Friday, 11 August 2017

The Advantages of Pressure

Hi folks,

In this article I want to talk about the two things that changed my sharpening life, these two things helped me make knives that I sharpen sharper than they have ever been and it's pretty simple. I have talked about them both before:

     * PRESSURE
     * TIME, ANGLE, PRESSURE - Equalization.




PRESSURE

     As you know, well as some of you know, I use four levels of pressure to sharpen and I do it every single time. I call then P4, P3, P2  and P1 with the "P" standing for Pressure and the numbers simply being a scale from Heavy Pressure (P4) to Feather Light Pressure (P1)

In and effort to make this as clear as possible, because I don't want anyone to thing that the numbers indicate pounds of pressure, i.e. P4 is 4 pounds, we can simply call this:

    BURR FORMING PRESSURE (P4)
    BURR REMOVAL PRESSURE (P3-P1)

 Also, there are a couple of important points to remember as I move along:

1. Burr Forming Pressure (P4) is the heaviest amount of pressure I use and I only use this once during the sharpening process, it is the level of pressure that I require to raise a burr and once that is done, once that burr has formed from tip to heel on both sides of the knife, I never use that level of pressure again on that same knife. 

2. Burr Forming Pressure is not a constant, defined level of pressure, it may vary for each knife. So if I pick up a knife that is very dull, like every single knife in the picture above, than I require a substantial level of pressure to form the burr, it only makes sense. However, if the knife is not too bad, dull yes,  but the edge is not deformed or in terrible condition, I will tone that level of pressure down a little. 

     My burr forming pressure needs to vary because my goal is to create a burr that is as subtle as I can make it, I don't want to blindly grind metal away by picking up every single knife and treating it the same way. So I use the appropriate level of Burr Forming Pressure to get the burr formed.

     You can experiment with this, pick up the knife and use a moderate level of pressure to see if the burr is forming in reasonable time frame, 1-3 minutes. If nothing is happening, then you can adjust the pressure. 

     The time required to form the burr using BFP (Burr Forming Pressure) will differ depending on the knife itself, whether it is soft or hard, stainless or carbon. It will depend on the stone you choose to start with, is it a 400 grit or a 1,000 grit stone.  Also, your level of skill will be a determining factor.

    The important thing to note is that these factors will play a role in how long it takes to form the burr, you can use the same initial level of pressure whether you are starting with a 400 grit stone or a 1,000 grit stone. You never want to be pressing down so hard that you lose control of the angle stability or it becomes comfortable.

     The bottom line is that you need to pick up each knife, look and feel the edge and form a sharpening plan:

*Stones to use from start to finish
*Burr Forming Pressure, how much do I need to start.

Actually, before I start any sharpening of a knife a series of plans unfolds.

Sharpening Plan

DAMAGE PLAN :         Do I need one and if so, make it happen, repair chips or the tip etc.
THINNING PLAN:        Do I need to thin the knife and if so, to what degree?
SHARPENING PLAN:  What progression of water stones do I need, what Sharpening Angle?
REFINISHING PLAN:  If the blade is scratched up, do I need to fix that, the handle?


My Sharpening Process
Pressure


STAGE ONE - BURR FORMING PRESSURE

     If after inspecting the knife to determine my sharpening plan,  I see that the knife is very dull and it is a hard knife, (58-67). I know that  my burr forming pressure will be heavy and I will start on a coarse stone, 220-400 grit.  I also know that I will also use a 1,000, 5,000 and possibly an 8,000 grit stone depending on the knife itself.  (High quality Japanese will mean an 8K finish)


    As my sharpening begins I use heavy pressure on the 400 grit stone. I move from tip to heel and then back from heel to tip on the right side of the knife. I then feel for a burr on opposite side of the blade and if there is none, I continue this pattern until one of two things happen: The burr forms,  or,  no burr forms after 2-3 minutes.  Either way I flip the knife to either continue the burr forming process (if no burr was formed on the first attempt or, to form a burr on the opposite side (If I did form a burr).  ( The reason I flip the knife after a few minutes where no burr formed, to achieve a balance on both sides of the knife. If I were to continue grinding on one side for several minutes to form a burr and did not do the same on the other side in terms of time spent, the bevels would not be consistent). 
s.  

