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 Post subject: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Sun Feb 09, 2014 1:58 pm 

Joined: Mon May 06, 2013 2:34 pm
Posts: 47
So, I finally got around to addressing the OOTB edge on my new Konosuke. I have been sharpening for a while with other knives, but this knife is a little unique for me in its composition. The primary bevel drops down and the cladding fades away with a wavy pattern to the core metal and edge, and out of the box there as a micro bevel. Now, the core metal that is exposed is pretty wide, I'd say almost 1cm on both sides (with a little more on one side). My other knives have significantly less core metal exposed and so I am a novice with this style of grind.

My progression was 1K, 2K Blue Aoto and strop. Goal was to take out the micro bevel and set a nice sharp, toothy edge. Now, I am getting a pretty damn sharp edge, but I feel I am hitting the cladding a bit, even though I "clicked in" to the stones and took some nice slow strokes. Am I missing something about the geometry on this knife? For those of you with a same knife, is the geometry convex as it reaches the edge? I thought I would get a scratch pattern that goes gradually up from the edge? Any tricks for getting that nice wavy pattern back? Where I have hit the cladding, I've actually polished it up more than how it came out of the box. Thanks!


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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Sun Feb 09, 2014 4:22 pm 

Joined: Fri Jan 17, 2014 6:02 am
Posts: 271
if you follow the main bevel, which seems to go all the way to the cladding from what I'm interpreting, it only makes sense that you'll be removing cladding as you sharpen. If that makes any sense to you


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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Sun Feb 09, 2014 7:12 pm 

Joined: Mon May 06, 2013 2:34 pm
Posts: 47
Picture is attached for reference. I followed the main bevel, with finger pressure just above the edge, maybe I was too high on the blade? It seemed like the edge was off of the primary bevel (with no secondary bevel), but maybe I was wrong? There was plenty of patina so I couldn't really tell visually when I started sharpening.


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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Sun Feb 09, 2014 11:34 pm 
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Joined: Tue Oct 30, 2012 12:20 am
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Here's my Fujiyama after 7 months of pretty consistent use:

Image


From the very start, I knew I didn't possess the ability or tools to maintain the finish that the polisher/sharpener is able to achieve,
or the ability to maintain the Shinogi to edge symmetry. I also knew that I preferred a certain way of touching the knife up.
I had already experimented with sharpening Japanese knives for a while.

Normally I can't stand patina on a Japanese knife, but I've decided to allow the edge itself (from the clad line down) to Patina...cause I don't mind it for my tastes at this point.
From day one I knew that the side of this knife would never touch the stone, cause I knew that I'd never be able to get it back to original.
Eventually, when the knife needs to be thinned, I'll send it back to Konosuke where it can be reconditioned by someone who knows what they're doing.
Sorry for the crappy photo; the lighting wasn't that good. :)



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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Mon Feb 10, 2014 2:45 am 

Joined: Mon May 06, 2013 2:34 pm
Posts: 47
Thanks for this - who do you have sharpen your Fujiyama? And how do you clean/polish? I guess my feeling is, I've got this awesome knife, so I better step up my sharpening skills and be able to take care of it. I've done a good job (I think) on my Takeda petty and other japanese knives, but this knife is a little unique. At least visually it's like a yanagi on both sides! I don't think I messed up the shinogi really, at least not so much that it couldn't easily be fixed by someone here. That said, I used it tonight to prep a bunch of vegetables and it is absolutely ridiculously sharp. I can also tell that the geometry is superb - really just falls through everything.

Anyway, back to my original question - does the Fujiyama have a convex grind?


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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Mon Feb 10, 2014 3:18 am 
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Posts: 571
It's possible that it's very slightly convex to help in releasing food, but I'm not entirely sure. It's hard to tell (for me anyway).
I touch the knife up myself, but that only involves a few light strokes on the edge itself. I know I'm at least capable of that. :)
I've become fully aware and honest with my, vs the sharpeners skills....and I know I'm not capable of grinding this knife
the way it should be.

Sure, I can grind away at a knife Japanese style...but... :ugeek:

I learned my lesson. Don't wanna mess with it...

