Honing and Sharpening - The Difference

Hi, I used to wonder what the difference between honing a knife and sharpening a knife was.  I have a good idea now so I will pass it along.
This is important because a lot of folks tell me that "their husbands sharpen the knives at home" so out of curiosity I always ask how he does it. Most of the time the response is "with one of those sharpening rods"

So to get things straight right off the bat,  a "Steel" does not sharpen a knife, regardless of the fact that it may be advertised as a knife sharpener. A Steel, whether it is made of steel, or ceramic is designed to hone a knife and is for edge maintenance.

Honing

Honing or steeling will keep a sharp knife sharp for a period of time, one cannot say how long but I can say that the knife will stay sharper if it is steeled. A new or freshly sharpened knife has a series of micro serrations along the edge. Invisible but they are there and they bite into whatever it is your cutting. Over time, these tiny teeth are pushed over to the side, the edge of the metal is fragile and the metal along this point (the edge of the edge) gets fatigued and just folds over. A hone or steel when used properly as in the picture here will push that fatigued metal back into place.

There are some key points to this though. 
1. You need to begin the process with a sharp knife, you CANNOT pull a dull knife out of the drawer and hone it sharp, even if you have the best steel or ceramic in the world. 
2 You need to do this often, build it into your cooking regime, do it every day before you cut your food. So keep the steel handy, not somewhere you need to root around for it.
3. The steel that comes with a block of knives is usually very cheap, not worth the effort, get a new one.
4. Honing or Steeling only works for a while, once the knife remains dull after you steel it, i.e. if it doesn't feel any different, put the steel away, it is time for it to be Sharpened. 
5. Do not abuse the edge with over steeling, it doesn't do anything but make it more difficult to sharpen.
6. This is an important step in knife maintenance but it is not done by a lot of people. It is easy to do  and only takes 2 minutes. You only need to run the knife down the steel from heel to tip 5-8 times with a little pressure, ease off on the pressure the last couple of times.


So what is sharpening?:

Sharpening on a whetstone

To sharpen a knife, you need to remove that fatigued metal completely and expose the fresh steel underneath. A whetstone is the best way to do this, it doesn't take off much metal and can restore the edge to the factory level easily and with a little more effort you can make it sharper than that.

So Honing is knife maintenance, keeping a sharp knife sharp, sharpening is the removal of metal from both sides of the blade at the edge of the edge. 

Once is it is sharp it can be honed again until the cycle needs to be repeated.

Now there are diamond steels that claim to sharpen a knife by removing metal but again, that will only remove metal at the primary edge, what about the secondary bevel?  You can purchase a whetstone for 30 dollars and keep your knife sharp for a life time.

Now....it is possible to use a high grit stone to hone your knife by using a trailing motion like the picture above but the best setup is a good steel or even better a Ceramic rod and a whetstone or two.

Shapton Glass

You gotta love SHAPTON :)

Another older knife, well used and love Buck.  Took a great edge and polish

Let's go hunting

Every now and then I get a hunting knife to do, or 3 and often, they are in rough shape.

I can sharpen a dull kitchen knife in 15-20 minutes but hunting knives are a different kettle of fish altogether, an hour at least is what I am looking at.
It's a stormy day here in Halifax so I thought I would take some work in progress shots and some final pictures of a very old and hunting knife with some serious damage to the edge. In fact, I think at one point the from 1.5 inches of this knife may have been serrated.

So here we go, a really cool little knife, I think this one has a very high carbon content, carbon is cool, I love carbon knives.

Very old but very loved knife, very dark in colour, scratched up (battle scars) and very dull.

Diamond Plates

The first step was to re-establish the bevels and edge. I used the Edge Pro Professional for this job, it excels on these type of knives. The one on the right is an Atoma 140 grit diamond stone, the larger one is a DMT extra course, 220 grit, these are specially cut to fit the Edge Pro and are fabulous at the heavy lifting portion of the sharpening process. While it is possible to get the knife sharp with these, my goal was to establish a new edge. I chose an angle of 20 degrees, and all the work was done at exactly 20 degrees from start to finish, 70 minutes later.

