a question about sharpening

[boblob]

for a long time i have this small diamond sharpener by victorinox and i use it to sharpen my swiss army knife like shown in the video with edge leading only, and it does a quick and nice sharpening to the edge and leaves a very toothy edge which i very much like in a pen knife...., i havn't put much thought to the process on why it works.

my questions are as follows
a. is it possible to sharpen a completely dull knife only with edge leading ? if so why do we bother to use scrubbing establish burrs on both sides and then de-burr ?
b. what is it that i am doing with my swiss army knife ? what i mean is what is actually happening to the edge? , why does it work perfectly good ?

i hope i explained myself well enough.
have a nice day

 

[Benuser]

A few remarks. Your Victorinox will have no contact with a board. It is when board contact happens, that a burr breaks or folds over the edge and dulls the edge completely. And a burr there is, unavoidably. As soon as bevels meet, or even before.
A coarse grit may work as long as no food is involved. Imagine a tomato sliced with a serrated knife: how will the slices look after a few hours?
How many cuts do you make with an EDC compared to a kitchen knife? Coarse edges, even when completely deburred, which is far from simple, have a poor retention. As soon as the teeth got damaged or abraded, it is dull.
A lot of steel gets abraded. I wouldn't like to have to maintain my kitchen knives with only a 220 stone.
With an EDC maintaining the original geometry is probably less relevant to most users. Most will be fine with a typical V-edge.
Edge leading only will work, instead of scrubbing. But it is terribly slow. Most abrasion occurs in the edge trailing part. I have the impression scrubbing on medium fine stones helps with loosening the burr.
By the way, the factory edges with Victorinox are quite OK, but very different from what you get with a coarse rod or diamond plate only. They got refined and deburred by buffing.

 

[HumbleHomeCook]

Pull-through sharpeners make no difference in how they perform if you go leading or trailing. You just go "leading" so you can get the whole blade.

All that thing is doing is tearing the steel perpendicular to the blade. There's no real burr as there is no folding of steel. It's just ripped away, which is why it feels coarse. Those edges also won't last nearly as long as a properly sharpened one.

IMO those devices belong in a survival kit and no where else.

 

[boblob]

Pull-through sharpeners make no difference in how they perform if you go leading or trailing. You just go "leading" so you can get the whole blade.

All that thing is doing is tearing the steel perpendicular to the blade. There's no real burr as there is no folding of steel. It's just ripped away, which is why it feels coarse. Those edges also won't last nearly as long as a properly sharpened one.

IMO those devices belong in a survival kit and no where else.

you did not click on the vid, i use a small diamond plate made by victornox, not the pull through sharpener

 

[HumbleHomeCook]

you did not click on the vid, i use a small diamond plate made by victornox, not the pull through sharpener

Aw. Understood, thank you.

 

[M1k3]

Why scrubbing instead of edge leading only? Time. You move the knife across the stone twice scrubbing, whereas edge leading you only move the knife across the stone once. I think it saves time if the knife is pretty dull. Kind of sort of sharp, maybe not so much when you factor in reducing and removing the burr.

Either way works though. Use whichever gives you better and more consistent results.

 

[cotedupy]

What Mike said ^

It's certinaly possible to sharpen a knife just with edge leading strokes, and I often do it if a knife doesn't require much work, just a quick refresh. Because the primary reason you might use back and forth motions is: time. It's twice as quick.

I can think of another couple of reasons too: Firstly - precise and consistent angle control is easier if you're not constantly lifting your knife off the stone. Secondly - using exclusively full-length strokes (edge-leading or edge-trailing) will almost certainly sharpen more of a belly into the profile of a knife over time.

 

[Pie]

I was always taught there’s no pressure (and thus less abrasion) on the edge trialing stroke of scrubbing. I try to comply due to weird angle and pressure changes when pulling.

That being said no doubt there’s metal being removed on the pull stroke. As mentioned the answer is Speed. I always question why some pocket knife guys only sharpened in one direction. Makes sense that geometry is less of a concern.

Metal removal and sharpening occurs on both strokes, there’s nothing wrong with what you’re doing, and it is effective, as long as you are satisfied with the results.

My one comment would be that edge leading like in the video would result in the lower chance of developing a burr, making it less likely to immediately roll and fail after one cut. Critical for the purposes of a pocket knife, most definitely.

 

[mike59]

Not sure I understand why doing the edge leading as in the video would not develop or would be less likely to develop a burr. Actually, I'm not sure I can understand how you can actually get it "sharp" without developing a burr. Seems like it would have to be like stopping sharpening before forming the apex. Also, isn't that what the "V" end of the sharpener is doing ... removing the burr? All that said ... I'm a novice and still/always learning so I look forward to any clarification.

