V. Knife sharpening – Practical Application tips & tricks

1. Determining the Angle

Sharpie black marker

Sharpie black marker

Remember that one of the most important parts of sharpening a blade is to make sure that you are doing so at the correct angle?  You can very easily determine if you are holding the knife at the right angle with the use of a ‘magic’ marker.  Just mark the edge of your blade with the magic marker and then make a pass or two at the stone with your knife.  An exact match would mean that your marker ink will be scraped off entirely from the bevel.  If only the ink at the tip is gone, then your angle is too high.  If the area where the primary and secondary bevels meet is the only area that does not have ink, then your angle is too low.

 

Another way to do this is to use direct light.  Put a strong light above the blade as it is lying on the stone.  Tilt the blade forward (this means pulling the spine away from the stone) and watch the shadow under the blade.  When the shadow disappears, you have your angle.

For those who prefer freehand, the thumb can be used as a guide.  Just put the thumb on the spine of the blade to make sure it is consistent.  It is often more difficult to keep the consistency of the angle when handling curved blades, and this often helps.

When sharpening your knife, you do not really need to maintain the edge or angle that it came with.  Remember that you are using the knife, and if the factory angle is not as sharp as you want it to be, you can lower the angle to your liking.

2. Keeping the Sharpness

One aspect of sharpening that boggles people’s minds is the length of time that a knife can remain sharp.  Although satisfied with their job after sharpening, a few uses would suddenly render the knife dull.  When this happens, one or more of the following factors may be at play:

i.            The Wire Edge – as mentioned earlier, this is the burr that masks as the knife-edge.  The burr turns downward and makes the blade extremely sharp to the touch.  This, however, snaps off after a few uses and leaves a dull edge in its place.  To avoid this, lighten your touch towards the end of your sharpening session to make sure that the burr is gone.

ii.            A Thin, Weak Edge – sometimes we want a razor sharp edge and we make the bevel angle really low.  This might give us a sharp edge, but it would also be a weak edge that could snap after a few uses.  Make sure that your angle is strong enough to give the tip enough support.  Double grinding would also help.

iii.            Edge turning – this happens if your blade has a thin edge that is thick enough to support itself.  If it is too thin, the edge will break.  A little thicker, the edge would turn to the right or left.  This is simply resolved by using the steel on your knife.  Unfortunately, you can’t see if the edge has turned with just the naked eye, so it can only be proven with the constant use of the steel, or if you could magnify the edge of a knife several times over.

iv.            Thick edge – this does not happen frequently, though it can still be an option.  Sometimes the angle of sharpening is a bit too high, and this would cause the blade to feel dull very quickly.  If you decide to change the angle of sharpening, you may end up with a more fragile blade though, so be careful what you decide to do.  This is not the problem most of the time though, so you may want to check the other solutions first before changing the angle of your sharpening.

v.            Soft Steel – when a blade goes dull really fast, it can also be a mistake in the heat-treating.  However, manufacturers nowadays are very precise with their procedures that this rarely happens.  If your blade goes dull quickly, try the above mentioned solutions first.  If that doesn’t work, then maybe you can contact the manufacturer.  They are often very open to feedback regarding their products.

 

3. Keeping the Edge Centered

There are times during the knife sharpening process when you find the edge is a bit off center.  Though it is sharp, it is not as aesthetically pleasing and not as precise as you want it to be.  This happens because of the burr method of sharpening.  One side is sharpened until the burr is formed, then the same treatment is done to the other side.  However when you process on the second side is done, the bevel on the first side is already markedly thinner.

To avoid this, you can use a method that allows you to switch sides.  If you start off sharpening the right side and notice that this is now the thinner side, the next time sharpening is done just start with the left side.  This should even things out.

As a personal practice, I do not wait for the burr to form on just a single side.  I sharpen a side for 20 seconds then check for the burr.  If none is found, I switch sides and do it for the same amount of time.  I do this repetitively until I find the burr, and then continue the sharpening process.  The fact that I flip between sides helps keep bevels on both sides even.

4. Putting it all together

As you continue your journey of using knives and sharpening them, you would see that there would be changes in how you approach the subject.  A lot of people nowadays seem to be gravitating towards the use of the thinnest edge that will not chip and break with frequent use.  And that does make sense.

Thin blades with low angle edges seem to cut best, and that is because of the amount of metal that is going through what is being cut.  Imagine a thick 25 degrees of metal slicing through rope.  It would take a lot more pressure to push that amount of metal through as opposed to a thinner blade.  The only thing you have to consider is how thin you can go.  If you plan to use your blade for soft materials, then you can go for a thinner degree.  If a certain knife is to be used for harder objects, then the edge would have to have stronger support when cutting.  Creating a secondary bevel may help.  If you are sharpening at 15 degrees, then create a secondary bevel by doing some light strokes at 24 degrees.

Coarse versus polished?  It really depends on what you plan to do with your blade.  Coarse edges would slice well, but polished ones would cut faster (such as when shaving).  If you plan to push-cut with your knife, consider polishing the blade a little bit more.  If you only plan to slice more though but always go for the finer grits, try ending with one of the coarser ones.  You might find yourself working with your knife at a faster pace.

Use the steel more often, because it seems to be working well for my knives.  The more you steel, the more aligned your edges get and that keeps them at optimal shape.  Remember to do this frequently though, because if your edge is misaligned and you are unable to use the steel as you continue to use the knife, the damage would worsen until you will have to re-sharpen the blade once again.

Stay Sharp Luc

 

 

 

 

 

 

 

 

 

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2 comments on “V. Knife sharpening – Practical Application tips & tricks
  1. Geof says:

    Great stuff here. As always, it’s good to hear from you – thanks for all your articles recently…
    Cheers
    Geof

  2. Peter says:

    Interesting read. All I have to do now is to put it into practice.

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