Japanese knife sharpening videos

[Ken S]

I emailed this link to Steve yesterday. He suggested I post it on the forum. So, without further ado......

https://40cooks.wordpress.com/2009/06/16/knife-sharpening-w-dave-martell/

Enjoy!

Ken

[Jan]

Thanks Ken for sharing link to those interesting videos.
I had a much faster connection directly to youtube:

https://www.youtube.com/watch?v=MezIEKGk9T0&feature=youtu.be
https://www.youtube.com/watch?v=mSyK67mqXEI&feature=youtu.be
https://www.youtube.com/watch?v=EtkwvoYaus4&feature=youtu.be

Jan

P.S.: What do you think, how accurately is Dave Martell able to maintain the bevel angle along the entire length of the blade?

[Ken S]

Jan,

Thanks for posting the improved links.

Good question about Dave Martell's bevel accuracy. One think I find fascinating about the machine shop world is that there are no absolutes. Measurements are "within tolerance". The amount of tolerance varies with the application.

Steve Bottorff told me (and covers the subject in one of the videos he posted on the forum) that when he wants "absolutely even bevels", he uses the Tormek knife jigs instead of handheld grinding.Steve and I know each other well enough to speak quite candidly. No marketing, just honest evaluation. Having personally watched Steve grinding knives, I can vouch for the very high level of skill and experience he brings to knife sharpening technique. Steve has kindly lent me two DVDs made by Dave Martell. I would place Dave in the same "guru" status as I hold Steve. So, Jan, back to your question, I suspect Dave's bevels are well within any level of practical tolerance for working knives. While a laboratory might measure minute differences, I would be reluctant to have my Tormek jigged bevels compared with such a master as Dave or Steve. (I am narrowing the gap, but still have a long way to go.)

I believe it is important to keep market realities in mind. Dave made the comment that he generally does not see the point in honing the edge of western knives beyond 1000 grit, due to their softer (compared with Japanese knives) steel. He makes his living with a mobile sharpening service, just as Steve does with his farmer's market booth. Their customers get knives sharpened well beyond new knife condition at a fair price and in a short amount of time. Razor sharp performance at a fair price and done today means more to the customers than having an "absolutely even bevel" at an absolutely high cost. A collector with a highly collectable trophy knife might prefer the absolutes. In that case, I am quite sure Steve or Dave can deliver that level of service for a fair, but much higher cost.

Ken

[Jan]

Thanks Ken for the reply with a broader consideration why and how we sharpen knifes. 

I am approaching the time when I will have to sharpen, for the first time, my expensive Japanese Santoku knife. I ask myself whether I'd entrusted Dave, or I'd rather do it myself. In my thinking, even a guru sharpener cannot maintain the bevel angle with an accuracy better than +/- 1 to 2 degrees.

Maintaining the constant bevel angle along the entire length of the blade is of great importance. When you slice a meat with a tendon, your hand will recognize some change in the behavior of the knife, caused by the local change of the edge angle. You will easily overcome it by applying more pressure, but under certain circumstances the knife can slide on the obstacle if it is encountered by slightly dull segment of the edge.

Jan

[stevebot]

When I started I was an angle fanatic, based largely on reading John Juranitch and using Lansky guides. I dissected guides and commented when they varied from their stated angles. I happened upon a 30 degree Cold Steel blade that would shave, and about the same time was experimenting with paper sharpening wheels. Paper wheels offer no angle control so I was sharpening freehand. Even with several degrees of variation these edge easily popped hair. I became a polish fanatic, researching finer and finer polishing compounds like Green Chrome. Then I discovered that these razor sharp edges would sometimes slip over tomato skins. Rough them up a bit on a fine ceramic steel or stone and you can still shave but are slicing better.

Today I am a moderate on both counts. Get the angle within a few degrees and the finish at 600 to 1000 grit and you have a fine useful knife.

For those not familiar with paper sharpening wheels sharpeningmadeeasy.com/paper.htm

For angle fanatics sharpeningmadeeasy.com/edgepal.htm   0.01 degree accuracy!

[Jan]

Thank you very much for sharing with us this segment of your life story, Steve. It's interesting and instructive at the same time. 

I'm in the enviable position to sharpen mainly for my pleasure and to have enough time to test different approaches. I do as it is written: "test everything; hold fast what is good".

Jan

[Ken S]

Jan

I believe Herman might say that you have "a sharpening hobby". Welcome to the club. Be careful, the sharpening hobby can become addictive.

Ken

[grepper]

I've had a very similar experience as Steve.

