Zeraph

So I've had a knife (6 inch blade) since I was 7 or 8. Its a fairly good knife. In fact its hanging on my bedpost. Its a buffalo skinner. But after doing what I was told not to, I ran my thumb over it parallel to see how sharp it really was. Turned out I didn't even get something like a paper cut! I had to push down quite hard to cut myself even the smallest amount (indentation really).

Is there a standard measurement for knife thinness (or sharpness?)

Is there any other way to tell if a knife is especially sharp besides running your thumb perpendicular (or parallel if stupid/brave heheh) to the blade?

For instance, should I be able to expect shave with my knife?

Assuming proper upkeep, and sharpening stones, etc.

KirStang

Used to be a Sushi chef. I loved sharpening my sushi knives.

A quick test is to take the blade and touch it to your thumbnail. If it 'sticks' a little, it's really sharp. When sharpening, I usually start with the 'perpendicular thumb test' as you described, and when it felt like I had a good wire edge, I'd move to a finer stone and do the thumbnail test.

I always started out with a thicker stone, like 500-1000 grit (IIRC), then finished with a 10,000 grit stone.

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Baraka_Guru

If it can't easily cut through a whole, ripe tomato without ruining it, then it's probably not sharp enough.

I remember when I used to receive kitchen knives from the sharpening service at the kitchen I used to work at. These knives would practically "melt" through the tomatoes. That's sharp. I wouldn't dare do the "thumb test" on those things.

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RogueGypsy

It depends a little on the utility of the knife, but in general, all knives should be able to shave.

The easiest way I've found to check an edge is to lightly tap the blade against your thumb nail perpendicular to the grain, then move it off with the grain. If it sticks or catches, the edge is keen. If it just slides off with no hesitation, the edge needs attention.

Just FYI; if you run your finger along a blade that will stick in your fingernail, you hit bone before you feel the cut. Never run you finger along the blade, you got lucky.

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Ilow

Pretty sure I could shave with my SOG Flash, not that I would, mind you. Good knives really hold an edge.

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KirStang

Damn, I haven't been able to get a really really good edge out of my SOG Flash after a year of EDC. I think I need better sharpening stones.

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bparker805

I sharpen knives as a side business. The test I use is to slice through a piece of paper. I "feel" the cut to sense any dull spots and then visually inspect the cut to make sure it's cutting clean. If its catching and not making that clean cut, back to the wheels I go.

Walt

Are you guys using an old school whet stone or something like a Lansky system? From my experience, it's damn near impossible to not get a good edge with a modern system.

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Cynthetiq

I need new chef knives.... they can't cut tomatoes without squishing them.


but my balisongs.... oh those were sharp sharp sharp.

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KirStang

I used an old school whet stone...

Question: Anybody know where I can pick up a quality whet stone? The ones I have don't do a very good job compared to the ones I used at work.

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Walt

How "quality" are we talking? From what I understand, a no-shit Nakayama whet stone will run you about a grand. If you're just out to sharpen a knife that will be used outside of the kitchen, I would recommend a Lansky-style system ($20) or the Spiderco Sharpmaker ($50). If you've got money to burn, check out Edge Pro ($100).

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bparker805

Not using stones. My set up consists of 2 motors that run a belt, and a series of wheels that hone and polish. Basically recreating a fresh cutting edge. I work more on kitchen cutlery but can handle pocket knives no problem (as long as we are excluding crap liquor store specials )

ChrisJericho

Sort of interesting, I have two main pocket knife EDC's, a SOG Aegis and a Spyderco tenacious.

Sort of like Kirstang said, the SOG I have just doesn't really sharpen that well anymore while the Tenacious has no problem getting scary sharp again after sharpening.

I do use the Spyderco sharpmaker, but I doubt that makes a difference. The sharpmaker works really well on all my other knives (like the kitchen knives I have) but the SOG just seems like it's toast.

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im2smrt4u

The paper slice is a good test for most general purpose knives. However, depending on the blade and edge geometry that isn't always the best indicator. You can have an edge that will scare the hair off your arm but won't slice paper smoothly. For safety reasons I don't suggest the thumbnail or finger tests (not that shaving hair off your arm is terribly safe, but anyway), but a good eye is the best check. You can use a jewler's loupe if you want to get super close.

