Stropping

[Pelagic]

Warstein, no problem. All you have to do is try cutting some rope with a 400 grit edge vs a high polished edge, you'll see although one is sharper, the other has much better cutting ability when it comes to slicing. And regardless of how coarse your finish is, if it is either hair whittling or close, it will do a good job on push cuts also.

On s110v for example, I like to get the blade as sharp as I can off the DMT 325 grit stone. I test it on arm hair, not touching the skin. I keep going until I see a few hairs get cleaved. That edge is fine on its own, but then I'll often briefly strop on 1 micron (wood) and 0.1 micron (leather). The strops simply ensure I didn't leave any burr on the blade and slightly clean up the apex. I keep it brief so I still have those 325 grit teeth at the edge, they are just more refined. And after the stropping it is normally hair whittling, at least against the grain of the hair. It pushcuts fine, and slices extremely well.

I do this because the steel seems to hold these "toothy" edges longer. I view it as a specialized high performance stainless slicer. Even after it dulls a bit it will still slice well. It would take too long to mirror polish it and the performance gain isn't worth it imo.

[vivi]

Hmmm, so well noted in my warehouse environment for work and most of my knives usage...you think I'd be better off trying not to strop on those particular knives?
I'm definitely more of a slicer than push cutter, other than thick rope or plastic strapping.

Really appreciate all your help along the way these past couple years Vivi.

You could still see benefits from stropping each side a couple times, just don't go crazy with it. I wouldn't recommend using strops for touch ups between sharpenings either. Give it a few licks on a stone, then strop 1-3 times per side.

Basically you want to use few strokes because you're just refining the edge, not trying to bring it to a new level of polish.

Warstein, it is possible to sharpen a knife with only a strop (MUCH easier on wood and with highly concentrated compound) but the more you strop the more you fatigue/jeopardize the integrity of the apex. Minimum stropping is best for a healthy edge.

Bench stones produce a more uniform apex that strops do. They also do a better job of leaving microserrations that aid in slicing. Stropping is more likely to cause a rounded apex, and the smoother edge won't bite into materials as well during a slicing motion.

This is why I tell people not to rely on strops or high grit progressions to achieve high degrees of sharpness.

It's possible to get hair popping sharp edges using any of the sharpmaker stones and no strop. Even the diamond and CBN rods. Definitely the mediums, those are pretty high grit.

Polished edges have their place, but a lot of folks would be better served with a toothier edge for their EDC.

Get your edge to where it smoothly shaves off the mediums, strop it gently only once per side, then try out that edge. It will push cut through things just fine, but will have vastly superior slicing aggression.

Vivi and Pelagic, thanks for your replies!

As said before, I can get all of my knives sharp enough, but I am not advanced enough to differentiate between polished and toothy edges to be honest.
So I´ll try out a "toothier" edge next time by doing the hole sharpening process just on the brown rods, that should do it, right? At least it should leave the edge toothier than by finishing on the fine rods and my strop.

But, question to both of you: Is it a bad thing necessarely rounding the apex by repeated stropping? Wouldn´t that be quite the same as convexing the knife, a kind of edge many people seem to believe is the best overall type anyway?

Convex edges are certainly a valid approach to sharpening. Rounding the edge will still produce drawbacks though. It means the edge will be a little thicker and cut a little worse, microserrations still get a little more polished out, etc.

You can definitely use only the brown rods to get a toothier edge. An easy test is to run your fingernail along the apex like you're checking for chips. If it feels smooth you've got a pretty polished edge. If it feels rough / gritty, it's toothier.

The different edge types will excel at different things.

Take two of the same knives and give one a 300 grit edge off a diamond stone, and take the other up to 8000 grit and strop.

The first knife will do a really good job of slicing through cardboard, rope, plants, breads, zip-ties, plastics in general, rubber tubing, etc.

The second knife will be amazing at push cutting through foods on a cutting board, carving wood and shaving. It'll be worse for most EDC stuff (At least for the things I use my knives for, your results my be different).

