Shaving or working edge?

[theletch1]

I'm wondering what everyones preference is on blade edges. Do you prefer an edge that is sharp enough to shave with or one that is just shy of being that sharp? For me it depends on what I'll be using the edge for. My kitchen knives all keep a shaving edge as does my smaller blade that I carry daily for SD. My Ka-bar (the large version), khukri and other blades that I carry when I'm camping or doing anything outdoors where hard contact is likely all get sharpened just shy of a shaving edge. My reasoning for this is that I always heard that a shaving edge was easier to damage or that the shaving edge made the edge more brittle. Is this a myth that I've heard over the years or is there some truth to it?

[Sukerkin]

Altho' I can't speak directly to the topic as I use 'long knives' {:D}, it is a long held truism that working blades should not be as acutely sharpened as those intended for more delicate use.

Obviously, with a sword, the wielder is putting a lot more kinetic energy into the point of contact, so a shorter blade may not be so critical when it comes to edge geometry; I would, however, think it would be prudent to err on the side of caution and not put a razors edge on a blade that's going to see some hard contact.

EDIT: Also, altho I apologise if I'm speaking words to the already wise here, when a blade is honed to a razpr edge, that edge does undergo some work/heat hardening and so becomes more brittle.

[SFC JeffJ]

I'm like you Jeff. Working knives about a 25-30 degree edge, SD knives at about 20, and my kitchen knives between 15-17 degrees.

The finer the edge the easier it gets damaged, at least from my experience.

Jeff

[jks9199]

It's a basic principle of sharpening any tool that you sharpen it according to the use you intend to put it to.

The entire goal of sharpening an edge is really to make it two-dimensional; in a perfect world, the edge would have NO width, only length where the two sides come together. The angle that you want those two edges to come together is determined by how you intend to use the blade; for some planes or chisels, for example, you may actually sharpen each side to a different angle. For knives, I tend to go with maybe between 15 and 30 or so for a daily light or multi-use (including self defense) or kitchen knives. For carving/utility use, I go a bit steeper, maybe 25 to 35 or even maybe almost 40 degrees for something like a hatchet.

What I personally find happens is that if you sharpen a blade at a smaller angle, you'll get an edge that can actually bend or distort under use, along with any issues about work-hardening or tempering the blade and making it brittle. So, that sort of angle won't hold up to more forceful uses, like woodcarving.

[arnisador]

I'm like you Jeff. Working knives about a 25-30 degree edge, SD knives at about 20, and my kitchen knives between 15-17 degrees.

I'm not quite so quantitative about it but I basically agree.

[SFC JeffJ]

I'm not quite so quantitative about it but I basically agree.
I use an Apex sharpener, so I can be really anal about the angle.

[Sukerkin]

I envy you in a way, Jeff as something to hold the angle constant is a godsend :D!

However, I still sharpen stuff the way my grandfather taught me when I was about five i.e. by eye and feel (and ear) :o.

That works excellently for many blades but I have found particular difficulty just recently having to do a 'repair' honing on a friends bowie shaped knife that someone had 'sharpened' to a perfect bluntness. The complex melding of edge curve and variable blade thickness made it a real challenge. The only solution I found was to work it in segments and try to make sure that I achieved an equal edge all the way along - I failed but it's good enough for camping work I reckon.

[Doc_Jude]

I'm like you Jeff. Working knives about a 25-30 degree edge, SD knives at about 20, and my kitchen knives between 15-17 degrees.

The finer the edge the easier it gets damaged, at least from my experience.

Jeff

You said it.

[theletch1]

I envy you in a way, Jeff as something to hold the angle constant is a godsend :D!

However, I still sharpen stuff the way my grandfather taught me when I was about five i.e. by eye and feel (and ear) :o.