    Once I have successfully formed a burr on both sides of the knife, consistent in size and running from heel to tip, I then reduce pressure by roughly 50%. I NEVER use P4 or burr forming pressure again on the knife that I am working on. So BURR FORMING PRESSURE HAPPENS ONCE.


Here is where I have fine tuned the sharpening process to achieve the second most important change I made to my process.  

In an effort to achieve uniformity and consistency in bevels I follow the procedure below for the remainder of the process.




STAGE TWO
BURR REMOVAL PRESSURE


   Since I have achieved a burr, it is now time to remove it and it is important to strive to finish with an edge that is as clean as possible, free from any metal fragments that interfere with truly sharp knives.

  Continuing on the COARSE stone, the same stone I used to form a burr, I move from tip to heel and from heel to tip on the right side of the knife. I now flip the knife and move from heel to tip and tip to heel. (This is the way I sharpen, if you start at the heel on both sides of the knife that is fine).
This is P3 Pressure: Light 
(Remember, you don't want to form additional burrs here so it is a challenge with a coarse stone not to but with practice manipulation pressure this way, it will happen)

   NOW I reduce the pressure again and still on the coarse stone I again move from Tip to Heel and Heel to Tip on the right side and flip the blade and move from Heel to Tip and Tip to Heel.
This is P2 Pressure : Very Light

Now for the final stage on the coarse stone I just "strop" the knife using trailing strokes, 3 strokes per side. This is the final stage for this stone before I check the edge.
This is P1 Pressure: Feather Light



EDGE CHECK

     This is another extremely important and simple act that really made a big difference for me. I hold the edge under a good light and look for any reflections on the edge. If I have not removed the burr that is normally visible to the naked eye under light, it will be revealed here. It is easy to see. If I do see any reflections, I just go back to P2 pressure, very light pressure and repeat the process and then check again under the light. I concentrate on the area of the edge where the reflections appeared. (You're holding the knife with the edge up here. This is the final check before moving on to another stone.)





STAGE THREE
BURR REMOVAL- REFINEMENT ON MEDIUM/FINE WATER STONES

    Now that the hard, critical work is done, i.e. burr formed and initial removal process complete, I switch to a medium stone, 1,000 grit.

    Now starting with P3 pressure, which again is nice and light,  I repeat the process as laid out above, moving from tip to heel and heel to tip on both sides, then I do the same with P2 pressure and finally the stropping motion (P1) and the pressure is feather light here, as light as you can get it.


    Now, I move to my finishing stone, usually a 5,000 grit stone and repeat the process and would do the same if I was going to use an 8,000 grit stone.

My final act may be stropping on bare leather.

   That is it, this all takes me about 12-15 minutes on a dull knife. Don't worry about the timing. The burr forming, P4 pressure stage can take anywhere from 1 minute to 7 or even more. It will depend on the steel, the condition of the knife, the burr forming stone you use and your skill. 

  The second important element that added to my sharpness levels and consistency, and, aesthetics was Time, Pressure and Angle and trying the best I can to equalize those on each side of the knife. (On a symmetric knife that is, 50/50 grind)

     I don't count strokes, so what I do is to work from tip to heel and heel to tip on both sides as evenly as I can. I do my best to maintain the same pressure and angle but all this takes time to learn. The knowledge that I should do this, or try to do it at least was for me, the most important thing.

    I really hope that this is all clear and that  you got something from it.




Respectfully
Peter Nowlan

















Sunday, 6 August 2017

keeping sharp knives sharp

Hi,
     As I have mentioned before, "how do I keep my knife sharp? is one of the most common questions that I get. The answer is easy but most folks won't do it.

     In fact, the majority of people don't get their knives sharpened at all, I have had people tell me that they just don't care if they are dull. Since you are reading this, you have an interest in sharpening so I will explain, what in my opinion is the best way to maintain your edge.

