How sharp is a sharp sword?
Appropriate edge sharpness..........
This is a question that has been bugging me a while. How do we test if a sword is sharp enough? One issue is that sharpness is somewhat subjective. I think part of the problem is that different types of swords, or maybe more accurately, different edge geometries will have different degrees of optimal sharpness. So how do we decide that a sword is not sharp enough and needs honing.

As I mentioned above, I am asking about optimal balance between sharp and tough, i.e. can a particular blade be made sharper but still be tough enough to retain its sharpness after some use with appropriate cutting medium.

Most new, high-end blades we get are probably optimally sharp. But after some use, touching, etc the edges would dull. How do we know that happened? Lets' say for practical purposes that I cannot remember how touching the edge felt when the sword was new, and lets also say that I am inexperienced enough to figure out that the the sword is not biting well enough into an appropriate cutting target.

So what this boils down to is if there is a simple test to figure if the current sharpness of a blade is appropriate for its type. In other words, how do I decide that it is time to ship my blade to Albion for honing ;), or take my chances with it. There are several descriptions of how to sharpen/maintain the edge of a sword. One of them being an appendix in David Lindholm's book on Ringeck's Long sword art co-authored by Peter Johnsson (the appendix that is). (It answered my questions about the leather strop, so I did not have to ask hijack another thread with my unlimited questions)

But before I decide to mess with the edge on any sword I want to be sure that it needs attention.

So how do I decide?

Thanks,

Alexi
Before Jason wraps a blade to hand it over the the cutlers, he tests it by cutting paper -- if it slices paper neatly and with no drag, it is acceptably sharp. Stropping as Peter has suggested should keep the edge functionally sharp.

Best,

Howy
Just tried the paper cutting test with my GADDHJALT and it passed the paper cutting test easily, the edge is almost factory fresh as I did use a white ceramic (Handheld) spyderco triangular rod very lightly followed by a smooth steel hardened spike to burnish. (Very very lightly so as to not create a secondary bevel.)

So I guess that if I did not improve the sharpness of the sword I at least did not make it less sharp!

Note that it passed the paper cutting test when I first got it. (Before I did anything to it.)

Sometimes the least you do to it the best it is. I.E. The obsession with "Razor" sharpness can lead to repeated and uneeded sharpening.

With knives I don't think of it as sharp if it can't easily shave hairs of my arm.

I guess with swords paper cutting sharp is sharp enough and making it razor sharp is not desirable even if achievable.

Not to compare apples to oranges: Were historical Japanese sword actually razor sharp or is their reputation for sharpness actually based on excellent edge geometry? (For actual combat not cutting competitions.)

Also for those tempted to sharpen a sword they should at least have the skill to sharpen a knife first!

And please NO power tools! (Should be obvious to all here but just in case for the clueless.)
With a risk of sounding ridiculous, please describe the paper cutting test. How do you cut the paper? Vertically: the edge of the paper is perpendicular to the blade's edge, and you push the blade down through the length of the paper with a slicing motion, or by laying the paper on the blade and pressing down (the letter opener effect).

As you might imagine, I tried cutting paper with the 2 higher-end swords that I have. The result is that I cannot take a peace of paper , hold it in one hand and slice it with any of my swords. I can do that with a knife I sharpened.

I can cut through harder paper/carton (pasta box for example) quite easily with the swords, bit the thin paper is a problem. The only way to cut thin paper (that I managed to get to work) was to lay the paper on the blade and press it down. That cuts the paper rather cleanly.

So my observation is that my swords bo not have the bite to cut thin paper with ah simple slicing motion across paper's edge.

On one hand, who cares as they cut through carton (pizza, or coke boxes) targets very cleanly. But (and I think that is a an obsession of mine which I do not know how to deal with) should they be sharper???? Probably not.............but .......... it bothers me :D

Cheers,

Alexi
Alexi;

I use note paper and cut into the edge of the paper with a slight slicing motion: One slicing motion not a back & forth sawing motion.

This is a more difficult with a sword lenght blade and I don't try to do this along the entire blade. (Only one section at a time.)

I avoid using a lot of speed or momentum in part for safety reasons as I have on occasion missed the paper and cut into my index finger: Yes paper cutting sharp is enough to easily cut "FLESH"! I never was happier that it was not razor sharp!

If you use very light paper you need an even sharper blade as the paper does not have enough body to put some resistance to the edge of the blade.