That works excellently for many blades but I have found particular difficulty just recently having to do a 'repair' honing on a friends bowie shaped knife that someone had 'sharpened' to a perfect bluntness. The complex melding of edge curve and variable blade thickness made it a real challenge. The only solution I found was to work it in segments and try to make sure that I achieved an equal edge all the way along - I failed but it's good enough for camping work I reckon.
That's the way I was taught as well. By eye, feel and sound. For me it's more feel than anything else. I've used a couple of the sharpening tools that hold the angle steady and just couldn't get into the very well. There's just something about sitting quietly and honing by hand that relaxes me. If you want a real challenge, Mark, try to sharpen a khukri. That curve toward the base of the blade can be a real pain to get sharpened.

[Sukerkin]

If you want a real challenge, Mark, try to sharpen a khukri. That curve toward the base of the blade can be a real pain to get sharpened.

:eek: I can well imagine :scared:.

[KenpoTex]

my SD knives have a "razor" edge (probably 18-20 degrees) and I don't use them for utility. My utility knives tend to have a little more of that "working" edge (25 degrees +/-)

[tellner]

I don't carry knives strictly for self defense. I carry knives which are mostly used for other things but can serve that purpose. All of them have a working edge.

[Brian R. VanCise]

I don't carry knives strictly for self defense. I carry knives which are mostly used for other things but can serve that purpose. All of them have a working edge.

Other than a few speciality items my knives are tools that I use almost every day in one function or another. So a working edge is very important to me! http://www.martialtalk.com/forum/images/icons/icon6.gif

[jks9199]

Knife sharpening and edge holding came up elsewhere... Anyone ever used Spyderco's Tri-angle Knife Sharpener (http://www.spyderco.com/catalog/details.php?product=77)? Or some of the similar gadgets out there?

For that matter -- anyone recommend any good sharpening jigs/clamps/gadgets?

[KenpoTex]

The Spyderco sharpener works pretty well, I've also got a Lansky that is okay.

most of my stuff I do "freehand" with a variety of stones and ceramic rods.

[chinto]

a working edge just a bit shy of shaving at say 20 to 23 degrees is what I would prefer on a knife for self defense. a strait razer to shave with is about 15 degrees or so... if I want a shave, I will use the razer, but the edge on it is delicate for cutting through muscles and clothing and what have you that you may need to do in a self defense situation. However, as sharp as possible with out being delicate is good as a sharp laceration will bleed much more then one that is made by a jagged or duller blade.

[Baphomet]

To begin, whenever I carry a knife, they always serve as one that can be used for a dual purpose, because if I get pulled over by a cop that wants to search me, for whatever reason, I want/need to be able to explain it away. Granted, trying to explain away my EKI Karambit can be difficult.

That being said, I almost always sharpen my knives to a 20/25 degree angle and then put a micro bevel on the edge of the knive using a ceramic. I've found that this tends to help with edge retention on various mediums.

[Ahriman]

First of all, I make more swords than knives, so my views may be distorted... :D
For my knives I pick sharpness depending on the intented use - not SD vs everyday, as I have a sickness that causes that I look at even kitchen knives as combat knives.
So - thrusters get more than 40 deg, sometimes more than 50 deg for more structural strenght, cutters get somewhere around 30-40 deg and slicers get 10-20. I don't like slicers, some of my buyers do, but I feel that they are too weak. But hey, I prefer at least 8mm thick HC steel as a base material for anything over 40cm overall...:uhyeah:

[punisher73]

I took some training and the instructor relayed what his filipino MA instructor told him. You should have two knives. One that is kept shaving sharp for your SD needs, and they other one is for working. You NEVER use your SD knife to do anything but that.

[tellner]

I've heard all the usual about "I have a multitool for utility work. I keep my knife razor sharp, and it is only for cutting human flesh." It's fantasy ********.

You should keep knives sharp and in good repair, but even a fairly dull blade will cut and stab very effectively. We just aren't put together all that well. There's no need for it to be shaving sharp.

You're best at what you're most familiar with. If you use your MilSpecOp MarkVI BlackTac TinyPecker 13 with Kung Fu Grip every day you'll be familiar with it and use it easily and naturally. If you're always taking out the Spyderco and doing things with it, that's the one that will practically be a part of your hand. Why trust your life to the one that will be more difficult to use? That's simple. It adds to the mystique and makes your SD knife some sort of magic totem. It violates Musashi's old common sense dictum "Strive to make your fighting stance your everyday stance and your everyday stance our fighting stance."

