Thread: JNAT & Nagura questions/identification - help!

Originally Posted by Brighty83

A worn 325 DMT would be best but second would be some sandpaper on flat glass or a tile.

Start at 220/400 and move up to 600 (or higher if you choose)

I don't like how DMT is lapping hard and fine grit stones.
I'd prefer to lap with set of silicon carbide (SiC) powders up to 1200 grit with just sheet of glass on some flat surface. Or with ceramic plate.
Use some water to make a slurry with SiC on glass. Distribute it evenly. And use 8-like motions for lapping.

Here it is on video: Как править японский точильный камень - Мастер класс по заточке ножей - YouTube

Originally Posted by Brighty83

A worn 325 DMT would be best but second would be some sandpaper on flat glass or a tile.

Start at 220/400 and move up to 600 (or higher if you choose)

Jnats are interesting stones and kinda like woman. You never know how it's going to go until after a few dates And, If you have never used one, it may take a while to discover her sweet spot... .

Like the analogy Brighty

Time to stop being the wallflower and just go ask the lady to dance!

Originally Posted by Nikolay

I don't like how DMT is lapping hard and fine grit stones.
I'd prefer to lap with set of silicon carbide (SiC) powders up to 1200 grit with just sheet of glass on some flat surface. Or with ceramic plate.
Use some water to make a slurry with SiC on glass. Distribute it evenly. And use 8-like motions for lapping.

Here it is on video: Как править японский точильный камень - Мастер класс по заточке ножей - YouTube

Thanks again Nicolay really informative!

Originally Posted by Nikolay

I don't like how DMT is lapping hard and fine grit stones.
I'd prefer to lap with set of silicon carbide (SiC) powders up to 1200 grit with just sheet of glass on some flat surface. Or with ceramic plate.
Use some water to make a slurry with SiC on glass. Distribute it evenly. And use 8-like motions for lapping.

Here it is on video: Как править японский точильный камень - Мастер класс по заточке ножей - YouTube

the problem is that the slurry tends to gather in the middle of the stone and it will never be perfect flat. The best way to lap is to use 3 stones with similar hardness, by rotating them you are going to get perfect flat surface on each of them. I personally use very used DMT 320, and then finish with a medium Jnat, it works super and leaves perfect surface on the stone. After that using naguras only further refines the surface of the base stone.

That's pretty much my exact routine. I'll sometimes add in a DMT lapping plate beforehand and use the 325 to remove the scratching.

A well worn 325DMT leaves a surprisingly smooth surface by it self but a second stone lapped with the same plate works wonders. Even going direct to a nagura can give the stone a gloss finish leaving the stone quite flat.

The 325 DMT plate by them self gets the stones so flat that I can briefly lift a dry Jnat off my table using nothing but a second Jnat and the very small amount of air between the two stones. The stones need to be extremely flat and smooth to stick together while they are dry.

Originally Posted by mainaman

the problem is that the slurry tends to gather in the middle of the stone and it will never be perfect flat.

Use sliding and rotating 8-like motions on slurry and you will have no such problem.

BTW when you are lapping jnats on hard ceramic or cast iron plate you wouldn't have troubles with wearing of the lapping plate so you don't need to use 3 plates or stones.


I have used silicon carbide slurry on glass/ceramics/etc lapping plate a lot of times always checking flatness with toolmaker's straightedge and I have never came accross any issues with flatness.

I'm still a little skeptic to how flat it gets with a plate and loose powder, that's how they used to make lenses in the old days.

Originally Posted by Nikolay

Use sliding and rotating 8-like motions on slurry and you will have no such problem.

BTW when you are lapping jnats on hard ceramic or cast iron plate you wouldn't have troubles with wearing of the lapping plate so you don't need to use 3 plates or stones.


I have used silicon carbide slurry on glass/ceramics/etc lapping plate a lot of times always checking flatness with toolmaker's straightedge and I have never came accross any issues with flatness.

Not going to work still, slurry accumulates in the middle and you can see that in the video you posted.
Then the base plate will also dish and the whole process gets inaccurate.
The correct way to do it to use Kanaban, but that works only with coarse grits and requires lapping from time to time as well.

Those things are sold in Japan for ~50 usd, and work well on low grit stones

here a video of a somethig that may work well

Originally Posted by Lemur

I'm still a little skeptic to how flat it gets with a plate and loose powder, that's how they used to make lenses in the old days.

You don't need to be so sceptic. Just try it and check the flatness. All you need for the experiment are a piece of flat glass ( thicker is better ),
some flat surface to put it on and loose powders of silicon carbide. It's very cheap and able-to-get.

It is much cheaper than DMT plates and it gives better surface condition of honing stone.

Sounds like the Norton flattening stone I have doesn't really cut the mustard?

From what I've read the DMT 325 is way better? I know DMT also do a lapping plate but at $160 cheap it ain't.. if a 325 is good I'd rather get that given the price difference.

I've also heard that the chosera 1k slurry stone works really well? Any thoughts?