At first I was all concerned about angles.  But now, unless circumstances really require it, not so much.  Most of the time I just follow the existing edge and don't even bother to measure it.   

I too use to think a polished edge was the thing.  Indeed it looks pretty, but most of the knives I sharpen are kitchen knives and I too have found that overly polished edges slide on tomato and other vegetable skins. If it's really razor sharp it will cut tomatoes, etc., but that level of sharpness tends to not endure long.  Some knives I even stop at about 300 grit and just spend a bit more time honing.  Works great.  It all depends on how the edge is going to be used.

I've used paper wheels.  You can get an extremely sharp edge very, very quickly.  With their high rotational speed they can generate heat quickly too, so from my experience at least you don't want to spend much time in one spot.  I like to use a jig and I don't have one set up for paper wheels.  I don't sharpen enough to have really refined my freehand skills and under close examination there is a lot of micro beveling in my freehand edges.  For all intents and purposes they still work great, but nonetheless it bugs me.

I guess it just depends on what you are after.  Interesting how it evolves over time.

[Ken S]

Interesting thoughts, Grepper. I feel I benefit from all the thoughts on the forum. Each poster has a piece of the puzzle. The sum of the whole is greater than the sum of the parts.

One interesting idea I have gleaned from Dave Martell is using Goop waterless hand cleaner on leather strops to clean them. In Hartville, for the first time ever, I had a problem with black gunk coming off of my leather honing wheel. (Stig, is that the dust you have written about?) I will try using Goop on my leather honing wheel and report the result.

Ken

[Jan]

Ken, Steve and Grepper, it seems that it is a general tendency, to be over time, less concerned about the bevel angles and more about what purpose the sharpened tool should serve.

I never was an angle fanatic, bat maintaining constant angle along the blade was always challenge for me. Thanks to my limited freehand skill I can achieve this using the knife jig or some support platform. My home made horizontal platform for knives (http://forum.tormek.com/index.php?topic=2562.135 ) gives me the opportunity to experience partial freedom of freehand sharpening. 

I think quite often about honing. In my thinking it's far more than just removing burr and achieving a perfect surface. I plan to visit metallurgist to discuss with him what the iron atoms near the edge do during our honing.

Jan

[Ken S]

Jan,

Every machine shop needs at least one worker who is more particular than the rest to serve as the quality inspector. You are one of the forum quality inspectors. By maintaining standards, we raise the bar for all of us. I think that is a very good thing. Consistency through good jig design need not be complicated to use. Simple jigs should be accurate and their use lead to better work if carefully designed.

Keep up the good work!

Ken

[Ken S]

I have been further exploring Dave Martell's technique. Some things of note:

Dave spends a lot of time discussing thinning the blade. Most knives have a tapered cross section. As we continue to sharpen with the same bevel angle, the blade near the edge becomes physically thicker. Thinning maintains a constant thickness. I have a lot more to learn about this. (Steve and Stig, I hope you will comment on this.)

Dave recommends always using the same kind of paper for paper testing edge sharpness. This makes sense to me. By using paper of the same thickness, the test medium is consistent. He keeps a ream of inexpensive copy paper in his shop and another ream of the same paper on his sharpening truck.

Ken

[Jan]

Some sharpeners use cigarette (rolling) paper for paper testing edge sharpness. It is quite challenging paper test, because the weight is below 20 g/m², whereas regular everyday copy paper has some 75 g/m². The paper weight itself is not sufficient paper characteristic, so it is really good idea to keep a ream of the same paper. 

Jan

[Ken S]

Jan,

Your cigarette rolling paper suggestion interests me on two different levels.
I would like to find the  most impressive paper which I can consistently cut while presenting the Tormek at future shows. Being able to cut paper at will is admittedly a crowd pleaser, and a presenter is admittedly a salesman.

The other level of interest is my ongoing effort for self growth through continual study and technique improvement. I try to add small steps in this building process, just as a brick wall is made up of many bricks.

An example of this is my new  habit of always using the ceramic steel Steve gave me before returning my kitchen knives to the wooden block. I pay close attention to the feel and sound of the operation and am striving to improve my technique. This is only a small step, however, the longest journey begins with a single step.

Ken

[Jan]

Ken, in my opinion the test with cigarette rolling paper is intended rather for internal use of the sharpener, but you will certainly impress the viewers with this advanced test. It just needs to practice and to know the types of knives for which the test works reliably. 

What concerns ceramic steels, it is know, that it achieves better results than the steel knife steels. This is because, the ceramic steels operate on different principle. Properly used ceramic steels grind a new consistent micro-bevel, while steel knife steels re align the knife edge.



Jan