I already carry around a lot of stuff. Adding an extra knife that I will almost certainly never use when I'm already wearing one that works perfectly well just doesn't make sense. If I'm carrying a pistol, I'm carrying a pistol. It's its own thing in its own place, not an extra copy that has to compete for the scarce "ready to hand" real estate.

Legally it's just stupid. Compare and contrast the following:

"Why yes officer. I have two knives because I want to keep one razor sharp just for cutting on people. I was extra careful to only use the special killing knife on him. I wouldn't want to use just any old tool for something like that. Nosiree. What do you mean 'Were you really afraid he was going to hurt you or were you looking for an excuse?'"

"My pockets? Sure officer. There's a wallet, a cell phone, a pack of gum, a pocket knife, some business cards, my keys, and an iPod. When he attacked me I was afraid he was going to kill me so I grabbed my pocketknife to defend myself."

[Ahriman]

Well, I always use the excuse of being a moving advertisement of my shop, or I'm just taking along my stuff to show them to some my friends. When they ask that why didn't I put them in a bag... "in a BAG? You know better than me how much of them gets stolen...."
I train in literally every free second I have with anything I made - though I prefer those I carry.
...
And as I make MY knives for ME, they always fit me. And as I MAKE my knives I don't have to care for their edges too much - even if I totally destroy one somehow, the shop is 5 minutes away by foot...
...
"even a fairly dull blade will cut and stab very effectively."
Stab yes, cut no... trivially even a freshly cut piece of steel will cut - skin and tissues. But even a rather sharp blade will have difficulties with thicker clothing. This can be helped with either a "razor" edge, or with the sooooo much overmistified microserration. Btw microserration can be simply achieved with roughly grinding the edge. Personally I prefer method 2... needs less caring, cuts nicely, and allows for a higher edge degree thus allows for a thicker blade... and I love thicker blades.

[punisher73]

I've heard all the usual about "I have a multitool for utility work. I keep my knife razor sharp, and it is only for cutting human flesh." It's fantasy ********.

You should keep knives sharp and in good repair, but even a fairly dull blade will cut and stab very effectively. We just aren't put together all that well. There's no need for it to be shaving sharp.

You're best at what you're most familiar with. If you use your MilSpecOp MarkVI BlackTac TinyPecker 13 with Kung Fu Grip every day you'll be familiar with it and use it easily and naturally. If you're always taking out the Spyderco and doing things with it, that's the one that will practically be a part of your hand. Why trust your life to the one that will be more difficult to use? That's simple. It adds to the mystique and makes your SD knife some sort of magic totem. It violates Musashi's old common sense dictum "Strive to make your fighting stance your everyday stance and your everyday stance our fighting stance."

I already carry around a lot of stuff. Adding an extra knife that I will almost certainly never use when I'm already wearing one that works perfectly well just doesn't make sense. If I'm carrying a pistol, I'm carrying a pistol. It's its own thing in its own place, not an extra copy that has to compete for the scarce "ready to hand" real estate.

Legally it's just stupid. Compare and contrast the following:

"Why yes officer. I have two knives because I want to keep one razor sharp just for cutting on people. I was extra careful to only use the special killing knife on him. I wouldn't want to use just any old tool for something like that. Nosiree. What do you mean 'Were you really afraid he was going to hurt you or were you looking for an excuse?'"

"My pockets? Sure officer. There's a wallet, a cell phone, a pack of gum, a pocket knife, some business cards, my keys, and an iPod. When he attacked me I was afraid he was going to kill me so I grabbed my pocketknife to defend myself."

When on duty I carry a specific knife that I do use as a "work tool", when I'm off duty and carry my knife, it's the exact same knife. So I don't have different knives for different jobs.

Also, when I'm carrying my off duty knife in public, I don't need a "work knife" I have never had to cut a box at the mall or anywhere else for that matter in public.

