polishes edges not good for general use cutting purposes?

H

hemi1300

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Sep 9, 2013
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been playing around with my edge pro for the last few weeks and really getting my technique down. First few i did were my kershaw blur's and went up to the 3000 grit polish tape for a great looking mirror edge. Edge's were definitely sharp and hair shaving, but just didn't seem quite as sharp as the factory edge on my spyderco paramilitary 2. Finally worked on the paramilitary 2 today and decided to finish with 400 grit stone, wow did it turn out great. Bevel and finish look almost 100% factory edge and when doing the paper slicing test it performs flawlessly (i'm guessing by finishing with 400 grit the edge still has tiny micro-serrations and grabs more so seems to cut better?) Love the look of a mirror polished edge, but am i crazy in saying an edge finished with 400 grit or even 220 seems to cut paper better?
 
Hmmm not me...

nearly all grits can create a shaving or paper cutting edge.

all my knives get polished on an 8000 grit (glass like) and I polish until it slices paper QUIETLY.



I get asked by many people to polish their edges after they see how my knives perform (kitchen, sushi bar, and hiking).
 
guess maybe my technique has just gotten better and leads me to think my 400 grit polished edge is sharper than my first couple runs up to 3000 grit polishing tape bc i was still trying to learn the machine lol
 
Practice makes perfect!

I freehanded with 1000-4000 stones fpr years until I jumped to 8000, it takes more of a steady mind to polish I suppose.

Not sure what kind of 400 grit you have, my lowest stone (coarse) is 440 grit, least of the polishing stones.
 
so will a polished edge hold up just as well for general usage vs a factory style type edge?
 
hemi1300 said:
been playing around with my edge pro for the last few weeks and really getting my technique down. First few i did were my kershaw blur's and went up to the 3000 grit polish tape for a great looking mirror edge. Edge's were definitely sharp and hair shaving, but just didn't seem quite as sharp as the factory edge on my spyderco paramilitary 2. Finally worked on the paramilitary 2 today and decided to finish with 400 grit stone, wow did it turn out great. Bevel and finish look almost 100% factory edge and when doing the paper slicing test it performs flawlessly (i'm guessing by finishing with 400 grit the edge still has tiny micro-serrations and grabs more so seems to cut better?) Love the look of a mirror polished edge, but am i crazy in saying an edge finished with 400 grit or even 220 seems to cut paper better?
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Try cutting phone book paper or news paper after using the 400 . At least my experience is a polished edge doesn't cut printer paper well, but will slice threw phone book paper. And visa versa. Like you stated the polished edge is not that toothy. I do believe a polished edge will stay sharper longer, I don't have any science to back it up, just my experience.
 
One of the very cool things, is that we can tailor our knives to our uses. Hwang is a pro chef, I think he has an idea, of what makes his knife work. I use a knife very hard at times, cutting lots of 1/4" cardboard and such. I also use my knife to cut things like seatbelts, and webbing. Some of my knives I like to have a bit of tooth to. That makes them cut better for me. I also like to have a couple of knives, that are polished. It all depends on what you want to cut.
 
This is one of the things I've always played with. For a knife that I know is going to get some serious sawing action, like for cutting rope (especially), I tend to leave a much rougher finish on it. But in general, I like my polished edges, just because they seem to hold up better under daily use. My theory is less jagged edges to rip off or get deformed when cutting, and less corrosion surface area, but that's just me.
 
I am a fan of the 400 grit for EDC, still toothy enough to grab zip ties, used to prefer 600 grit, but the 400 is better for me, the more dirt involved, the lower grit gets used more.

I don't recommend using high grits when learning the edge pro, from the sound of it you aren't apexing cleanly and only polishing the bevels, not refining the apex.
 
The apex being clean & pure is what it's about. Doesn't matter if it's 320 grit or 2000+; both can do well for most tasks. The more meticulously one takes care to refine the cross-sectional geometry at the apex, the better it'll be. This is most noticeable when cutting paper; if the apex is truly sharp, no matter the grit, it'll cut phonebook paper, printer paper, cardboard & plastic with ease. I use phonebook paper to 'test' my edges for readiness; if they cut this paper smoothly, quietly and with no snags or catches (burrs) from heel-to-tip, either SLOOOOWWLY or rapidly, they're ready to go for anything else as well. I first came to this realization after finishing an edge on sandpaper through 2000 grit, plus additional polishing on strops with compound.

