Why the need for toothy edges if mirror polished edge push cuts so much better?

herektir said:
It can take a long time to get that perfect polished edge working through the grit progression. Becuase i free hand sharpen, its not worth the time it takes to obtain that kind of edge compared to how long the edge lasts in use. 800 grit and an occasional touch up on a fine ceramic rod works, is fairly quick, and it cuts well.
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In my experience as well
 
Me too: Polished edges are way overrated.

I hardly ever go finer than a worn coarse Dia-Sharp, then touch ups on a medium stone. I often go straight from Extra-Coarse to the medium stone just to de-burr.

Gaston
 
This thread makes me think of trying something. Recently, I have been going back and forth between coarse edges and fine edges and testing them. I think I might try making my own "combo edge", with the hilt side of the blade finished to about 400-600grit, and the tip side finished to a 2000k+ polish. Has anyone ever tried such a thing?
 
I have also found that an extremely well polished and hair splitting sharp edge lasts a really long time. I've been getting knives shaving sharp for a long time, but with recent improvements to my sharpening setup, and the new ability to get knives to cut free-hanging hairs, I have been shocked that such an edge lasts. I thought it would be very delicate, but it's not.
 
Alfazulu said:
This thread makes me think of trying something. Recently, I have been going back and forth between coarse edges and fine edges and testing them. I think I might try making my own "combo edge", with the hilt side of the blade finished to about 400-600grit, and the tip side finished to a 2000k+ polish. Has anyone ever tried such a thing?
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Yes, on the extreme end, I think they're called partially serrated blades.
 
Alfazulu said:
I have also found that an extremely well polished and hair splitting sharp edge lasts a really long time. I've been getting knives shaving sharp for a long time, but with recent improvements to my sharpening setup, and the new ability to get knives to cut free-hanging hairs, I have been shocked that such an edge lasts. I thought it would be very delicate, but it's not.
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So it will maintain hair whittling sharpness even after cutting say 10 ft of cardboard?
 
That statement doesn't mean much without context. For some tasks, highly polished is better, for others a coarser finish is better. Use the edge that suits your work.
 
Ankersons test is a controlled and measured draw cut/slice on a 5/8" manila rope. It is in regards to a pull cut and the "bite" imparted.
The quote posted above was taken from page 105 and was in response to the quote below with Jims full response quoted as well.
chiral.grolim said:
Did any of the steels perform "better with a polished edge"?? I simply assumed that they all performed worse in this test, polishing the edges had the effect of bringing the performances closer together so that abrasion-resistance was less noticeable. Using a coarse edge potentiates the effect of abrasion-resistance, so long as you avoid leaving the edge so coarse that it crumbles - e.g. in CATRA tests of various steels cutting silica-embedded cards, 325-grit (45um) was behind 600 grit (25um), while 8000 grit (3um) was also behind 600 grit. Jim is using 400 grit ~37um. I can't remember how many cuts each steel was making before that change...
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Ankerson said:
None of the ones listed in the Polished edge section did near 300 cuts...

So yeah polished edges perform a lot less.
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See test here:
http://www.bladeforums.com/forums/s...based-on-Edge-Retention-cutting-5-8-quot-rope
 
I've read that barber shears work better when there is a little bite to the edge. Course a straight razor works best with a polished edge.
 
That's better. So a more accurate statement in proper context would have been "highly polished edges perform a lot (sic) less when draw cutting Manila rope."

And scissors used for cutting hair definitely work better with a slightly coarser finish due to one very important factor - a highly polished pair of scissors will be prone to pushing the hair right out of the scissors because the edge doesn't grip the hair, allowing a good portion of the hair to slide/be pushed along the 'V' as the scissors are closed. A grind with a little tooth lets the edge grip the hair and hold it in position while it's being cut.
 
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Polished edges are good when carving wood or chopping,otherwise,for most other tasks are not so good.Coarse,and somewhere in the middle edges draw cut better,period.In my opinion,cutting paper is not really a test.Geometry of the blade is just as important as sharpeness.
 
How do you test more of a coarse edge? For example, With finer edges a test is cutting phone paper.
 
linuxology said:
How do you test more of a coarse edge? For example, With finer edges a test is cutting phone paper.
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Depends what you're 'testing' for. Cutting phone book paper is just as useful for a coarse edge as for a finer edge, if you're looking for edge defects like an incomplete apex, edge damage like nicks or dents, or for burrs. A lot can also be learned about the crispness of the edge, in seeing how easily the edge 'bites' into the paper on first contact; or even better, in seeing how (or even IF) the edge will bite into the face of a phonebook page, instead of into the edge of the page. Taken even further, try doing the above tests AFTER using the blade for some other 'real world' cutting tasks, like cutting rope, wood, cardboard etc. If the edge still performs well on the phonebook paper after doing some of these other things, that's a good indicator of the durability of the edge produced.


David
 
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Why the need for 2wd trucks if 4wd and awd handle so well. Preference, ease of maintenance


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Examples of what 400 grit SIC looks like when I sharpen with the stones I use.

DSC_5553.JPG
 
bgentry said:
What do you cut and how do you cut it? That's really what determines the optimal blade finish. Try cutting a bunch of cardboard boxes into pieces with a highly polished edge. It will cut really nicely... for a while. Then it will quit. Try the same thing with a rather coarse edge. Say 100 micron. The cuts aren't quite as whisper quiet, but it *cuts* and cuts well. See how long this edge lasts compared to the polished edge.

In my limited testing, I found the coarse edge to last roughly 3x as long as the polished edge in this type of use.

Jason B once described some CATRA testing he was involved in where the 320 grit edge lasted something like 3x (or more maybe?) longer than the polished edge.

It's all about what you're cutting and how you cut it.

Brian.
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I hate to admit it as I love with a passion that smooth cut feeling of a polished edge. But I can concer that this is correct. The edge geometry and steel type and HT can effect the polish edge to last longer, it's not really going to compair to how long a corse edge lasts. Sadly..... oh well coarse edc all the way I guess. I'm still collecting my favorite polished blades though 😊 ya love what ya love ya know?
 
blade dude said:
Why the need for 2wd trucks if 4wd and awd handle so well. Preference, ease of maintenance


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Don't forget cost.... cost is a huge factor here, that's like asking why d2 blades and 8cr13mov when there's m390, elmax, cpm-20cv, vanax, and magnacut? The answer, because those other steels basicly add a 100 to 400 dollars extra to the price tag just by being involved. Price is a huge matter in almost every circumstance. That's why companies like CRKT exist. They take famous designed knives, remake them (with permission of course) using cheaper costing materials, and sell them for a more affordable cost. So why 2wd you say? The answer is usually because it's good enough and you can afford it 😂
 
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