Knife sharpening

I know that many people love the Shape(?) and Kevin Tan just mentioned the DMT Aligner Kit, which sounds very interesting in light of Joe's comment on using a 15% angle on M2 steel. Would someone help to educate me further on the whole subject? I am not a novice and use a plate glass/wet paper system finishing w/ a green paper, 10,000 (?)grit, with a Veitas alignment guage for sharpening my chisels. I've actually been finishing with a power strop and getting a razor sharp edge but want to replace the power strop. That all being said I have a hard time putting a consistent edge on my knives, especially the heal and tip of my smaller ones.

Thanks

Man, theres all kinds of schools of thought on this. I have a slew of knifes, but I suck at sharpening, and I've tried lots of jigs and such. If I had the where-with-all, I'd invest in one of the cardboard wheel systems, like the Dunn's. However, mostly I rely on sharpening steels to keep my edges up-to-snuff, and I much prefer a carbon blade, you can keep the stainless, thanks. If they get to dull, I struggle with the stones to get them back to where the steel will work. Big difference in sharpening steels too. The best, in my opinion, are the ones made by F. ****. Some folks rave about the diamond steels, but I've never owned one.

Diamonds. Yeah.

My brother bought a diamond stone a while ago when he got his first Benchmade. I thought I'd check it out for him, since he's not as good with a stone as I am. I grabbed an old SAK from my tacklebox and ran it across a few times. I looked at the blade and saw that familiar bead of dust on the blade. I went to wipe it off on my jeans and sliced neatly through the denim. On the backstroke, not trying to cut at all. I was really impressed, if not slightly scared waiting for the blood to start flowing. .

As it was explained to me way back when in cooking school, a diamond stone or steel is just a very fine grit sharpener. Steels, such as the F. **** are magnatized rods that do not sharpen per se, but finsih the sharpening of a stone by aligning the microscopic metal fibers into a unified edge.

When cutting these fibers are the first to dull and a couple licks with the magnetic steel regularly when cutting will keep your knife sharp much longer. Also, the reason to avoid acids on your knife is because they remove these fibers and you must take the blade to a stone to renew them. You can still have a sharp knife without the fine metal fibers, just not as sharp.

I am interested in these cardboard wheel systems. Never seen one. I've always sharpened my knives on a commercial kitchen tri-stone.

Greg

nethiker: Definitely right about diamond "steels" -- they're just straight, fine sharpeners.

Not quite right on smooth steels. Smooth steels aren't magnetized, and don't work by aligning metal "fibers" (steel is crystalline in structure, not fibrous) on a microscopic scale. However, smooth steels are a great tool to have. They accomplish their work on a macroscopic level: as a knife is used, the blade edge indents, impacts, and gets mis-aligned. Often, especially in something like a kitchen knife, which typically uses very soft steel, the edge is still "sharp", but doesn't feel sharp because the soft edge has been pushed and impacted so that it no longer points straight down. A smooth steel smooths the edge back out and aligns it so it's pointing straight down again ... not through magnetics, but by mechanically re-aligning the edge against the metal steel.

Each time you steel and re-align the edge, the edge weakens a little bit, and eventually you'll need to re-sharpen again. But steeling, especially with soft steels as found on commercial kitchen knives, can really increase the time between sharpenings. It works on harder steels too, just not quite as dramatically.

Joe

The easiest sharpeners are the ones like Lansky and Gatco make. You secure the blade into a clamp, and move the stone in it's preset angle. Very hard to mess that up, but a bit too slow for me. I like he the Spyderco Sharpmaker 204. Very easy to use. Easier to get different angles on each side than the Gatco or Lansky, but not easy. Just keep the blade perpendicular to the table. If I can get a hair shaving edge with one, then just about anybody can use it. MUCH easier than trying to a flat benchstone, and it will sharpen the harder steels as well.

I was not thrilled with the Lansky system, frankly, for one main reason> Unless you have a reference point to attach the jig in EXACTLY the same place on the blade each and every time, you end up recutting the angle every time. On smaller blades it's easier to keep that location. If you are a fan of the big blades(like me), it's more difficult. Also, on at at least one of my blades, the Lansky will not reach the whole edge without being moved. It's a BIG blade, a George Tichbourne Bowie. Depending on which directions the jig location is off by, it causes more work, and removes more metal. I like the subtle tolerance a steel provides.

