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What Natural Stone Characteristics for Polishing Wide Bevel?

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tostadas

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I have another question for you guys for a newbie to naturals. After reading lots of threads about on beginner tips for naturals, I see a wide range of recommendations for types of stones to start with. It seems that good stones for sharpening and edge maintenance are not necessarily the same as those for polishing wide bevels.

I'd like to try out a natural with the aim of achieving a smooth looking kasumi finish on wide bevel knives. I created this list of general stone features from my limited understanding based on research of natural stones:

Hardness (soft, medium, hard) I think JNS rates these on a scale from 1-5
Coarseness (pre-polish, medium coarse, finisher)
Aggressiveness (slow, fast)

So what characteristics would be best to look for, and what would you suggest I try without spending too much (~$50-100)?
 

nakiriknaifuwaifu

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A finisher koppa has worked well for me and you should be able to pick one up on BST within your budget. There's little point getting a mid-grit Jnat and then finishing it on synths.

So going by your criteria, I'd say maybe medium hardness around 3 (2.5 - 3.5), estimated 6k+ or 8k+ grit, with satisfactory speed (as long as it's not painfully slow it should be fine).

If you're buying on BST, you could ask for pictures of the slurry and something that has been finished on the stone to get an idea of what sort of finish the stone gets you.

I'm still pretty new to Jnats, but that was my goal picking up my first one and I've been pretty happy with it so far.
 

Matus

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I would first ask - what results are you getting at the moment with synthetic stones in this regard?
 

tostadas

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I would first ask - what results are you getting at the moment with synthetic stones in this regard?
With a shapton 1k, I am getting decent contrast, and uniform scratch pattern. However, the finish is too rough for my liking as I notice the drag when cutting things. Shapton 2k is also not bad in terms of uniformity. The surface still has more drag than I would like, and I also would like to remove the visible scratch pattern. When I try with the shapton 5k, I dont work up very much slurry, and it may be due to my pressure being off, but there are areas, particularly near the tip where I lose the haziness and instead get streaks of shiny (for lack of better description). I don't know if it has more to do with the 5k stone itself or my technique, but that is about the point where I feel like the scratches start fading, but the finish trends toward more of a mirror than matte.
 

Matus

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The reason I asked was to see, whether you have done this with synthetics before going to naturals. Since you did and given your synthetic stones, I would try to find some cleaner stone at around lv2.5-3.0. Maybe a suita or something along those lines. But most likely you will need a budget of $200-$300 to find a nice stone without hard lines or particles and with a usable size.
 

tostadas

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The reason I asked was to see, whether you have done this with synthetics before going to naturals. Since you did and given your synthetic stones, I would try to find some cleaner stone at around lv2.5-3.0. Maybe a suita or something along those lines. But most likely you will need a budget of $200-$300 to find a nice stone without hard lines or particles and with a usable size.
Are there smaller versions of those stones that are still usable, for less cost?
 

DHunter86

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You could try to get uchigumori koppa at about Lv 2.5 to 3 hardness. Either small ones, or larger ones (which you'd need to dig out the toxic lines) at that price. I got a large one for about 60USD from Namikawa, with a couple of toxic lines. Not too hard to dig out with a triangular diamond nail file.

With the Uchi, I'd recommend first using your shapton 5k to to get a high polish on the core steel, then go to the uchi to clean up the streaks.

Are there smaller versions of those stones that are still usable, for less cost?
Definitely usable if you can find clean smaller koppa. Just that you'd have limited "real estate" to work with and you should be mindful of getting a consistent polish on the whole bevel.
 

Badgertooth

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Koppa is the gateway drug.

And you’ll reap the benefits later of having to learn on a slightly smaller stone. Anything with a hardness under level 4 should do the job as long as it’s a clean stone without too much garbage lying in wait in terms of inclusions and particles. Namikawa is a bit of a crapshoot. if you’re in the states try Bernal Cutlery. They have some nice koppa for cheap.
 
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