Hi Phil, I know it's a pain with the Lansky because you have to keep moving the clamp, but what you could try is grind in a more obtuse primary edge. In other words, sharpen then at whatever angle you're using (say it's 17º), then go back and grind in a 21º edge. The 17ºwould be your secondary edge, and the 21º would be the primary edge.
If your knives are getting dull too fast, it means you're sharpening them at too acute of an angle for the quality of the steel or the job you're doing with them. You could also try steeling the knife with a smooth steel before and after each use.
The steel in the Forschners is relatively soft and might not be a big improvement over what you already have.
Here's some info from the
Sharpening FAQ
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A frequent complaint I hear is, "I sharpened my knife and did a good job, it was really sharp. But then after just a few uses it went dull." Why does this happen?
One of the following factors -- and many times a combination of those factors -- is at play:
1. Wire edge
If the burr is not properly ground off, but is instead turned downwards, your knife will feel razor sharp. However, the burr quickly turns or snaps off, leaving you with a very dull-feeling knife. Be sure to use a light touch at the end of the sharpening process and make sure the burr is gone.
2. Thin, weak edge
If the bevel angle you chose for your knife is too thin for your usage, the edge can chip and get really wavy. Try using a larger edge angle, or at least double-grinding the edge.
3. Edge turning
In regular use, all edges turn to some extent. If your edge is much too thin, it will be damaged as above in #2. If it's only slightly too thin, it will quickly turn out. As long as the
the edge is not being damaged, but simply turning, you don't necessarily need to re-grind a thicker edge. Instead, see if frequent steeling will give you the performance you need, it can really work wonders. Keep in mind it's difficult to see a turned-out edge by eyeball -- only using the steel will tell you conclusively if this is your problem.
4. Thick edge
A thin edge will feel sharper than a thick edge. If your edge
is too thick, when it starts to dull even the slightest bit it
may no longer feel so sharp anymore. Consider using a lower angle and seeing if that helps. Of course, your thinner edge will be more fragile than the thicker edge, so you may end up chipping the edge out, and the thinner edge may not be feasible. I personally feel that this is rarely the real problem, so be sure to try the other solutions first.
5. Soft steel
Occasionally, a manufacturer or maker will make a mistake while heat treating, and the steel in the blade will end up too soft. No matter how well you sharpen, your blade will still go dull quickly. Often, soft steel is the first thing people point at when their edges dull quicker than expected. But this problem really is relatively rare; in the vast majority of cases, it is one of the above reasons rather than soft steel that's the problem. So if your edge dulls too fast, don't blame the steel until you've exhausted the above options. If it's still dulling quickly, contact the manufacturer, they are often interested in testing to see if they made a mistake.
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