That reminds me, I need to work on my pocketknives. I have a Spyderco Sharpmaker, which is a semi-freehand system. Good product, but the stones are fine ceramic, so not really too helpful when the edge is dull. Much better for keeping an edge sharp. I may need to employ professional help since I no longer have a grinder at work...

---------- Post added at 06:58 AM ---------- Previous post was at 06:53 AM ----------

The AUS 8 in the SOG is tough to get sharp by hand. It is on the softer side, so one bad pass on the Sharpmaker can undo all your progress. Easier to handle on a grinder IMO, where you can do 99% of your work in one pass.

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Shadowex3

great I feel terrible now for using a kitchen knife sharpener on a generic 440 stainless lockback. It's sharp enough...

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Zeraph

Hmmm. That skinning knife I've had for like 15 years is definitely dull then. Do blades dull over time? Or was I swindled? Its barely been used. Only skinned a few game with it.

im2smrt4u

They won't dull just sitting unless they are rusting. Does the blade indicate a type of steel? A brand?

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Zeraph

Thought I already said; Original Buffalo Skinner made in Germany, I think by Solingen Germany.

im2smrt4u

Sorry if I missed that, I was replying via my phone.

FYI, Soligen is a city in Germany. For a long time, it was well known for it's high quality steel. These days, the best steels come from Japan and the USA. However, from the research I have done, the knife you describe could be as old as the 1950's. If it is an older knife, it should have a high quality steel that should take an excellent edge.

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TheCrimsonGhost

Shave wit that bitch!

RogueGypsy

I was a die hard Whetstone user until a few years ago when I needed to replace one of my fine Japanese stones. The price had tripled and there was just no way I was going to spend $150 on a single stone. I do some fine wood working as a hobby/pro so I'm a little more anal about sharp tools than the casual user. That and dull knives just irritate me. I came across the Scary Sharp Method SCARY SHARP looking for an alternative to expensive high maintenance Whetstones. I also discovered that it's more about technique than tool. To give you an idea of how effective it is, I use higher grits (2000-8000) to sharpen new razor blades for my utility knives.

I've since tuned the method and I can take a blade from blunt to shave in about 15 minutes, by hand. Tuning an edge takes about 2 minutes.

If I have a severely neglected blade: I start with a course diamond sharpener, then go to the method listed above. I only use Sic (Silicone Carbide) paper. The stuff you find at Auto paint shops is the most consistent. If you want the best, it's Meguiar's (the car wax company). After the Diamond I work up progressively from 220 to 2000 grit, about 6 passes per side/per grit. If I want a perfect edge (mostly on planes and chisels) I'll go up to 4000 grit, then strop it with jewelers rouge. On kitchen knives I finish with a ceramic stick after 2000 grit.

This is by far the fastest, cheapest, most consistent, method I've found and I've used just about everything. But like I said, it's all about the technique. Use a guide if you have too, but learn to hold a consistent angle with light pressure and all will be good.



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Methods, application and intensity of application vary by the individual. All legal wavers must be signed before 'treatment' begins. Self 'Medicating' is not recommend. However, if necessary, it is best to have an 'assistant' or 'soft landing zone' nearby. Any and all legal issues resulting from improperly applied techniques should be forwarded to: Dewy, Cheatum & Howe, Intercourse, PA 17534. Attn: Anonymous.

KirStang

Oh forgot. A test I used to do: Pull out a section of saran wrap, gently place your knife on it. If it cuts the saran wrap that way--it's sharp.

Being a sushi chef, we used to get huge 200' rolls of saran wrap, so I'd always double check sharpness that way.

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Walt

Yes. That your knife has lost its edge is most likely due to minute oxidation/corrosion. To a lesser degree, an edge can dull due to atomic migration, though from what I understand this is only noticeable on extremely fine edges over a long period of time.

It sounds like you guys take sharpening waaaay past that of most folks.

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Shadowex3

from the edge or flat?

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Cimarron29414

I learned my sharpening concepts from Alton Brown. Basically there are two kinds of dull. The first is that the blade is "sharp", but the edge is now wavy due to use. This can be resolved using the whet stones and sharpening rods. Basically, you are taking the waves out of the edge and getting it back to a straight line.