ETA - just looked a website and it does not mention burr removal with the V end but just that it's a finer stone cut at correct angle ... but still, to me it seems that it would remove the burr - assuming there is one.

M

 

[Delat]

Not sure I understand why doing the edge leading as in the video would not develop or would be less likely to develop a burr. Actually, I'm not sure I can understand how you can actually get it "sharp" without developing a burr. Seems like it would have to be like stopping sharpening before forming the apex. Also, isn't that what the "V" end of the sharpener is doing ... removing the burr? All that said ... I'm a novice and still/always learning so I look forward to any clarification.

M

In linked section of the video he’s flipping over for each edge-leading stroke, so he’s essentially deburring on every stroke.

I do the same when I debur, with very light pressure. I can actually feel the burr under the edge - it’s kind of a wobbly feeling having the wire folded under there as opposed to the clean bevel.

 

[mike59]

In linked section of the video he’s flipping over for each edge-leading stroke, so he’s essentially deburring on every stroke.

I do the same when I debur, with very light pressure. I can actually feel the burr under the edge - it’s kind of a wobbly feeling having the wire folded under there as opposed to the clean bevel.

Yes ... definitely a honing/stropping type of sharpening method. Thx

 

[Nemo]

Not sure I understand why doing the edge leading as in the video would not develop or would be less likely to develop a burr. Actually, I'm not sure I can understand how you can actually get it "sharp" without developing a burr. Seems like it would have to be like stopping sharpening before forming the apex.

Burr formation is a balance between burr creation and burr abrasion. Edge leading tends to abrade the burr more than edge trailing. Edge trailing tends to create more of a burr than edge leading. That's not to say that edge leading won't create a burr, but it will probably be smaller and this may or may not put it below what is perceptible.

The other thing that affects the balance between burr formation and burr abrasion is the force (often described as "pressure") with which you push the blade into the stone. Heavy pressure tends to draw out the burr (and speed up metal removal). Light pressure tends to abrade the burr. I'm not sure if this is because most of the pressure is applied on the edge trailing stroke (so as pressure decreases, the balance between edge leading and edge trailing tilt towards edge leading) or whether something else is at play. Look at Pete Nowlan's (@Sailor) very useful knifeplanet.net sharpening school videos for a demonstration on how to do this.

Also keep in mind that a burr doesn't create the edge, removing steel at the edge does. The burr is just a marker we use to let us know that our grinding has reached the edge. This can be a bit deceptive- it's certainly possible to create a burr before reaching the edge. The steel from behind the edge can plasticity deform past the edge (creating a burr) without actually removing any steel at the edge. My impression is that this is more likely with firm pressure, so if you use the decreasing pressure method, it's a reassuring sign that you have reached the edge if you quickly form a (smaller) burr at lighter pressure levels.

 

[Rangen]

The steel from behind the edge can plasticity deform past the edge (creating a burr) without actually removing any steel at the edge. My impression is that this is more likely with firm pressure, so if you use the decreasing pressure method, it's a reassuring sign that you have reached the edge if you quickly form a (smaller) burr at lighter pressure levels.

Excellent post. This part does not entirely match my experience -- I've been able to create burrs with light pressure, while still not reaching the edge. What I've switched to instead is using burr symmetry as an indicator.

After reaching the point where pressures are low, and stroke counts on each side are low, I'll take 5-10 light edge-leading strokes on one side, and feel the burr. Then the same number on the other side. Does the burr feel the same? If not, if it's heavier on one side than the other, then I know I have not reached the edge on the side whose strokes created the lighter burr (which I would then confirm with a microscope, which helps my confidence in this method). If the burr felt the same on both sides, then I figure I'm good (microscope tends to back that up), and start reducing stroke counts on each side more.

As I get more familiar with using specific stones and steels, sometimes I can just say "wait, I have a burr, but it's not as pronounced as it should be given the steel, and the stone, and the pressure; bet I have not reached the apex yet."

 

[Legion74]

Not sure I understand why doing the edge leading as in the video would not develop or would be less likely to develop a burr. Actually, I'm not sure I can understand how you can actually get it "sharp" without developing a burr. Seems like it would have to be like stopping sharpening before forming the apex. Also, isn't that what the "V" end of the sharpener is doing ... removing the burr? All that said ... I'm a novice and still/always learning so I look forward to any clarification.

ETA - just looked a website and it does not mention burr removal with the V end but just that it's a finer stone cut at correct angle ... but still, to me it seems that it would remove the burr - assuming there is one.

M

Before I started learning to freehand sharpen, my sharpening tool of choice was the Spyderco Sharpmaker system. With that thing you are instructed to do edge leading, alternating strokes on the hones, progressing to finer grits.

To the best of my knowledge it does not create a burr, at least not one that can be felt. It does produce a pretty sharp edge, though.