Removing too much material

MikeC

MikeC

Joined
Sep 16, 2005
Messages
1,364
In one of my post on general knife discussion, several people mentioned proper sharpening whereby the minimal amount of material is removed to acquire a sharp edge.

I use a lansky diamond sharpening system, not the greatest but I like it. Am I messing up by sharpening with this type of system? Is this removing too much material? What sharpening methods or techinques should be avoided in order to not remove too much material? Also what methods or techinques should be utilized so to remove only the minimal amount of material required to achieve a sharp edge?

Thanks in advance
 
think of it this way; you have x amount of material to remove to sharpen your knife, how long do you want this process to take? diamonds will do this faster then most other methods, so beyond this is mostly knoledge & technique.
 
Hi, Mike. IMO it's important to check your progress regularly when sharpening. That way you can tell when you've done what's necessary -- for example, raising a burr -- and also avoid removing more metal (and doing more work) than you need to.

Many people use a Lansky or similar sharpening device, as well as diamond stones, so I'm sure there's nothing to worry about there. Just use good judgment, watch your progress and don't get carried away. Actually I think most folks have the opposite problem, getting impatient before they've done enough work to where the edge bevels totally meet, so I would guess it's unlikely you're overdoing it.
 
I agree with DOW most people don't remove enough. I wouldn't worry that your grinding off too much with a Lansky. If you have been useing a powered grinder maybe it would be a problem, but it rarely is with hand sharpening.
 
It depends on how much, and to what, you are using your knife = how often do you need to sharpen your knife.

Then, it depends on how dull you let your knife to be before sharpening. Your edge look like this when it is sharp: V When it is dull it look like this: U To get a U- shape to a V-shape you need to take away some material from the edge. Lets say 0,5 mm steel.

In my mind, it is better to sharpen before the edge gets dull = maintenance sharpening = you sharpen very little, just slide the sharpener along the edge 3-4 times on each side. This take away about 1-2/1000 parts of a mm from the edge = you can do this 250 times compare to 1 grinding.

Scandinavian knifes (belt knifes) have secondary bevel. This secondary bevel is about 2-3 tens of a mm wide = when you can se it, stop grinding. When you sharpen your knife, it is the secondary bevel you sharpen. When you sharpen it, it will be wider and wider for every sharpening you do. In the end it will be about 6 tens of a mm wide – and your knife feels dull what ever you do with it. That is the time to grind the first bevel until that the secondary bevel is back to 2-3 tens of a mm. Then your knife is sharp again. After that you start to sharpen the secondary bevel again and so on.

The secondary bevel shall have 1-3 degrees higher angle then the first bevel. Let’s say that you have 10 degree on the first bevel. Use then 2 degree more for the secondary bevel = 12 degrees). Then you use your knife as usual. If the knife work as you like it to do, and the edge holds 10 times longer then before – keep that angle. If you like your knife to be sharper, go down to 1,5 or 1 degree. If you like to have an edge who stay sharp longer, go up to 2,5 or 3 degrees.

The secondary bevels angle is a personal thing. You “balance” the secondary bevel for just your way of using your knife – and your needs.

Doing this together with maintenance sharpening, you take away very little material from the blade.

Thomas
 
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