# Understanding repair progress



## toufas (Feb 10, 2016)

[video=youtube;VXAqeb1ANlg]https://www.youtube.com/watch?v=VXAqeb1ANlg[/video]
Greg has fixed my knife here.
I asked him to provide some play by play on the whole thing, and I would like some more info. I know he is busy so I don't want to bother him more than I should!
He has sent me the following:
2:25 - Normal sharpening (removing the chips) on the 300 grit stone. You are starting from putting pressure on shinogi line. Once the whole blade is polished you can jump to edge sharpening. You have to put pressure on the edge. Just change position of your fingers.
3:08 - burr removal on 1k (only because I am repairing your knife - remember that ura is very delicate and you don't want to make it flat)
3:14 - Kept repairing on 300grit
3:35 - ura again
4:20 - Polish beer hehe
5:16 - I am doing exactly same thing as previously, but on the JNS 800 grit stone. Chips are removed now. As you can see I spent most of the time on removing those damages.
6:00 - One more time uraoshi on the 1k, just to be sure that it is totally flat. If it is not flat, then you will not be able to remove the burr.
6:16 - From now on I will use only high grit stones to sharpen back side - now it's 6k from JNS
6:34 Natural Red aoto
7:26 - After 6k I am cutting very delicately in to the wine cork to remove the burl. Be carefull here, because if burr is big you can rip it of the blade and create the chip.
7:31 All the same as previous. Just polishing on the Red Oohira
8:14 - Shapton Pro 8000 - uraoshi sharpening
8:20 - microbevel on red oohira - just lift the angle on the highest grit stone you own and create very delicate microbevel if you need it.
Flip the burr over - strop and do uraoshi to clean the edge
8:58 - I have used diamond plate to create mud on the oohira to polish your blade a little bit mire. You can use wine cork to do that.
9:08 - strop on leather

My questions: why you dont want to make the ura flat? I thought that its supposed to be flat?
Wouldnt the 800 be enough to repair the chips? Is there a reason you start that low, go to 800 and then 1000? Why the jump from 800 to red aoto/6000?

Any other comments you guys can make, please feel free to do them


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## Mrmnms (Feb 10, 2016)

Wow , he sharpens really fast! I don't do a lot of single bevels, but on the ones I've done the backs are concave. Maybe just working the back enough to evenly remove the burr created. Just flattening the edge for me. His 800 grit choice of stones seem to enhance the shinogi line. I'm sure someone with more experience can explain this better.


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## JBroida (Feb 10, 2016)

what he means is that he's trying to not over flatten the back and get rid of the urasuki (hollow ground part)


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## Mrmnms (Feb 10, 2016)

Thank you Jon


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## rick_english (Feb 11, 2016)

Impressive work. Anyone know where to get that 80 grit powder he used at the beginning?


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## skewed (Feb 11, 2016)

toufas said:


> My questions: why you dont want to make the ura flat? I thought that its supposed to be flat?
> Wouldnt the 800 be enough to repair the chips? Is there a reason you start that low, go to 800 and then 1000? Why the jump from 800 to red aoto/6000?
> 
> Any other comments you guys can make, please feel free to do them



Just in case you are still unclear about this: the back of the knife is hollow ground (concave) with a narrow rim around the entire edge that is 'flat' or on the same plane. He only flattens the rim on higher grits to lessen the flattening of the entire back on the knife (the rim will grow rapidly on course stones and less rapidly on finer stones). I believe the rim that I referred to is the uraoshi while the concavity is the urasuki. The hollow grind is there to to speed up sharpening of the back of the knife since you only remove a small amount of metal from the uraoshi/rim instead of the entire back of the knife if it were flat rather that concave.

..."ura is very delicate and you don't want to make it flat." I think he is referring to the uraoshi and that if you use courser stones then the uraoshi will expand quickly making the entire back of the knife closer and closer to being flat, in other words, reducing the hollow grind/urasuki.

I hope that helps.

I am not an expert and hope others with correct me if I am wrong.

Cheer and thanks for sharing that great vid!
\rj


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## toufas (Feb 11, 2016)

What about the grit progression for the edge side? What is the reasoning on that?


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## toufas (Feb 11, 2016)

JBroida said:


> what he means is that he's trying to not over flatten the back and get rid of the urasuki (hollow ground part)



Is that the reason that you don't use a low grit stone on the ura?


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## skewed (Feb 12, 2016)

Moving from ~800-1200 grit to ~6000 grit is a fairly natural progression. Also, yes, that is the reason to use high grit stones on the ura. It will diminish the wear on the ura


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## natto (Feb 12, 2016)

rick_english said:


> Impressive work. Anyone know where to get that 80 grit powder he used at the beginning?


It looks like silicon carbide powder, usually used to flatten stones.:scratchhead:
http://www.fine-tools.com/abrichtblock.html


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## Matus (Feb 12, 2016)

rick_english said:


> Impressive work. Anyone know where to get that 80 grit powder he used at the beginning?



Maxim carries it too.


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## _PixelNinja (Feb 12, 2016)

rick_english said:


> Impressive work. Anyone know where to get that 80 grit powder he used at the beginning?


It's Maksim's "C Powder". 

Every time I want to buy some he's out *sadpanda*


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## natto (Feb 13, 2016)

rick_english said:


> Impressive work. Anyone know where to get that 80 grit powder he used at the beginning?


It looks like my guess about the c powder was correct. 80 grit may be a bit rough for clean up, but from the vid the result looks good. I would expect deeper scratches, so the tool might be important too. Does anyone know his tool?

Greg's cleanup looks pretty good!


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## _PixelNinja (Feb 13, 2016)

natto said:


> It looks like my guess about the c powder was correct. 80 grit may be a bit rough for clean up, but from the vid the result looks good. I would expect deeper scratches [...]


That's because the C Powder breaks down.


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## MAS4T0 (Feb 13, 2016)

It's a real shame that Greg isn't taking on any more sharpening/ repair work. I know that he has his reasons, but the Greg was the go-to man any kitchen knife repairs you needed doing in the UK. He's done some great work for me in the past, with a great turnaround time, and he always over delivered on expectations. I'm now trying to learn to do more myself as I don't know of anyone else to send high-end knives to without incurring big customs bills (especially since Maxim is so busy).


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## JBroida (Feb 13, 2016)

MAS4T0 said:


> It's a real shame that Greg isn't taking on any more sharpening/ repair work. I know that he has his reasons, but the Greg was the go-to man any kitchen knife repairs you needed doing in the UK. He's done some great work for me in the past, with a great turnaround time, and he always over delivered on expectations. I'm now trying to learn to do more myself as I don't know of anyone else to send high-end knives to without incurring big customs bills (especially since Maxim is so busy).



huh? when did he stop?


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## _PixelNinja (Feb 13, 2016)

JBroida said:


> huh? when did he stop?


He put up a message on his website last year that he was going on an indefinite hiatus from taking in work.


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## MAS4T0 (Feb 13, 2016)

JBroida said:


> huh? when did he stop?



He posted a note on his website a few months ago and I contacted him recently to ask if/ when he was going to take on new sharpening/ repair work. He said that he's not taking any more on at the moment and that he was focussing on knife making, but expressed that it was as a hobby rather than as a business.


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## brainsausage (Feb 14, 2016)

Is there a vid that isn't sped up? Its kinda annoying not being able to see the actual work being done real time.


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