high spot + hello

T

Tommy93

Joined
Jan 26, 2017
Messages
7
Hi guys i'm brought to the blade forum seeking advice i'm currently a serving chef and well feeding up to 2000 people my knives get used ALOT! so i also sharpen them with a steel and a lansky sharpening system once in a while. i'm also currently awaiting a TSPROF K02 if i ever get emailed back to pay and have it sent to me!

so my problem i have is a high spot in 3 or 4 of my most used knives, my question is what is the best way to deal with this problem, taking from the heel or from the belly, tip and point! here are some pictures, many thanks in advance for taking the time to read and help me with the issue!

Tom.

s18gld.jpg

2da0ugj.jpg

2wqwp5l.jpg

33lfo14.jpg
 
Looks like you're using extra pressure right in that area. Also with the guided lansky, the angle is not true as you move along the edge. Basically the angle is decreasing as you get towards the point, so that ends up with a greater angle at the "high spot" from the bevel being ground more aggressively there over time.
 
The easiest and fastest way to correct this issue is to take your coarsest stone and grind the protruding edge FLAT against the stone. Taking care to only really grind down the heel. You will only be removing material.
Once it is all lined up with the current edge, and the protrusion is removed, you have to resharpen the edge.

Take a straight edge and mark the height of the current cutting edge to the back of the heel so you know how much material has to come off to get a straight cutting edge. By doing this, you will remove the offending material the quickest.
 
I just watched 2 videos on youtube by repair shops regarding your issue. You need a completely flat surface to stand you knife on its edge then put a light behind it and you will see light between the surface and your knives edge exposing the area that has the belly, don't remove any of the heel. Take a marker and mark the area that needs to be removed to end up with a straight blade from the heel forward. Go back and forth until you have a completely flat blade from the heel forward.
 
Tommy93 said:
2da0ugj.jpg
Click to expand...
In this pic, you can see that your sharpening system isn't hitting the heel of the blade, as evidenced by the scratch going up the flat.
Due to this, you aren't sharpening the heel, and the last 1" or so, isn't being beveled as the front portion of the blade.

I would like to see a pic of how you mount your knife (this particular one) in your system. This way maybe we can help prevent this from happening again.

cash71 said:
I just watched 2 videos on youtube by repair shops regarding your issue. You need a completely flat surface to stand you knife on its edge then put a light behind it and you will see light between the surface and your knives edge exposing the area that has the belly, don't remove any of the heel. Take a marker and mark the area that needs to be removed to end up with a straight blade from the heel forward. Go back and forth until you have a completely flat blade from the heel forward.
Click to expand...

So you want him to have the heel to remain proud of the current edge and taper the edge grind up to meet the belly?

This would remove A Lot of the cutting edge and reduce the life of the knives while changing the cutting geometry, cutting edges presentation to the object being cut as well as widening the blades primary bevel making the knife perform more poorly due to being thicker behind the edge.
 
Forget the sharpener and get a new set of knives, after all this is bladeforums not sharpenerforums ;) But seriously I had the same thing happen with my kitchen knife, but not as bad as yours. I had to take it to my grinder to remove the extra material at the heel. But there is still the issue of the "return" it is the thick area of the bolster that goes all the way down to the heel of the blade. You will have to get rid of that because it will lift the sharpening stone off the heel of the blade.
 
ahh i've been looking at the miyabi knives that don't have that heal, problem is i use the knives up to 10 hours per day chopping and i have huge hands so i have to have a big handle! so picking knives is a nightmare :P
 
That high spot (recurve) is known to be a result of heavy use of honing rods ('steels') on kitchen knives, as it removes more metal in the areas as shown in your pics, near the heel of the blade. The additional complication in fixing it, is the integral bolster behind the affected area, which prevents the rear portion of the edge from making contact on the cutting surface. As long as that bolster is in the way, it'll continue to be a problem. Others who've dealt with this problem have 'fixed' it by grinding down the bolster behind the heel, so it's no longer lower than the lowest portion of the cutting edge. After getting the bolster out of the way, the edge itself must be ground straight & flat again to eliminate the recurve; that's usually done by grinding off the cutting edge with the blade held as if slicing (vertically into) the stone, then the bevels restored and sharpened. Much more easily done on a bench stone. Grinding all that steel away will take a very, very long time to do with the Lansky setup, using it's very small hones.

The narrow Lansky hones can also lead to further exagerating the 'recurved' portion of the blade, in overgrinding that portion with the narrow hones, trying to get it sharp again. I used to use a Lansky system, and had that issue with some of my knives. This is another reason a larger (therefore wider) bench stone will do a better job in resetting the edge correctly.


David
 
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NJBillK said:
The easiest and fastest way to correct this issue is to take your coarsest stone and grind the protruding edge FLAT against the stone. Taking care to only really grind down the heel. You will only be removing material.
Once it is all lined up with the current edge, and the protrusion is removed, you have to resharpen the edge.

Take a straight edge and mark the height of the current cutting edge to the back of the heel so you know how much material has to come off to get a straight cutting edge. By doing this, you will remove the offending material the quickest.
Click to expand...

This ^

Is best to use a belt grinder and roll the edge back and forth so you get a nice curve, or even a bench grinder can make short work of this job - apply water often to the steel with a sponge if it can't be easily dipped. Once the bolster is ground back you'll want to thin out the steel right at the plunge line or just leave it with an unsharpened bit just above the bolster. Or it can be done on a coarse stone.

That 9cm Wusthof might be ready for the bin, the rest look like an "easy" fix.
 
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