Sunday, 9 September 2018

Edge Retention - Powerless

Hi folks,
     The topic of edge retention is one that has been swirling around on various knife sharpening forums for many many years, it is a topic that I don't will ever end because there are no finite solutions, no magic formula exists to increase the life of an edge. Please remember, these are my opinions only, I'm basing what I say on years of experience, a decade of trying to figure it all out and I have finally reached a place where I no longer lie awake at night thinking about it, believe me, I've done that.




   The reality is that as a knife sharpener, I have three duties that I should fulfil, tasks that will have my customers come to me for a sharpening service as few times as possible, to widen the gap between a full sharpening, to increase edge retention.  Now a knife owner has many more responsibilities than I do and there are also some things that we can't control. The steel the knife is made of, I can't change that and yet it is the key factor to consider, the quality, the hardness of the steel that the knife is made of greatly influences edge retention. (I will talk about my responsibilities later in this article)

   Here is the confusing parts, parts that I find confusing that is. We often hear the terms "polished edge" and "toothy edge" but what does this have to do with how long a knife stays sharp, I don't fully understand the science behind it but I will do my best to explain.

    On one hand, we have folks, smart people who are convinced that a toothy edge on a knife will last longer than a polished edge.  I don't know the answer but I don't think it has anything to do with the actual toothy edge (1,000 grit edge for example) as opposed to a 6,000 grit edge. Why would an edge that is not fully refined, a toothy edge, stay sharp longer and is it actually sharper or does it just "feel" sharper.?



This is not a toothy edge, it's just a picture of a knife I worked on. We can't see a toothy edge with our naked eye.

Some people say a toothy edge lasts longer, some don't agree and will polish the edge with no fear of it impacting edge retention, in fact they do it to enhance edge retention.

     Also,  are we talking about all knives or just the average, "soft" knives, knives with a hardness of 54-56, which encompasses a whole whack of knives. And hard knives, 60-67, especially all those dream knives that fall in the range of 63-64, what difference does it make if they have an 8,000 grit edge, which many do, they still have great edge retention.?

     Here are my thoughts on the matter, this is the way I solved the problem for myself. I have come to realize that a sharpener is almost powerless in his or her efforts to completely solve the edge retention issue, to make it go away because as I said there are only three things that I can do to promote good ER (Edge Retention) and yes I will mention them later on.






     I do not understand why a toothy edge retains its edge longer and I am not saying it does. What I do believe is that a soft knife, if over refined, in other words, if I sharpened it up to 6,000 grit for example can experience a poor ER. This is because the area behind the edge, the secondary bevel, the area that supports the primary edge is reduced in width over time, with repeated sharpening which in effect is weakening the primary edge.  There was a study by a group of engineers that determined this.

Here is the problem that I have with all of this:

    Let's say we had 20 identical knives and sharpened 10 of them to 5,000 grit and 10 to 1,000 grit. Then, we cut the identical food products, or something until the edge failed. We did this with both sets of knives and then, maybe, we could see results that would lead us to believe that the 1k edge did indeed last longer.

     This is all fine in a laboratory type of environment but once a knife leaves my hand, who knows how it will be treated. where it will be stored, how it will be washed and what type of cutting board will it be hitting on day to day basis. How will the knife be maintained, what type of Steel does the owner use, if any and is the owner have skill with a Steel or he is just slapping the knife against it and removing the established edge? (I remember bringing a freshly sharpened knife into a chef, it was extremely sharp and the first thing he did was use it open a heavy plastic wrapped cut of meat, that 30 seconds took the edge off.)

(Don't worry, I will provide what I think is the best edge in terms of sharpness and edge retention.)




  Now from a physics point of view, a polished edge will not only slice better but will have improved edge retention. According to the author Chad Ward in his awesome book An Edge in the Kitchen:
He writes about Force equalling pressure over area and an edge 1,000 of an inch thick and one pound of pressure concentrates 1,000 pounds of pressure per square inch at the edge. On the other hand, a toothy edge is like a fine row of needles with each point coming under pressure, so these individual points are on their own and wear down and roll over. You cannot argue the science here. I am just telling you what he wrote, I didn't write it but I have to agree with it.

We are talking about kitchen knives here cutting food, not an edge designed to cut rope and cardboard.