The Dunn sharpening system is shown/described at: http://www.dunnknives.com/serv01.htm

He is really the first to get a complete system "out there" and somewhat commonly available. However, the same system, in kind of a "bare bones" configuration is also available from somebody else, whose name I can't recall, but it's talked about in some detail at BladeForums.com
Be forewarned, that forum is to knives what this one is to lights. Theres LOTS of info, so you will have to do some digging. The biggest difference, between the two systems is simply that the Dunn outfit is complete with motor and ready to go, while the other system requires that you have, or obtain, an 8" grinder to mount the wheels on. If I can dig up a link I will post it.
By the way, I am in no way related to Mr. Dunn and have no vested interest in his business, I'm just another KnifeKnut! And I HATE a dull knife!

The first trick is to sharpen at a precise angle -- 15/30 degrees for really good steels, such as S30V, and 20/40 for lesser steels, such as 420 or 440A.

The second trick to to sharpen until you raise a burr, which is a very, very fine wire edge that bends over slightly on the opposite side of the blade edge that you are stoning.

With a dull knife, you go through a progression of coarse, medium and fine stones, raising a burr each time and gradually taking that burr off by switching sides of the blade edge using less and less pressure. Don't keep sharpening after you raise the burr because you are just wasting steel.

If the edge is already sharp, you can use a Spyderco Sharpmaker. But the trick here is to have the right angle on your blade. The sharp maker has a 15/30 degree angle and a 20/40 degree angle (20 degrees for one side of the edge and 40 degrees for the combined angle of the edge). If your blade edge has a different angle, the Sharpmaker won't find it.

To see if your sharpening angle matches the blade edge angle, paint the edge of your blade with a magic marker and then take one light pass with the stone in a fixed-angle sharpening system, such as the Lansky, EdgePro or Sharpmaker (ceramic rods). The stone will scrape off the magic marker and you can see whether the sharpening angle is correct. If not, change angles on the sharpening system or reprofile the blade to the angle you want.

The Sharpmaker is nice for quick sharpening to keep the edge in shape. But it takes forever to reprofile, so use one of the other fixed-angle systems and match the angle to what the Sharpmaker can handle (15/30 or 20/40).

Some people will to an initial bevel of 15/30 degrees and then a secondary bevel of 20/40 for a sharp blade that is a little stronger.

For a super sharp edge, use a strop system.

A Lansky or, better yet, an EdgePro Apex, will keep a good angle and quickly reprofile the edge or re-establish a dulled or damaged profile.

Josey

Having used a variety of systems for quite a number of years, I gotta say I use the Lansky most often, but as it has been said above, it isn't my first choice for big knives. I consider a knife with a blade over 6" as a big knife. Anything under that and a Lansky works great. I have not used an Apex system, but I'd sure like to give it a whirl.

Josey has it right for sharpening small knives. I'll add this (and somewhere there's another thread with this same info) -- if you use a marker to blacken the edge of the blade and then very lightly run it across the hone, you can get a good indication of whether or not the angle is correct. How? Well, if the angle isn't right, you will either take the ink off just the very tip of the edge (and then the angle is too steep) or off the back of the edge (and then the angle is too shallow). If the ink is removed from the entire edge of the blade, ya got it right, Bucko!

The most important thing about sharpening a knife is to keep the angle consistant throughout sharpening. That is the number one reason why most people cannot get a sharp edge. Lansky, Apex, Catco, and other systems do that for you, and that's why they are so successful. Now, sharpening developes a very fine edge that is usually very brittle. Taken to an extreme, this edge can become a "wire edge," wire thin and extremely sharp, but curled over and fragile. It breaks off easily. Therefore, if you find that you are sharpening often but your knives go dull rapidly, this is probably what's going on. The good news is that it is easy to detect and easy to get rid of.

After you've put an edge on a knife, very (very!) carefully and very lightly run your thumbnail down the width of the blade (from spine to edge). If you feel the edge catch your thumbnail as it crosses the edge, you have a wire edge, since the edge has curled over. Think about it -- your nail can only catch if the edge has wired out since a proper edge should let your nail slide right off. Get rid of the wire edge by increasing the angle and very lightly run the knife over the hone. That should remove the portion of the edge that has curled over.

