What's the deal with polished edges?

[dshreter]

I just got a new zdp calypso jr. in the mail, and just like my previous one, its the sharpest knife I've ever had. It struck me that this knife, like almost all new pocketknives, has an unpolished bevel. Instead, it's sharpened on a belt I assume, and you can clearly see the scratch lines all along the edge in a single bevel (no micro bevel).

When using a sharpmaker though, its considered important to use the smooth stones to approach having a polished bevel. When using waterstones it's also considered very important to have a polished bevel.

So what gives? Does a polished bevel actually do anything? And if so, why is a new knife with an unpolished bevel so extremely sharp, and specifically how is this different than the edge achieved sharpening on the rough sharpmaker stones for example?

[THG]

Polished bevels don't matter. It's what happens at the edge. Most of my knives come with belt sanded bevels and a microbevel that's more finely polished.

[The General]

Polished bevels do matter.

Spyderco knives do not come with polished bevels due to cost. It costs money to bring an edge to a polished state. Time, belts and it all adds up.

A polished bevel, and as Spyderco knives have V bevels, so the edge would be polished as well. Gives a finer edge that lasts longer. Though for some tasks some prefer a more toothy edge. This does break down quicker though.

A Spyderco knife might come very very sharp out of the box, but its rarely a polished edge. Its a good edge, one of the best for a production knife company but I do take my edges to a much higher level of polish as a matter of course.

I am pretty sure Sal would say they could polish the edges but would you all be prepared to pay an extra $5 or $10 for this? The average user certainly would NOT and Spyderco knives are meant to be used!

Sometimes I find myself being a bit critical of this or that in a Spyderco and I have to get up and walk around the room and remind myself that I am comparing a value knife to a custom or a Sebenza. Its easy to forget but Spyderco knives are about giving the most bang for the buck. Its a fine line and while I would prefer a better level of edge refinement. I know I can do this myself so it does not worry me. If it bothered a person, I think that person would be able to do it themselves. Everyone else? Probably not even aware.

[dsmegst]

I really like the factory edge on Spyderco knives.

The edge is ground on a belt as stated but they are also finished on buffing wheels. That leaves behind a very unique edge.

The edge has rather aggressive ridges at pretty much 90 degrees. But unlike typical edges from a high grit grinders, the edge is polished. It's probably polished with cloth wheels and that means all those ridges and valleys are polished and any left over burrs and teeth are gone.

So you're left with an edge that can slice well and push cut well too. It has plenty of bite to quickly start cutting unlike a very finely polished flat edge. It's a very good compromise.

My sharpening method results in a very flat high polish edge but while it will push cut and whittle hair, it doesn't have that "bite" I like also. I'm thinking about adding some fine micro serrations as the finishing touch from now on.

[AJF]

I'm thinking about adding some fine micro serrations as the finishing touch from now on.

Dan, would you do that by giving it a few passes on coarser stones?

Thanks,

Andrew

[The General]

Dan, would you do that by giving it a few passes on coarser stones?

Thanks,

Andrew

Yes.

[chuck_roxas45]

I wonder if you could get the same effect from sharpening at 320 grit then just adding a microbevel with a higher grit, say 600.

[wongKI]

Not too sure.

I think the way many people do it is use a low grit then a high one, for example 120 grit belt, then power polish (like the paper wheels).

[The Mentaculous]

I think toothy edges work great as long as they're fine (like spyderco's factory edges generally are), but I completely agree with the General that a polished edge will last longer. Remember that all those tiny teeth can bend and get deformed much easier than a uniform edge. It also depends on what you need it for; if you're slicing tomatoes, a toothy edge is great---cardboard, not so much, in my experience.

Since I got some green stropping compound a month or so ago, I have barely needed to use my sharpmaker at all. A good stropping works like magic to bring back an edge in need of a minor touch up, and you quickly get a very true edge. Plus you save the steel you would be taking off using a stone . That's the ideal method for me at least so far, but yours may be different.

[THG]

Polished bevels do matter.

Not when it comes to cutting.

[Evil D]

I can see in certain situations where polishing would be better, but personally i use and sharpen my knives so often that it's a giant waste of time for me. Too much extra work since i don't use a belt sander or paper wheels or anything powered. If i had all those toys and could throw down a crazy sharp polished edge in the time i can sharpen with stones, then i probably would too.

[unit]

Polished bevels don't matter. It's what happens at the edge. Most of my knives come with belt sanded bevels and a microbevel that's more finely polished.

The micro bevel does the cutting and because it is so small you can not see it very easily.