I've settled into edges that finish up anywhere in the 800-2000+ grit range, most of the time. I'll often start lower, with re-bevelling at 320 or so. But, with the sandpaper touch-ups and stropping that gets done down the road, most all of mine hit their peak usefulness after they've developed a near-mirror on the bevels (depending on steel, that usually starts around 800 grit on sandpaper).

The only exception I've noticed, is with S30V. It really takes well to a more toothy finish, which seems to mesh with the somewhat toothy nature of the carbide-heavy content of the steel. Something akin to a coarse or fine DMT (325-600 grit) finish really seems to 'pop' with this steel.


David
 
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After carrying and using polished edges (around 1 micron) for a while, I've started moving in the other direction. As long as the apex is done correctly, even a very coarse grit finished edge can shave and whittle hair. The extra "toothiness" of a coarse edge does help in certain applications like cutting plastic bags, tomato skins, and other similar materials.

Though, after using polished edges for so long, what I call "coarse" (e.g. six microns) is actually pretty refined for a lot of people.
 
Obsessed with Edges said:
The apex being clean & pure is what it's about. Doesn't matter if it's 320 grit or 2000+; both can do well for most tasks. The more meticulously one takes care to refine the cross-sectional geometry at the apex, the better it'll be. This is most noticeable when cutting paper; if the apex is truly sharp, no matter the grit, it'll cut phonebook paper, printer paper, cardboard & plastic with ease. I use phonebook paper to 'test' my edges for readiness; if they cut this paper smoothly, quietly and with no snags or catches (burrs) from heel-to-tip, either SLOOOOWWLY or rapidly, they're ready to go for anything else as well. I first came to this realization after finishing an edge on sandpaper through 2000 grit, plus additional polishing on strops with compound.

I've settled into edges that finish up anywhere in the 800-2000+ grit range, most of the time. I'll often start lower, with re-bevelling at 320 or so. But, with the sandpaper touch-ups and stropping that gets done down the road, most all of mine hit their peak usefulness after they've developed a near-mirror on the bevels (depending on steel, that usually starts around 800 grit on sandpaper).

The only exception I've noticed, is with S30V. It really takes well to a more toothy finish, which seems to mesh with the somewhat toothy nature of the carbide-heavy content of the steel. Something akin to a coarse or fine DMT (325-600 grit) finish really seems to 'pop' with this steel.


David
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David for the win. No matter the grit, be it 2 or 2 million, geometry is where it's at. Your choice after that, with bevels, micro's, and level of polish, is all subjective to the end user.
 
L2bravo said:
David for the win. No matter the grit, be it 2 or 2 million, geometry is where it's at. Your choice after that, with bevels, micro's, and level of polish, is all subjective to the end user.
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You have 2 million grit!? How much would getting a knife sharpened up to that cost? I want to cut a hole in the fabric of space time!

Geometry is right, though. If the edge is fully profiled, I you can achieve shaving sharp on many grits (I have actually gotten shaving sharp off of an 80 grit belt). The biggest "if" is the angle. You can go down to a scalpel edge and get it screaming sharp, or go super obtuse and basically never get a sharp edge. My ZT 550 is current profiled to a little over 20° inclusive and cuts like a monster, but my BM Pika is around 40° inclusive and cuts... like a brick. Edges were sharpened the same, it is just all up to geometry.
 
I typically go up to 0.5 micron and finish on bare leather. It cuts fine whether it's paper, plastic ties, saran wrap, or cardboard.
 
dkb45 said:
You have 2 million grit!? How much would getting a knife sharpened up to that cost? I want to cut a hole in the fabric of space time!

Geometry is right, though. If the edge is fully profiled, I you can achieve shaving sharp on many grits (I have actually gotten shaving sharp off of an 80 grit belt). The biggest "if" is the angle. You can go down to a scalpel edge and get it screaming sharp, or go super obtuse and basically never get a sharp edge. My ZT 550 is current profiled to a little over 20° inclusive and cuts like a monster, but my BM Pika is around 40° inclusive and cuts... like a brick. Edges were sharpened the same, it is just all up to geometry.
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One thing we haven't talked about, is durability. How is that 0550 at 20 degees? I am sure that with it's high grind on that blade, it does cut good at that edge, but I would fear it being a little fragile at that point.
 
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