For taking care of the patina, I use the slurry from my Coticule, which has an 8-10k grit, so it cleans up the knife without
scratching or too much polishing...just enough to get rid of the patina. There are powders available that accomplish the same thing.



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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Mon Feb 10, 2014 5:11 am 
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Heh, the grind is actually slightly concave! Yup, slightly hollow ground. I found this out when I thinned out Aarons Fujiyama Blue #2 240mm Gyuto and Funayuki. Started on my Rotary Platen to thin, then moved on to the flat platen and there were still some deeper scratches. When I looked at the blade more closely, I saw that it was hollow ground, more so near the Shinogi. This gives it that nice crisp line. When they grind most knives, they are often done on a large diameter grinding wheel, and the grinds are very often a slight hollow grind. They manage to blend it in, but there is often a slight hollow running down the blade road. I first saw this on some other knives when I went to flatten the blade road to try my hand at kasumi finishes. There was a slight area down the blade road from heel to tip that was still bead blasted when most of the other area had the stone finish; when I held a straight edge, I saw that it was slightly hollow ground there.

For sharpening, just keep doing the micro bevel for now. A zero edge on many knives is not the best edge for general use and is very difficult to achieve and incredibly fragile if you just go straight into it. You can probably even strop it back to sharp several times before using the stones on it. When you are ready to thin it, you can probably lay the bevel flat on the stone and work that way for a while. The trick is to keep pressure on the blade road up to the shinogi line, but not past the shinogi line. I think there are some youtube video's about this. This one was just posted! http://www.youtube.com/watch?v=jqe71SKhajI. The first few times go slowly since you have to start with completely flat stones and make sure the stones are flat to get your bevel flat and don't try to fully flatten in 1 step. Softer stones do help, but some people use hard Shapton Pro's for the first few steps and then move to harder stones. J Nats will leave more contrast between the core and cladding, synthetics will give a more even/shinier/polished look to the blade.

I will often thin with a belt sander and take it up to a nice satin finish. They helps the blade have more convexing to it and gives a much cleaner look than the stones would, but without the Kasumi finish with the high contrast between core and cladding. I use the Norton Non Woven pads below after the belt sander and either leave it at that finish or go on to the acid etch.

To clean up scratches/patina, I found some stuff that I love to use! Trying to get Mark to stock these:
http://www.woodcraft.com/search2/search ... on%20woven
They give a satin finish much easier than the MicroMesh pads do; they are much more aggressive and still give a nice look to them still. The will also hide a lot of scratches, too. When I thinned the Kono's and other knives, there will often be some deep grinding marks or other marks left from the original manufacturing process that are perpendicular to the blade edge and the satin finish helps to hide those marks. Removing them fully in 1 step may make the blade too thin. They tend to show up when I acid etch, but a non etched finish really hides them well.

The Maroon and Green ones are fairly coarse and can often be found at hardware stores as metal prep pads. The Grey is awesome for removing patina and leaves a nice, shiny satin finish and the white pad helps to bring out the shine even more. Whenever I acid etch a blade, I use these first to smooth out the blade and bring it to a consistent shine and then wash and etch. I strop the blade on the pad with the pad on a counter or some other hard surface. You will need to resharpen after using these, but often just need to use 1 stone. If I use the grey or white, I just touch up on my finishing stone normally. I haven't tried these pads on a knife I thinned with stones to remove the stone marks, but with a belt thinned knife, or any factory satin finished knife (especially with cladding), these work very well! If there is a sharp Shinogi line, I do the blade road first and then the "flat" area above it, which is also often slightly hollow ground/forged. It will make the Shinogi less sharp, but still looks good!


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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Mon Feb 10, 2014 6:24 am 
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You may be confident Taz with taking on thinning a knife like this, but I'm not. :lol:

I think a lot of guy's like to think they can handle it. :D

(...I know that I ain't Fujiyama... 8-) )

Interesting stuff about the grind. It's almost impossible to see with the eye...
I'll have to check those pads out. For now, the slurry seems to be workin pretty good.

I was resolved on just sending it back to those that made it to have the work done, but if your available and have time,
maybe I'll send it to you instead.



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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Mon Feb 10, 2014 7:28 am 
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Yeah, I'm used to working with metal :) The belt sander makes things quicker and a bit easier. I will see if any of the pics of Aarons funayuki that I thinned came out well enough to post.