Technique does matter as using even a razor sharp blade won't work if the angle of attack is wrong.

Maybe others use some sort of holder for the paper or they use a roll of paper as a target.

Another way is to use a much larger sheet of paper, pierce the paper with the point of the sword and then finish the cut by pulling the sword through the cut: You must then takes note of any part of the blade that catches or rips the paper.

Also running the blade, "CAREFULLY", small section of the blade at any one time on a fingernail should tell you were it is sharp & were it is dull: As long as the edge feels like it is biting and not sliding it is sharp enough.

Not an expert at this so maybe others have a better technique.

Note that testing for sharpness too often guaranties that you are dulling it
Jean Thibodeau wrote:
Alexi;

I use note paper and cut into the edge of the paper with a slight slicing motion: One slicing motion not a back & forth sawing motion.


Yep, that is what I tried with no success. I used normal printer paper or note-pad paper, with the same success, or lack there of.

The finger/nail mehtod yielded similar results.......blades not as sharp as the knife that slices paper.

So I am pretty convinced that my swords are not sharp enough to slice paper clean. Should I worry though, since as I said with a swing they can cut soft targets with much give cleanly .

Alexi
Alexi;

If you use a magnifying glass, 8X, and a strong light you can look for reflections comming from the meeting of the bevels to see if they meet at a zero edge (Theoretical Zero Edge).

On a butter knife you won't have any trouble seeing a flat at the edge, with a razor sharp edge you might see what looks like micro serrations, if you cannot see flats or barely perceive them you need very little work to get to paper cutting sharp.
(With a strong enough microscope even a razor edge would look rough with flat irregular imperfections.)

The angle at which the bevels meet is also important, with a very obtuse angle even a perfect zero edge will have difficulty cutting paper but the same edge in a cold chisel will cut mild steel without significant dulling.

Define your target, then how sharp defines itself.

If you do decide to sharpen you have to learn the best way to do it without creating a secondary bevel if you want to maintain a swordlike edge. (I am personnaly experienced putting a good edge on knives & except for very prudent touch-ups I too would like to know more about sharpening swords properly.)
Alexi Goranov wrote:
Jean Thibodeau wrote:
Alexi;

I use note paper and cut into the edge of the paper with a slight slicing motion: One slicing motion not a back & forth sawing motion.


Yep, that is what I tried with no success. I used normal printer paper or note-pad paper, with the same success, or lack there of.

The finger/nail mehtod yielded similar results.......blades not as sharp as the knife that slices paper.

So I am pretty convinced that my swords are not sharp enough to slice paper clean. Should I worry though, since as I said with a swing they can cut soft targets with much give cleanly .

Alexi


Alexi,

Stop obsessing over your swords edge and relax :D

It's more than sharp enough to do anything you'd require of it.
Patrick Kelly wrote:


Alexi,

Stop obsessing over your swords edge and relax :D

It's more than sharp enough to do anything you'd require of it.


I require of it to cut paper, split hairs, cut floating silk, and sever limbs without even touching them................
Ok, OK ..the last few are a bit excessive :D

Having in mind that unsharpened swords can cut mats ( this might not be universal but it is observed), we do not really need much edge to do damage to an opponent.

But I still want a paper cutting sharp edge...........................Yep, it is official! I am obsessed, or possessed, or just plain nuts.

Alexi
Alexi Goranov wrote:

But I still want a paper cutting sharp edge...........................Yep, it is official! I am obsessed, or possessed, or just plain nuts.

Alexi


Think of the real circumstances of use of a medieval sword:

The sword's owner takes it out of the armory or down off the wall and straps it on. He then marches or rides at least three or four days, if not longer, to reach the place where he is to fight. Once the opposing forces have seen one another and agreed upon a field of battle, perhaps half a day is spent detailing armor and sharpening weapons. If this particular weapon is owned by a knight with ready access to a sharpening stone, he will go into battle with a sword that is not obviously rusty. Once he has used his blade, if he survives the fight, the sword will be cleaned in the field. If he is not on extended campaign, then the sword will be transported home again over a period of days. If additional fighting is required, the blade may be corroded by bloodstains throughout the duration of the campaign.

This is not a description of a razor sharp weapon. If you are in search of the perfect edge that a modern home tool shop can produce, you are not looking for the same edge that would actually have been on the sword when it was in practical use.
Steve Fabert wrote:
Alexi Goranov wrote:

But I still want a paper cutting sharp edge...........................Yep, it is official! I am obsessed, or possessed, or just plain nuts.