Here are the three things that I can do as a sharpener to help with edge retention.

Number 3:

Sharpen the knife at an angle that is appropriate for the given knife. I sharpen hard knives between 10 and 15 deg per side and I sharpen soft knives between 15-20 degrees.

Number 2: 

Finish the knife at the right grit, although the overall impact on edge retention is minimal in my opinion, when you consider the guy cutting a plastic bag open, whether I finished the knife at 1,000 or 2,000 grit is insignificant in terms of edge retention when you consider that the knife could be used on the wrong cutting board or chucked in a drawer. I finish soft knives anywhere from 1,000 to 3, 000 grit and hard knives can go up to 8,000.

NUMBER 1  
The most important thing that I can do is EDUCATE people, tell them what not to do with their knives and manage their expectations when it comes to how long the knife will stay sharp.


     In my opinion, the best way to keep a knife sharp is to ensure that it is thin behind the edge and the edge is clean when finished. This thinning reduces friction, a knife edge is under constant siege, it is subjected to a lot of pressure every day as it slices through a huge variety of products and then comes in contact with the cutting board.



 All that I can do is sharpen the knife to the absolute best of my ability keeping the rule number 2 and 3 in mind and then help folks understand that the edge is a microscopically thin strip of metal and it will fail eventually, so treat it with respect.


Peter






Saturday, 1 September 2018

Controlling Space

Hi Folks,
     I know that my articles are not as frequent as they were but I am running out of things to talk about, I don't want to write something just for the sake of writing it. I want to wait until I find a subject that I think, and hope will be useful and interesting.

    To that end, this article is about finding a sharpening angle and learning to maintain that angle and once you can do that, everything gets easier, and sharper.

   Years ago I fretted about choosing the right angle to sharpen a knife at. I was afraid chefs would know that I sharpened their knife at a different angle than they were used to. That worrying was all for nothing, thousands of knives later and a decade passing by, not one chef has commented on angles, they never will.

    There is a simple method to find a good sharpening angle that you can use to start your sharpening journey, the PINKY ANGLE. (You can continue your sharpening journey with this angle as well)

(I saw this on a video by Shun, I didn't come up with it but I have used it to teach many novices)




    All you need to do is place the tip of your pinky between the spine and stone and you will create an angle of about 16 deg, it's approximate but it's good enough. Remember, it's not the actual angle, it's the ability to maintain that angle, whether it is 15 deg or 17. 5 deg, your goal is to be able to keep that angle stable, to control the space between the spine of the knife and the stone. You control that space and sharpness follows.

    Once your muscles have adapted to this angle, once muscle memory has been achieved,  than you can easily manipulate that space to arrive at and maintain different angles. I only use two angle so sharpen at, a Dream Knife angle of about 12 deg per side and an Average Knife Angle of about 19 deg but again, sharpening your knives, all of them at the pinky angle is fine, use to to build muscle memory.


   



    Learning to sharpen a knife by hand isn't difficult but it is not easy, if it was, everyone would do it.
The process itself is easy to learn. The hard part is actually committing yourself to practising, to creating muscle memory.  You need to learn to control that space, sharp knives are inevitable after that.

Manage your expectations though, we all learn at different rates. 

Always remember the four Pillars

Passion,
Practice,
Patience, and
Persistence.

Peter










Wednesday, 8 August 2018

Back to the Basics

Long time no see.

This article is all about helping novice sharpeners start their journey the right way, I didn't myself but I've learnt much since those days. First of all, it's important to know what is NOT important at the moment and in some cases, never that important.



     It's all so vital to know that to be a successful sharpener and that just means making a dull knife a knife that can be used again, a knife that slices whatever it is you're cutting rather than tear at it. You need to make a knife a pleasure to use again, and that is not too difficult.

    I am very frequently asked what the best stones to use are, a fair question of course but know that if you just starting out, and perhaps experiencing a little difficulty, having the best stones in the world, if there is such a thing, is not going to help.

   For now, forget about things you may hear like :
- What is the best grit to finish a European knife,
- What is the best angle to sharpen a knife at for cutting vegetables;
- What is best, a toothy or polished edge;

These are things that having nothing to do with learning to sharpen and these topics can be discarded.