The second kind of dull is that the edge has been worn down flat. In this case, the whet stone or sharpening rod can not restore an edge and it must be professionally honed. This will remove steel from the blade and restore a sharp edge.

I don't know if this is true and that's all I have.

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Zeraph

So I got a nice little knife sharpener.
Smith's PP1 Pocket Pal Multifunction Sharpener

I've been sharpening my blade but its not quite getting sharp enough. It tends to leave a slightly rough edge to it (though it is sharper than before).

But the sharpener has a carbide, ceramic, and diamond rod sharpeners. I'm confused which I should start with and finish with. Also wondering if maybe its my own skill or if I should need to do it longer. I sharpened it for about 15 minutes. While its sharper it doesn't pass the 'cut through nail' test.

I started with the diamond rod, then the ceramic, then the carbide.

RogueGypsy

You dulled it after sharpening it, the ceramic should be the last step. Start with the Diamond, finish with the Ceramic. The Carbide is for serrated blades.

I find it easier to move the sharpener over the blade with this type of tool, so I'll explain the process as though that is what you are doing.

-Hold the knife in your 'weak' hand and the sharpener in your 'strong hand.

-Place the back of your weak hand on a table or the counter to steady it and hold the blade perpendicular to the table. If it's easier for you, you can hold the sharpener still and move the blade over it.

-Hold the sharpener against the blade at the desired angle. 20-23 deg is typical for kitchen and pocket knives. To find the angle of the blade, rock the sharpener on the edge to feel where it sits flat. There will be 2 angles ground on most knives. The first, nearest the spine, will be steeper, the second is the edge you want to sharpen . This is the hardest and most crucial part of sharpening any edge. KEEP THE ANGLE CONSISTENT. You can get an edge that will slice paper using a brick, if you keep the angle consistent. Once you can keep a consistent angle between the blade and sharpener, you can do what you want with your hands/sharpener/blade, making it easier to sharpen.

-Run the sharpener from the front bolster to the tip, or from tip to bolster, whichever is more comfortable, with the edge, (a thin sharpener like you have, makes it difficult to get a consistent edge when using it like a stone, going across the edge) using light pressure. No need to grind on the blade, you're just removing a little bit of steel to get the edge keen. I like to take 5 passes per side before alternating, Just make sure you make the same number of passes on each side, otherwise the blade may get sharp, but the edge will be off-center. It shouldn't take more than 10-20 passes per side if you keep the angle consistent. Don't stop until the blade is as sharp as you would like. Running your finger from the spine off the edge of the blade on each side, you should feel a slight catch. That's the Burr that forms when your two bevels have come together perfectly. Try the finger nail test, cutting paper/plastic wrap or shaving some hair. It helps to run the Ceramic over each side once first, to remove the Burr.

-Once you have the edge you're looking for, use the Ceramic to polish the edge. Keep the same angle and use the same technique as with the Diamond. Depending on how course the Diamond is you may have to work the Ceramic longer. Polishing the edge removes any burrs that have formed during sharpening and the polish helps the edge to wear less, lasting longer.


The key holding a consistent angle. Once you master that, sharpening will be quick and easy.

TL;DR: Use the Diamond at a consistent angle along the blade until a burr forms, then use the Ceramic at the same angle to remove the bur and polish the edge.


Once the blade is sharp, an occasional touch up with the Ceramic should keep it sharp for quite a while.

Using a stone/sand paper is much easier, but less portable. Just master the angle and you'll be doing fine.


I came across this on YouTube looking for something to help you visualize what I'm talking about, I almost spit coffee on my monitor when I saw him using a cinder block.



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Methods, application and intensity of application vary by the individual. All legal wavers must be signed before 'treatment' begins. Self 'Medicating' is not recommend. However, if necessary, it is best to have an 'assistant' or 'soft landing zone' nearby. Any and all legal issues resulting from improperly applied techniques should be forwarded to: Dewy, Cheatum & Howe, Intercourse, PA 17534. Attn: Anonymous.

Zeraph

Thanks. That helped. That let me get it sharp enough to cut paper with its own weight and start to cut my skin if I placed it on my arm and slowly moved it (stopped pretty quickly tho hehe). Still not sharp enough to shave with. I know its technically possible but it almost seems like an urban myth.

edit: just gave shaving with it a better try. Put shaving cream on and it did get some hairs. I could eventually shave my whole face with it. Hurts like a motherfucker though! heh

RogueGypsy

Shaving will take a little more work, you need to polish and strop the edge to get a clean shave. The Ceramic will get you most of the way there, but leather is what you need to for that last bit of polish.


