A good edge?

db

Joined
Oct 3, 1998
Messages
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I seem to be overly fussy about my edges, I seem to resharpen or steel them all the time. My question is how long should a good edge last? What do you look for before you will resharpen?
 
A good edge should last at least as long as it takes to get it from it's sheath to the workpiece. Long enough to finish the work is the better.

You should sharpen it when it gets dull.

You can tell when it's dull because it won't be cutting as easily as you'd like it.

People obsess about edge retention and sharpening far more than they should. It's a tool, not a deity. If it's doing what you need it to, it's working. If not, sharpen it or get a tool better suited to the task at hand.
 
Db:

how long should a good edge last?

When I buy a knife the geometry plays a large part in the choice. If I am grinding on the knife every day that geometry is not going to be that way for long. I want a blade material that can hold an edge well enough so that the lifetime of the blade is of a decent length. This should be many years.

What do you look for before you will resharpen?

Performance loss. On push cutters the blade will start to tear and on slicers it will start to slip.

Blade materials with high edge holding give you much more than just not having to sharpen as much. Steels that are very hard with high wear resistance and decent toughness can take edge geometries that are not practical on lesser materials. This can lead to a great difference in cutting ability. 3V for example can hold a no bevel edge, 420J2 simply cannot. The difference in performance between both steels taken to extreme edge limits is staggering.

-Cliff
 
I like Snickersnee's response. I like to sharpen too, but generally have to use the blade until the job is done, no matter how dull it gets. To me, this is a matter of good steel, heat treatment, and edge shape, but mostly good steel. S'why I like CPM420V. Anything of lesser edge holding pedigree than 440C doesn't cut it for me, and I have developed a preference for Cobalt and CPM420V for smaller knives, and high carbon tool steels for larger knives.

Harv
 
Well, most of the time I can use another knife before the job is finished, if the first one gets dull. I do have more than one knife.
My question is really how dull do most let their knife get? For how long should a good edge last, I know that steel, heat treat. and what is being cut, are all factors. So, with that in mind what does a edge have to do for you to say yep that knife really holds a great edge?
 
I have found that really hard to quantify. The only way I have been able to come up with any useful information is side by side comparison of knives.

I once did a side-by-side comparison between an M-2 AFCK, and ATS-34 AFCK, and a CPM440V Spyderco Military. On paper, you would expect a big difference, but I cut hundreds of cuts on hardwood with each blade, and never got to the point where one was obviously cutting better than the other.

My conclusion: all premium knife steels, properly heat treated, hold an edge great.

If you have a job that you regularly do, like field dressing a deer, you can establish a baseline for that job. But generally, you just have to go by your own comparisons, and those of other owners and knife makers.

I generally don't carry a sharpener with me on a daily basis, but I do sharpen after any day when my edge gets a lot of use. How dull the blade gets depends on what I run into, otherwise, I generally touch up after every day that includes some use that is adequate to impact sharpness. I like my edges to grab at my skin with very light contact, so I touch up the edge after any day when that goes away on a significant portion of the edge.

Harv



[This message has been edited by Steve Harvey (edited 03 August 1999).]
 
Yep, Harv I am the same way about my edges. As to the different steels I have found a little better edge preformance but not a hole lot. I have yet to try some of the newer steels like the CPM family or the non-steel blades.
 
I keep a polished edge on my carry knife and I like to keep it sharp enough to shave at all times -- I'll let it get so dull it doesn't shave well, pulls the skin and might require a second pass, sometimes there's a spot on the edge that won't shave at all -- then it's time to strop it. It'll only need a few strops to be back to normal. (I use a strop glued to the back of a hone and charge it with tripoli compound. I seldom have to use the hone, just the strop.)

That's just one datum point for your survey; I'm not arguing a knife that won't shave well is useless -- obviously people manage to use them ... but I don't; I give it a couple of strops every time it gets that dull.

-Cougar Allen :{)
 
Okay, I'm fussy about a really good edge also. But when I find myself fussing *too* much -- like sharpening way too often -- I get suspicious. Typically, what I find is that for some reason, on this particular knife I've left the burr on as a "wire edge". A wire edge cuts like nobody's business for a few seconds, then needs to be steeled or resharpened to get it back up to snuff. Maybe it's the heat treat on this particular knife, or maybe it's the steel, or maybe I've just been sloppy. But if I'm sharpening too often, I carefully attack the burr the next time I sharpen, with a light-touch double grind and a stropping.

Joe
 
smile.gif
 
Db :

My question is really how dull do most let their knife get?

Not dull at all. I am with Cougar on this. Dull knives are very dangerous to use. Mine are always very sharp and if they can't hold an edge long enough for that to be possible they are either returned, given away or are destroyed in a meaningful manner.

what does a edge have to do for you to say yep that knife really holds a great edge?

Wear down gradually without chipping or rolling. If this is the case the edge can be maintained at a very high level for weeks with just regular steeling and the occasional strop / rod.

As an example, the Uluchet has a D2 blade which has a high enough RC so that it resists rolling and that it wears slowly. After a day of hard use on soft materials (soft woods, flesh etc.) it would only need a couple of wipes with a ceramic rod and you would be hard pressed to know it was used. However the RC is also low enough so that it can take hard impacts without chipping and only indents enough to blunt it slightly. This is fixed with a little work with an fine DMT hone (a minute or two) and then the ceramic rod.

-Cliff
 
Many people will tell you a dull knife is dangerous and a few people will argue with that -- but one thing for sure, a knife that's sometimes sharp and sometimes dull is very dangerous. You never know how hard to push it or what it'll do.... If you keep a knife shaving sharp it could be dangerous to let someone who's not familiar with using sharp knives use it, but you know what it'll do and you know better than to do fool things like test the edge by pressing your thumb into it, or wind up like a baseball pitcher to hack at a piece of string....

The convex edge of the Uluchet contributes to its durability, too ... edgeholding is great; I've only taken a couple of swipes on a strop with it since I got it. It arrived sharp enough to shave *comfortably* and it's still that sharp. I haven't chopped any really hard wood with it, but that edge is really well supported, and that cryogenically treated D2 is good stuff.

-Cougar Allen :{)


[This message has been edited by Cougar Allen (edited 05 August 1999).]
 
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