Thinning JCK Nashiji, what is happening here?

[Twister]

Got it to this state last night. Took me almost 2 hours, but I took it as learning...

I had to go between 1000 and 6000 quite many times. Every time I returned to 1000 - instant dull grey all over.
Also difficult to see what is beneath that grey layer. So when back with the 6000, more scratches revealed. This happened many times.
At the end I almost felt like crying when most of the grey was cleaned and then saw scrathes again and new I had to go back to 1000 and thus back to a lot of grey

Getting rid of the grey with 6000 was also something really strange. During the 2 hours it seemed when I held the knife 45° to the stone, like when sharpening, the grey just did not reduce.
I tried just about everything - varying the angle (of "knife handle to stone"), pressure, placing of fingers, how much mud on stone and flattened the stone few times during the session.
At the end, only turning the knife to 90° to stone and going with lightish pressure seemed to make a difference and worked the best. Touching up with newspaper also took some of the light grey which the 6000 just did not reduce.

So next time thinning and polishing this knife, I'll get some coarse stone, like Gesshin 400, and also have a go with the nashiji part. Just to get some challange and learn more
Perhaps some extra high grit polishing paste might be worth a try? Or perhaps a loaded strop?

[ThEoRy]

I'll say this too, you have stumbled upon a good technique. When creating a kasumi finish, it is light pressure when working in the mud which achieves the best results. So, work up a mud then play around in it with only the weight of the blade as your downward pressure and you will see a more even scratch pattern and or kasumi finish depending upon the stione.

[harlock0083]

Did you request the thinner profile from Koki?

[Squilliam]

It sounds like you're very confused to me. You should not be trying to make the wide bevel all the same reflective colour. The soft cladding is meant to turn dark on your stones, using low pressure helps. It's called kasumi and it looks nice. It's the finish many natural stones leave.

Check out this thread for more: http://www.kitchenknifeforums.com/sh...-single-bevels

[zitangy]

I had the first thinning session for a JCK Fu Rin Ka Zan W1 petty. http://japanesechefsknife.com/Furink...eSteel#1Series
Started with King1000 stone and after a while swithced to King6000.

These are pics after ~5min of work with King1000:


What is happening here? Why does it turn into blunt grey?

D> I believe that it is from the mud. I do not think that 5 min on the 1000grit King stone will not remove the cladding. and as the original striations are still there.. it means that teh cladding is still there. Normally, I try to remove till the original striations are evened out.

a) some stones leave dark shades adn some light. IF shades are uneven, I normally use sandpaper 600 grit to remove mud shades and make it even.TO add some greyness I wld either use cork with mud or sandpaper with mud

b) Playing with Mud. pressure and how dense the mud is plays a part.

b) On the polishing stone.. some leaves "cloudish" shine.

c) for my thinning jobs,, either I use sandpaper or bring the stone to the knife... preferably smaller ones from old worn out stones thats broken into smaller pieces.

You lost be below...

Firstly, is my understanding correct here:
1 = Hira, Nashiji finish
2 = Shinogi line
3 = Kireha, this part is stainless clad, or?
4 = "Hagane line"
5 = Hagane, White no1

.

RGds d

[ar11]

Not sure if it helps, but I've been trying to thin my Tanaka on a King 1k/6k combo. Noticed a lot of the graying issues you noted. After a lot of back and forth on stones decided to hand sand with 1000 grit wet sandpaper which was already pretty loaded. The second pic is after 30 secs of scrubing, I still had work to do on the heel but you get the idea. You can still see scratching from the sandpaper in the after photo, but I used #000 steel wool as a followup and it got rid of most of the scratching. Probably going to use my oscillating multitool to polish up the blade to a nice shine.

*one thing i learned the hardway not to do was rub BKF onto the carbon blade because it creates random greying discoloration which can be a PITA to take out.

Before



30 sec after

[Twister]

Did you request the thinner profile from Koki?

Yes I did, but after my purchase it went sold out, so I probably got what was left in stock. Little over 2mm thick.

Thanks to all for helping here. I am very happy with the knife now.