop.

There is some good info in the vid but some of it is not as relevant to knife sharpening, I think a vid like this about knife sharpening would be great.

 

[Barmoley]

Just to illustrate how sharp an edge can get with a strop when used by someone with high skill

Might just be stropping is not the issue

 

[HumbleHomeCook]

Just to illustrate how sharp an edge can get with a strop when used by someone with high skill

Might just be stropping is not the issue

And I'd say Shawn gets pretty good edges.



As far as I can remember, Shawn has always had strops in his options bag and used them frequently. One of his most frequent sayings is, "Strops enhance, they don't create." Like many others he cautions against using strops to make up for less desirable stone work. The point not being against strops but pushing us to get better on the stones. Shawn is of course well aware of Todd's work on SoS.

 

[Kawa]

I might be wrong but,

I think BESS scale measures sharpness by showing how much pressure is needed to cut the wire.
A very toothy knife and a 'too slick knife for kitchen use' can both have the same BESS score, or sharpness.

Yes, stropping enhances my BESS scale numbers and in my case, makes my knife sharper. But it doesnt show when i refined too much and when the edge is too slick for some kitchen tasks.

 

[esoo]

BESS measures the ability of blade to cut in a vertical motion (which we might call a tap chop).

It doesn't measure how a blade is reacting in push cut/pull cut/rock chop where there is linear motion in addition to vertical.

It is a measure of sharpness, but not an all encompassing one.

 

[Barmoley]

Sure, but BESS was also used in the OP linked video that makes the conclusion that strops should not be used. If we are discussing the results and conclusions of the video and how these are applicable to use of strops in knife sharpening then surely we can't all of a sudden disregard the use of BESS or we have to disregard the whole video.

 

[esoo]

Sure, but BESS was also used in the OP linked video that makes the conclusion that strops should not be used. If we are discussing the results and conclusions of the video and how these are applicable to use of strops in knife sharpening then surely we can't all of a sudden disregard the use of BESS or we have to disregard the whole video.

I'm not trying to discount BESS - it is useful. I was just responding to the point above mine in regards to how a low gram BESS score knife might not be ideal for kitchen use.

In the context of the video where we are talking planes which cut at 90 degrees to the edge, it is probably the most accurate way to judge sharpness.

 

[salparadise]

So I am not sure flatness of the bevel is the ultimate goal or that it is even achievable using our methods. Some swear by stropping and others swear against it, so I wonder if compound, and stropping medium make a large difference, as well as just how long one does it. I‘ve seen some of the best sharpeners do Final few passes on a strop, loaded or otherwise and they get excellent results. In my understanding stropping is not for sharpening, but for refinement and final deburring,

Now that I’ve thought more about it, yesterday’s session was successful. Two stroping passes, literally, per side on newsprint and that blade is sharp… enough to shave arm hair and glide through newspaper. Which for most purposes is sharp enough for a general use chef’s knife.

It’s still amazing to me how much sharper even two passes makes the blade feel to the touch.

And while getting down to fundamental principles is great, even for straight edged tools saying that it is only about flat bevels, apexing, and deburring is overly reductive.

In that it skips the description of variables, complexity and skill required in achieving these, yes, but anyone who can do these three things consistently is no beginner. Imho.
Agree about edge leading strokes, but again, the intent was to reduce to the essential objective.

I still have much to learn, yes.

 

[enchappo]

In that it skips the description of variables, complexity and skill required in achieving these, yes, but anyone who can do these three things consistently is no beginner. Imho.
Agree about edge leading strokes, but again, the intent was to reduce to the essential objective.

Not just that, no. Notably it’s the fact that a flat bevel isn’t an essential objective. And stating these fundamental principles as you did would lead a beginner up the wrong path imho.

Also think it is important to be clear about what your objective is. Is it sharpness? Keenness? A working edge that lasts?