I will answer them quickly here so we can forget about them.
- Whatever grit  you want but between 1,000 and 3,000 will work nicely
- You don't need specific angles for specific items, learn one angle at first.
- Not important, there is no right answer, the best edge is a CLEAN edge,  free of any remaining burr.


  Don't get hung up on the brands of water stones, you can start with a 1,000 King stone for $30.00. You will learn to develop muscle memory and consistency on this stone as well as any other stone. In fact, until you build muscle memory, you won't appreciate the feedback and results you obtain from various stones, they may all feel the same.



    The most important thing to know about knife sharpening are the fundamentals, an understanding of what it is that you need to do. With this knowledge, it's pretty much just practicing and as boring as that MAY sound, it is the key. There are no quick tricks to learn, you just need to practice until your body gets used to the new motions of sharpening and those muscles necessary for sharpening start to develop.


   Angles: Just use one angle at first, remember that all kitchen knives are sharpened between 10 and 20 degrees basically so why not split it, why not sharpen your "learning stages knives" at 17 deg per side for example.  I suggest using your pinky to find the right angle, your pinky isn't changing shape so if you put  your pinky between the stone and the spine of the knife you will get an angle of 16-18 deg, depending on the width of your pinky. Experiment with it and did you know that there is an angle guide on your iPhone.(Swipe left while on the compass App and experiment with that)

 
   I think we can place the art of knife sharpening under two broad categories, BURR FORMATION and BURR REMOVAL and I have said this many times in previous articles I know.
If  you have watched the Sharpening School Videos on Knifeplanet.net, everything you need to know will be demonstrated and talked about.  They are easy to find and are linked on my website.

Sharpening School


To summarize:

Don't get hung up on everything you read on knife Forums and on YouTube. Find a video that you like and stick with it and then get down to building muscle memory and in turn, confidence.

You will have problems of course, we all do so when it happens, just slow down and focus and be patient. If you are not having fun, put the knife down for a while.

Don't hesitate to email me if you have questions.
sharpenerpeter@gmail.com



Peter

Thanks for sticking around.










Sunday, 24 June 2018

My final Knifeplanet Video

Final Video

Lesson Six is the final lesson from me and it is simply an attempt on my part to help folks realize that the basic fundamentals are easy to pick up. It is not that hard to make a dull knife sharp with some practice and knowledge. You will always be improving but to break through the barrier, if you stumbled upon one, is entirely possible.



The most important lessons I learned were from mistakes that I made and many of the mistakes were generated by me listening and trusting everything I read and saw about sharpening. I ran into people just trying to sell me things without taking the time to explain that I didn't really need a 15,000 grit stone, a 320 grit would have been and is much more beneficial.

There are several techniques that work, the trick is to find one that you enjoy using and can easily repeat over and over and of course it does the job of burr formation and burr removal.

Peter


Sunday, 3 June 2018

Fundamentals - So Important


Hi folks,

I get a lot of emails from people experiencing problems when they start to sharpen. Typically, the edge is not that sharp or seems to get dull again after being sharp, during the sharpening process and edge retention is poor.

There are two issues here, the edge retention issue can be put aside, once you can effectively sharpen a knife, edge retention is not something that should stop you from using your knife, you will be able to fix that.

Here is what I normally tell people who are experiencing problems learning to sharpen.

Slow down, start from scratch and that begins with an understanding of the fundamentals.

FUNDAMENTALS:


     Understand that the objective, the purpose of knife sharpening is to make a knife that no longer functions in a kitchen, function again, and to be able to do that repeatedly.  That is all there is to the objective and you don't need the knife to be absolutely razor sharp to do that, you need to get it to a point where it can penetrate a tomato skin easily, effortlessly.  That ability comes with an understanding of the fundamentals.

     When a knife is no longer sharp, the primary edge, a very thin line running from heel to tip is no longer a thin line running from heel to tip, it is broken line, parts of the edge have folded over as a result of metal fatigue and this is perfectly normal.  Sharpening involves re-establishing that primary edge by sharpening the knife at a certain angle on both sides on a whetstone until the two sides meet at the Apex. The more precisely you can do this the more refined that primary edge is until eventually it is microscopically thin and quite sharp.

     You need to be able to hold an angle relatively stable, the exact angle is not as important as your ability to keep it steady as you sharpen, on BOTH sides, which is not easy at first.

