Polished edges.

S

Spongebobby

Joined
Oct 11, 2010
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Polished edges are great, for push cutting, shaving, and whittling, not much else. Atleast 80% of my cutting needs require a little teeth, like the edge off a fine arkansas stone (which does leave tooth). I usually test toothiness by running the edge over a callous with no pressure and seeing if it cuts a layer of skin. This edge is so much better for rope, or fish, or skinning a critter, which is a lot of the cutting i do, and it still works for boxes, or whittling, or shaving if i had too. What about you guys? What kind of edge do you keep of on your EDC's that might encounter any task imaginable?
 
I find a polished edge to meet my needs including my skinning knives. They seem to stay sharper for longer too. Kitchen knives all get 1000 grit chosera edges.
 
Cutting skill is = to sharpness. If your cutting skill is not developed in fine edges then it may lead you to conclude they are not as useful.

Sharp is sharp, the only thing that is a constant is the change in edge roughness. Find the edge roughness you like and perfect it. One edge is not better than the other just more suited to a specific task.
 
I didn't find anything that I couldn't cut effortlessly, with my bevels polished to a 2000+ grit shine. It's more about the purity and integrity of the edge's apex. If that's good, it really doesn't matter to what degree of polish one finishes. The most common mistake made, I'd bet, when 'polishing' the bevels, is getting a little over-zealous and rounding over the edge itself. It takes longer, and requires much more effort and focus, to correctly finish an edge to a higher polish. And it's therefore easy to make more mistakes along the way, and blame the poor cutting on the 'polished edge'. Keep the apex as pure and tight as possible, along the entire length of the cutting edge, and the results will speak for themselves. BTW, this also applies to a toothy edge. If the apex itself is in good shape (geometrically), and all burrs & wires have been eliminated, a coarser, toothy edge can do many of the same things normally attributed to polished edges (like push-cutting).

EDIT:
I've started to view a 'good edge' as it might be seen in cross-section. More so, if viewed as thousands of paper-thin, cross-sectional 'slices' of the blade itself, stacked end-to-end, from heel to tip, to form the 'whole blade'. Imagine a push cut into the edge of a sheet of paper. In order to do that effectively, only the very narrow segment of the edge in direct contact with the paper needs to be 'sharp'. If adjacent cross-sectional 'slices' of the segmented edge aren't quite so sharp, the blade might still be able to push-cut. But a draw or slicing cut would be dimished, because not all segments of the edge are equally sharp. If, on the other hand, each individual cross-sectional 'slice' of the segmented edge is equally able to effortlessly push-cut on it's own, then a slicing cut, utilizing all of those segments in a seamless sequence, would be automatic. This might seem a somewhat convoluted way to view it, but I've found it useful. It's what I picture in mind, when I emphasize a pure apex along the entire length of cutting edge, from heel to tip.
 
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I don't really quite get this whole toothy vs polished, since I pretty much always take my edges as far as I can and I still haven't met a cutting task which my edges couldn't handle because they were polished.
I've cut plenty of rope with polished edges and I actually prefer the clean cuts they make, compared to the hint toward frayed ends I get with a very sharp coarse edge.
Cardboard isn't a problem either -- just that it dulls the edge and I therefor use box cutters for that. A polished edge goes through cardboard like butter though and a coarse edge does it very well too, but definitely not better.
I find that I must use more force with coarser edges than with polished edges, which I don't like. I want the knife to do the work instead of compensating with force and risking that I may slip.
If a polished edge is scary sharp then yes, it is easier to cut yourself with it than with a scary sharp coarse edge; by just barely touching it, but since it's packed with so much performance one can and should be more delicate with it.
 
I keep both. I tend to like toothy edge for EDC though as like you say its just more versatile and IMHO cuts faster. But knives that spend the majority of their life in a case or on display nothing beats a mirror edge. Especially on a steel that takes a good polish.
 
Most of my knives go 1k Chosera or maybe 3k. If it takes a good polished edge like my M390 BM710 then it will surely get one, but my Mini Grip(154cm) and my H&K Mini Auto(440c) don't usually get them.

I don't determine which gets what from how often I carry it, just by rather or not it will hold it long enough to make it worth while.

I notice very little difference for most tasks, sharp is sharp to me.
 
I used to try to make my coarse edges as fine as possible using finishing techniques (coarse grit stropping etc), but now try to produce the most refined edge I can that still has tooth - there's a big difference. True enough, some grinds work better or longer at certain tasks. One test I did after I could reliably produce hair whittling edges - take a coarse edge and chop a green branch about the size of your thumb - I was using a 3.5" blade on branches about as big around as my thumb. Swat some green leaves with the same blade. Now work your way up through to a polished edge. The coarse one slices freehanging leaves much better, the fine edge chops branches with far less effort. There are many such tests you can do - produce the edge that works best and longest for what you do. Sharp is sharp, but edge grind has a huge effect is how and what and edge can cut well.
 
This topic is interesting to me. Im not new to knives and iv had a few polish edges come out really nice and scary sharp. But its the hours spent getting the edge that turns me off. And with 154 cm i couldnt seem to hold a that edge for too long on a user. Now i carry s30v, elmax or m390 and i cant imagije how long it would take to get a polished edge by hand. I used a worksharp and completly trashed a few blades and its left me scared to attempt to sharpen anything, even by hand.

