Who reprofiles/sharpens a new blade before use?

David45

David45

Joined
Oct 27, 2017
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330
Im still learning a lot here. I’ve read that an edge really doesn’t perform up to it’s potential unless the original edge is redone for some reason.
Is redoing the original edge recommended?
 
If you sharpen freehand, it doesn't make that much difference.

If you sharpen with a guided system, it does. If I find a factory edge is not very sharp, I always re profile to an even dps, usually 15 dps.

On something like the Sharpmaker, a factory edge that is 15 degrees on one side and 19 degrees on the other, will cause you problems. Using the 30-degree inclusive angle, you'll sharpen the 15 degree side perfectly, but only wear down the shoulder on the 19 degree side.
 
I did in my Scrade hollow handle "survival" knife. Cheap China-made knife with a lot of potential. The grind was uneven from the factory and the shoulder between the primary and secondary bevels was too pronounced. I fixed all that on a belt sander and convexed the edge. Much better now! (Also chopped off the upper guard and forced a patina in the blade.)

I'd say it's not done as a rule, but only to correct a problem.

IMG_0676.jpg
 
Factory edges are almost universally thicker than they ought to be. As such, any knife I get usually gets reprofiled to 12-15° per side before its first use.
 
only if it needs it - not all of them need it.
i was very happy with the edge on the kershaw injections that i picked up recently. I will use them until they need touch up - or until i get the itch to reprofile somethign
 
Unless hes talking about certain steels coming from makers with a soft burnt edge from overheating?

If thats the case only way to know is use it and see.

Unless makers start hand sharpening edges wich will Probably add to cost (even though it should be included)
 
Well, if a brand new knife cuts and works properly on my ordinary tasks why sharpen or reprofile it?
I have some Spydercos, some Kershaw and some Ontario blades. I never had to sharpen or reprofile any of them before first (testing) use.
I just use them until them does not properly do the job, then some few touch ups and when I feel that is time to go to “spa” then yes, it’s time to loose a little bit here, a little bit there.
 
Teppojutsu said:
Unless hes talking about certain steels coming from makers with a soft burnt edge from overheating?
If thats the case only way to know is use it and see.
Unless makers start hand sharpening edges wich will Probably add to cost (even though it should be included)
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I think this is what I had read something about or the possibility of a “burnished” edge that needed to to be “fixed” notwithstanding the sharpness of the factory grind. Thanks for your collective advice.
 
Only if it's dull and needs it. Otherwise I'll wait till it gets used a bit, loses its edge, then I'll really go to work on it.
 
David45 said:
I think this is what I had read something about or the possibility of a “burnished” edge that needed to to be “fixed” notwithstanding the sharpness of the factory grind. Thanks for your collective advice.
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Yea the idea is that the edge apex is such a thin cross section of steel that it is really easy to overheat using belt grinders (especially dry)

So you might have to sharpen past the overheated part to get to the "good" stuff :thumbsup:

Edited to add i dont find this acceptable either if its a known thing people should be able to buy a knife without haveing to sharpen past a TECHNICAL fault.
albeit a small one
 
Used to much more than I do now. But since I started buying a little nicer knives, they have been arriving in better condition. A burnt edge is one of those things that cannot be easily seen without use. But uneven bevels drive me nuts. Plus, an edge that's too out of whack will be more difficult to resharpen and even touch up. So once a new blade needs more than a periodic strop, I break out the KME and give it "MY" edge. Once the bevel is set even, keeping it sharp is much easier and will last longer with just stropping.
 
David45 said:
Im still learning a lot here. I’ve read that an edge really doesn’t perform up to it’s potential unless the original edge is redone for some reason.
Is redoing the original edge recommended?
Click to expand...

I'd probably not quite phrase it as 'recommended', but instead would suggest that it's almost always a big improvement, if one is willing to undertake the task.

Some knives will come with a factory edge that's perfectly usable, or sometimes even pretty good. But most knives will have pretty mediocre edges from the factory, at least as compared to how they could perform with some additional thinning and a complete, full apexing of the edge (so many will be a little bit short of that). A lot of factory edges that seem hair-popping sharp from the factory, are that way due to sharp burrs along the edge, formed in the final finishing & buffing/burnishing of the factory-ground edge. Some of those burrs are pretty stout, and may last a little while; so, the factory edge's sharpness will seem to hold up for a bit. But, when that stout burr wears away or folds, the thick edge geometry behind it will virtually stop cutting in it's tracks. That's a sign the edge could be thinned somewhat, or maybe a lot, to make it cut much better, for quite a while longer.


