Anyone else having trouble with their Morihei Hishiboshi Karasu 9k?

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GeassEffect

GeassEffect

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I just cannot seem to get a feel for this stone when I'm trying to polish bevels. I use a diamond plate to flatten it and splash it with some more water. Then I go to town. It feels okay-ish the first 1 or 2 passes, but then I can always feel the steel catching on something and then I have these ugly silver streaks on my bevels. It just feels really gummy and rubbery in general. It gives a nice and toothy edge but I just cannot seem to polish well with this stone.

Also, is anyone using the Suehiro Rika 5k for bevel polishing? I always seem to get little particles in the swarf which scratch up my finish...
 
ethompson said:
What diamond plate are you using? How well worn is it? sounds like maybe you're leaving imbedded diamonds in the surface. Another potential cause is sharp edges on the stones. Do you round the edges of your stone after flattening?
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It's a DMT DiaSharp 140 (?) grit plate. It's definitely a bit worn, but the scratching doesn't happen with my other stones.
EDIT: I always round off the corners of my stones
 
I tried again today with your suggestions. I soaked the stone for 10 minutes and I used lighter pressure - I'm still underwhelmed tbh. The stone still soaked up a lot of water and the feel was better but still very rubbery. Lots of tiny scratches in the finish. IDK maybe I got an off model.

Just to get a comparison I spent a few minutes flattening a small spot on a uchigumori koppa I got off ebay a bit of time ago. Even with the small, ****** surface I made the uchigumori koppa felt waaaay better and produced a more beautiful result. Even when the blade road felt like it got caught on the stone a bit there was no burnishing effect. Might have to get a full size JNAT of the same kind.
 
Run hot water on the stone, or soak it in hot water, it should ease up the scratches, slurry more, sharpen more smooth and gliding. Works on Jnats too. But yeah, in general I prefer jnats for high grits because they feel better .... Usually.
 
Using the appropriate Nagura stone might help solve those problems.
 
refcast said:
Run hot water on the stone, or soak it in hot water, it should ease up the scratches, slurry more, sharpen more smooth and gliding. Works on Jnats too. But yeah, in general I prefer jnats for high grits because they feel better .... Usually.
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Just tried that, I soaked the stone for like 30 mins in hot water - that really made a difference. The stone didn't load up much at all and I did not get any white streaks in the kasumi finish. I'll experiment some more with this, thanks for the suggestion!
 
I frustration-bought a Kitayama 8k because I saw people praising it to the high heavens - it feels better but it also loads up really quickly, which leads to those white streaks. I'll try soaking it as I did with the Morihei 9k, let's see...
 
GeassEffect said:
I frustration-bought a Kitayama 8k because I saw people praising it to the high heavens - it feels better but it also loads up really quickly, which leads to those white streaks. I'll try soaking it as I did with the Morihei 9k, let's see...
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Apologies if this is unhelpful, but at that level of refinement, you could probably buy a koppa sized natural stone for a similar price to those synths - @ared715 has lots of good stuff at the moment.
 
Yeah, the hot water really makes a difference.

For example, I had a Tsushima stone, notorious for being too hard, I've soaked in room temperature water for months, still was sorta hard. But when I ran hot water over the surface for a couple minutes, it felt amazing and so much better, slurried, and no stray scratches
 
About the Suehiro Rika 5k - now I cannot get this stone to work properly. When laying the bevel flat on the stone, I get deep, shiny scratches. Doesn't seem to matter what I do to the stone, I tried flattening it, I tried soaking it longer (30 mins), I tried the hot water trick (which really makes the other stones I have shine). Idk what it is, could I have corrupted the stone somehow?
 
If during flattening, you use a diamond plate, sometimes the diamonds get stuck . . . Use a nagura to clean the surface after flattening. Should abrade away any stuck diamonds.
 
I started this game with DMT stones that I had used on hunting knives. For that they were ok but I would not let a "good" knife near them. Seemed they always had debris coming off them. I've used the Morihei 4 and 9K without problem (but at the end of the day I'm not much of a polisher).
 
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