I would argue that polishing the other bevels DOES matter, but the cost involved is substantial relative to what many users feel they need. Here is a very basic demonstration of this (and a few other) concept(s). Plenty of variables here, but I like to think this demonstrates something regarding polish level on the bevel(s).

I would also suggest that a coarse finish offers a very different result than serrations.

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[unit]

I can see in certain situations where polishing would be better, but personally i use and sharpen my knives so often that it's a giant waste of time for me. Too much extra work since i don't use a belt sander or paper wheels or anything powered. If i had all those toys and could throw down a crazy sharp polished edge in the time i can sharpen with stones, then i probably would too.

I also do not use power tools to sharpen. You might be surprised at how little extra time it takes to polish a blade from a coarse stone finish to a fairly high polish.

A couple days ago I re-polished my two primary EDCs (a VG-10 Endura, and a CTS-BD1 Mule) in under 30 minutes (including cleaning up the stones and packing them away). This included repairing the compression in the Mule blade. Once I reset the bevels, polishing from Coarse to 0.5 micron took about 10 minutes....so yeah it takes 30% longer I suppose, but lets face it, if you are reading this, you probably have 10 minutes laying around somewhere

[AJF]

Dan, would you do that by giving it a few passes on coarser stones?

Thanks,

Andrew

Yes.

Thanks.

[AJF]

Ken, thanks for referencing that nifty little video. It is a great illustration.

Andrew

[dsmegst]

Regarding power tools, once it's setup, it saves a ton of time.

My bench grinder is setup with the slotted paper wheel almost all the time. If I need a touch up, I set my guide to the right angle (the guide is an upright free standing arm made from a coat hanger) as marked on the side of the wheel. Start the grinder and make 2 or 3 light passes. The old buffing compound on the wheel is enough to do the work.

This takes less than 30 seconds and I'm done. It takes place of touching up on the Sharpmaker and stropping afterwards. The compound is 2 microns and due to wear and speed, it will leave a shiny hair popping edge. A little bit of extra care will let me whittle hairs but I don't need that for EDC.

I've recently setup an extra slotted wheel with .5 micron compound and it's a complete overkill. I tried it on a whim and I'm thinking it was a waste of time and money. It produces a REALLY shiny polished edge but aside from looking good and allowing me to duplicate the hair whittling tricks, it doesn't add anything. I don't bother with it unless I'm showing off.

[dj moonbat]

Once you've got a polished edge, it only takes a matter of a minute or two to polish it again. Then, every few months, you have to re-bevel. It's not that big a deal. But in terms of cutting power, it is a big deal. A really polished edge just glides through cuts.

[unit]

Regarding power tools, once it's setup, it saves a ton of time.

My bench grinder is setup with the slotted paper wheel almost all the time. If I need a touch up, I set my guide to the right angle (the guide is an upright free standing arm made from a coat hanger) as marked on the side of the wheel. Start the grinder and make 2 or 3 light passes. The old buffing compound on the wheel is enough to do the work.

This takes less than 30 seconds and I'm done. It takes place of touching up on the Sharpmaker and stropping afterwards. The compound is 2 microns and due to wear and speed, it will leave a shiny hair popping edge. A little bit of extra care will let me whittle hairs but I don't need that for EDC.

I've recently setup an extra slotted wheel with .5 micron compound and it's a complete overkill. I tried it on a whim and I'm thinking it was a waste of time and money. It produces a REALLY shiny polished edge but aside from looking good and allowing me to duplicate the hair whittling tricks, it doesn't add anything. I don't bother with it unless I'm showing off.

I would agree that the differences between a 2 micron finish and a 0.5 micron finish are largely cosmetic/ego. My finish on a 3 micron stone whittles hair just as good as a 0.5 micron finish (as far as I can tell)...so why do I put on the 0.5 micron finish?...I like the looks and I just plain like to know I have it (ego, I suppose).

You said a mouthful there (bold). I really do agree, but I still take that last 0.5 micron step most of the time (perhaps because I own the strop...might as well use it...and it only takes a couple seconds to pull it out).

[dj moonbat]

You said a mouthful there (bold). I really do agree, but I still take that last 0.5 micron step most of the time (perhaps because I own the strop...might as well use it...and it only takes a couple seconds to pull it out).

Yeah, Ken isn't really all that into polishing the edges. He just does it 'cause he already has the strop...

[mikerestivo]

Ken - Thanks for creating and posting the video. Visual demonstration of this brought it home more for me about polishing and sharpening angles. - Mike