Knife sharpening in my opinion falls under just two broad categories:

             BURR FORMATION and BURR REMOVAL

     Everything we do when we sharpen is moving us towards achieving these goals. Our goal is not to make the knife so sharp that it will slice the top of a tomato without holding the tomato, our goal, our immediate goal is to build Sharpening Muscle Memory in order for us to sharpen at a chosen angle and keep that angle steady, consistent.


    Keep the process simple, you don't 20 water stones, you just need a few at the most.

You don't see me getting all hung up on water stones.
:)



     Seriously though, just 2 or 3 stones is all you need and until you become pretty good at sharpening, i..e you have the basics down and you can your knives nice and sharp, just stick with a good coarse, medium and fine stone combination. I never use my 10k and up stones anymore, the most important stones in my collection are coarse stones, ones that range from 120-800 grit.

                                                         PRESSURE

    It is important to understand how pressure can help you create incredibly sharp edge.
So again, Burr Formation and Burr Removal are achieved by varying levels of pressure as you sharpen.

When I pick up a knife, after inspecting it for any damage, I always start the sharpening on a coarse stone. The level of dullness and the steel will determine which coarse stone I choose and, just as importantly, what level of pressure I will begin forming the burr with.



     You know by now that I use four levels of pressure on each knife with the heaviest level of pressure, P4, being the burr forming pressure. It will change, i.e. the amount of pressure I use depends on the knife, it's condition and the steel it is made from. I just don't start grinding away pressing down as hard as I can every time. Your common sense will guide you and it is something you just need to get the hang of, it isn't hard, you won't ruin your knife or anything. Making mistakes is part of the learning process, I make them all the time and what I have learned from them is what I am passing along but don't be afraid to make mistakes.

     Let's say I pick up Masakage Yuki or a Fujiwara like the one in the middle in the picture above. Even though the steel in these amazing knives is very hard, it's a "good" hard and they are easy to sharpen, burr formation can be very quick so I will start one of these knives at 400 or 500 grit with moderate pressure. I always start with moderate pressure to see how the knife feels on the stone and I will adjust it, heavier, lighter or keep it the same, depending on how the burr forming is coming along. So this is something I just adjust for every knife, the one thing that is constant during this burr forming stage is that I use the heaviest level of pressure that I will use only at the burr forming stage, I start a little lighter than I think it will require, I don't want to remove metal needlessly.

After the burr has been formed on both sides, I check the condition of the edge under a light to see if I can spot any light at all. The goal is to see no light at all and if I do see even a spec of light I will return to the coarse stone with enough pressure to remove the metal causing the light reflections.

Now, since the bur is formed, it is all about burr removal and I start removing the burr, on the same coarse stone by reducing my pressure by 50% (p3) then by another 50 (%) which means the pressure is not very very light and finally, feather light pressure and a stropping motion to finish the work on the coarse stone.

(all this is shown in the sharpening videos avail on my website)

Pressure






    In summary, if you are having some difficulties, stop what you are doing and then just go back to the very basics, raise a burr, make sure you are sharpening the edge of the edge, not up in the secondary bevel area and just focus on the objective.

    Don't sweat angles, find a sharpening angle by holding the tip of your pinky under the knife, between the spine of the knife and the stone and that can be your angle to sharpen, to build muscle memory and strengthen your technique.

Have fun doing it as well, relax.



Peter


















Sunday, 6 May 2018

Dull is on the prowl

   

     I get a lot of emails from folks learning to sharpen who complain about dullness setting in very quickly after they have sharpened the knife. Or the knife is sharp at 1,000 grit but seems to be dull after a 5,000 grit workout.

   I get so many of these questions that a pattern emerges and I think the answer is not to difficult to find and the solution is not hard to identify and put into action.




   Something I have seen first hand is improper use of a hone, (Steel) after sharpening.  The primary edge of a knife, when sharp, is a microscopically thin strip of steel that forms the Apex of knife and runs from heel to tip. If you pick up a Steel and slam it against the knife, the chances of you hitting the target area, which is the fatigued metal that has shifted out of place from the centre of the knife, the chances of moving that back into place with a steel is remote if not done with some attention to detail. I have seen cooks knock the edge off a a knife in 10 seconds with improper technique.

    Steeling, (honing) should be done carefully, and as in the top picture. So if steeling habits are poor, it is doom for the edge of a knife and a waste of time, especially when too much pressure is used.