[Bloke]

I agree with the sentiment here and I started to post yesterday but it got long winded ... take two. :rolleyes:

For what it’s worth, I sharpen two ways now. Zero grind Scandi’s of simple carbon steels used primarily to push cut timber I refine the edge, finishing on a translucent Arkansas (I don’t have an ultra fine Spyderco bench stone) and final finish with ultra light stropping on stiff leather and chrome oxide.

Knives used on fish and game and pocket knives I seldom if ever go above 1200grit. Most often I finish at 400-600grit and micro bevel when required only on the medium (brown) SharpMaker rods but I never strop.

Rightly or wrongly, like Vivi, I too believe convex edges don’t cut as well as a true “V” edge if you can actually achieve one in the first place. By that I think the only way to achieve a true “V” is off a robust guided system with care. I also think if you hand sharpen unless your Mr or Mrs Protractor Hands your apex will be somewhat convexed by default. If you then micro bevel you’ll add to the convex and stropping will only further exacerbate the situation.

I’m also sure how we sharpen will ultimately determine how strong and durable our edge will be. Speaking of myself, I’ve used strops as a crutch to prop less than sound sharpening skill in times gone by. Particularly by pulling burrs straight. Edges feel wicked sharp shaving arm hair and cutting paper but sharpness falls away after the first cut into something abrasive like cardboard that pulls, bends, crushes or just rips off the burr pulled straight by the strop and we’re left disenthralled by our new “Super Steel” blade that doesn’t hold an edge worth diddly.

This is still long winded but what I’ve found is; there doesn’t seem to be a substitute for edge strength and retention to a clean apex, irrespective of grit size which is finished with ultra light and deliberate passes on a clean sharp stone that actually cuts any burr away and finally finished with a light strop on a girlie soft office worker’s palm.

Just my $AU0.02c worth. :)

[TkoK83Spy]

Thanks again guys. I think part of my problem is having so many knives, that I typically just touch them up after use. But as time goes one with me cutting a lot of abrasive materials 5-6 days a week, eventually touch ups won't suffice...and this is where I'm a novice. I enjoy learning new things and the challenges along the way! It feels good to be able to ask questions and not be ridiculed and receive some great ideas and answers. I really appreciate all your replies and help along the way!

[cycleguy]

OK stupid guy question here, but I am going to ask it anyway!!!!

What is the grit level of raw leather ... for both smooth leather and course leather???

I see compounds offered for strops that have ranged from 3K grit to 32K grit. I have tried leather strops raw and with 5K grit compound and found I can enhance as well as diminish with stropping.... regardless if raw or with compound.

I have a Case Moon Stone (I fully suspect it must be a genuine stone from the moon that has unobtainable qualities by anything here on earth but seems much like a fine ceramic stone). I do quick touch-ups with it and find the results impressive.

You're the first guy I've run across in years that has one of those CASE Moon Stones. I'm certain that it was one of the earliest ceramic stones available. Because after I bought mine I"ve maybe talked to one or two others who also had one of those. I found the CASE Moon Stone to be quite a unique type of sharpening stone. I'm interested to know where you got yours and when. I got mine in the mid 80s and haven't even seen one for sale since the late 80s. I doubt if CASE made it so I'm curious as to what company made it for CASE?

The main reason I raise that question is that for the past year I've been experimenting using the finest and hardest stones to do my stropping with and I've had some really interesting results. And that CASE Moon Stone is a very hard ceramic stone IMO.

I got it off the workbench in the back of Dad's garage a long long long time ago. He's close to 90 and I'm close to 60. Suspect he picked it up in the 70's or earlier. He was/is a big case pocket knife guy; he likes other knives too.

This is total speculation on my part but I suspect it is made by Coors. Yep, Coors! They do more than suds.

Follow this link, ceramic history starts way back in the 40's and look around the 80's where it mentions knife sharpeners. Also note the reference to ceramic and alumina.

www.coorstek.com/english/about/history/

Here is another link that mentions alumina and the Case Moon Stone.

http://swingleydev.com/ot/get/196027/thread/

I've connected some loose dots to get to my speculation so I could easily be 100% wrong.