Now, how sharp do you want your knife? How fine should your hones be? Should you use a strop? All that depends on what you are going to cut. Cutting rope and cardboard a lot? Maybe you don't want to go for a super fine hone and stroping. Scary sharp edges are only good for fine slicing or shaving. A "working edge" that isn't so extremely sharp will last longer for heavy cutting. Working knives usually do not have thin edges and very shallow angles. If you are slicing tomatoes or cutting out newspaper articles or the like, maybe it's time to go for the finer hones and stroping.

How do you test an edge to see if it's sharp? A lot of folks shave the hair off their arm, but this is dangerous and more of a macho thing. Plus, it is a real good way to draw some blood. Don't ask how I know. Another method is to lightly run the edge over your thumbnail -- if it catches with no pressure, it is sharp! This is also not a very safe method. Again, don't ask how I know it's not safe. Safest method is to take a piece of paper about 6" long and hold it in one hand while lightly trying to cut it while it hangs free. If you can cut a free hanging piece of paper, you have a sharp edge.

Final thought -- sharpening knives and testing the edges can be a dangerous thing to do. Pay attention and don't try to show off. One little goof can mess up your whole day.

I use a spyderco sharpmaker on all kinds of steels (S30V,VG10, ATS 134, 154CM, M2, D2....) and have had excellent results on sebenzas, MOD, Microtech, spyderco, BM, .... and so on. The apex system is a also another good syster but takes longer to set up than the spyderco. Just my $0.02


Ryan

I have a CRKT slide sharp arriving today. Looks like a variation on the Spyderco in that it has the stone straight up and down, and the blade fits a jig to hold an angle.
I'll let you know how it works once it arrives.

This site provides a lot of good basic info on sharpening;
http://users.ameritech.net/knives/index.htm
sharpening can be as addictive as lights /ubbthreads/images/graemlins/rant.gif

Josey is exactly rite I learned the craft from my grandfather who's living was a knife and tool sharpener. what a knife or tool is used for determines the edge angle ground onto it, maintaining that angle as best you can while sharpening will speed the process. My Gandpa always said to try and carve a slice from the stone while drawing the blade from handle or heel to tip with even pressure if a tip required more work then the body of the blade start at the tip and put the tip onto the stone push it while rotating the edge from tip to body just the opposite of normal sharpening. this keeps from wearing a belly in the body of the blade trying to sharpen the tip more. turn the edge toward you in good light and look for bright spots bright shinny spots on the edge are dull. I have moved from a set of stoned to diamond sharpening blocks in extra course, Course, Medium, Fine and I finish with a ceramic rod. IMO its best to keep your edge maintained while in use as apposed to waiting till it wont cut anything to sharpen it. I keep a small ceramic rod with my while hunting, fishing and even at work to keep my edge touched up.

If you have tons of time, patience, and want picture perfect edges, get a wicked edge system, not cheap but it a competent sharpener.

If you prefer quick, try wet stones.

I've tried all kinds of sharpeners, strops, stones, and dmt type stuff.

I like stones.
I use a 1000 grit for initial sharpening, once sharp, all it takes is about 30 seconds to hone back to skin splitting sharpness.

I like easy and scary sharp.
I wish I had the luxury of stropping my knives for hours on end, even though they make hair popping edges, who needs hair popping edges if it dulls after a few uses??

MrJino said:

I like stones.
I use a 1000 grit for initial sharpening, once sharp, all it takes is about 30 seconds to hone back to skin splitting sharpness.

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I always wondered why water stones came in so many grits yet oil stone only in three, coarse/medium/fine. They are the same abrasive, aluminum oxide, just held together with different binders.

Not sure either, but I'll never use oil stones!

MrJino said:

Not sure either, but I'll never use oil stones!

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Why? If it's the mess of the oil that turns you off know you can use them with water, I do and they work fine. I've even read some use them dry.

They're also cheaper then water stones and last longer due to the binder, although I understand the quick breakdown of the water stone is what makes them so quick/efficient. Tempted to try them but they look messy, and pricey.

P_A_S_1 said:

Why? If it's the mess of the oil that turns you off know you can use them with water, I do and they work fine. I've even read some use them dry.

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It's a huge mess.

I can sharpen and polish my knives in under a minute, with oil, I'd take almost an hour. Avoid oil!