Polished Edge: When, Why, What Steels??

[vivi]

Something appears amiss with the new emojis- they’re ENORMOUS!

Haha, some of these are pretty fabulous....

[u.w.]

Oh Sh** hahaha!
LMAO!
Those are Super Fabulous!

u.w.

[ZrowsN1s]

All I can say for certain is coarse and fine edges cut different. And I have my preference.

Much like the way Vampires and Werewolves are made, I was bitten by a highly refind edge when I was 7 and have been fascinated by them for the last 35 years.

[FK]

I only polish my ZDP knives because that stuff works brilliantly with a high polish convex edge.

Agree 100%, I find stropping with diamond on thin hard leather is very fast and gives a fantastic long lasting apex. Really like my Delica, Endura and Stretch with ZDP-189 and polished edge.

Regards,
FK

[metaphoricalsimile]

You're correct, I'm not particularly interested in someone claiming I am wrong, without explaining why.

So if you think polished edges have superior edge retention, maybe post why? Or make a video?

My videos are not controlled scientific studies, we do agree there. They're just casual videos meant to show general observations, e.g. this coarse edge will cut this rope more times than this polished edge, or this X grit stone will give Y knife a shaving sharp edge, no grit progression required.

But I've never said that you're wrong. What I've pointed out is that you haven't shown sufficient evidence for your claims, and that your claims contradict a lot of other evidence. Those are very different things to say. A particular criticism about your rope cutting video is that you didn't actually count the rope cuts made with each blade. You are also cutting with a factory edge w/ a factory edge bevel vs. a course edge with a custom narrow bevel. It is pretty accepted that narrow edge angles, controlling for all other factors, already increase edge retention against abrasive materials. If you actually want to show specifically that coarse edges give better edge retention with H1 steel you should be setting both edges to the same angle so that the final grit is the only factor you are testing, and you should also record numbers.

[Kevinim82]

I think I found the guy who could end the polished edge v. smooth edge debate with enough data points to break my proton microscope and pocket protectors for good.

http://www.cliffstamp.com/knives/forum/ ... 143,page=2

I’ll say for a backyard scientist, Vivi’s video on course edge may not be full of numbers and controlled variables, but it raises the right questions, and gives a compelling solution to long cutting escapades.

Thank you Vivi for producing videos on your own working theories. We can’t all paint like DiVinci; a Bob Ross painting to most is worth just as much.

I prefer the hotel paints where the guy paints modern movie references into them.
https://www.instagram.com/p/CMcmYbenUzb/

[Baron Mind]

I sharpen most my knives to a high polish because there us nothing more satisfying then an effortless slice. When the blade glides through material with almost zero force it gives me a certain satisfaction. I know that polished edge won't last as long as a coarser edge for most uses, but I thoroughly enjoy the feeling, and enjoy sharpening just as much.

[wrdwrght]

I sharpen most my knives to a high polish because there us nothing more satisfying then an effortless slice. When the blade glides through material with almost zero force it gives me a certain satisfaction. I know that polished edge won't last as long as a coarser edge for most uses, but I thoroughly enjoy the feeling, and enjoy sharpening just as much.

Ah, at last a Zen answer to which I can relate. I don’t seek high-polish, but I love finding the ghost of an edge while sharpening freehand. Positively calming.

[Baron Mind]

I sharpen most my knives to a high polish because there us nothing more satisfying then an effortless slice. When the blade glides through material with almost zero force it gives me a certain satisfaction. I know that polished edge won't last as long as a coarser edge for most uses, but I thoroughly enjoy the feeling, and enjoy sharpening just as much.

Ah, at last a Zen answer to which I can relate. I don’t seek high-polish, but I love finding the ghost of an edge while sharpening freehand. Positively calming.

A) "us" should obviously be "is", but I can't believe I used the incorrect version of "than"! For shame!

B) Yes! Freehand sharpening is more art than science, and is demonstrably less consistent than guided sharpening, but when you really nail the sharpening and pass all your sharpness testing freehand... there is no better feeling. :)

[Bolster]

B) Yes! Freehand sharpening is more art than science, and is demonstrably less consistent than guided sharpening, but when you really nail the sharpening and pass all your sharpness testing freehand... there is no better feeling. :)

I dunno, man. The feeling of a guided stone, a perfect angle, and a high polish is a thrill too. For me it's the differnce beween a hand-held drill and a drill press. I'll take the drill press for accuracy and results every time, if I can.