New Edge cut in, ready to move to the water stones.

Latte 400

Now the fun starts, the idea is to maintain a constant angle which the Edge Pro forces me to do, now with the Latte 400, a really nice stone, I can begin to remove the deep scratches left by the diamond plates. This will start the sharpening process too, I had marked the edge of the edge with a sharpie to ensure I was on target.

From the 400 Latte, I went to the Edge Pro 220 stone, it is just a matter of patience and constantly checking the scratch pattern. I wasn't just going for a sharp knife, I wanted a mirror like finish to really give it that pop. It's an enjoyable process watching the metal transform from it's original completely dull and severely scratched/damaged edge into what I hope it to be at the end.

The knife is sharp know, easily slicing telephone book paper, now to continue the refinement of the edge and move up in grit from the 140 to the exquisite Shapton Pro 15,000 grit stone.

Now I can see it becoming a much more refined edge, it is very sharp now and I could have stopped the process anytime, this is overkill but we love overkill. This is enjoyable. This knife deserves the attention.

15K Shapton, it doesn't get much better than this when talking Japanese Water Stones

(You can see all the stones I used here, 12 in total)

This is final stone in the process. 

It is hard taking pictures of the edge, the light doesn't do me any favours but you can see here that the bevel has a nice polish now. It looks like liquid in certain lighting conditions. 

After this, the final step was to strop the knife, I used a balsa strop laden with a diamond spray to put the final touch.

All done.

During the process, I put some dish soap, just a drop on the stones, it helps a little when trying  to achieve a mirror finish. This knife was sharpened at 20 degrees up to 15,000 grit and stropped with a 75,000 grit spray on balsa.  

I'm hoping the owner will be pleased. 

Let's get more Acute

Hi,
We know that Japanese knives and now some European knives come from the factory with acute angles of 15-18 degrees per side. Most of the European knives we buy such as the majority of the Henckels lineup come at 20 deg and some brands of knives can have an angle as high as 25 deg per side.
So what is the big deal, what's the problem with that you may ask:

There is no real problem, the reason that many knives you buy come with a 20 deg angle is that they (makers) know that the steel in the knife is not hard enough to support a more acute angle.  The edge of a knife is very thin, that is what makes it sharp, if the edge of that knife is composed of soft steel, it only makes sense that it will not hold up to much abuse.

What is soft steel and how the heck can steel be soft in the first place?

The steel in knife is measured on scale of hardness, the Rockwell Hardness Scale,  if you see a number like HRC 56 on your knife that is a medium hardness and very common. Now even one digit higher or lower on that scale represents a significant difference, so a less expensive knife have a hardness of 54 which is relatively soft, even if it is steel. Now Japanese hand made knives, the full carbon knives can have a hardness of 62-64 which is a very significant and the steel is extremely hard.

So if you have a "hard" knife it can be sharpened at very acute angles and stay sharp for a longer period of time, there is no way to say how long...it's just longer and it makes sense.

Japanese Nakiri - Full Carbon knife, very hard , 12 deg per side.

So can we sharpen a soft knife at 15 degrees per side?

Certainly, we can sharpen it at 7 deg and it will have an incredibly sharp edge. HOWEVER, that edge will fail very quickly, on day one even, the first time it cuts anything.

Basically, unless you have a knife that is 60-65 on the scale of hardness, you don't want to go below 15 deg per side, it just won't hold it's edge.  Also, keep in mind that there is price to pay for these very hard knives, they are brittle and can chip easily. If you dropped a 500 dollar Japanese carbon knife it could chip, the tip could break off or it could snap in half.  If you drop a 50 dollar Henckels, it will probably just make a mark on the floor or nothing at all, unless you bent the tip.

Acute is good if the steel can handle it, otherwise, keep it at 19 degrees.

Henckels at 19 degrees

Wusthof at 10 degrees - Edge Life Expectancy - 15 minutes