Some older pics:
His 240mm gyuto, Boy Blue after thinning/etching:
Image
Image

High polish off of the belts:
Image

Choil shot after thinning:
Image

With the belts and going to a high polish, any scratches that were deeper/not taken out by the earlier grits really stand out. Especially in areas that were slightly hollow, a belt won't get into those areas easily to clean them up. It would really change the knife to regrind everything flat first and then refinish/convex and then reblend. The pads do a good job blending those areas nicely and hiding any deeper scratch marks from the orig. grinding and the regrinding. When I etch, the deep scratches really pop out, but with the pads, you don't even know that they are there. The top part of the knife was forged and slightly hollow/uneven from the forging process and the Shinogi line can also be uneven due to that as well. I would try the pads on your knife to restore the nice look to it. If you thinned on a 1K and then 2K, the scratches shouldn't be that deep to remove. You can also use some fine grit (start at like 320-400 and go up from there) sandpaper on a piece of cork or hard rubber to clean up the blade road.

From the knives I have seen from Aaron, the Fujiyama are ground really thin. Even when he sent them to me for thinning, they had been used/sharpened for a year in a pro kitchen and still cut pretty well, so thinning shouldn't be an immediate concern, especially for a home cook. My Tanaka Sekiso 240mm went from August to the next May or June with stropping on balsa with 1 micron Boron carbide paste and only saw the stones in June because I acid etched the blade and needed to touch it up from the etching/refinishing process. Many times the knife can be kept sharp by stropping on your finest sharpening stone or leather/balsa strops. You will go a long time before you really need to thin, depending on how you sharpen. When you are sharpening, you will often only need to go back to your highest stone to touch up the edge. I would look at picking up a Rika 5K or another stone in that range to use for the touch ups; or a J nat finishing stone. Going down to a 1K stone each time you sharpen isn't needed and will remove steel quicker than you really need to leading to needing to thin out more frequently. I know some people/places recommend a little thinning each time you sharpen the knife, but that is for a full sharpening, not when only a touch up is needed.

Single bevel knives will have a convex blade road that leads right into the edge. A double bevel gyuto may have a similar construction, but most will need at least a micro bevel to give some strength to the edge. I would not try to remove the micro bevel on the Fujiyama. Keep it there and as you sharpen, it will get a little bigger. When you notice that even when fully sharp, it's not cutting as well as it used to, you can knock down the shoulder between the edge bevel and blade road and thin that area a bit, but you should be a long way from that step considering the knife is new. I saw a Masakage Mizu Suji that a customer had done the same thing; he fully flattened and polished the blade road and took the knife down to a zero bevel edge; the blade road went into the edge. It chipped horribly and with minimal pressure. The edge was just too thin/weak. Even as I was trying to work chips out with a stone, the edge was flexing and chipping out around the stone! I had to flatten the edge, put in a steeper edge bevel and then rethin/clean up the blade road. Single bevel knives can have a stupidly thin edge, but also have the back side sharpened and the user must be incredibly careful not to damage the edge. Double bevel knives should not be taken down to this point as a general rule, keep that micro bevel!!!


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 Post subject: Re: Konosuke Fujiyama Blue #2 gyuto and sharpening
PostPosted: Mon Feb 10, 2014 6:48 pm 
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Thanks for that!

That's exactly why I left the sides of this knife intact. There's just too much involved in the grind and the Shinogi, the finish; too much for my current skill set.
I lightly strop it on my Coticule and it does a beautiful job. No lower grits here. :)

I learned from going through a few previous Kurouchi knives, Japanese style, how quickly one can go through metal (especially when sharpening is fun).
And based on the fact that I was into the traditional swords for a while and had read all about what goes into making them (a lifetime of developing a single skill), I knew
ahead of time what I was getting into, and what I shouldn't do....if I liked the original knife.

There's still a ways to go on my knife till it needs to be thinned and as time goes on, the intervals between stropping get wider and wider. :)
...and realistically a person doesn't need to be touching these things up continually, unless of course it's your livelihood and the products depend on it.

The photos look great! I like the Choil shot. It'll be a good thread in the future for reference...

Hopefully this helps out Chocolatecurry too!



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