Coarse edge = Micro serrations yes or no

[unit]

Very simple.

Do you believe a coarse finished edge is the same as a serrated edge (only on a smaller scale) or not.

 

[Obsessed with Edges]

I think 'coarse' is wide open to interpretation. In many cases, to me it just means, 'unfinished' or 'unrefined'. Look at a coarse edge under magnification, they look pretty ragged most of the time. It's not hard to see that at least some of those 'serrations' are just weak, ragged bits of metal, which will break/blunt/fold quickly.

I do think it's possible, for skilled sharpeners/makers, to put what may look like more useful and uniformly-shaped 'teeth' on an edge. But to me, that's not what I think of as 'coarse'.

Just my 2 cents'...

 

[Buck268]

I will say that some of my knives just seem to work better if I finish on a lower grit.

 

[HeavyHanded]

I didn't vote one way or the other, as my answer is "yes, no, kinda". There are definitely some similarities, but overall they are not quite the same. For starters, coarse edges do not have a uniform repeated cutting pattern. There isn't as pronounced a difference between the highs and lows on a coarse edge relative to a serrated edge. IMO any ground edge that hasn't been completely polished will cut somewhat like a serrated edge, its all a question of scale. No matter how much you blow up an image of a coarse edge, or shrink one of a serrated edge, they just aren't going to look that much alike. When I examine one of my 80 or 120 grit edges through a loupe, it looks very much like a 2000 grit edge only the scale is different. In either case though, I find there is as much variation in the side to side weaving of the edge as there is in the up and down along the edge (look straight down at the cutting edge using magnification). The cutting edge is changing its angle of attack on more than one plane, unlike a serrated edge. As the grit size shrinks, these variations and the total distance across the cutting edge becomes smaller relative to the structure of the stuff you're cutting.
It should be mentioned that there can be some real differences between serrations from one manufacturer to the other. The more shallow ones (Benchmade comes to mind) have more in common with a coarse edge than, say, CRKT's pattern.

 

[unit]

I didn't vote one way or the other, as my answer is "yes, no, kinda". There are definitely some similarities, but overall they are not quite the same. For starters, coarse edges do not have a uniform repeated cutting pattern. There isn't as pronounced a difference between the highs and lows on a coarse edge relative to a serrated edge. IMO any ground edge that hasn't been completely polished will cut somewhat like a serrated edge, its all a question of scale. No matter how much you blow up an image of a coarse edge, or shrink one of a serrated edge, they just aren't going to look that much alike. When I examine one of my 80 or 120 grit edges through a loupe, it looks very much like a 2000 grit edge only the scale is different. In either case though, I find there is as much variation in the side to side weaving of the edge as there is in the up and down along the edge (look straight down at the cutting edge using magnification). The cutting edge is changing its angle of attack on more than one plane, unlike a serrated edge. As the grit size shrinks, these variations and the total distance across the cutting edge becomes smaller relative to the structure of the stuff you're cutting.
It should be mentioned that there can be some real differences between serrations from one manufacturer to the other. The more shallow ones (Benchmade comes to mind) have more in common with a coarse edge than, say, CRKT's pattern.

Fantastic! I think this is going very much in the direction I wanted to explore.

Would you say that the only difference between the "micro serrations" on an edge finished with 800 grit and the "micro serrations" on one finished with 12000 grit is the scale (or size of the "serrations")?

 

[HeavyHanded]

Fantastic! I think this is going very much in the direction I wanted to explore.

Would you say that the only difference between the "micro serrations" on an edge finished with 800 grit and the "micro serrations" on one finished with 12000 grit is the scale (or size of the "serrations")?

Without having the tools to get a good look at anything finer than 4000 grit or so, I really can't say. The photos that some of the other forum members have posted would lead me to that conclusion though. You also have to consider that as the grit size shrinks, the total distance across the cutting edge shrinks as well, so size of serration and cutting radius become proportionately smaller. I'd have to imagine the qualities of the particular steel factor in there too.

