# Rounding off spine and choil



## mark76 (Nov 29, 2014)

I want to try to round the spine and choile of a carbon knife (white #1 laminated with iron). On the spine I'll use the shoepolising technique

What grit sandpaper (wet-and-dry type, I understand) should I start with? And what grit should I end with for a nice polish?


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## chinacats (Nov 29, 2014)

Not sure of your knife, but I usually stay with a round file and then go 180, 400, 800, but that's just me...the file makes quick workf of it and the sandpaper cleans it up nicely.
Cheers


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## mark76 (Nov 29, 2014)

Thanks! Only... a file? Won't you blunt the file as fast as or faster than the knife? This knife is at around HRC 61.


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## riba (Nov 29, 2014)

mark76 said:


> Thanks! Only... a file? Won't you blunt the file as fast as or faster than the knife? This knife is at around HRC 61.



(your average file is about 60 - 61 hrc)


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## XooMG (Nov 29, 2014)

I use a rough diamond file followed up by 100-grit and then work up from there.


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## icanhaschzbrgr (Nov 29, 2014)

You mostly would be rounding soft iron, which is easily removed by any abrasive. I usually use sandpaper. 100, 240, 400. Could go higher if I'm after mirror, but for just rounding purposes I feel 400grit is enough


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## chinacats (Nov 29, 2014)

mark76 said:


> Thanks! Only... a file? Won't you blunt the file as fast as or faster than the knife? This knife is at around HRC 61.



Yeah, your core steel is 60 or so, but the iron laminate is soft...file will make quick work of it.


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## mark76 (Nov 29, 2014)

Thanks guys! I got the sandpaper today and will use it tomorrow.


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## Benuser (Nov 29, 2014)

Get P120 automotive sandpaper on linen, "Metall", by Robert Bosch.


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## EdipisReks (Nov 29, 2014)

I usually use foam-backed sandpaper. Makes it easy.


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## Ruso (Nov 29, 2014)

I use wet-dry 220 grit sandpaper to do the work and 800grit to smooth it out; Via shoe-shining motions and a vice.


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## labor of love (Nov 29, 2014)

I have a kurouchi knife that has a pretty sharp spine. Any tips on how to minimize the loss of the kurouchi?


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## XooMG (Nov 30, 2014)

labor of love said:


> I have a kurouchi knife that has a pretty sharp spine. Any tips on how to minimize the loss of the kurouchi?


One could use masking tape...I haven't had too much trouble with loss of kurouchi from spine rounding (much more of a problem with thinning and bevel flattening), but if I were trying to be somewhat careful, I'd use clear nail polish to prevent stray grit from scratching away the sides, and then pull it off with acetone afterwards.


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## cclin (Nov 30, 2014)

I use Norton 47855 Metalsand Emery Sandpaper to round spine and choil. For kurouchi finished knife, I use liquid gun blue for touch-up but it wear up very fast & gun blue won't work with stainless kurouchi .....


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## mark76 (Nov 30, 2014)

Thanks guys!

This morning I did the job. It was this knife: http://www.kitchenknifeforums.com/showthread.php/20596-Tadafusa-small-Santoku-KNT-135-(EU) .

I started off with 100 grit sandpaper. But that took quite a while... And the sandpaper loaded up really quickly. Then I thought, I have diamond files, too. My Wicked Edge stones!

So I treated the spine to my 100 and 200 grit Wicked Edge stones. Then sandpaper again: 100 - 180 - 240 -320. I wasn't looking for a polished spine on this rustic knife, so I stopped there.

Then I took the knife to the stones, since it had a terrible edge. (A nice grind though, but just not sharp.) It's wickedly sharp now.

And now I like the knife so much, I withdrew it from sales . It's gonna be my go-to knife for the coming time. I'm really curious how reactive the cladding is...


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## mark76 (Nov 30, 2014)

And then I also did my Teruyasu Fujiware gyuto. (Yes, I've got one  .) I wasn't sharp on the spine, but it could use some easing. And I had the confidence now.

This time I brought it to 600 grit, although it didn't really need that. It's super-round and quite polished!


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## riba (Nov 30, 2014)

Sounds like a big success, congrats


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## icanhaschzbrgr (Nov 30, 2014)

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Please feel free to insert pictures in the above placeholders


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## XooMG (Nov 30, 2014)

mark76 said:


> Thanks guys!
> 
> This morning I did the job. It was this knife: http://www.kitchenknifeforums.com/showthread.php/20596-Tadafusa-small-Santoku-KNT-135-(EU) .
> 
> ...


One of my knife epiphanies was cleaning up the grind and easing the spine and choil of a 135mm funayuki, not unlike what you're doing with the Tadafusa. Once it was finished up reasonably well and more comfy, it became one of my favorite little knives, with some of the best cutting characteristics I've come across. Made me look at all my other knives to see if there might be something even better hiding under the surface.

Please share pics when you can.


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## panda (Nov 30, 2014)

Looks like you've discovered a not so well known recipe for great cutting performance. Thick spine, hollow forge, large secondary asymmetric bevels, thin behind the edge. I've tried the tosa funayuki as well as the 210 suji, quite a bargain when properly tweaked.


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## mark76 (Nov 30, 2014)

icanhaschzbrgr said:


> Please feel free to insert pictures in the above placeholders



I'll make some pics of the Teruyasu Fujiwara later. You can find the before-pics of the Tadafusa in the B/S/T forum. I don't think my camera is good enough to clearly depict the easing of the spine...


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## mark76 (Nov 30, 2014)

I posted some pics of the Teruyasu Fujiwara here. The photos are made with my mobile phone. When my DLSR is back, I'll make some better pics.


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