[kobold]

Pete, as usual, is a good resource. Here are his results for LC200N: https://youtu.be/iY-MMOmEiYA?t=316
Polished wins in this case.
My fixed blades in 3V, Elmax, Cru-Wear, I also keep polished with Bark River White Compound on a leather strop, but they are all bushcraft knives intended for wood processing.
I also read XHP 'likes' polishing.

I enjoy the tactile feedback of freehand sharpening, so I always freehand my folders and my progression is always similar: start with DMT coarse or fine depending how worn out the edge is. After these, I can and I usually do go to XF and XXF. Then the finishing stone is always the Spyderco UF and I always strop about 10x with 1 and 1/2 micron in the end. This works on all steels, no exceptions. KISS.
When there is a problem, it is most likely that the geometry is off (too thick - needs thinning) or that I made a user error.

A desirable result of freehand sharpening (some might disagree) is a microconvexed apex, which is stronger than an angular one.

Now, this progression won't automatically look like mirror polish, especially if I used a coarse plate, but it will feel close enough. And I enjoy when I push cut through material effortlessly. The reason for serrated knives is to do what PE knives can't, after all.

Another, often overlooked advantage of a mirror polish is better corrosion resistance.

[me2]

If I have a multibladed pocket knife, the shortest blade will get a high polish edge. The longest blade gets a coarse edge. I also polish choppers for things like wood more than blades used for thorns or grasses. Those are big blades so it is done within reason since it takes so much time.

[Steampunk]

For me, a polished edge on an EDC blade should never lack 'bite'. How high of a grit, and on what stones or sharpening media you can take a blade before it loses all functional 'bite', depends upon the steel and how you go about 'polishing' it.

Some steels at certain heat treatments, respond great to high grit stones or strops. Taking them to coarse or medium grit stones or plates can almost feel like a waste of metal, since they come back so easily, and take such a 'happy' feeling edge on fine abrasives. Spyderco's Italian-made N690 knives feel kind of like that to me.

Some steels, like ZDP-189 (I've also found SLD to respond similarly.) don't always deburr real easily on the stones at lower grits. If you thin/regrind blades, you can also find once you get to a certain thinness, that using too coarse of a stone can sometimes both simply generate a burr faster than it can be removed, and also just simply be a waste of metal. I often take these up to at least 6-12K.

Some steels, like HAP-40, get real happy with a coarser edge as long as it's still properly deburred. Steels that can take a coarse, 'Crispy' edge, that can still shave hair, are pretty special. Whenever I've taken it up too high, it loses its bite, and the edge retention starts to tank. I can get away with 'hybrid' edges, that have a big jump between the last stone and the diamond compound, but fully polishing this steel feels like missing the point. A properly deburred 400-1K edge on these is pretty special; especially if stropped with 1-micron or finer diamond afterwards.

Aogami Super is a neat one. It'll do the coarser grit, 500-2K edges for hard work that needs some teeth, and it'll hold that. You can also take it up to 0.1-micron, and it'll hold that, too. Not as long as HAP-40, CPM-M4, etc, but long enough, and without strictly needing diamonds or even SiC.

Simpler 10xx steels really respond to high polishes; especially at higher hardness. Fun, 'lightsaber' edges can be put on these with Surgical Black or Translucent Arkansas.

Once you figure out the sorts of steels that take the sorts of edges you like on the sharpening tools at your disposal, it's simply a matter of finding the tools made from those steels that suit certain needs... If you need a real straight-razor sharp, push-cutting blade of a short length, pick a steel that can take that sort of edge. If you need a longer blade for slicing, pick a steel that can take and hold a really toothy edge. Heat treatment can really change the sharpening character of different steels, but generally, certain characteristics apply.

[jasonstone20]

I usually run polished edges (up to Spyderco UF or Surgical Black Arkansas stone) on most of the EDC knives, since my natural cutting motion is more of a push cut, along with my preference for using and keeping my blades at a high sharpness (arm hair shaving to head hair whittling) vs a working edge. A polished edge also helps with corrosion resistance, and I live in a fairly wet and humid climate (Pacific Northwest) and usually carry my EDC knives inside the waistband and to my bare chest for neck knives.