Thread: Nagura Progression and a scratched Ozuku

Interesting observation. I have several J-Nats and several Naguras, from soft to extremely hard.
I have a questione: did you flatten your nagura?
I always flatten one sinde slightly, so there are no high spots that can easily scratch a stone.

Even my hardest nagura do not scratch my stones unless I use them incorrectly: too much pressure, or unflattened.

Don´t jump into conclusion about the hardness of your stone and nagura because of random scratches from your nagura.
This doesn´t necessarily mean your Nagura is harder than your Ozuku.
However one thing kinda startles me, why did you asked for a Tomo Nagura softer than your Ozuku?
Usually you specifically ask for the hardest Tomonagura. I don´t see a problem because it probably doesn´t matter that much, but I´m curious

One other factor to consider is loose diamonds from your lapping plates could scratch the stone.
Can you take good pics of the problem and post here?

I just finished lapping my J-Nats with some really coarse DMT's and then using the J-Nats with the scratches. The scratches did no harm. I also have some hard tomanagura stones and I work up a slurry using the edge of the toma, but I rounded it over first. Raising a slurry is much faster that way.

Just my $.02,

Lesslemming, good points raised mate.

In answer to your questions, I have indeed rounded off the nagura's edges and have been using flat sides to raise the slurry. It takes considerably longer of course but I'm doing what I can to preserve the surface of my Ozuku (and trying to work out the solution to this scratching issue!)

In regards to the tomonagura, I asked the vendor to send a stone that would be suitable for my ozuku; the tomonagura should be softer than the base stone and as I bought the tomonagura separately, I didn't want it to scratch my Ozuku.

What a lovely piece of irony - it's the nagura's scratching my base stone and not the tomonagura!

@ Randydance That's exactly what I've done with mine, chamfered the edge of the tomo nagura very smooth...

Originally Posted by mainaman

One other factor to consider is loose diamonds from your lapping plates could scratch the stone.
Can you take good pics of the problem and post here?

Stefan, don't think it's the plates. Reason being I've been using the Atoma exclusively until now with no ill effect. It's definitely the nagura as I've noticed the scratches after the first honing session.

I will try and get some pics up mate. It will be interesting getting the right angle to see them though, like I mentioned they're not massive gouges and probably don't affect the results.

My main concern is that they're there in the first place and I'm keen to maintain that glass-smooth surface of my finisher.

Will see what I can do re: pics.