     

Steel and Ceramic Hones (NOT the best but very good)

    Through the years, cooks, butchers and homemakers have used a Steel to maintain their knives. I believe that the steel in knives was different 40 years ago so a skilled butcher did have the ability to maintain and edge with an old worn out steel Steel.  These tools are still in use of course and most older chefs will tell you that it's all they need. "Been using this steel for years, why fix something if it isn't broken"


   I am not saying that these Steels don't work, when used properly, I am saying that there is a better way to keep the edge up, better than a ceramic hone. This is particularly true of hard knives, 58+.
If you took a Fujiwara for example and ran a steel over the edge, a metal Steel, there is a very strong possibility that the metal that is fatigued and has moved from the centre of the knife would break off instead of being re-aligned.  The metal is too hard, it wont' flex.

Fujiwara and 400 grit Naniwa Chosera

     If you think of the metal that has become fatigued, the metal making the knife dull as metal being pushed back and forth by a Steel, it is just becoming more fatigued. It is being pushed back into place, if done properly by the steel but it is still weak. You are not strengthening the steel in the knife by doing this, you are at the very best, moving tired metal back into place where it will be subjected to the force of every day use again and in a short amount of time will just bend over again.


 
Takeda 

   Instead of moving fatigued metal around, why not just remove it and we can do this with a whetstone, a finishing stone. Something 4,000 grit and above. It is easy to do and is just a matter of applying trailing strokes, using light pressure to remove the metal that has done it's job. Take it away and expose the fresh steel underneath. You do this at the same angle as the knife is sharpened at or a little higher, not lower.

  I think a leather strop is even better than a Steel. The other benefit of using a whetstone to maintain the knife is that it promotes muscle memory. To me, it just makes sense to remove fatigued metal using the same products I used to sharpen a knife.

Leather strops


   The problem in a professional kitchen is that this approach takes time. It is much faster just to pull out a steel rod and use that than to stop what is being done, go over to the water stone and use it. It is too bad people just wouldn't get together and buy one 5,000 grit stone, even a 2,000 grit stone is okay, better than any other hone.


   Just my thoughts, please contact me if you have any questions or criticism about it, I am always open to discussions on sharpening.


My email


  Having said this, if you are doing something to maintain your knives, good for you, most people don't so you have that going for you, kudos to  you.
Peter












Sharpening School updated

Thinning

This new lesson is all about thinning a knife. Jon Broida shot the video and I wrote the article.

Wednesday, 19 July 2017

Building Basic Skills

Fundamentals

Folks, if you have not read the article I wrote with Jon Broida's help which is on Knifeplanet, you should. It covers a lot of very useful information, but I will discuss some points here as well.

    Novices often get frustrated when starting with Angles. There are two elements to this, one is actual SHARPENING ANGLE  and the other is the ability to stabilise that chosen angle, to hold it constant while you sharpen.

    Let's deal with the easy one, the choice of a Sharpening Angle.



    These are the pictures from the Knifeplanet article.

     Your choice of angle should be determined by the knife you are sharpening and to some extent, to what you are cutting but for now, let's make that choice based on the knife, i.e. the steel used to make it. The useful pictures above will tell you that all knives are sharpened between 10 and 20 degrees per side, you can choose any angle you want. The guideline illustrated above are designed to enhance the cutting performance of a knife and edge retention. For example, if I am going to sharpen a dull knife that is relatively soft, i.e. 54 on the hardness scale, my SA (Sharpening Angle) will be 20 degrees per side, or as close to that as I can manage. Remember, we are freehand sharpening so these angles are not precise, but they can be very close and exact precision is unnecessary.

     I choose this angle (20 deg) because it is "safe" angle in terms of the steels ability to keep that primary edge in place, to prevent it from failing for as long as possible. This angle will provide the necessary support to the edge. It will still fail and roll over eventually but we can't stop that, if we are using the knife. I could sharpen that same knife at 12 deg if I wanted to, however, the period of edge retention, the time it takes to go from extremely sharp to useless would be much shorter as the supporting steel behind the edge is thinner, there is not much there to keep that edge in place.