Im currently carrying a 581 barrage with m390 and the factory edge is VERY toothy. Toothiest thing iv ever carried but it is scary sharp. I took a strip of hair from elbow to wrist in one sweep. But, i want a polished edge on it just because. I just dont know how to go about it with m390.

Would arkansas stones work on m390 or would i need a diamond bench stone or something?
 
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Nah, a polished edge is a luxury. It's not necessary, it's connoisseur thing.

If done by a skilled sharpener though, it represents the finest possible edge you can possibly achieve, so it's sort a grail-thing too. It isn't just about whether or not it is better for this or worse for that. For some it's that it is the finest possible edge, which is sharper than a scalpel for surgery and stunningly beautiful, just like expensive jewelry. It absolutely isn't necessary for most tasks, but there is something quite special about using a well sharpened, beautifully polished edge, because you know you've made that edge as fine as you could. Look at Katanas and Samurais. Their swords were sharpened for a couple of months to truly be "perfect", yet the vikings chopped heads off to the left and right with ruggedly sharpened broadswords, as did the Romans etc.
 
Polishing isn't entirely a cosmetic thing. In particular, I've noticed that a convex with polished shoulders (to 2000+) makes cardboard cutting almost scary. The friction between the shoulders of a bevel, and the material being cut, makes a huge difference in how much the blade binds up in thicker & deeper material. More polish --> less friction --> 'slick as glass' cutting in tougher material.
 
I agree with you 100%. I'm just saying that a polished edge is about finesse. That blade of yours, when it goes through that cardboard like as if it was water... isn't necessary, but man oh man there is a difference between that and a new box cutter.
 
Ah, its 3am here in Texas and i just finished putting a polished edge on my barrage with m390. Started with a two sided diamond stone and then to a two sideded ark stone then stropped on an old belt with stainless polishhing compound and then mothers mag polish. Its not perfect but damn its scary sharp and looks much better. I made it all night without cutting myself and then when i was cleaning the blade under running water i sliced my middle finger open. Oh well, its sharp. Now ill see how this m390 edge holds up.
 
Yeah, that is one of the main drawbacks to a highly polished edge -- it cuts you decisively if you just caress it with a feather's touch. The other main drawback to me, is the time it takes to get an edge like that.
 
boki_zca said:
Polished edges for wood cutting, and toothy for everything else!
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^This sums it up pretty well for the most part.

stoffi said:
Yeah, that is one of the main drawbacks to a highly polished edge -- it cuts you decisively if you just caress it with a feather's touch. The other main drawback to me, is the time it takes to get an edge like that.
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I just had a second go at a machete I'm giving my buddy for his Bday. Decided it needed a bit more polish with the 6000 grit King. On my pocket knives, I usually just backhone a few passes and leave the edge with a bit of microtooth, but this time I did some grinding as well before the backhoning (cause choppers work better as polished as you can get 'em). Followed it up by stropping on plain newspaper. I could tell from the sound it makes cross-cutting newspaper that it was pretty clean, but even I was surprised when it caught on my fingernail and almost went right through. Gotta remember to be more aware when handling stuff that has some mass.


Edit to add: total time to go from factory dull through filework and polished with waterstones - one and a half hours. I'll be sending a warning note with the Birthday Card - hope he reads it before handling the thing...Maybe I should call ahead...
 
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stoffi said:
One and a half hours?! That's quick if you did it freehand!
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Thanks!
I've been wondering how much time it takes to freehand some tasks so set my watch up on my bench. Me vs 16" Bolo machete from CS straight from the factory. Took just over 10 minutes a side to file the initial bevel-work, then 10 minutes a side on the 1200 grit King waterstone and a quick stropping on newspaper. At this point it was good enough for my backpacking standards - shaves arm hair and crosscuts newspaper pretty quietly. Decided since it was a gift I'd better go all out, so the next night I redid the 1200grit work (less than 10 minutes/side) and followed up with the 6000 grit King and stropping which took up the balance of the second 45 minutes. Felt those were some respectable times, probably from going so quickly is when I started getting sloppy handling. Held it up to do a final check for burrs and the edge bit into my pinky fingernail like a fish hook - grabbed on while I'm squinting through a loupe with the other eye closed. Had to very slowly lower it down and carefully extricate the thing. If I'd flinched when I felt it catch I'm positive it would have made it through, that would have bled pretty good...
 
Apparently i got my barrage much sharper than i thought. I got curious and decided to disassemble the knife to clean it up and see how the axis assistworks. I should have looked around for a video or diagram before i tore into it but im hardheaded. I acidentally released the tension on the coil sprig and couldnt get it to go back together correctly. In the process of messing with it for 20 minutes i managed to cut myself 4 more times pretty good. The last cut was crazy, i had the knife open and edge facing up and put just the slightest presure on the edge just to hold the knife from falling over and it went into my finger as if it were hot butter. Blood was everywhere but i couldnt stop laughing cause i was pretty excited that i got my blade that sharp. My girlfriend thinks im freakin nuts.

Mowing the yard today sucked and goin back toorrow wil suck. Typing this out suck too.
 
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