SKF

[SKF]

I recently picked up these two stones and wanted to know if anybody can tell me about them

[Grey Doffin]

I know that these stones shouldn't be used to polish Japanese swords. Grey

[ROKUJURO]

Steve,

where have these stones been quarried? If they are not Japanese, it might be difficult to find out the provenience as grindimg stones are found all over the world. Green ones are a bit rare.

In case these stones are not related to Japanese sword polishing, this thread should appear in the IZAKAYA I believe.

[Tensho]

Not sure about the green one, but the other is a Hindostan. 

[YourBabyBjornBorg]

That green one could be artificial or from China. The single largest natural wet stone product is a similar kind of homogeneous green stone at around 800~1000#.

 

[Grey Doffin]

Jean said "In case these stones are not related to Japanese sword polishing, this thread should appear in the IZAKAYA I believe." In case these stones are related to Japanese sword polishing, this thread should disappear. We are supposed to have zero tolerance for amateur polishing here; no properly trained polisher would have to ask about the stones.

Grey

[ROKUJURO]

Grey,

in principle, you are correct, but I saw his workshop in the background of the photos, so I hope he's just an innocent woodworker without bad intentions!

[SKF]

These stones were brought from Japan during World War II pass to my uncle and then to me. I just had hoped someone here had knowledge of their origin. My uncle told me the green one was used to flatten and correct the large one and create a slurry. I don’t mean to mislead or belittle anyone here just looking for info thank you.

[Tensho]

 

1 hour ago, SKF said:

These stones were brought from Japan during World War II pass to my uncle and then to me. I just had hoped someone here had knowledge of their origin. My uncle told me the green one was used to flatten and correct the large one and create a slurry. I don’t mean to mislead or belittle anyone here just looking for info thank you.

Here's some of my hindostans. The striations are a classic indicator of them and why I believe it is one. The 2 on the far right and the separate picture haven't been cleaned and still have old oil and grime. It looks like yours has been used with oil as well. 

 

What is the size? "Most" American stones fall within the 2x8×1/1.5 inch range. 

[ROKUJURO]

Many old grinding stones have been "killed" by using them with oil. 
As a general rule, all porous stones should be used with water. Stones that are so dense that water does not penetrate (like fine Arkansas types) should not be used with oil but only with low viscosity petroleum or lamp oil.

Grinding stones that have been used with lubricating oil can in many cases be "revived" by cooking them with laundry detergent.

[ROKUJURO]

4 hours ago, SKF said:

These stones were brought from Japan during World War II, passed to my uncle and then to me. I just had hoped someone here had knowledge of their origin. My uncle told me the green one was used to flatten and correct, the large one to create a slurry. I don’t mean to mislead or belittle anyone here just looking for info. Thank you.

Steve,

you may well use your stones for woodworking tools or carbon-steel knives. As usual, you have to test them for their effect which depends mostly on the grain size. Generally, natural Japanese stones are soft and are best used for flat grinding. Never use them with oil!