Japanese Natural Whetstones Lifespan?

[The Forest Ninja]

Just wondering,

I got a bunch of various Japanese Natural Whetstones and was wondering if any of you have used one until it was all gone?
Like has anyone purchased lets say an 1,000 gram J Nat, killed it? If so how long did that take and what type was it?

As I build my stone castle.

Cheers

 

[mockit]

I think that unless you are a professional who uses them 3-5 days a week, they will likely last you a lifetime. @milangravier has plenty left on his monster-size Mauro after what I imagine is very regular use. I have kept an eye on that stone over the course of his many videos, and it's still gigantic.

 

[gentiscid]

They will outlive you!

 

[ethompson]

It's doable, but very unlikely unless you are a professional sharpener or woodworker. A 1kg stone will roughly be 200x70x30 or similar. I'd expect at least 10 hours of use per mm for in a polishing context. For a maker doing multiple blades per week at 15 minutes per side that'd be 50 hours of use and therefore about 5mm worn away. So a 1kg stone would easily satisfy a professional for 6 years... Something like a very soft akapin would wear faster and a hard kiita would wear much, much slower.

So yeah, you can easily get hundreds and hundreds of projects out of a single full size jnat. They wear, but not at a rate that should be of concern for the vast majority of users.

 

[The Forest Ninja]

It's doable, but very unlikely unless you are a professional sharpener or woodworker.

Wondering how long a Japanese Sword polisher's stones lasts for.
May have find one online and ask.

 

[ethompson]

Wondering how long a Japanese Sword polisher's stones lasts for.
May have find one online and ask.

You’re going to get the answer, “it depends.” The do so much more shaping of the stone to match the blade and so much more pressure (typically but not always) used that how they wear stones isn’t really comparable to our application here. Worth satisfying curiosity though.

 

[The Forest Ninja]

I'm convexing one end of my bench stones especially for polishing a convex blade.
Flat grinds are something above my ability now. Convex edge was more natural for me.
Learning belt sanders will take time like anything else. Will look at jigs so I can grind better.
But yeah, so many viables involved.

 

[ethompson]

To each their own, but I’ve never found convex stones terribly good to use. You can polish a convex surface on a flat stone fairly easily and the convexity on knives is subtle enough that o generally find it more efficient and consistent to use a flat stone 98/100.

 

[milangravier]

I think that unless you are a professional who uses them 3-5 days a week, they will likely last you a lifetime. @milangravier has plenty left on his monster-size Mauro after what I imagine is very regular use. I have kept an eye on that stone over the course of his many videos, and it's still gigantic.

Yeah I bought that huge Maruo shiro suita 2 years ago exactly, was 65mm thick when it arrived. Now it is close to 55mm I think. So about 5mm every year. But I have bought other stones in the same range to try to save that stone, and I used it intensively only one year I think. I love that stone, it's just the best working stone I got, so I save it for some knives where I need best preparation possible before going on a finer stone.
I got now a even more huge monster stone from @ethompson, most likely a shobu akapin, and I am using now those two stones for polishing my knives.

@The Forest Ninja it really depends the work you're doing and the stone. You want best combo to wear the stone the faster you can ? Full polish san mai blade with wrought iron clad and a soft prefinisher like maruoyama stones or soft shobu. If you work only that combo you will eat stones at breakfast.
Best combo to save stones ? Hard honyaki with very very high hamon and a hard piece of ozuku stone (I don't garantee a good result).
Basically the softer the material to polish and the softer the stone : you will wear the stone faster. Polisher generally search for balance and will work a soft clad with a harder stone and a harder steel with a soft stone.
Soft stone will behave super super soft on wrought iron but will feel much harder on hard steel.

 

[Mr Kooby Shemayrew]

Not entirely relevant to knife sharpening but…..

This is a very old Nakayama Mizu Asagi. It came from a long since closed down barber shop and it is a barber hone, very hard and slow wearing. I guarantee it outlived the previous owner.

The Maruka stamp being half-way worn through is pretty amazing to me. This would be the era before diamond plates so this was likely accomplished on Mikawa Naguras. It would take about a lifetime to wear this stone like this for razors.

Generally this stone is too smooth for knife-work but stopping at a botan nagura does give a pretty darn nice knife edge.

 

[Nemo]

They last long enough for inflation to make the extortionate prices you paid for them seem trivial.

 

[The Forest Ninja]

This would be the era before diamond plates so this was likely accomplished on Mikawa Naguras.

It's possible another similar stone was used like a Tomo Nagura.
I don't have a Diamond Plate yet and use as much as possible a
similar stone as to get pure slurry.