Polished Edge: When, Why, What Steels??

Discuss Spyderco's products and history.
vivi
Member
Posts: 13846
Joined: Mon Oct 29, 2007 8:15 am

Re: Polished Edge: When, Why, What Steels??

#61

Post by vivi »

Woodpuppy wrote:
Tue Jul 27, 2021 8:13 pm
Something appears amiss with the new emojis- they’re ENORMOUS!
Haha, some of these are pretty fabulous.... :unicorn :shooting-star :pinata :rainbow :crown :cupcake :butterfly :bouquet :rainbow :pinata :pinata :pinata :pinata :pinata
:unicorn
User avatar
u.w.
Member
Posts: 570
Joined: Mon Apr 09, 2018 7:25 am
Location: VABch

Re: Polished Edge: When, Why, What Steels??

#62

Post by u.w. »

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

u.w.
User avatar
ZrowsN1s
Member
Posts: 7324
Joined: Sat Jan 30, 2016 5:08 pm
Location: San Diego, California USA

Re: Polished Edge: When, Why, What Steels??

#63

Post by 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.

:respect :usflag :bug-red
-Matt a.k.a. Lo_Que, loadedquestions135 I ❤ The P'KAL :bug-red

"The world of edges has a small doorway in, but opens into a cavern that is both wide and deep." -sal
"Ghost hunters scope the edge." -sal
FK
Member
Posts: 630
Joined: Fri Sep 24, 2004 10:33 am
Location: CT USA

Re: Polished Edge: When, Why, What Steels??

#64

Post by FK »

Bill1170 wrote:
Tue Jul 27, 2021 9:50 pm
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
Member
Posts: 554
Joined: Sun Jun 28, 2020 7:56 pm

Re: Polished Edge: When, Why, What Steels??

#65

Post by metaphoricalsimile »

vivi wrote:
Tue Jul 27, 2021 2:00 pm
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.
User avatar
Kevinim82
Member
Posts: 671
Joined: Sun Oct 27, 2019 12:04 pm

Re: Polished Edge: When, Why, What Steels??

#66

Post by 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/
Was never a space cadet, but with LC200N I might be more in space than a cadet.

MNOSD 0009
Baron Mind
Member
Posts: 475
Joined: Tue Mar 13, 2018 4:18 pm

Re: Polished Edge: When, Why, What Steels??

#67

Post by 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.
User avatar
wrdwrght
Member
Posts: 5078
Joined: Tue Mar 01, 2011 9:35 am

Re: Polished Edge: When, Why, What Steels??

#68

Post by wrdwrght »

Baron Mind wrote:
Thu Jul 29, 2021 7:54 pm
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.
-Marc (pocketing an M4 Sage5 today)

“When science changes its opinion, it didn’t lie to you. It learned more.”
Baron Mind
Member
Posts: 475
Joined: Tue Mar 13, 2018 4:18 pm

Re: Polished Edge: When, Why, What Steels??

#69

Post by Baron Mind »

wrdwrght wrote:
Fri Jul 30, 2021 8:00 am
Baron Mind wrote:
Thu Jul 29, 2021 7:54 pm
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. :)
User avatar
Bolster
Member
Posts: 5573
Joined: Sat Mar 03, 2007 1:27 pm
Location: CalyFRNia

Re: Polished Edge: When, Why, What Steels??

#70

Post by Bolster »

Baron Mind wrote:
Fri Jul 30, 2021 11:07 pm

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.
User avatar
kobold
Member
Posts: 1809
Joined: Mon Aug 24, 2020 12:38 am
Location: The Swamp

Re: Polished Edge: When, Why, What Steels??

#71

Post by 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.
Military/PM2/P3 Native Chief/Native GB2 DF2 PITS Chaparral Tasman Salt 2 SE Caribbean Sheepfoot SE SpydieChef Swayback Manix2 Sage 1 SSS Stretch 2 XL G10
me2
Member
Posts: 370
Joined: Sat Dec 08, 2012 11:37 am

Re: Polished Edge: When, Why, What Steels??

#72

Post by 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
Member
Posts: 13
Joined: Thu Aug 05, 2021 1:28 pm

Re: Polished Edge: When, Why, What Steels??

#73

Post by 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.
User avatar
jasonstone20
Member
Posts: 69
Joined: Tue Jan 06, 2015 6:29 pm
Location: Portland, OR

Re: Polished Edge: When, Why, What Steels??

#74

Post by 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.
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp, May his memory be a blessing

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"Life is GOOD!"
--Stefan Wolf, May his memory be a blessing

--Ken Schwartz, May his memory be a blessing

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Post Reply