Stone polishing whole knife (Kato/FM)

[KenjiF]

I’ve seen some incredible Kasumi stone polishes on FM’s, Kato’s and other knives with a blended shinogi and would love some tips on how this is done. Is it like a hamaguri polish that you just keep going till you reach the spine? Are you doing parallel and perpendicular passes on the stones? I’ve seen some cool jigs like maxim at JNS has what looks like a Sen but instead of a blade it’s a small stone he is running up and down the knife road… I’ve been able to get nice results with sandpaper, sic, finger stones and powder abut I’d love to be able to do the majority of the work on the stones so there are no low spots. Any tips?

 

[ethompson]

Is it like a hamaguri polish that you just keep going till you reach the spine?

Pretty much, just need to be conscious of how the grind behaves edge to spine and heel to time to vary your approach along the way.

Are you doing parallel and perpendicular passes on the stones?

Yep. I alternate with each grit. Doing so will make sure you aren't grinding in new low spots and are erasing all your scratches as you go.


This is one of my favorite polishes to work on. I've got several blades on my sharpening station waiting of this treatment now. It is very, very time consuming (it is a lot of surface area after all), but rewarding.

Some tips:

• Get to know your knife before starting - what is the grind like, what type of taper are you dealing with, is there asymmetry, etc.
• You'll have to work with the handle off the blade
• Change up grip and approach with each area of the blade as makes the most sense. Just because it looks / feels weird doesn't mean it's wrong
• Work in sections on knives with a lot of taper, but make sure your sections overlap so you're actively blending as you go.
• Convex stones (as in the opposite of dished) can be helpful with very convex geometries and non liner taper in maintaining that geometry.
• finish with strokes parallel to the spine / edge

Followed the above process more or less on the Kato I did. Looking forward to improving the result with the next one I’m working on, but all bench-stone work for me as that’s my weird little passion.

 

[KenjiF]

Awesome! Thanks man that’s great advice. I saw your Kato polish and and that’s what inspired this!

 

[KenjiF]

I want to do my 210 WH and FM. I think I might ease the shinogi on my cheap mazaki first and try that knife before I attempt the Kato and Kono… what grit did you start on Kato @ethompson?

 

[ethompson]

I want to do my 210 WH and FM. I think I might ease the shinogi on my cheap mazaki first and try that knife before I attempt the Kato and Kono… what grit did you start on Kato @ethompson?

Those vertical grind marks don't come out without a fight, I started at 180 grit.

Mazaki often has a hollow above the shoulder, check for that before starting perhaps.

 

[KenjiF]

Those vertical grind marks don't come out without a fight, I started at 180 grit.

Mazaki often has a hollow above the shoulder, check for that before starting perhaps.

Yeah I got rid of that day one. Pushed shinogi up and made it more flat/convex.
The one thing I’m a little confused about is a convex stone. In my mind it makes more sense if the stone is concave so more of it matches the grind but I know sword polishers use convex stones with convex grinds… I’m missing something because I’d expect that to cause more of a hollow grind…

 

[KenjiF]

Yeah I got rid of that day one. Pushed shinogi up and made it more flat/convex.
The one thing I’m a little confused about is a convex stone. In my mind it makes more sense if the stone is concave so more of it matches the grind but I know sword polishers use convex stones with convex grinds… I’m missing something because I’d expect that to cause more of a hollow grind…

Oh I misunderstood. Yes the maz definitely is hollow between shinogi and spine. I think I would leave the spine where it is and grind shinogi enough to get rid of the hollow.

 

[KenjiF]

My Kato has low spots near the kanji on both sides which is good I guess so I’m not going to loose any of the engraving. The FM has a hollow in the bevel about 8mm up from the edge about 4mm thick all along the bevel. Anyone know if this is on purpose? For food release and such?

 

[dragjp]

Spot on thread, I started a full kasumi practice project with a petty last weekend too. Looking forward to improve and do it on fancy knives.
And a question- for stone powder, sic and such, what do you guys use to rub them on the knife?

 

[ethompson]

And a question- for stone powder, sic and such, what do you guys use to rub them on the knife?

For sic @refcast knows better than I, he uses it to great effect while I've never used it for polishing.

For stone powder and diamond pastes I use hard felt. The little pads you'd use on the bottom of furniture would work and the larger hard felt blocks are awesome too
https://www.rockler.com/pumice-stone-rotten-stone-and-felt-blocks-application-blocks-sold-separately

 

[ethompson]

The one thing I’m a little confused about is a convex stone. In my mind it makes more sense if the stone is concave so more of it matches the grind but I know sword polishers use convex stones with convex grinds… I’m missing something because I’d expect that to cause more of a hollow grind…

With extremely pronounced convexity like swords it is helpful as you can be very targeted where you remove metal and I've found working perpendicular strokes on the convex surface leads to easy maintenance of strongly convex geometry.

Where it really benefits in kitchen knives is dealing with non linear handle, something like a Kato or Shig or Mazaki where the spine tapers in very quickly above the heel and you have a concave surface.

 

[dragjp]

For sic @refcast knows better than I, he uses it to great effect while I've never used it for polishing.

For stone powder and diamond pastes I use hard felt. The little pads you'd use on the bottom of furniture would work and the larger hard felt blocks are awesome too
https://www.rockler.com/pumice-stone-rotten-stone-and-felt-blocks-application-blocks-sold-separately

Ordered some larger ones, and glad that the little ones from ikea many years ago could be useful again, though in a very unexpected circumstance heh.

 

[esoo]

Fake it until you make it - i.e. stone dust

 

[crocca86]

This was only uchigumori powder and mash pad

 

[crocca86]

This was done by Lee Migoto cutlery on stone

 

[NickMinton]

Are there any books or articles with illustrations? I’m a visual learner, so reading all of this only gets me so far in understanding

 

[jedy617]

Are there any books or articles with illustrations? I’m a visual learner, so reading all of this only gets me so far in understanding

If you are interested in polishing, Milan gravier has plenty of 2+ hour long Instagram videos (also on his small YouTube channel I believe) where he goes step by step polishing a knife from the ground up, explains his movements and what stone he uses and why. Very valuable info that he puts out for free, especially since he is one of the best out there.

 

[KenjiF]

@jedy617 @JuniperGhosts His videos are gold. Would definitely recommend. I can do a really nice sic/uchi powder, micromesh Kasumi finish. A bench stone finish is the next level up I think and is more versatile. And I won't have that voice in my head saying 'you can't polish a turd...but you can roll it in glitter'