Diamond Whetstone

I bought a diamond whetstone for flattening my sharpening stones.

Here it is.
I don't really know which whetstone is best, so I just went with one that appeared at the top of the Amazon search results.

By the way, I'm planning to buy Shapton stones when I add to or replace my current ones, but the Shapton flattening stone was way too expensive, so I gave up on that.

This is the whetstone I use at home.
Even at a glance, it doesn't look like the surface is flat.

By the way, this is the whetstone here. (The photo above is the #1000 grit one)

As is often suggested when you look up flattening online, I'll draw lines on it with a mechanical pencil.
Once these are all completely erased, it means the surface is properly flat.

I got lazy with the #400 grit one, so I drew fewer lines, but it looks like this.

Time to start flattening. (I had soaked the whetstone I'm flattening in water beforehand.)
I started with the #400 grit one. (The diamond whetstone is also #400.)
As shown in the photo, I placed the diamond whetstone on the bottom and rubbed the whetstone I wanted to flatten against it.

As you rub it, you'll see a slurry-like substance start to appear like this.
I've heard that when sharpening blades with a regular whetstone, it's better not to wash away the slurry, but when flattening with a diamond whetstone, I felt it worked better if I washed it off frequently. (It doesn't feel like it's grinding when the slurry is there.)

After grinding for a while and looking at the back, it looked like this.
As expected, it seems the middle was more worn down.

It became clean like this.
Since I was using the same grit, it took quite a while (about 30 minutes), but the work itself was simple.

Next is the #1000 one. (The diamond whetstone remains at #400.)
It seems standard to use a coarser grit for the flattening tool, so I suppose this is the correct way to do it.
Since the grit is different, it grinds away faster than before.
Here too, it seems the middle was worn down. (It's a mystery why some parts of the edges are also worn.)

This one became clean quickly. (About 5 minutes.)
If it's this easy, I think I'll try to do it every time after I sharpen a blade.

Finally, when I tried it lightly with the #1000 diamond whetstone, the surface became smooth.
It feels good to have it clean.

I'm looking forward to the next time I sharpen something.

So, that is all for today.