Knife sharpening question

Posted by: ScouterMan

Knife sharpening question - 10/19/07 06:06 PM

I have read a lot of posts here regarding knife selection, and a common theme I read is the ability to sharpen a knife properly will make or break a knife.
I am pretty bare bones about this, using a Fiskars ceramic rod sharpener. I find it easy to use, as I have always had a hard time maintaining the correct blade angle to get a “proper” edge.
My questions then would be, “What IS proper sharpening technique? What should I be doing to improve my sharpening technique?”
Posted by: Ors

Re: Knife sharpening question - 10/19/07 06:26 PM

I think the angle depends on the knife. I've asked similar questions, and I'll pass on what was suggested to me. Get a couple of inexpensive Moras to practice your technique with. This is especially important if you have an expensive knife that you want to protect, and not ruin. Color the cutting edge with permenant marker. This way you can see if the angle you are using is removing the metal or not. If the marker is still there when you're done, you haven't sharpened the knife. There are books and videos that give step by step instructions, though the names escape me now...one book..."How To Sharpen Everything" or something like that.

The main thing is to just practice! One of my favorite sayings is, "If you have to think about it, you don't know it well enough". Of course I don't recommend shutting off the brain while working with sharp metal objects, but I think you get the point.

Good Luck!
Posted by: billym

Re: Knife sharpening question - 10/19/07 07:04 PM

If you don't mind the variation of freehand sharpening buy a few low priced blades or practice with a well worn user that you have. Now just keep practicing and focusing on how you hold the blade against the stone. Your edge will not be as "neat" as the factory edge but still sharp.
I was always able to get a sharp edge freehand but I like the neatness of the edge when maintained by a Tri-angle Sharpmaker from Spyderco. This gives most users a very consistent and razor sharp edge. With the Sharpmaker's ceramic rods it is best to sharpen regualry. If a knife gets really dull the ceramic rods with take a long time to have an effect.

Some use a black tipped marker to black out the actual edge so when freehand sharpening they can see where they are contacting the stones.
Bill
Posted by: raydarkhorse

Re: Knife sharpening question - 10/19/07 10:36 PM

your angle is going to be dependent on the type of knife and what your goint to use it for. I find that for most of my knives is between 22 and 25 degrees works best.
Posted by: Hookpunch

Re: Knife sharpening question - 10/19/07 11:11 PM

I have tried ceramic, diamond and waterstones. Without a doubt waterstones will get your knife sharper than any other method. I suggest a 1000 grit stone. This will sharpen your sport knives and kitchen knives the best once you learn how to use them.

The only drawback about it is that you will need to invest in a stone flattener, or perhaps a 12" by 12" tile and 220 grit sandpaper to flatten out the stone.

In the field though the best choice is a diamond sharpener. I suggest the DMT monocrystalline type, they last longer.
Posted by: ssbauer

Re: Knife sharpening question - 10/20/07 12:28 AM

I like Scandi grinds because it is easy for me to maintain the angle and sharpen them in the field. Typically, I use a diamond sharpener in credit card size.

When at home, I like the simplicity of a Spyderco Sharpmaker. Quick and easy...

However, I convex my axes and machetes using sandpaper and a mouse pad. Since this is not diffcult and creates a sturdy edge, I have recently begun to convex some knife blades also. After the initial pain of getting them in the right shape, I can pretty much maintain them using a strop.
Posted by: KenK

Re: Knife sharpening question - 10/20/07 01:11 AM

The Spyderco Sharpmaker is a wonderful system. I used a similar system made by Smith, but the Spyderco Sharpmaker allows me to choose between a 20 degree or 15 degree angle. I also purchased a set of diamond rods for it which work well if I need to reprofile a blade. My days of using a free stone were left behind back in the '70s when I got the Smith ceramic rod set.
Posted by: Frankie

Re: Knife sharpening question - 10/20/07 01:41 AM

For in the field I'm considering the type of honing stone used by Ray Mears and Michel Blomgren, a diamond on one side and fine ceramic on the other:

http://www.fallkniven.com/misc/eng-sharp.htm

If you need your knife to shave wood for fire making for example, the best is the sabre grind (3 on the diagram, as found on Mora knives) or else it's more awkward to use a secondary micro bevel. This grind will shave wood basically like a chisel. The secondary bevels are used to keep the edge sharp for a longer time while not having to remove too much metal, in a kitchen for example but you will need a specialized system to maintain the right angle. But the advantage of the single wide sabre grind of the scandinavian blades is that it's easier to maintain the angle obviously.



Theoretically, there's 5 stages in sharpening:

1. coarse, removing material; (not always needed)
2. Medium, polishing; (around 400 grit)
3. Fine, polishing; (around 600 grit)
4. Hone, polishing; usually you start using ceramic at this stage. A bathroom or kitchen ceramic tile will do the job.
5. Strop, to remove the burr and reconfigurate the angle like a microscopic convex grind. You can use your leather belt.

Theoretically, you have to triple the number of strokes you used at each stage. For example, if you took 10 strokes at the medium stage, you'll need 30 strokes at the fine stage, 90 strokes at the hone and so on.

You may start by experimenting with wet & dry sandpaper sticked on a board (with carpet tape for example) and then you'll know more what to buy as a specialized tool.

Frankie
Posted by: OldBaldGuy

Re: Knife sharpening question - 10/20/07 02:07 AM

Two easy ways, at least in my opinion, to sharpen a knife are the convex edge, obtained by placing wet/dry sandpaper on a mousepad, and drawing the blade, spine first, across the paper. The mousepad under the sandpaper pretty much takes care of any bevel problems, and the Lansky sharpening system. It allows you to chose the bevel you want, and holds it for you...
Posted by: Stretch

Re: Knife sharpening question - 10/20/07 01:51 PM

I have a Lansky, which works ok, but I like the SHarpmaker best. It's probably a mastery thing...I haven't spent enough time playing with the Lansky.

I agree with Raydarkhorse....22 to 25 degrees (or 25 to 30 for me), but most knives will come from the factory ground between 25 and 40 degrees. Even knives ground at 40 degrees and above will cut just fine and get razor sharp if you like that angle.

Like someone said, you can use a Sharpie black marker to color the edge, then after a few light strokes on the stone you'll know pretty much what your edge angle is.

I never used a Fiskars ceramic system, so advice on technique is not for me. The biggest problem in any sharpening system, I think, is not sharpening the edge. Usually we're sharpening the "shoulder of the edge" and not the edge itself. Sharpie marker helps there.
Posted by: KenK

Re: Knife sharpening question - 10/20/07 08:34 PM

I wish Spyderco would make a mini-Sharpmaker with two medium grit half-length sticks that would slide inside a plastic base that is setup with both 30 degree and 40 degree holes.
Posted by: Anonymous

Re: Knife sharpening question - 10/21/07 12:28 PM

What's close is the Smith's 3in1 sharpener. It's the same style as the Sharpmaker but it's smaller.

Unfortunately it only has the white sticks. It does however have a 750 grit diamond surface and a v-notch carbide sharpener.
Posted by: dchinell

Re: Knife sharpening question - 10/22/07 06:18 PM

For a more portable field kit, I can recommend the AG Russell Field Sharpener rig.

It has a pair of diamond rods and a pair of 400 grit brown ceramic rods. These are 4 inches long and 1/4 inch in diameter.

The angle is 15 degrees (30 degrees compound) which corresponds to the "back-bevel" slots on the sharpmaker. If you keep your knives that sharp you're set. Otherwise, you can put the final touch on the 20 degree (40 degree compound) edge freehand.

Bear