As to your two "scenarios", those are straw man arguments to justify your position. You could very easily have a small utility knife on your keychain for cutting boxes and have your "carry knife" as well. Why do you have the other knife? I am trained as a first responder and I needed a little bit larger knife to be able to break a window if needed to get into a vehicle with someone trapped and be able to cut the seatbelt without putting them at risk, or if I need to quickly cut clothing or a tourniquet until other medical help arrives. My off duty carry knife is always carried for the protection of life, mine or someone elses.

[tellner]

Straw man? I don't think the word means what you think it means.

I'm talking about the perception of the legal system from the judge down to the cop. In the US carrying a knife specifically for self defense is viewed with a lot more suspicion than carrying a gun. Outcomes in the courts were worse for defensive knife use than defensive gun use the last time I saw any sort of study which was admittedly years ago. Knife carry laws are often much harsher than gun carry laws.

A knife is already problematic.

Now suppose you are being interviewed or interrogated. If you say you picked up the kitchen knife when the burglar came through the door or you have a pocket knife that you carry anyway and used to defend yourself that's one thing. But if you say you specifically carry a second knife just for that you're running straight into the psychological issues I already mentioned.

If you say that you only keep that knife for stabbing and cutting people you're looking worse by the minute even if you add "only for legitimate self defense of course." If you add that you make sure your long-pig-only knife is kept - and I quote - "razor" sharp so that it's more effective at wounding people you are going to lose the arresting officer, the investigating officer, the district attorney, judge and jury. Look at how much trouble the more socially acceptable gun owners have with "Black Talon" and other SD ammunition and why a lot of the best defensive firearms instructors are awfully cautious about any mods on self defense guns. Multiply that by the knife pucker factor.

I will admit to having a bayonet that fits on my shotgun. But if the situation is so bad that eight rounds of #0 buckshot or Remington Solid Copper slugs don't stop a home invader the added legal hassles of stabbing him with a bayonet are the least of my worries. I'll probably be looking for garlic, wolfsbane, crosses and a priest to finish the job.

[punisher73]

Straw man? I don't think the word means what you think it means.

I'm talking about the perception of the legal system from the judge down to the cop. In the US carrying a knife specifically for self defense is viewed with a lot more suspicion than carrying a gun. Outcomes in the courts were worse for defensive knife use than defensive gun use the last time I saw any sort of study which was admittedly years ago. Knife carry laws are often much harsher than gun carry laws.

A knife is already problematic.

Now suppose you are being interviewed or interrogated. If you say you picked up the kitchen knife when the burglar came through the door or you have a pocket knife that you carry anyway and used to defend yourself that's one thing. But if you say you specifically carry a second knife just for that you're running straight into the psychological issues I already mentioned.

If you say that you only keep that knife for stabbing and cutting people you're looking worse by the minute even if you add "only for legitimate self defense of course." If you add that you make sure your long-pig-only knife is kept - and I quote - "razor" sharp so that it's more effective at wounding people you are going to lose the arresting officer, the investigating officer, the district attorney, judge and jury.

I believe I used it correctly. You posted one scenario/response to support what you believe, that is a "pocket knife" that you carry and use for everything is one thing. The straw man scenario/response is a characture and an exageration of a self-defense knife.


I have two knives because I want to keep one razor sharp just for cutting on people. I was extra careful to only use the special killing knife on him. I wouldn't want to use just any old tool for something like that
That is an EXTREME exageration of the position that everyone would agree is dangerous and would prove the other position right.

My response is a reasonable one and supports carrying a knife specifically for self-defense when asked by the police.


I am trained as a first responder and I needed a little bit larger knife to be able to break a window if needed to get into a vehicle with someone trapped and be able to cut the seatbelt without putting them at risk, or if I need to quickly cut clothing or a tourniquet until other medical help arrives.

People would look at that statement and find it reasonable, and it is a reason to have a very sharp knife for more than cutting open a box at work.

I agree, that ANY weapon brings a special attention to you from LEO. I have told many people I would rather shoot someone than have to stab them. The public perception is a HUGE difference. I am in total agreement with that. My only disagreement was the characterization of people who carry a knife that is for "shaving only".