 

[unit]

Without having the tools to get a good look at anything finer than 4000 grit or so, I really can't say. The photos that some of the other forum members have posted would lead me to that conclusion though. You also have to consider that as the grit size shrinks, the total distance across the cutting edge shrinks as well, so size of serration and cutting radius become proportionately smaller. I'd have to imagine the qualities of the particular steel factor in there too.

I suspect that you are correct. I also feel that this "distance across the cutting edge" is one factor of departure between the notion of "micro serrations" and true serrations (serrations essentially exist in a single plane when considered on the scale of the serrations where "micro serrations" are 3-dimensional in the scale of the relief of the edge).

Another factor is number of scales of features present on a serrated blade. We can explore that later. (typing on my phone at the moment).

 

[jimnolimit]

maybe i can help out. i just used a "coarse" stone (i think it's around 200-300 grit) to sharpen my spyderco centofante 3 (VG10). here are two pics of the edge under magnification. my microscope is rated at 20x-400x.

the first pic is around 40x:

the second pic is around 375x:

 

[KennyB]

I don't really think so, but I can't really describe why... But basically, the edge between the points on a serrated grind is very fine and tiny when you compare it with the overall size of the serration. Take into account how wide the teeth are ( not at the edge, but I mean the actual point itself ), and then how much space lies between the span of each point. With microserrations it's just not the same, the edge that lies between each point is not really that much thinner than the teeth themselves and so when they dull they're just gone and you're left working with the base edge. With a serrated blade, these teeth will be there for MUCH longer, and so that fine edge between the teeth is going to be there for MUCH longer as well. That's really the big difference I see.

I think microserrations biggest advantage is that they help distribute load across points like serrations do, but they're so small that they don't really alter the resulting finish of the cut that much. Then also like serrations, they might help to make some cuts "better", because they tear and cut at the same time.

I think it's mostly a matter of design and proportion though. If you took the serrations on a Spyderco blade, and scaled them down to the point where they would be "microserrations", they would probably still outperform the microserrations just by the nature of the geometry and design.

I think microserrations are genuinely serrations, I just don't think that they can perform anywhere near the same as a serrated blade itself because the size difference in relation to all the other parts, and mostly because the edge between the points will not be as thin in relation to the points and span of the serrations as they would be on an actual serrated blade.

 

[richard j]

jim, if you were to finish that edge (strop on leather or slotted paper wheel for example) that would take off any points that might break off during use and make the remaining points sharper and more durable.

 

[unit]

I think microserrations are genuinely serrations, I just don't think that they can perform anywhere near the same as a serrated blade itself because the size difference in relation to all the other parts, and mostly because the edge between the points will not be as thin in relation to the points and span of the serrations as they would be on an actual serrated blade.

I think I can see the merit to this thinking.

A coarse edge (stropped or otherwise) then magnified to the scale of an actual serrated edge and compared to an un-magnified edge will show some differences). Essentially what I am suggesting is to blow up the "micro serrations" and compare them to conventional serrations.

The first difference we would note is the symmetry of the serration (and lack of symmetry of the "micro serration")...DUH!

The second thing to notice is that a freshly sharpened serrated blade will be essentially the same edge thickness at all points (the tips of the teeth, the sides of the teeth, and the troughs between the teeth). I lack the ability to magnify a "micro serration" to verify this, but I suspect that it will not be universally sharp (the tips of the teeth, the sides of the teeth, and the troughs between the teeth). That is pure conjecture I will admit.

The third thing we may expect to see is that all of the points and troughs between the points on a serrated blade will lie in the same plane. I believe that stropping the coarse finished edge may align the points of the "micro serrations" a bit, but the valleys between will not necessarily lay in one plane (if they even contain sharpened areas). Again, conjecture, but I presume that if the valleys do have sharpened portions, they will be random and not oriented in the same cutting plane.

What does this mean? And where do I get this concept from?

Basically, if you cut tissue (skin, muscle, whatever) and view the differences in the cuts at the scale of the "micro serrations" you will see more tissue disruption, than you would with a polished edge (thus the reason the medical industry uses polished scalpels instead of stropped coarse edges).

Before you jump...keep reading.