David
 
The reason that I buy a knife is to sharpen it. I have loads of knives already that can do the job. I simply want to experiment with new knives. I buy knives with different alloys or heat treatments so that I can learn about their sharpening and edge retention characteristics. I would never buy a knife and not immediately start improving the edge. In college I had a business going door-to-door sharpening things. Sometimes those things were scissors or old reel type lawn mowers. You learn a lot sharpening other people's crappy knives. It is rare these days, but back in the 50s and 60s it was common to find chrome plated kitchen knives. You needed a sander or grinder to even start on them. Tool steel Gerbers really demand diamond hones. Anyway, you learn by experimenting.
 
If it rides on the shoulder on my sharpmaker, I’ll reprofile the edge to suit when it needs sharpening.
 
It depends. If I know the steel will hold up to a much thinner edge in the way I plan to use the knife, I reprofile it right away.

Otherwise, I'll usually inspect it to see if the factory edge is good. I try to carry it for a day out where I know I'll need a blade and put it through the usual paces. By the end of the that first carry day, I'll know if I like the way it came or if it needs to spend some time under the stones.
 
Well, I did it, to my new PM2 S110V “Blurple”, it was slow go on slowest speed KOWS (standard guided set-up) at the 22.5 degree setting. I started with a new Norton 120 belt and easily got a good bur (as instructed by them) which worked it’s way out as I finished with the next two belts.

I really like convex! Now it’s easily as sharp as the original edge. I’m impressed by this little knife!

Also, it’s Casey Lynch blue short clip is a wonderful addition.
 
Always. Most knives come too thick from the factory behind the edge, for me. I always sharpen them on the Edge Pro to the angle of my choosing. If, by some stroke of luck, the factory edge matches the angle I want it at, then I just continue up to a higher grit than it was originally finished at.
 
David45 said:
Im still learning a lot here. I’ve read that an edge really doesn’t perform up to it’s potential unless the original edge is redone for some reason.
Is redoing the original edge recommended?
Click to expand...

Let me say this about that :
When I buy a tool invariably I view it as a blank and that I am going to take it home and make something useful out of it. (that's the case more and more in this modern world of people designing and manufacturing things that they have never put to actual use in the real world).

So yes nearly any knife I buy gets the edge grind angle made more narrow/shallow. Very often the thickness of the blade right near the edge gets ground thinner, often by half and since I am into the aesthetic and how it cuts for what I cut I mirror polish (ish) the edge bevel.

There have been exceptions; three come to mind :
Benchmade Ritter Griptilian
Spyderco Gayle Bradley One
Spyderco Para Military 2 M4 (we need a heart/love "face" button so I can use it here)

But yes most knives are ground by people who don't use them for people who have no clue about how to use it to keep from destroying the edge. A recipe for dull and boring in more ways than one. You want to compare stock knife edges to see what I mean ?
Pick up a Swiss Army knife new out of the box (love the knives HATE the factory edge).
use and compare that for a week of actual use to a :
decent quality small Japanese kitchen knife (can be had for ~$40) thin ground near the edge, shallow edge angle, very often frighteningly sharp from the factory)
. . . oh boy another chance to post a pic of mine I have named "The Little Monster". Now that's a proper edge. Delicate and damageable in the wrong hands but I could EDC one with no issues and it reflects superior cutting ability.

IMG_3374.jpg
 
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I find that usually factory knife edges on folders are set at 20+ dps and that's just too steep for me for most purposes, especially doing touch-ups.
On the other hand folders with edges at less than 20 dps have a tendency to chip or roll because of the lack of refinement on the factory sharpening process.
I can see why these makers put such a steep angle on the knives so they are more robust and will hopefully never see the knife again for warranty but with a little more attention to materials and heat treatment and final sharpening they'd make folks like us happier in the end.
All that said, I usually take mine down (Depending on the knife. If it's an expensive one with some half-assed obtuse grind I'll ship it directly back for a refund, but if it's a reasonably priced model I'll adjust it myself) to 17 dps (depending on material and usage) then microbevel at 20 dps then strop. No polished edges for me.
 
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