CG

[vivi]

Thanks again guys. I think part of my problem is having so many knives, that I typically just touch them up after use. But as time goes one with me cutting a lot of abrasive materials 5-6 days a week, eventually touch ups won't suffice...and this is where I'm a novice. I enjoy learning new things and the challenges along the way! It feels good to be able to ask questions and not be ridiculed and receive some great ideas and answers. I really appreciate all your replies and help along the way!

What I do is grind the factory bevel off completely on a new knife, and replace it with a thinner bevel. Usually around 10 degrees.

From there, I use the fewest strokes I can to microbevel it at 15dps. I figure the microbevel makes the edge more uniform, because I form the apex in about 6-10 strokes. Takes a lot more to form the apex when you're grinding a full bevel. Great for quick touch-ups.

But eventually the edge does get thick enough cutting ability goes down. So I simply reset the bevel the same way I did when the knife was new. Fresh apex, then repeat the microbevel process.

Once you get the hang of it, it's a very efficient setup. I get superior cutting performance compared to factory edges, and they touch up quicker.

I avoid polished bevels for this reason. Every time I need to reset the edge I'd have to go through the full grit progression again. Not worth polishing parts of the blade not going the cutting IMO, unless you need a little extra corrosion resistance.

[Wartstein]

Bench stones produce a more uniform apex that strops do. They also do a better job of leaving microserrations that aid in slicing. Stropping is more likely to cause a rounded apex, and the smoother edge won't bite into materials as well during a slicing motion.

This is why I tell people not to rely on strops or high grit progressions to achieve high degrees of sharpness.

It's possible to get hair popping sharp edges using any of the sharpmaker stones and no strop. Even the diamond and CBN rods. Definitely the mediums, those are pretty high grit.

Polished edges have their place, but a lot of folks would be better served with a toothier edge for their EDC.

Get your edge to where it smoothly shaves off the mediums, strop it gently only once per side, then try out that edge. It will push cut through things just fine, but will have vastly superior slicing aggression.

Convex edges are certainly a valid approach to sharpening. Rounding the edge will still produce drawbacks though. It means the edge will be a little thicker and cut a little worse, microserrations still get a little more polished out, etc.

You can definitely use only the brown rods to get a toothier edge. An easy test is to run your fingernail along the apex like you're checking for chips. If it feels smooth you've got a pretty polished edge. If it feels rough / gritty, it's toothier.

The different edge types will excel at different things.

Take two of the same knives and give one a 300 grit edge off a diamond stone, and take the other up to 8000 grit and strop.

The first knife will do a really good job of slicing through cardboard, rope, plants, breads, zip-ties, plastics in general, rubber tubing, etc.

The second knife will be amazing at push cutting through foods on a cutting board, carving wood and shaving. It'll be worse for most EDC stuff (At least for the things I use my knives for, your results my be different).

Warstein, no problem. All you have to do is try cutting some rope with a 400 grit edge vs a high polished edge, you'll see although one is sharper, the other has much better cutting ability when it comes to slicing. And regardless of how coarse your finish is, if it is either hair whittling or close, it will do a good job on push cuts also.

On s110v for example, I like to get the blade as sharp as I can off the DMT 325 grit stone. I test it on arm hair, not touching the skin. I keep going until I see a few hairs get cleaved. That edge is fine on its own, but then I'll often briefly strop on 1 micron (wood) and 0.1 micron (leather). The strops simply ensure I didn't leave any burr on the blade and slightly clean up the apex. I keep it brief so I still have those 325 grit teeth at the edge, they are just more refined. And after the stropping it is normally hair whittling, at least against the grain of the hair. It pushcuts fine, and slices extremely well.

I do this because the steel seems to hold these "toothy" edges longer. I view it as a specialized high performance stainless slicer. Even after it dulls a bit it will still slice well. It would take too long to mirror polish it and the performance gain isn't worth it imo.

Vivi and Pelagic, thanks once more for your replies and really helpfull advice, I appreciate that a lot!

