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Show us your Japanese Natural Whetstones

Steve56

Ask me about shaving naked!
This surely will be interesting when you are going to compare one stone with the other.
Do you do this or do you just hone away.
If you do compare? do you test the hardness/cutting ability of the stone or just the edges the stone produces?

The first thing that I’ll do after unpacking them and smelling them for honing solution is a visual check for flatness then I’ll take a small mellow diamond plate and rise a little slurry on each to get an idea of the hardness. I’ll flatten the ones that need it.

Next, I’ll take 2 stones and 2 shave ready Gold Dollars, raise a thin slurry on each stone and refinish the Gold Dollars and test HHT. I’ll do this for all the stones and will have a rough idea of fineness based on HHT.

During honing, I’ll watch to see how fast the slurry darkens, that tells me something about speed.

At this point I have a very rough idea of hardness, speed, and fineness, so I’ll pick 2, refinish the Gold Dollars and shave test the two, and note the ‘winner’. Then the next two, and the next. By the time I’ve done this, I’ll have a better understanding of what I have.

To test individual stones, I do this by shave test, cycling a set of selected razors across each stone. I do this because some stones are better at hard steel than others, some stones do better on Sheffield steel, etc. My test razors are

1. Gold Dollar
2. A Hayashi or Towa user (Japanese steel, medium grind)
3. A Filarmonica 14 user (thin grind)
4. A Sheffield
5. A Henckles Friodur (‘normal’ stainless)
6. A Puma Inox (hard, thin steel that’s finicky about the stone).

By the time that I’ve shaved 6 times off a stone with 6 selected razors I pretty much know what it can do and is suited for. I’ll have a decent idea if it’s a cutter or a polisher, a prefinisher or a grail stone, etc.
 
Thanks for sharing your process. I pretty much do the same... Apart from testing the Stone with different razors, which of course is a great idea i will implement in my testing routine.
 

Steve56

Ask me about shaving naked!
Thanks for sharing your process. I pretty much do the same... Apart from testing the Stone with different razors, which of course is a great idea i will implement in my testing routine.

The Gold Dollar, Filly 14, and Puma are kind of sensitive to stone quality. If the stone can make silent HHT on any or all of these, that tells me something. If it can do that on these 3 it’s always a winner. The Sheffields, Japanese, and Henckles are more forgiving.
 
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Steve56

Ask me about shaving naked!
Playing around with the mikawa nagura lot, 740g and it’s all grit rich, the slurry from all of them darkens fast. These are likely a set, they all have the same stamps on them as far as the 3 that have legible stamps, but no layer stamp. They’re all producing smooth slurry, except one feels kind of ‘grinchy’. So I’m fairly happy with them.

I’m going to have to shave test them for fineness, I tested each on one side of a worn near wedge with one side done with a vintage stamped koma.

They’re arranged in order of hardness, left to right top to bottom. The first softest stone polishes better than the vintage koma. The next one polishes about the same. The third top row makes a slurry that doesn’t seem as smooth as the others, but the polish is similar to the vintage koma, it has a crack in it that I’m not fond of. The bottom stones are fairly hard, and polish as well or better than the vintage koma.

The last two are 145g and ¥1200, which would be about 27 cents/g in today’s dollars if this was sold in 1970. The larger piece is 200g and ¥1300 or about 22 cents/g in today’s dollars. Anybody know what koma sold for in Japan in the 1950s-1970s?

HHT testing was interesting. I used a hard fine finisher for the base, and got indistinguishable silent HHT root out. Root in, the first (upper left) seems coarsest, the next two the same, and the two bottom row returned silent HHT root in. The two ‘priced’ stones are definitely koma grade, with the striped one being pretty hard and a little harder than the other.

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