The Edge of Retention

Ready for Flattening

As a sharpener for other peoples knives, my challenge is not getting the knives sharp, it is keeping them sharp. In fact, that is an all consuming issue as I strive to keep people from having to return more than 3 times a year for sharpening. Of course, there are people who see it as an annual event, i.e. getting their knives sharpened professionally.
Hats off to them, the majority sadly enough do it once in a lifetime if at all.

The real issue is doing restaurant knives, the "house knives" which are inexpensive and often abused knives. When I say abused, I just mean that often, the people using them don't own them so they are not prone to caring for them the way we do our own personal knives.

SO how do I keep those sharp in a professional kitchen for a month at least?

Well after years of experimenting and reading I have what I think is my best solution but the bottom line there is no magic trick to keep them sharp for more than a few months.

The problem I am having is this:

I turn in ten razor sharp knives to a restaurant. I don't see what happens after that but I know that they are steeled with poor steels using poor steeling habits. Steeling in fact for me is a bit of an issue. I spend a lot of time working on a precisely formed edge, as precise as I can make it with my hands. Years of working on this has enabled me to get a nice edge but I just don't see how slamming that edge against a steel is going to do anything but destroy it.

My biggest issue therefore with restaurant knives is that despite my best efforts. it is possible that the edges I turn in on day one are gone on day two.  (I have given up trying to talk to people about steeling and I am almost to the point where I give up restaurant house knives)

Back to edge retention:

Imanishi 220

I am finding that a nice strong clean edge built on a foundation of coarse stones is not only allowing to get the knives sharper than I have ever seen but I am finding that they are staying sharp longer.

Here is what I do. (Remember that I am starting with knives that have gone dull, the edge has failed and metal has to go)

(I will explain how this could help you too though later)

I strive to get the job done, i.e. from dull to very sharp with three stones consisting of 2 coarse and one medium stone.

I use a 400 and I make sure that the knife is sharp, as I have stated in previous posts, I spend the majority of time on this first stone and I get the job done with variances in pressure. By the time I am finished, and I am using weight of the blade pressure with the 400, the knife is sharp enough to be handed back and put on the line. Patience is key here and having a stone that you enjoy using will help a lot. (The stone in the picture above, the 220 Imanishi is not one that I enjoy, so I don' t use it, I have decided to sell it. I have to like I use so I use another 220 when I need one, the Naniwa)

The Chosera 400 is one that  I love. 

Now after the 400, I could go right to the 2k Naniwa Atoshi or  Chosera 2k and finish there. However what I do next is take out my Naniwa Professional 600 and repeat the process. Now it doesn't take long, the edge is already set, there is nothing to fix just a little more CR (Coarse Refinement) and again I use the Moderate/Light/Zero pressure pattern that I like.

NOW the edge is awesomely sharp and strong and now I finish on the Green Brick of Ecstasy and again I use the same pressure pattern but this is a quick job. I finish with trailing strokes (stropping) and that is it.  The edge is polished but there are still lots of teeth there and most importantly the edge is strong, able to handle some abuse for 4 weeks or one day dependant on the steeling.
I would prefer that the steels stay hidden and the edge fail naturally, not assisted by someone who thinks he/she is helping.

So the key is a nice strong edge and and edge that fails on it's own time.


NOW, how the heck does this help the average sharpener the guy/girl who sharpens their own knives only. Why do you need a coarse stone if you are going to be keeping your knives sharp with your beloved 1,000 grit stone?

If you use your 1k stone often enough I suppose you don't need a coarse stone. However, what if you had a 600 or even 800 grit stone to supplement your 1k. Would that not help build a stronger edge and save some wear and tear on your 1k stone?

What if you just let the edge go a little longer than normal and think " I wish I had something just a little coarser". Or what if you get a little nick in the edge.

In my opinion, it couldn't hurt  but if you are on a budget the 1k is good enough if you are vigilant, if you keep an eye your edges and keep them sharp and that means working on them weekly. Now by working on them I just mean some light trailing strokes, stropping them for a minute or two to keep that edge nice and clean. Get rid of any metal the succumbed to the pressure and got tired out and decided to roll over. Do it a favour and remove it with that stone.

Clean edges are key.

If you have a higher grit stone, the Suehiro 5k for example, that is fine to use as well, perhaps you could use that as your HONE, to keep your knives pristine. Then, every now and then use the 1k to get a little deeper into that edge.
I always think of a knife edge as a "V" formed by thousands of layers of steel. My job is to peel off the outer layer and expose the new layer underneath. The top one did it's job, it's time to discard it.

Dull knife owners don't do this, they just keep punishing their knives and  their food.


I really hope you go something from this. Know that these tidbits are founded on actual experiments with monitored results. The idea comes to life then I get the cooks involved or anyone else for that matter.

As I started off this post, making it sharp is the easy part, keeping it that way is not so easy but it's enjoyable trying to solve the riddle of edge retention.

Peter