round sharpening stone odd shape,whats it for

[international3414]

4" diameter,1.5" thick,,two grits,.,,something i have had for a while,ever seen one?.,.,TIA

[lptools]

Curved gouges? lathe turning tools? That's the woodworker in me, making a guess!!! Regards, Lou

[rustyfordgarage]

Look up norton jb74 machine knife stone. The groove is to protect your fingers.

[Bill Houghton]

I've seen axe stones with that groove, too.

[Batz]

Yes that's an axe stone.

[skipskip]

Yes that's an axe stone.

how does it work?

[Bill Houghton]

Yes that's an axe stone.

how does it work?

Hold the axe in one hand, and cup the stone in your palm, with fingers in the grooves, keeping them well away from the exposed face of the stone.  Lubricate the stone (spit was common when doing sharpening in the field) and rub it over the edge.  As with any sharpening, you're abrading to a sharp edge.  Most axes, except side axes and the like, have two bevels meeting at an edge, so you'd work both faces.

[international3414]

This 4" round silicon carbide (Crystolon) stone has both a coarse side (120 grit) and a fine side (320 grit). Used for sharpening and honing paper and cloth-cutting knives and planer knives. The groove around the middle of the stone protects fingers and provides a secure hold. 4" in diameter by 1.5" thick.
...............

[Lostmind]

I have one in the box , been in my tool box for 30 years or more. Very nice stone , comfortable to use.
I think they call it Ergonomic ? now

[Batz]

http://www.knifeshopaustralia.com.au/norton-axe-sharpening-stone-10-cm