Re: Can\'t get shaving sharp with a lansky
Okey, Dokey, this will be a little long, but here we go...
I've been a user of the Lansky system for many years and have been able to get scary sharp edges on virtually any knife I've tried. Here's what I do:
Angelpoise has the first part correct -- mark the edge with a Sharpie marker. If the ink comes off at only the top or the bottom of the edge, you have not got the angle correct. If the ink comes off along the width of the edge completely (or close enough), write down the angle you are using for later reference. Not every knife has the same angle of grind. You need to establish the angle for each knife as it relates to the Lansky (or whatever system you're using). If the maker or manufacturer uses a 22.5 degree edge and the Lansky is set up for a 20 or 25 degree edge, you'll have to make the knife fit. The Lansky is not infinitely variable.
I use diamond hones. Yep, they are not as cheap as other hones, but they work faster. You can use any of their variety of hones. In fact, most of this will apply to any sharpening system, but since consistency is critical, use the Lansky. Remember, though, you really can take off too much metal, so pay attention to what you are doing.
Start with a coarse or extra coarse hone. Examine the edge of the hone under a bright light (Gee, where can we get one of those?). I use a jewelers loupe to get a close up view but some can "eyeball it" or use a magnifying glass. Check to be sure you are sharpening all the way down to the very edge. If not, keep going until you do. You need to establish the angle and that might mean taking off what seems like a bit more of the edge than you think. Be sure to hone the edge until you get the entire edge worked 'cause if you don't you won't ever get a sharp edge. This is where most people goof it up -- they aren't patient enough. You need to so this to get the edge established, but usually you only need to use as coarse a stone as this rarely after you do it the first time.
Once you have the edge coarse honed, just repeat with progressively finer hones. Examine the edge as you go along to be sure that you are still maintaining the same angle.
Check for a "wire edge" or a burr that forms when the knife edge seems to become very sharp. What often happens is that the edge rolls over, forming a wire edge/burr. This is very shrap but quite brittle. If the knife seems to go dull very quickly, this is probably what has happened. Get rid of the wire edge by backing off the angle slightly (move the hone up one slot) and very lightly run the hone along the edge on both sides to remove the burr. Remember, you need only very light pressure and only one or two strokes to do this. Continue to hone or finish by stroping with a strop or a flat piece of cardboard to polish the edge if desired.
YMMV, but I use a fine diamond hone and then an extra fine hone (1000 grit). I finish with a Sapphire stone (2000 grit). Then I strop the blade with a leather strop that I only occasionally charge with a yellow strop paste (you do not need much). This is for an extra sharp edge.
If you don't use a lot of slicing cuts (paper, tomatoes, and the like), but use push cuts (rope, cardboard, and so forth), you do not need as sharp an edge as this. If that's the case, you don't need more than a medium fine or fine stone.
Now, as to checking how sharp the edge is, do not try to shave hair or see if it will catch your fingerprints unless you want to use up a few bandaids or get a stitch or two. Paper that you hold loosely in your free hand is much less painful. It's one of those "Don't do what I do, do what I say" things.
Remember, for safety's sake, you only need a knife that is sharp enough to cut what you need to cut. Most of us are not surgeons.
Here's some more advice, learn to use a steel and/or a strop, and you will sharpen a lot less often. Frequently knives need to have the edge realigned, and not resharpened. Why grind away your knife blade if you don't need to?
Hope this helps.