Vivi, I really do just basic, and not advanced sharpening, so all I have is a regular SM (brown and white rods), an unloaded leatherstrop (rough and smooth leather plus the wood the leather is attached to) and a work sharp guided field sharpener. Certainly the rough and then the fine diamond coated plate of the latter are the coarsest sharpening "stones" I own (I normally only use the diamond plate of the sharpener in order to sharpen out bad chips on my fixed blades, other than that I´ll take my SM almost all of the times)

I guess I´ll try to sharpen one of my Enduras only on the finer diamond plate of the work sharp and another Endura utilizing the regular sharpmaker process plus stropping. So I can compare what you pointed out in your reply

[emanuel]

Convex edges are certainly a valid approach to sharpening. Rounding the edge will still produce drawbacks though. It means the edge will be a little thicker and cut a little worse, microserrations still get a little more polished out, etc.

I'll have to disagree with you on that, and I'll explain why. The main geometrical advantage of a convex edge/convex grind is the replacement of the secondary bevel and shoulder with a continuous curve, plus the continuous push of the material being cut away from the main grind, reducing drag. Also, the "behind the edge" thickness can be reduced to be as thin as a classical secondary bevel, without its drawbacks. It also allows for the best performance when doing deep cuts, but also for shallow cuts due to the same continuous curvature.

So a convex grind will always cut better than a similar full flat grind with a shouldered secondary bevel, no matter how thin that said knife would be behind the edge (realistically). If the same cutting edge angle is used and the other variables like edge finish and blade shape is kept relatively constant, the convex knife will perform better except in very specific tasks. (wood working and fine control cuts, where the convex will cut deeper but tends to want to slide itself out of the wood).

[Pelagic]

I think Vivi meant an entirely convexed bevel (like an axe has) versus a perfect "V" apex that's convexed from the apex angle to the shoulder. The latter does cut better than a standard V grind as you stated.

[vivi]

Convex edges are certainly a valid approach to sharpening. Rounding the edge will still produce drawbacks though. It means the edge will be a little thicker and cut a little worse, microserrations still get a little more polished out, etc.

I'll have to disagree with you on that, and I'll explain why. The main geometrical advantage of a convex edge/convex grind is the replacement of the secondary bevel and shoulder with a continuous curve, plus the continuous push of the material being cut away from the main grind, reducing drag. Also, the "behind the edge" thickness can be reduced to be as thin as a classical secondary bevel, without its drawbacks. It also allows for the best performance when doing deep cuts, but also for shallow cuts due to the same continuous curvature.

So a convex grind will always cut better than a similar full flat grind with a shouldered secondary bevel, no matter how thin that said knife would be behind the edge (realistically). If the same cutting edge angle is used and the other variables like edge finish and blade shape is kept relatively constant, the convex knife will perform better except in very specific tasks. (wood working and fine control cuts, where the convex will cut deeper but tends to want to slide itself out of the wood).

I agree with this on paper, but in my experience it is difficult to maintain precise angles while using convex sharpening methods. I only experimented with them for about two years, so maybe this is something one learns with additional experience?

[emanuel]

I agree with this on paper, but in my experience it is difficult to maintain precise angles while using convex sharpening methods. I only experimented with them for about two years, so maybe this is something one learns with additional experience?

Convex edges are the easiest to sharpen for the average user, you don't need to hold constant angle to get a decent edge. But if you want that crisp edge we guys and girls on here like, with good apex integrity, you are correct that you need extra care to not round it off, way more than the average V edge.

What I do is sharpen on 800, then 1500 grit silicon carbide sandpaper with slightly soft backing, then touch the very edge on 306UF, but with not even the weight of the knife as pressure in order to create the smallest burr possible. Then I go to 1 micron diamond on very hard leather, paying close attention to keep the knife as flat as possible, so the edge barely touches the leather, similar to how I would use a balsa wood strop.

The convex I like is a very slight convex, almost a full flat grind with a slight curve all the way to the edge, so it doesn't feel.... "axey" :D. The small neck-knives that Kyley Harris @cKc knives used to make come to mind as having a similar geometry. I remember being in my mid teenage years and watching his videos on youtube a decade or so ago, it got me really interested in trying that geometry at first chance. Funny thing, I learned a lot more english watching knife videos on youtube than in school lol. About a quarter of my knives (10?) are full convex, all fixed blades.