Speaking of pressure:

Corey in Phoenix, amazing knife sharpener.


    A student told me that he was able to get the knife nice and sharp on the 1,000 grit stone but it seemed to get dull again after the 5,000 grit stone. I asked him to show me his routine and it rapidly became obvious that pressure was the culprit.

   Sharpening comes down to Burr Formation and Burr Removal. In order to form a burr a certain level of pressure is necessary of course, I call it P4 pressure, the heaviest pressure that I will use during the sharpening of one knife. Once I have formed the burr on both sides I reduce pressure by half and then again by half and then on the last level of pressure, P1 Pressure, it is merely a feather light stropping motion.

   By the time I get to a 5,000 grit stone, my pressure is light to begin with so in the case where the knife was getting dull again, the fella was just using too much pressure, forming burrs again and dulling the knife.  It takes practice to manipulate pressure but it is very important.






   Usually, a sharpening issue can be resolved by something very simple, it comes down to going back to the basics, the fundamentals.

Peter
















Monday, 9 April 2018

Setting UP

Hi Folks,
I've been away on a cruise, no knife sharpening although I did meet the Executive Chef on board and we talked about sharpening so I got a little fix at least.

     One thing that I never gave much thought about when I started sharpening full time, i.e. every day was the setup, my Sharpening Station.  At first I was working in the basement in a poorly lit area, no water nearby and definitely not ideal but I did sharpened there for two years.

    Finally, after several different attempts I got the setup I needed but even then, I found a way to improve it.  First of all, you don't need anything elaborate at all. I've seen pictures of sharpeners in Japan hunched over a container of water with the stone resting on a 2"X 4" board over the water and they had been in this environment for years.

Lighting is huge for me, I need a very good source of light to help me sharpen but that is pretty easy. I just got one of those jewellers type of lamps that clamp onto the side of the desk and I got that from Lee Valley Tools for 40 bucks. It's perfect, even has a magnifying glass attached to it.




    This is my current set up. The desktop is extremely sturdy and at the perfect height for me, that is important if you sharpen a lot, but not critical if you are a casual sharpener. Often I stand right here for 4-6  hours without moving my feet too much so it is important to be comfy as I sharpen. 

    The change I just made recently was going from the Shapton Pond which is absolutely fantastic to this plastic hotel pan and the Stone Bridge. I bought the Stone Bridge from Jon Broida at Japanese Knife Imports and as you can see I sharpen at a slight angle. This just aids in water management a little but it doesn't make much of a difference, and it is an optional setup with this particular stone bridge which is made by Suehiro and is quite superb. The water and soaking stones make it rock solid, nothing moves that should not be moving as I sharpen.  What I like about it is that I don't go through nearly as many micro fibre towels as I did on the Pond. I was doing a wash every day but now, with the water here I don't need the towels as much.

   The only thing I was worried about with this setup was testingthe edge with wet finger tips, would I be able to detect sharpness and yes, you can certainly do it. It takes a little getting used to but also, if the edge feels sharp with wet finger tip pads, it is definitely sharp.

  This setup cost me about $130.00 Cdn but the bridge itself is only $40.00 USD, its the Exchange Rate, shipping a getting hit by customs that make things add up. No regrets at all. 

  I can still use my beloved Shapton holder and I use the Pond when I sharpen anywhere else but here at home.







As long as you have a setup where you can stand, or sit, comfortably with a good source of light and left undisturbed you are going to be just fine. As long as the stone is stable and doesn't move around at all when you sharpen, which is distracting, you're good.


Karasu 9,000

Speaking of stones, I just bought this beauty from Tosho Knife Arts in Toronto, the Karasu 9,000 which is the first 9k stone that I have ever seen or heard of. It is not only quite beautiful but it's just an awesome finishing stone. Harder than the amazing Kityama 8,000 but that's okay. Now they say that this one mimics a natural stone or has a blend of synthetic and natural stones.

The dream knife is a Masakage Kiri and it is for sale if you live near me in Halifax. It's from Knifewear so as you may know I sell some of there knives here in NS for them. 

Take care and thank you for visiting my Blog. 






(This is a hunting knife, fixed blade that I did yesterday by hand and finished it at 6,000 grit.