Now cut tissue (skin, muscle, tomato, whatever) with a fresh serrated blade and view the disruption to the tissue again on the scale of the serrations (or even a slightly smaller scale). I believe that you will see that there is less tissue disruption than a scaled comparison to a coarse edge...demonstrating that the concept of "micro serrations" is more like a VERY fine saw, and less like tiny serrations.

Therefore I agree that the answer is "yeah, sort of, but kind of different"...and I did not offer that choice...dang trick question!

 

[eKretz]

I think you are over-thinking this big time. AFAIC, a saw is a serrated edge, and the term serrated does not imply that all "teeth" be in the same plane, either vertically or horizontally. In fact, quite the opposite. Look up the term in a dictionary or thesaurus. One definition IIRC is "notched like a saw" and synonyms are "saw-toothed," "notched," etc. Also, many saws have varied tooth height and spacing to help cutting action and clearing of swarf, or debris.

Whether the serrations or "micro-serrations" quickly wear or not is irrelevant to the discussion. It is clear that the highest points of a serrated edge wear the earliest, and the height of the serrations will play a major role in how long the serrated edge will continue to cut. (Or continue to resemble a serrated edge, even). The determining factor in whether an edge is serrated or not is its starting condition at the time of sharpening, not whether it will wear into a more uniform edge with use. (As any serrated edge will eventually, determinate factor being length of use between sharpening).

A coarsely sharpened edge is effectively "micro-serrated" without doubt. The only difference is in the amount of time the edge will last and the cutting forces on a "real" serrated edge may or may not be more or less depending on the application. One must remember that there are so many variables in materials being cut, materials used to make cutting implements, and cutting edge geometries that making vague general statements about any of the above is little more than conjecture and waste of time.

Btw, the last several paragraphs in the post above are completely contradictory and make no sense to me at all. You think that a serrated edge cuts with more tissue disruption, but really less?! Why aren't scalpels serrated, then? Or...? Please clarify. I'm pretty sure that it has been proven that a finely sharpened polished edge cuts with considerably less tearing and damage on the cellular level. You can see a real world example by cutting up half an apple with a serrated edge and half with a polished fine edge. The apple slices will show a marked difference in their rate of browning.

 

[HoosierQ]

Nothing simple about that question I am afraid. I bet this thread ends up 10 pages long and then closed when people get hostile.

Contstructively: I think that may be a factor but those same micro serrations are also fragile little pieces of steel. So if your cutting wood, it will dull. If you are copping food on a board...same story. If you are fileting fish, you may find that a courser grit edge does well on that soft tissue.

You will get as many discrete opinions on this subject as you get responses. I personally go for a refined polished edge because I have a nice little shop in which to polish them. I would not bother in the field...I'd just whack a utility edge on there or a microbevel and keep cutting 'til she wouldn't cut no more.

 

[unit]

Nothing simple about that question I am afraid. I bet this thread ends up 10 pages long and then closed when people get hostile.

Contstructively: I think that may be a factor but those same micro serrations are also fragile little pieces of steel. So if your cutting wood, it will dull. If you are copping food on a board...same story. If you are fileting fish, you may find that a courser grit edge does well on that soft tissue.

You will get as many discrete opinions on this subject as you get responses. I personally go for a refined polished edge because I have a nice little shop in which to polish them. I would not bother in the field...I'd just whack a utility edge on there or a microbevel and keep cutting 'til she wouldn't cut no more.

I realize that it is not simple. The gut reaction that most people have to the original question is VERY simple, yes/no/other(and discuss).

The point of a discussion is to discuss/debate/learn...if everything was simple, there would be no point in posting a thread here.

Regarding 10 pages? Great, I welcome good discussion.

Regarding locking it down? Why? I see no reason why this should become hostile.

I think we can discuss our findings professionally, and so far we have. I see no reason to extend the discussion to how durable one is over the other, or to debate what is better...the thread can go where we take it, but personally I do not care to discuss in yet another thread the superiority of one thing over another (polished/microbevel/coarse/fine/serrated/micro-serrated/etc).

Go there if you like...I am only interested in exploring the similarities and differences between a Coarse finished edge and a Serrated edge. I really hope we can be civil about that...