To get it sharper spend more time honing it with the Ceramic until the Bevel is completely polished and smooth like a mirror. Look at the very edge of the blade, if you see any reflection or light at the edge, it's not sharp. When the edge is right, it looks like a dark line, no reflection.

It's really a lot easier with different grades of stone or with sand paper where you have more control with the grit. Right now your going from Diamond to Ceramic, which is like going from 100 grit to 4000 grit. It's going to take a lot of work with the Ceramic to get that edge to shave smoothly.

One trick I use when working with unfamiliar stones is to take a Sharpy or other permanent marker and cover the bevel you're sharpening. Make a few passes with the Ceramic, then look at the Bevel. You'll be able to see the marker in the scratches left by the Diamond that the Ceramic hasn't smoothed. Keep working the edge until the marker is gone.

Using a magnifying glass or jewelers loupe to see the edge better helps too. Keep working at it, it sounds like you're getting there.

You can also use a leather belt to strop the blade to razor edge. You can use it bare or add some jewelers rouge to make it go quicker.
When stropping you move the blade the opposite direction that you would with a stone. Instead of edge pushing into the stone, you drag the edge (at the same angle as your bevel) along the leather. If the blade is moving away from you, the edge should be toward you so it dragging along the leather instead of pushing into it. When you reach the end of a stroke, lift the blade, keeping the same angle. Your edge is going to be very fine at this point, so if you don't lift it off of the leather at the same or less of an angle, you will curl the edge and lose what you just worked to achieve.

If you don't have a leather belt or strap, cardboard will work. Watch the last step in that video, how he strops with the card board. Leather just works better.


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Methods, application and intensity of application vary by the individual. All legal wavers must be signed before 'treatment' begins. Self 'Medicating' is not recommend. However, if necessary, it is best to have an 'assistant' or 'soft landing zone' nearby. Any and all legal issues resulting from improperly applied techniques should be forwarded to: Dewy, Cheatum & Howe, Intercourse, PA 17534. Attn: Anonymous.

Shadowex3

Just remember depending on what you're using that knife for you might not want an edge that fine. Plus the angle you usually sharpen a knife at is a bit different from the angle a good shaving razor's sharpened at.

RogueGypsy told you pretty much everything you need to know but there is one nifty tip I learned from some straight razor fans that recycle old barbershop hones: Draw a grid on your block and then sand that against some sandpaper on a mirror (or other really flat surface). Lets you see whether your working surface really is flat or not.

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Zeraph

Wait, the edge should be dark?! How is that? I thought I was polishing it to a mirror finish?

RogueGypsy

The bevel is what you are polishing to a mirror finish. I may have transposed 'bevel' and 'edge' above. My bad.

The Bevel is the angle on each side that creates the edge when they come together. I like this polished, it slides through material easier as your cutting and it looks good.

The Edge is where the two bevels meet. It's what cuts. Unfortunately I can't explain it, but when the edge is right (very sharp) it does not reflect light. I like to think it's because it's so sharp it cuts light. But that's just me. More likely, the edge is so thin our eye just can't pick up any reflection, causing it to appear dark. I can usually see it looking at the side of the blade as well. A smooth polished line, leading toward the edge and thin dark strip.

Looking at you blade, edge on (directly at the edge), the left and right bevel should be shiny and between the two a thin dark line.


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Methods, application and intensity of application vary by the individual. All legal wavers must be signed before 'treatment' begins. Self 'Medicating' is not recommend. However, if necessary, it is best to have an 'assistant' or 'soft landing zone' nearby. Any and all legal issues resulting from improperly applied techniques should be forwarded to: Dewy, Cheatum & Howe, Intercourse, PA 17534. Attn: Anonymous.

Shadowex3

If you're getting a shiny edge that means you've probably got a wire edge or folded it over.

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Zeraph

Ahhhhh I get it, thanks.

KirStang

FWIW, a fellow sushi chef gave me a lead to this water stone:




I get a good wire edge out of POS $15 kitchen knives.

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