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Newsletter Article - The Cosman Sharpening Method

I am constantly looking for methods and techniques that will make my sharpening system better and more efficient.  David Charlesworth's “ruler trick” is the most revolutionary new sharpening technique to come along in the last 50 years and it is central to my sharpening system’s success!  My sharpening system takes just 30 seconds, leaves a flawless surface on the wood, and its only downside is the cost of the stones.



I have been refining my sharpening system for years and I don't think there is a lot of room for improvement with my current system.  My rule for incorporating new refinements into my sharpening system depends on the answer to this question: Will the refinement enhance the surface of the wood to a degree that the unaided hand or eye can tell a difference?  If the answer to this question is “No” then why bother with the refinement? 


I believe my system is at the point that the only room for improvement is in the cost of the stones.  I tend to believe you get what you pay for, so I am skeptical of finding a "better and cheaper" stone; but I am always looking! 


I also believe that no matter how good a sharpening system is it must be convenient and quick, or hand tool woodworkers will delay sharpening opting instead to work with dull tools rather than take the time to re-sharpen.  Therefore, my system is a freehand one; it requires no jig set-up time.  You can literally re-sharpen your blade in 30-40 seconds.  For some, this sounds too good to be true, so the big question is, "Can the average woodworker learn my system"?  From my experience of teaching this system to hundreds of students, the answer is a resounding “YES!”  


A big factor to sharpening success is body mechanics.  Because of this, my technique involves using a low sharpening station.  My sharpening platform is just a few inches above my knee, though this will vary from person to person.  I got my first clue to lowering my sharpening station from watching my students struggle while attempting to sharpen at bench height.  They would struggle trying to move the blade in a tight circular pattern on the stone while at the same time pushing it back and forth along the length of the stone.  The result was a rounded over mess that both frustrated the student and messed up the blade’s primary bevel. 


By experimenting I discovered that a lower sharpening platform helped solve some of the problems my students were experiencing.  A lower sharpening platform offers two big benefits: 1) it moved the pivot point from the wrist to the shoulders and 2) reduced the time you must hold a blade angle while sharpening.



When trying to maintain the set angle (holding the blade to the stone), the further the blade is from the pivot point the easier and more accurate it is to maintain the set angle.  I coach my students to have a firm but not tight grip on the blade, lock the wrist and elbow and pivot from the shoulder while keeping both arms in synchronization.  Lowering the sharpening station and locking the wrist and elbow transfers the pivot point from the wrist to the shoulders. 



The grip is all important to keep the wrist from becoming the pivot point.  It’s like shooting a pistol, gripping a golf club, or holding a pool cue, your grip on the blade must be consistent every time.  The "grip" needs to be removed as a variable in the sharpening process.  I go into detail in many of my videos and in my workshops on how I hold the blade properly for sharpening.  The pressure needs to be RIGHT at the cutting edge of the blade.  That means placing 4 fingers at the edge of the blade and creating uniform pressure dispersed evenly across the edge.  I interlock my thumbs to tie my two hands together and I use the hole in the middle of the blade as an index point for my left index finger (I'm right handed).



The second benefit of a low sharpening station is being able to lean over the stone with your body.  This allows me to move the blade across the stone using body motion instead of arm motion.  The focus of my arms and grip remains singular; keep everything locked and the pivot point at the shoulders.  That achieved, I simply rock my body pivoting from heel to toe to move the blade back and forth along the length of the stone while at the same time using my arms to move the blade in tight circles along the width of the stone.  This keeps the stone wear even and consistent. 


The final factor is having stones that cut fast.  The body position I have described is not the most comfortable position to be in, so you need a fast cutting stones to minimize the time you must hold this position.  A fast cutting stone is a quality stone. My sharpening system uses a 300/1000 grit diamond stone that can

 cut a new secondary bevel in 5-10 seconds and a Shapton 16,000 HR glass ceramic stone that can polish a tertiary bevel in 10 seconds.  A little pricey but worth every penny. 

With my sharpening system you can sharpen your blade in 30 seconds and get back to work.  This makes re-sharpening your blade not so painful and that means you will re-sharpen more often instead of working with a dull blade.  That makes your craftsmanship easier, more pleasurable, and creates a flawless surface on the wood.