Alexi


Think of the real circumstances of use of a medieval sword:

The sword's owner takes it out of the armory or down off the wall and straps it on. He then marches or rides at least three or four days, if not longer, to reach the place where he is to fight. Once the opposing forces have seen one another and agreed upon a field of battle, perhaps half a day is spent detailing armor and sharpening weapons. If this particular weapon is owned by a knight with ready access to a sharpening stone, he will go into battle with a sword that is not obviously rusty. Once he has used his blade, if he survives the fight, the sword will be cleaned in the field. If he is not on extended campaign, then the sword will be transported home again over a period of days. If additional fighting is required, the blade may be corroded by bloodstains throughout the duration of the campaign.

This is not a description of a razor sharp weapon. If you are in search of the perfect edge that a modern home tool shop can produce, you are not looking for the same edge that would actually have been on the sword when it was in practical use.


Hi Steve,

I was afraid my post will leave such an impression. So I completely agree with you......the blade does not have to be razor sharp. I have no intention on shaving with it, so that is quit OK :D

Further more I am not a medieval warrior (for good or bad) whose sword has to cope with the realities of warfare. So if my sword can be sharp (paper cutting sharp) I would like it to be that way. As a collector I would like to be able to appreciate the details of the sword quality, sharpness being one of them.

So how sharp were the medieval swords. I would like to believe that they were pretty sharp. Not necessarily razor sharp, as they had to endure banging against other swords, shields, bones, flash, etc, etc.......

As I said, I do not need a razor-sharp blade. But to cut paper the blade DOES NOT need to be exactly razor sharp. As Howard Waddell wrote above, Albion tests sharpness by simply slicing through paper.

So I would like my swords to be at least "Albion sharp", whenever possible. As I acknowledged above, this degree of sharpness might be excessive for the sword to perform well in "real use".

Cheers,

Alexi
Hi Alexi

There are days that I can have a paper cutting sharp sword in hand, and not be able to cut the paper. Its me, not the sword....

But even so, I don't sharpen swords, paper sharp, I sharpen swords, sword sharp.

Just for the heck of it, I tried cutting paper with the sword I cut seven 2L bottles in one pass this last Saturday. Couldn't cut the paper. Me or the sword? Its still plenty sharp enough.

At lunch, I cut 5 "onion rings" from a 2L bottle, so as far as I'm concerned the sword is sharp enough.

For what its worth, in the last 2 years I've had five swords sent back because the owner wasn't happy with the sword's sharpness. Twice the owner was right, the sword wasn't sharp. The other three times, the sword was sharp enough to cut onion rings from a 2L bottle without trouble..... or more than sharp enough for a functional sword.

So..... its possible that your sword is paper cutting sharp, and you're having the same problem I am handling the paper..... or maybe it isn't that sharp, but its still more than sharp enough.

Maybe test the sword on an appropriate target? Odds are your sword is more than sharp enough.........

Auld Dawg
Angus Trim wrote:
Hi Alexi

There are days that I can have a paper cutting sharp sword in hand, and not be able to cut the paper. Its me, not the sword....

But even so, I don't sharpen swords, paper sharp, I sharpen swords, sword sharp.

Just for the heck of it, I tried cutting paper with the sword I cut seven 2L bottles in one pass this last Saturday. Couldn't cut the paper. Me or the sword? Its still plenty sharp enough.

At lunch, I cut 5 "onion rings" from a 2L bottle, so as far as I'm concerned the sword is sharp enough.

For what its worth, in the last 2 years I've had five swords sent back because the owner wasn't happy with the sword's sharpness. Twice the owner was right, the sword wasn't sharp. The other three times, the sword was sharp enough to cut onion rings from a 2L bottle without trouble..... or more than sharp enough for a functional sword.

So..... its possible that your sword is paper cutting sharp, and you're having the same problem I am handling the paper..... or maybe it isn't that sharp, but its still more than sharp enough.

Maybe test the sword on an appropriate target? Odds are your sword is more than sharp enough.........

Auld Dawg


I already mentioned few times that I think my swords are sharp enough to do sword-like things like cutting boxes and bottles and probably mats. But they cannot (at lest readily) cut paper. Now I'd be even more worried if my swords could cut paper but not cut boxes, bottles, mats, etc. I do not want to turn this "cutting paper test" into the definition of that sword performance is all about.