     Now, you can always try sharpening at different angles once you have built up muscle memory in an effort to gain as much cutting performance from your knife as possible. If you typically sharpen at 20 deg per side, try 17, see how the knife holds up, you can always go back to 20 deg. Gain muscle memory first though, you can do  this down the road a little.

    You can find the angle, i.e. what the 20 deg angle looks like, i.e. how high the spine of the knife off of the stone is by various means. You can wing it, you can hold the knife at 90 deg to the stone, i.e. straight up and down and just lower it until you get to what you think is 20 deg or whatever your SA is. You could create a little guide, a stack of quarters for example as a visual clue. There are angle guides available and there is an Angle Meter in your iPhone in the Compass App. Just swipe left.





     Just do a little experimenting to see how it works, if the screen turns red, just tap the screen to get it back to black. It is very accurate. Remember however, this just shows you what your chosen SA looks like, you'll be on your own once you start sharpening and there is much to take in.


   


     In the video shown on Lesson #2, I describe a four level pressure system, this has proved to be an excellent system for me in terms of burr removal which of course leads to a clean edge and sharpness.

     However, when you are just learning, if this is confusing, i.e. trying to hold and angle and manipulate pressure at the same time, just use a couple of pressure variances. One moderate and one light. You need some pressure to form the burr. Why not call these two levels of pressure:

     BURR FORMING PRESSURE
     BURR REMOVAL PRESSURE


     Use whatever level of pressure is necessary to form the burr but keep it at a level that enables you to work at that same level, i.e. it is not so hard or soft that it becomes difficult to maintain.


HOLDING AN ANGLE

    This is the more difficult part but there is good news: This is the difficult part for all of use when we are learning, this is nothing new, this is your body getting accustomed to a different motion. It will get used to it and in time, with PRACTICE, you will be amazed at how well you will be able to keep your wrist steady and you will see a difference in your edges and bevels, your consistency will grow as your muscles adapt.

    Since we are not using an Edge Pro which removes angle issues, we need to build SM.


SHARPENING MUSCLES 
(SM)
HOW TO GET THEM


        Here is another easy part to learn, building muscle memory is easy. There is no quick fix, holding an angle steady while you sharpen, any angle is a skill that can only develop with practice. However, you an expedite the process, you can speed things up a little but it takes effort. The only way that I know of to increase sharpening muscle memory is to sharpen. You need to sharpen many knives before it starts kicking in, before your body figures out what it is you are forcing it to learn.

     Get a good Chef Knife that is undamaged, its 8' (203 mm) in length and consider this as your new best friend. Paint the edge with a sharpie and remove it by sharpening at very very light pressure, you are not actually sharpening the knife you are working at holding the angle, this is exercise.  Now, repeat the process on the other side, concentrating on holding that angle, there is nothing else going on around you, just you doing some exercise.

     Now when you have done that, and it may take a minute or less, do it again. Do this ten times per side and put the knife down.  You should do this about twenty times and you will see an improvement for sure in your ability to hold that particular angle. At the same time, you are also developing your ability to manipulate pressure and hold it steady, sharpening and pressure holding skills are being developed.

    This is going to be boring perhaps so just do it for five minutes and give it a rest but don't give up on it, it will work. Your muscles adapt quickly and in no time you will notice it getting much easier to hold that angle.

   This SM growth will have the added benefits of improving your confidence, solidifying your technique and making everything you are doing in regards to sharpening easier, more effective and a heck of a lot of fun.

Coarse, Medium, Fine (L-R)


PASSION
PRACTICE
PATIENCE
PERSISTENCE

The four pillars to successful sharpening.


Peter Nowlan



    














Saturday, 15 July 2017

Sharpening Lesson Number 2 is up on Knifeplanet

Sharpening Fundamentals

I don't know if the article that accompanies the video is something that I can improve upon. The article is a must read if you are going to watch the video. Jon Broida helped me quite a bit with it as well.

If you are interested in learning to sharpen a knife, this will help you out, I'm very confident about that.

