Sharpening a lopsided blade

T

Twindog

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When my Ti-Lite became dull, I had no luck sharpening it. So I painted the edge with a magic marker and saw that the Lansky stone was not hitting the edge of the right side of the blade.

My idea was to sharpen the blade first at 20 degrees per side and then finally sharpen it at 25 degrees per side.

I'm at the point where I have a good, narrow edge at 20 degrees on the left side, but the right side edge (width of the edge being ground) is about three times as wide as the left side and the stone overshoots (misses) the actual blade edge by as much as 1/16th of an inch.

I'm not sure where to go from here. Do I keep grinding the right edge until the stone will actually start sharpening it? or do I need to have the edge professionally re-profiled?

Thanks for any help -- Josey
 
I have had this happen too. My lansky had a bent clamp which caused this.

Also, depending on how the knife is clamped to the angles on the face of the blade, the angle can be different on either side.

Try doing only one side at a time until you get the profile you want (use the lower angle side.)
 
Thanks, Klattman:

I checked my Lansky and the clamp is a perfect 90 degrees, and the angle on both sides of the blade is identical.

The Ti-Lite has a spot where the seam down the middle of the blade meets the break for the upper false edge, so I have a good reference spot for the clamp. And even turning the clamp around, leaves the same problem: the right side edge angle is way steeper than the left's.

In order to sharpen the edge on the right side, I have to raise the angle to 30 degrees. I suppose I could sharpen both sides to 30 degees, but that seems like too much angle for a knife blade.

On the other hand, I will have to remove an awful lot of Aus8A to get the right side down to 20 degrees.

Josey
 
Well basically if you are sure all of your angles are correct you need to make a choice. You can take the time to grind down both sides to the same 20 degree angle, which would give the best edge. Or you could take the easy way out and just hit the very edge of the blade with the 30 degree angle. This will give a more obtuse edge that won't cut as well, and will eventually require you to remove more material anyway, but it will be quicker now.

I would suggest just spending the time to do it right the first time out, and grind down to 20 degrees per side. There are some things that you can do to speed up the process. First you could get some extra coarse diamond stones for the Lansky system. You could also buy a coarse diamond bench stone or coarse stone and start grinding away at about the angle you want to end up with. The process of removing material to get to the edge can be a bit rough and doesn't need to be a precise angle. Doing it freehand will give a knife with more scratches, but probably get you there faster. Using the Lansky with a diamond rod will give better looking results, as you will only grind to the point that will actually be on the edge.

Also read the Razor Edge Book of Sharpening, it goes into great detail on how to get the perfect edge.
 
Twindog said:
Thanks, Klattman:

I checked my Lansky and the clamp is a perfect 90 degrees, and the angle on both sides of the blade is identical.

The Ti-Lite has a spot where the seam down the middle of the blade meets the break for the upper false edge, so I have a good reference spot for the clamp. And even turning the clamp around, leaves the same problem: the right side edge angle is way steeper than the left's.

In order to sharpen the edge on the right side, I have to raise the angle to 30 degrees. I suppose I could sharpen both sides to 30 degees, but that seems like too much angle for a knife blade.

On the other hand, I will have to remove an awful lot of Aus8A to get the right side down to 20 degrees.

Josey
Click to expand...

Sounds familiar, I had the same problem with a number of blades. (I actually bent the clamp trying to hold onto very narrow blades). So it is your blade. In that case, since flipping the clamp doesn't work, I would suggest doing the 20 degree bevel freehand (raise a burr on one side, then the other) and putting a final edge bevel on with the lansky. Find the angles that correspond on either side.

Technique is not so important if you are just back-bevelling.
 
Thanks ErikD and Klattman:

I tried freehanding with an extra course diamond stone, but it's not going to work. Now that I'm looking more carefully, I can see that the grind of the blade is not symmetrical. Must have been a mistake at the factory.

I think I'm going to have to sharpen it at a steep angle on one side (30 degrees) and a lower angle (20 degrees) on the other side. It'll probably be OK.

Thanks for the help.
 
Just to close this out, I did sharpen one side to 30 degrees and the other to 20, and it is razor sharp. The magic-marker is really the trick. With a lopsided blade, I couldn't sharpen it because the stone was not hitting the actual edge.
 
Twindog said:
... Must have been a mistake at the factory.
...
.
Click to expand...

This may be a part of the design? I am not familiar with your knife, but I have a few slipjoints that the blades are purposefully 'crinked' or off center. You just have to be aware of that to sharpen them...

Anyway, I'm glad you got it performing again.
 
G'day,
I use a clamp system like the Lansky and have found this problem on many knives--including a Sebenza. Your case does sound extreme though.
I usually 'bite the bullet' and do the re-profiling, often having to grind the correctly-angled side quite a bit if the edges are lop-sided as well as having different bevels.
But then I'm compulsive about good bevels and sharp edges!
Greg
 
This is something I have a problem with, are there any sharpening instructions out there for idiots? I've watched several people do it for me, including my father, two of my friends and a retailer. I use a stone, I'm thinking about getting a rod for serrations, because those are starting to go dull. Thanks.
 
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