I hope no one interpreted my questions as bating fights, or asking what is best or what anyone prefers...I really do not care what everyone prefers...personal preference is just that, and there is no need to defend anyone's here (at least not to me anyway). I think personal preference is indisputable...no reason to go there.

 

[unit]

I think you are over-thinking this big time. AFAIC, a saw is a serrated edge, and the term serrated does not imply that all "teeth" be in the same plane, either vertically or horizontally. In fact, quite the opposite. Look up the term in a dictionary or thesaurus. One definition IIRC is "notched like a saw" and synonyms are "saw-toothed," "notched," etc. Also, many saws have varied tooth height and spacing to help cutting action and clearing of swarf, or debris.

Whether the serrations or "micro-serrations" quickly wear or not is irrelevant to the discussion. It is clear that the highest points of a serrated edge wear the earliest, and the height of the serrations will play a major role in how long the serrated edge will continue to cut. (Or continue to resemble a serrated edge, even). The determining factor in whether an edge is serrated or not is its starting condition at the time of sharpening, not whether it will wear into a more uniform edge with use. (As any serrated edge will eventually, determinate factor being length of use between sharpening).

A coarsely sharpened edge is effectively "micro-serrated" without doubt. The only difference is in the amount of time the edge will last and the cutting forces on a "real" serrated edge may or may not be more or less depending on the application. One must remember that there are so many variables in materials being cut, materials used to make cutting implements, and cutting edge geometries that making vague general statements about any of the above is little more than conjecture and waste of time.

Btw, the last several paragraphs in the post above are completely contradictory and make no sense to me at all. You think that a serrated edge cuts with more tissue disruption, but really less?! Why aren't scalpels serrated, then? Or...? Please clarify. I'm pretty sure that it has been proven that a finely sharpened polished edge cuts with considerably less tearing and damage on the cellular level. You can see a real world example by cutting up half an apple with a serrated edge and half with a polished fine edge. The apple slices will show a marked difference in their rate of browning.

You bet I am overthinking this! That is why I come here, to think deeply about subjects that most people never consider.

My reference for what a serrated edge is is a collection of NUMEROUS folding knives, fixed blades, and kitchen knives. All examples I have seen have one continuous sharpened surface that follows some wavy/angular/jagged trace that tends to lie with in a single plain (most often the plane is shared by the back face of the blade or primary bevel). A few knives have slots cut into them...and I do not consider them to be a serrated edge as the slots are not in any way sharp and therefore fail the definition of "edge".

A saw blade by contrast generally has teeth that are sharp on one side, and there are recesses between these sharpened teeth to allow cut material to be carried out of the cut. Saws cut a volume out of the media (as you say "swarf", the width of the loss measured perpendicular to the cut direction is frequently referred to as "kerf"). By contrast a serrated edge separates the media and removes no measurable kerf.

A coarse edge disrupts the tissue to some degree along the cut. This disruption I interpret as similar to kerf, except that it is not removed like sawdust, it is left hanging from the surfaces left after the cut (as disruption).

It would seem that we agree that serrated edges are not like saws...however I think "micro serrations" (a term that I hear used to represent a coarse edge in some circles) are more like a saw than a serrated edge.

Sorry for the confusion (in my last paragraphs)...I will re read and clarify. Is it possible that my post is helping you to confuse serrations and "micro serrations" as the same thing? That is what this is about. The thought that "micro serrations" (note the quotes) is perhaps a misnomer.

I am not arguing...just exploring the term and if it truly represents a coarse edge (stropped or otherwise).

I have thoughts, but I am trying to learn and help others to think along these lines and explore with me. I am not above being wrong, and I may be in my thinking.

Edit to add.

I reviewed the last few paragraphs. Re read it (I did not change anything) realize that "micro serrations" and serrations are being used in that discussion to discuss 2 very different things. Replace "micro serrations" with "coarse edge" if you like, and see if you follow.

Basically I am saying that the medical industry does not use Coarse edges or "micro serrations" because a polished edge disrupts the tissue less and heals faster. Serrated edges (true serrated edges) are also not used because the DO disrupt tissue more than a plain edge, but I am suggesting that they do NOT disrupt tissue on the scale that a coarse finish will (once scaled up to a similar dimension of edge relief). By "edge relief" I mean the irregularity owing to the tips of the teeth and the depth of the troughs in between.

