Doubt you'll hear much from them in shavingdoms' cyberspace, but rest assured, a silent Gülenist secret society army of razor-bevel-concaving fools is out there, slinking in the shadows, and one planned day coming all at once for your flat whetstones. They just don't want to hear any retorts from gssixgun, steve56, daltongang, and the rest of the 'flat earth society'.

This stone’s been made convex on one side, as a cylinder, of about a 22’Ø curve.   It took me a little more than two hours and ~$4 of abrasives to finish it.  I have a special cylindrical version of my lapping plate, and I can’t make them for a reasonable price anymore, for some reason it costs a lot more to make a big cylinder than an ellipse, no matter who you shop it to.  But it will take years of use to flatten this stone meaningfully, meaning that it would require resurfacing; if you’re anal, get a Norton 75x20x20mm prep stone, wrap some sandpaper around the top of this stone, and shape one 20mm x 3″ facet of your prep stone so that it is concaved to match the convexity of the bench stone.  Use that to rub down the big guy before each session and that’s all you’ll ever need to do.

This stone is of great use in both the razor world and for kitchen cutlery, and I’d recommend using diluted Ballistol with it, or committing it to extremely fine mineral oil for a most luxurious experience.   The Ballistol way’s smelly, and you have to keep mixing in water to dial in the thickness you like, but you can clean it up with degreasing soap of any kind, or just real hot water.  The sewing machine oil way, cleanup’s a bit more complicated, and I’d argue not worth it.

Includes birch wood base.  Made in France.