Does air dull knives?

It depends on the hardness and wear resistance of the steel. For example if I sharpen an Opinel on a rod I can very easily just push the edge to one side or the other as the steel is soft. This will produce an edge which is very sharp on the side, it shaves very well, but it dead dull on the other side. You basically have just created a hook like on a scraper.

The worst combination is a very soft steel with a high wear resistance, like 55 RC 440V. The steel demands a high pressure to cut into the carbides, however the steel is so soft it will burr and flop very readily. A high wear resistance has to be combined with a high hardness to allow sharpening to a fine finish with minimal effort.

You can go as heavy as you want during the initial shaping, however once you get down to sharpening, no more than 5-10 strokes at maximum, use enough pressure to get the necessary honing action, but no more. You also want abrasives that are very aggressive so make sure they are freshly cleaned and not clogged.

-Cliff
 
When using any sharpening rig, the pressure you use should decrease as you progress with each grit. STart hard with the coarse stones and as you are enaring the end of using those stones, lighten the pressure. WHen you switch to the white stones, use moderate pressure and lighten up as you go.


Here's a tip when steeling (see my earlier post and Cliff's latest one on this thread for more info on this)always steel before you are going to use your knife, not after. When you steel your knife and then put it away, the knife's edge will deform back to it's original, less sharp position.

Japanese Chef's sharpen their knives every day- kinda makes sense if you always want the sharpest edge! Sharpen before each day of use.
 
Originally posted by Doug Selsor
I swear the same thing about any of CRKT's AUS6 stuff.

Doug
Click to expand...

OMG! I was never sure I was really observing what I thought I was: I have a CRKT Neck Peck and I would get it razor-sharp and put it into the neck sheath, wear it around but NOT USE IT, and I'd take it out and it would no longer cut skin on my finger as it did when I first put it there sharpened.

I think, though, that was Lavan is experiencing is the folding or blunting of a wire edge. That could explain why the knife is sharp when put away, but comes out of the sheath dull, or is dull after the first use. Some knives rattle in their sheaths, and I have noticed that many sheaths fail to keep the knife held so that the edge is suspended inside without touching anything. Makes me kinda paranoid that my knives' edges are dulling just from the action of insertion into and removal from the sheaths.

Lavan, when you have finished sharpening, bring the blade close to your face, edge away from you, looking down at the side of the blade at a 45 degree angle. Hold a blue LED flashlight (like an Innova Photon II) above the blade sorta near your temple. Tilt the blade a bit back and forth to see if you catch a reflection of the blue light in a tiny line at the edge of the blade. It will typically appear on the side of the blade opposite the last one you stroked on your stone. This "wire edge" can make your knife feel very sharp, but it is illusory since it is a weak wafer of metal that will break, bend or flatten on use of the blade. You'll be left thinking that somehow your knife just went dull really quickly.

The trick to sharpening seems to be to do it increasingly gently as you near finishing. By the end, a wire edge indicates that you have made both bevels meet at an edge, and a thin strip of metal kind of has nowhere to go. You then need to get very light in your strokes, sometimes slightly increasing your grinding angle (lifting the spine of the blade a little higher off the stone), and switch side to side frequently, to remove this "burr" without simply pushing it to the other side. EXTREME GENTLENESS is required. Take my word for it -- I usually spend the better part of an HOUR or TWO per knife, just removing the burr and assuring myself it's really gone. I even bought a jeweler's loupe to examine my edges.

Keep at it. Read the sharpening FAQ here and you'll know all you need to know. Good luck!
 
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