If you then take the coarse edge and scale it up to a dimension similar to the dimension of a serrated edge (where the " teeth" are a few mm tall) and make a cut it will shred whatever you are cutting...by contrast a true serrated knife will not shred the media to a similar degree.

Does that help explain the idea? I freely admit it is difficult to represent this with words. I welcome the questions, but I hope we can keep them constructive instead of argumentative.

 

[Obsessed with Edges]

When I think of a 'true' serrated (or 'micro-serrated') edge, there's nothing (in my mind) about it that is even remotely 'coarse'. To me, any serrated edge that's expected to be truly effective and durable, over the long run, must be deliberately created as such. To me, that suggests a higher degree of refinement, as opposed to something 'coarse'. This is why I don't see any similarity at all, between the two terms.

In my view, there are 'coarse' edges, and there are 'serrated' edges, but one doesn't imply the other, at all.

Having said that, I'll move on now.

 

[jimnolimit]

jim, if you were to finish that edge (strop on leather or slotted paper wheel for example) that would take off any points that might break off during use and make the remaining points sharper and more durable.

i de-burred the edge during the sharpening process and afterwards i did a few swipes on copy paper to clean off the edge. if i get a chance later on tonight i'll run the knife on the coarse stone again (maybe i'll use a coarse diamond stone instead) and i'll take edge pics of the burr, de-burred and before and after stropping on newspaper.

 

[unit]

jimnolimit, I meant to respond to you earlier. Fantastic images my friend!

I think much stronger magnification is probably necessary to explore the edge irregularities (particularly those areas between the high spots).

Looking at what you provided, it is evident that you are quite proficient at sharpening! Thanks for sharing. What grit is your "coarse" stone (or what make and model is it)?

 

[jimnolimit]

jimnolimit, I meant to respond to you earlier. Fantastic images my friend!

I think much stronger magnification is probably necessary to explore the edge irregularities (particularly those areas between the high spots).

Looking at what you provided, it is evident that you are quite proficient at sharpening! Thanks for sharing. What grit is your "coarse" stone (or what make and model is it)?

thanks.

im not 100% sure of the grit (maybe 200-300) of the stone i used. i have 200 grit diamond that i'll run the knife over later to compare it to. if i get a chance i'll see if i have some coarser sandpaper (maybe 80-120 grit) to exaggerate the "micro serrations" and give us a better pic. i'll also try scoping the edge at different angles to get a better pic.

 

[unit]

When I think of a 'true' serrated (or 'micro-serrated') edge, there's nothing (in my mind) about it that is even remotely 'coarse'. To me, any serrated edge that's expected to be truly effective and durable, over the long run, must be deliberately created as such. To me, that suggests a higher degree of refinement, as opposed to something 'coarse'. This is why I don't see any similarity at all, between the two terms.

In my view, there are 'coarse' edges, and there are 'serrated' edges, but one doesn't imply the other, at all.

Having said that, I'll move on now.

I am not sure I follow. I agree that a coarse edge can be refined, perhaps via stropping, and I would agree with a concept that a fine, coarse, or any other finish are similar in that they differ only in scale (i.e. if viewed under the appropriate magnification, it could be difficult to say which is which if the scale was obscured).

I agree that an edge finished on a coarse stone is QUITE different form a serrated edge. But I think that a refined edge that some label as "micro serrated" is similar in some regards to a serrated edge, but also different...so I would not say they are cutting in the same way.

I hope you do not choose to move on permanently, I would like to learn your interpretation of "micro serrations" and how you create them...and if you feel they are like typical serrations, or similar in some regards, but also different in some regards.

Where I feel that "micro serrations" (as I understand them) differ from serrations is that the "teeth" on a "micro serrated" edge may be sharp on the sides and in the troughs, but not necessarily or completely. I envision a nearly random collection of facets between the teeth...some of which may have sharp boundaries, but not necessarily aligned with the edge.

I appreciate your insight!