I am aware that I have somewhat excessive, and maybe largely unnecessary demands. It is like demanding filleting knife to cut butter. But if some of my swords can be sharper and still retain that new sharp edge after normal use, why not sharpen them?

Alexi
Alexi;

What I have gotten from everybodies comments is that I am now very happy with paper cutting sharp as I now understand
that it means that my swords are "SHARPER" than the minimum standard needed for real world (Historically correct) cutting.

My personnal obsession with "Razor" sharpness will now be reserved for my Tactical Folders.


For everybody else:

As I asked in an earlier post : How sharp were Japanese swords made for fighting (12th century?)
as opposed to more recent or modern ones made for cutting.
In my ignorance of the real thing I always assumed, according to myth, that Samurai swords were "Razor" sharp!?

In other words is this true or was the standard of sharpness similar to "European" normal Sword sharp!
I guess we need to hear from those who are experts on Japanese swords.

(Don't mean to highjack this post but I think my question is at least distantly related to the original question.)
"In my ignorance of the real thing I always assumed, according to myth, that Samurai swords were "Razor" sharp!? "

Japanese swords are no "sharper" than their european cousins. They are certainly not "razor" sharp. They have the appropriate edge geometry to do their assigned task. As has been stated many times before, cutting performance has as much to do with the skill of the swordsman if not more so.

Alexi,

It has become apparent to me that only you can answer your question. You've already been given the appropriate answer more than once, yet you insist on leading this thread around in circles. No offense meant, but we're beating a dead horse here.
Alexi Goranov wrote:
Patrick Kelly wrote:


Alexi,

Stop obsessing over your swords edge and relax :D

It's more than sharp enough to do anything you'd require of it.


I require of it to cut paper, split hairs, cut floating silk, and sever limbs without even touching them................
Ok, OK ..the last few are a bit excessive :D

Having in mind that unsharpened swords can cut mats ( this might not be universal but it is observed), we do not really need much edge to do damage to an opponent.

But I still want a paper cutting sharp edge...........................Yep, it is official! I am obsessed, or possessed, or just plain nuts.

Alexi


And don't forget, you must be able to cut milk jugs into hundreds of tiny slivers :D
Patrick;

Thank you for the answer about samurai swords, we always seem to hear these stories about someone accidentally lightly touching the edge of a samurai sword and getting seriously cut.

Then there are the historical legends about floating leaves being cut by a sword as they touch the edge in a stream or of the sword being so sharp that the leaves avoid the edge completely.

Still I found this discussion usefull as it has completely changed my understanding about Sword sharpness.

(Dead horse, yes, but a good ride before it died!)
maybe not swords but
I too am 'obsessed' with sharpness in tactical folders. ( none of my swords are good enough to meet any of those standards) My little brother introduces me to his friends as 'the knife freak'.

in my experience the ultimate test for edge sharpness is taking thin slick highgloss magazine paper and rolling it into a loose tube w/ no wrinkles and cutting without sawing or slicing at a very low angle of attack. (around 5*) this requires a much sharper edge than either the hair test or edgewise paper cutting. I use EzeLap Diamond stones for course work (flat) then an ultra ultra fine spyderco closed cell ceramic flat stone. it was very hard to find and expensive. it beats a strop and puts a literal mirror polish on your edge bevel. however, it takes a lot of honing and it would be a waste of time to use the ultra utlra fine if the knife were not already 'hair sharp'

also kill anyone who tries to give you a "quick sharpener" those POS's are the death of many a good knife. also my flat ceramic stone had sharp edges that could scratch a kinfe's finish or scrape metal off of the edge. i cured this by radiusing the edge very slightly with the diamond stones.( due to the hardness of aluminum impregnated ceramic)
Patrick Kelly wrote:

Alexi,

It has become apparent to me that only you can answer your question. You've already been given the appropriate answer more than once, yet you insist on leading this thread around in circles. No offense meant, but we're beating a dead horse here.


But circle is the perfect shape :D

I am aware that I have posted the same answer/ opinion few times because I got the same responses with few exceptions.

What I was looking for was: "Do not sharpen your sword finely. It is a BAD idea for.............reasons" . All I got was "Your sword is sharp enough to do its job" (I was aware of this before I started the thread).

What I needed to get out of it was whether having a sharper (according to some standards) blade (cuts paper, but cannot shave with it) is a BAD idea.

So I got what I need from this thread, even though I seem to have done it in the roundabout kind of way.

Thanks to everyone that participated.

Alexi

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