II. Knife sharpening – understanding the baisics

How do I get a sharp edge?

Let’s have a quick overview of the sharpening process.  If some parts of this are confusing, you may look through “The Razor Edge Book of Sharpening”.  Other items will be further clarified later in this short guide.

knife sharpening the burr

knife sharpening the burr

When you grind, start with one side first as this will not get you to a full tip.  You must grind until you feel a “burr” or a wire on the opposite edge of the side that you are grinding.  When a burr forms, it means that you have ground the steel all the way to the edge, and that the tip is so thin that it is “spilling over” to the other side of the knife.  This is a critical part of the procedure because if you do not get to create the burr, then your knife will not be as sharp as it could be.  Once you are able to feel the burr, then you can flip the knife over and repeat the grinding process on the other side.

!Take note that some people might advise to count the strokes before flipping the knife over.  No number of strokes will be able to guarantee the appearance of the burr.  What you really need to do is feel for the burr before turning the knife and sharpening from the other side.

Once the burr is formed from both sides (of course it will not be retained on the side that you just sharpened), you can now switch to finer stones.  The goal is to make the edge smooth and remove the burr.  This time, you will need to alternate sides as you stroke from edge to tip of the blade.  You can switch to a finer stone each time.

Do be careful of edges that seem extremely sharp.  Sometimes the burr is directly downward, which would give you an idea that the edge is extremely sharp. However, this is really just a burr that is called a “wire edge”.  This will break the first time that you use it.  If you have really sharp knives that dull very quickly, you might be experiencing this.  To avoid this, you might want to try double grinding, and then give the knife a quick stropping once you are done.  Also, when you are almost done with sharpening the knife, make the last strokes lighter so that you could avoid raising another burr.

knife sharpening stone

knife sharpening stone

For the stones, I use a 300 or 400 grit if I see that the knife I’m about to sharpen is rather worn down.  Once satisfied with the edge of the blade, I move on to a finer stone, perhaps one with a 600 grit.  For finer blades, the 1200 grit might be the last stone to give its final edge.  On a personal note, I do not like waiting until my blade is fully dull before starting the sharpening process.  This allows me to start with one of the finer stones, and not the 300 – 400 grit that I usually use.

 

 

I also prefer to use a leather strop (like this one on the right side)

leather strop

leather strop

This principle holds true to all sharpening systems.  Take, for example, a V-type blade.  Sharpening could be started on the right hand side until a burr is seen.  Once it is felt, then a switch to the left side could be done until a burr forms once again.  Once the burr has been raised from both sides could the instructions of the manufacturer be applied, and an alternate sharpening mode can be done.

What about the angle?

Knife sharpening angle

Knife sharpening angle

The angle plays a huge role in the sharpness and the strength of the blade.  If the angle were small, it would make the blade feel really sharp.  However, this would also mean that there would be less steel behind the blade, and the sharpness would quickly vanish from the blade after a few uses.  To give you an idea, a surgeon’s blade would have a thin, low angled sharp edge while an axe would have a an edge with a high angle.

The angle of a razor blade would be around 12 degrees, and since it is chisel ground, your final angle would be 12 degrees.  On the other hand, regular knives would have two angles: 15 degrees to 24 degrees on either side, meaning the blade would vary from 30 to 48 degrees.  Whatever blades you are using though, do not concentrate on what the angle should be.  Instead, be sure to be consistent in holding the blade at the chosen angle.

Further information can be found in the sections regarding convex edges and chisel ground edges.

 

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