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bathonuk
04-13-2013, 05:48 PM
Hello. Today one guy has sent me his ZDP-189 knife. I thought that it will be easy but after close examination i have noticed that it is not straight what is not a problem. The problem is with grind. I think that it is 90/10 knife.


https://lh6.googleusercontent.com/-m9NGumuyA4I/UWnOqZe1wvI/AAAAAAAANAc/Mr-vaDWZ3oo/s675/20130413_124243%280%29.jpg

Red arrows show original primary bevel (or shinogi). The rest is a bevel which was grinded later. Guy who send me that knife said that it was like this before and that he sharpened it on diamonds (i think that it was diamond rod or something). Green arrow indicates lower spot on the edge. Other site of the knife does not have a bevel like this. It only have original bevel marked with red arrows.

Here you can see overgrind on the heel.

https://lh3.googleusercontent.com/-n1VfdMoRLQM/UWnOuwpEcpI/AAAAAAAANAk/_Pr6Br_wGd4/s675/20130413_124259.jpg

What would you suggest me to do? I was thinking about lifting shoulder of additional bevel (made with diamonds) to that shinogi line and make it even. Then sharpen it.

You can see that knife here. It's in the middle of the page:

http://www.japanesechefsknife.com/SPECIALS.html
ZDP-189 Santoku.

If you need any other pictures then let me know.

Marko Tsourkan
04-13-2013, 05:51 PM
That knife needs to be reprofiled and reground on a grinder.

M

bathonuk
04-13-2013, 05:54 PM
hmmm. That's bad. I've got a belt sander but I've never done that before. Any suggestion how to do it??

Marko Tsourkan
04-13-2013, 05:59 PM
You would be better off sending to somebody who has done this before, or in other words, a knife maker who will do this repair for you.

M

bathonuk
04-13-2013, 06:02 PM
Ok anyway what would you do if you had to explain that in words?? is it similar to thinning behind the edge, make the cutting edge even and then sharpen?? Maybe I will try to do that if this guy agree.

Squilliam
04-13-2013, 09:17 PM
Personally I would sharpen the knife with an angle of 15 degrees until you get rid of the flat spot. It will be all wobbly above the edge but it will be sharp. If you can even out the grind on the stones or with a machine, then that would be the second step.

Dave Martell
04-13-2013, 09:19 PM
That knife needs to be reprofiled and reground on a grinder.

M

Yeah looks the same to me as well.

kalaeb
04-13-2013, 11:21 PM
Wow, I don't claim to know anything about sharpening, but that is messed up, and ZDP no doubt...good luck.

knyfeknerd
04-13-2013, 11:43 PM
That knife is whacked out! Good luck man!

panda
04-14-2013, 01:08 AM
use it as a cleaver

TB_London
04-14-2013, 08:20 AM
That looks like it was caused by having a bend in blade, so that parts of the bevel are touching the stone but parts aren't. Either that or really bad sharpening....
If it isn't bent it'll be fixable, a belt grinder being the easiest approach, taking the usual precautions to avoid overheating (New ceramic belts will cut better with less heat)

bathonuk
04-14-2013, 08:59 AM
Ok so this guys has found some pictures of the knife OOTB.

http://img515.imageshack.us/img515/7713/dsc03514f.jpg

This is the movie before i've started my work:


http://www.youtube.com/watch?v=-Sc1B6l0pIk

I started with Bester 500 with no results. Then i've used dmt coarse (which is hardly cutting). After DMT i came back to bester but i've used narrow side. Eureka!! It's cutting like hell.

This is after maybe half hour:

https://lh3.googleusercontent.com/-z14aQVAPh6c/UWqNnOMErqI/AAAAAAAANBU/MdklEUrJBQg/s675/20130414_120438.jpg

and then after maybe one hour:

https://lh3.googleusercontent.com/-sE59SpUn8LU/UWqnRclrFxI/AAAAAAAANBk/cyolWn-NagE/s675/20130414_124956.jpg

https://lh6.googleusercontent.com/-5mLpn64gEXs/UWqnVkrdoDI/AAAAAAAANBs/oY8xRRQVn14/s675/20130414_125035.jpg

https://lh3.googleusercontent.com/-QWgZqFdx3uE/UWqnZTyNcII/AAAAAAAANB0/lbs2rATMzts/s675/20130414_125104.jpg

https://lh4.googleusercontent.com/-uWoPdwSooos/UWqneVgV_mI/AAAAAAAANB8/DiI_Vgzvhco/s506/20130414_125131.jpg


http://www.youtube.com/watch?v=OWI5ZR4xoDY

I will continue tommorow. I like the results because I thought that it will be immpossible but it's not bad. I have never done that before. Tommorow I will try to straighten the blade.

TB_London
04-14-2013, 09:11 AM
Looks like progress, are you keeping the asymmetry?

bathonuk
04-14-2013, 09:16 AM
Hard to say. I was thinning mostly right side because it was awful. It does look like 90/10 grind but I will try to make it 50/50. I just have touched left side for a while and will try to continue that tommorow. Also i tried to remove low spot by putting knife vertically on the stone and cutting like this.

panda
04-14-2013, 01:43 PM
good lord that thing is fat. you have some serious patience! you might be better off keeping it asymmetrical because it's so thick.

mkmk
04-14-2013, 04:33 PM
Ugh -- what a job to do on stones. ZDP is awfully cranky to handle that way.

bieniek
04-14-2013, 04:37 PM
Come on! Go for it ! :laughat:

bathonuk
04-14-2013, 04:44 PM
Hey guys it will be fun to do. I was scared because most people say ZDP-189 ...... be afraid, it's pain in the arse etc but to be honest it wasn't that bad. I will spend maybe one hour tommorow on thinning and that's it. Then I will polish it. I took some measurements: (heel, middle, aprox 2cm from tip)

Spine: 2.70 2.63 2.23
Shinogi line: 0.72 0.58 0.53

What do you think?? Should I thin it more or leave it like this?? I will definitely grind the left side tommorow because mostly i did right side today.

Zwiefel
04-14-2013, 08:16 PM
I don't have anything substantive to add to this.

Just two comments: 1) great work!, doesn't it feel awesome to do a repair like that?; 2) I'm totally psyched that I could look at the original photo on that and actually see and understand what was wrong...my nearly 1 year on this forum hasn't been for naught!

bathonuk
04-15-2013, 05:23 PM
Zwiefel it really does feel awesome especially that I know that in this situation I can sharpen better than somebody else:D hehe. To be honest i feel good because i have never done that before and now i've got opportunity to learn.

bathonuk
04-24-2013, 07:33 AM
Hi guys. I have finished fixing it. I was straightening it for a few days and now it's good. It's not perfect but it was my first time and i had to be careful. The only thing I regret is that i didn't remove all scratches after diamonds and the edge is mirror finished with scratches.


http://www.youtube.com/watch?v=clJDHzk6QiI

Squilliam
04-24-2013, 08:51 AM
Very nice. I knew you could do it :)

Dream Burls
04-24-2013, 09:38 AM
Nice Grgegorz! Keep up the good work.