Peter

Friday, 7 July 2017

Looking Glass Bevels/Edge



    Hi all,

      Often, when folks bring me a folder to sharpen I will ask if they want a highly polished finish or not and most of the time the answer is yes. So when I tackle this job I usually take out the Edge Pro Professional which excels at this type of thing. However, this time I did it freehand with full sized stones.

    The way I do this is to first and foremost make the knife sharp on the very first stone and in this case I used a Naniwa Chosera 400. The secret is to reduce the depth of the scratches as much as possible on each stone. You can't do a half assed job on the coarse stone and then hope the 5k stone will do the trick. So I spend a lot of time on the 400 stone and I use at least four levels of pressure on that stone. The idea is to just keep reducing the depth of the scratches in the bevels with ever diminishing levels of pressure and water to keep everything nice and clean, no grit debris.

   Once I am happy with the first stone and the knife is sharp I move to the 1,000 and repeat the process but with less pressure. I'm not forming a burr, I am just refining and polishing. The polished bevels will really start to show at the 3,000 grit level. In this case I used Naniwa Chosera including the 10,000 grit stone to finish it off.

  Of course this polish won't last long out in the field but it does look nice and is exceptionally sharp.

  In terms of stones required, I think you need at least 3,000 to 4,000 grit but the 2,000 Naniwa Aotoshi (green brick) is a fantastic polishing stone.


At the end of the day, this type of finish is not that important, getting a nice strong and sharp edge takes priority, every time so don't think this is something  that you need to be able to do. I've screwed this up lots of times, believe me :)

Peter

Thursday, 29 June 2017

Uneven Bevels

Hi folks,

     A question I often get is if I have ever experienced a problem getting both sides of the knife to have perfectly even bevels. Yes I have and it is a common problem, that is not really a problem and I have learnt to correct it.

TO CLARIFY: By uneven bevels I mean one side having a larger surface area than the other. Both bevels can run perfectly parallel to the edge, I am not talking about one spot on the bevel being a little higher than the rest. 

   I found that as I sharpened starting on the right side of the knife that when I was finished, either that side or the left side seemed to have a wider bevel and it was often the left side. Regardless of how careful I paid attention to my angles, it seemed to happen often.

   Now I have seen Japanese knives come and they look like this out of the box so this isn't something that novices do and it just disappears. I have also noticed that it is an aesthetics issue, not something that prevents the knife from being sharp.



   I think that the cause of this is caused by one or all of three things:
     * Different Angles
     * Different levels of Pressure
     * Unequal amount of time spent sharpening on each side.



    I found that as I worked to raise a burr, if it was a lengthy process, i.e. more that three minutes, I noticed the problem more. So I would grind away on the right side of the knife to get the burr to flip over to the left side, as we know, the burr always forms on the opposite side of where we are sharpening. Then, when I flipped the knife, if I didn't have to spend as much time on the left side, there is case of not balancing the timing.  Also, it is possible that my pressure was different on my right side than the left.



 


    To prevent this from happening, I am very aware now of how much time I spend on each side so if I have not raised the burr when I start the sharpening process within 2-3 minutes, I flip the knife anyway and start grinding on the other side, then I flip and start over again until the burr forms. Once it does form, it is a quick process I find.  This action alone seems to have solved the problem for me.

   However, just being aware of it caused me to be more vigilant as I sharpen, to continuously look at the edge/bevels to ensure that everything looks even, on 50?50 grinds of course.




      If this is something you are experiencing, try managing your time as evenly as possible and of course your pressure. I don't know if it as much of an angle issue though. I have seen this on knives sharpened on an Edge Pro where the angles do match perfectly so this left me with time and pressure.






    It is not a big deal and as I have said, I have seen world class knives with uneven bevels but still beyond razor sharp, not very often but it can happen, we are human after all and not perfect . All we can do as a freehand sharpener is our best to duplicate our efforts on both sides of the knife and to acknowledge that mistakes happen for a reason, they make us better at what we do.



                                                                             AND
IT COULD ALWAYS BE WORSE