Nagura Progression and a scratched Ozuku

I recently aquired a set of Asano stamped nagura, together with a tomo nagura (from a reputed vendor) and have been using the stones as prescribed.

However, I have since noticed that my Ozuku Asagi (a very hard and fine stone) has scratches on its surface which weren't there before. Pretty annoying.

I'm a bit disappointed as I know the naguras are supposed to be softer stones and the vendor purposefully sent me a softer stone than my asagi for my tomo nagura...

Has anyone else experienced this and can anyone suggest best course of action?

That would bother me too, but the scratches probably will have no affect on a razor. If they really bother you, you would have to lap the surface of the stone to refresh the surface a little.

Have you bevelled/smoothed the edges of your tomo nagura? It was probably that stone during slurrying that caused the scratches. Even if it is softer, a sharp edge dragged along the smooth surface of the stone would likely cause a bit of a scratch.

What color is your stone? I've found some darker grey stones show scratches no matter what you do...it's like the light just refracts differently on the surface of the stone.

Otherwise, you might be using a bit too much pressure when raising a slurry.

a few tips that might apply to your problem.
when making slurry do not use a lot of pressure.
Chamfer the edges of your tomonagura, sharp corners with a lot of pressure usually= scratched stone.

Thanks for the tips guys. I will lap the stone properly tonight and do some further diagnostics on each nagura and and their effects on the Asagi.

FYI I did chamfer the tomo nagura, but maybe its my pressure. I just can't imagine it would be the nagura, most likely the tomo that's causing the issue.

Jim - the Asagi is a grey colour, similar to the one Stefan used in his nagura video tutorial.

I'll post back with my findings after some trial and error tonight.

Thanks gents.

Elliot

I was pretty serious about lapping all my scratches out but I've decided to hold off until I figure them out. As said above, most scratches don't effect honing. Use your nagura to smooth out the stone in the long run, don't use pressure, careful with them kamisori! A flawless surface has been difficult to maintain during my learning curve but I'm learning they aren't detrimental to honing, provided I understand what caused it and don't do it again.
Getting a balance of water on the hone helps too, too little or a lot is bad for slurry making. Spritz or splash your nagura just before using too, IME.
Edit: I don't know about y'all but my tomonagura takes a while. Like 100 (soft) circles on every little part o' the stone just to get started. Thats the one most likely to scratch because I'm trying to get milky slurry too fast, IMO.

Also, this thread may give some food for thought as far as lapping, nagura use, and honing.
Read this post (http://straightrazorpalace.com/hones...tml#post423219)
and this post (http://straightrazorpalace.com/hones...tml#post423388)

Cheers pal :)

Quote:

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Originally Posted by bassguy

Also, this thread may give some food for thought as far as lapping, nagura use, and honing.
Read this post (http://straightrazorpalace.com/hones...tml#post423219)
and this post (http://straightrazorpalace.com/hones...ml#post423388)

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Wow...I can't believe that was a thread I started 2 years ago!

Quote:

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Originally Posted by MrMarx

I recently aquired a set of Asano stamped nagura, together with a tomo nagura (from a reputed vendor) and have been using the stones as prescribed.

However, I have since noticed that my Ozuku Asagi (a very hard and fine stone) has scratches on its surface which weren't there before. Pretty annoying.

I'm a bit disappointed as I know the naguras are supposed to be softer stones and the vendor purposefully sent me a softer stone than my asagi for my tomo nagura...

Has anyone else experienced this and can anyone suggest best course of action?

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I know that polishing laps often have channels cut in them
to let fluid and grit move... Fine little scratches should not hurt
anything and they will vanish (or accumulate) with use.

In the translation
http://straightrazorpalace.com/gener...tml#post840723
there is a comment about nagua and the risk of largish bits chipping
and edge. I am not an owner of J-nats so you may find things
in there that I missed that may apply to your rocks.

I am not a big fan of lapping hones beyond the need to
keep a progression of hones flat. The last hone is an
exception a slight concave shape on the final polisher/ finish
hone where a micro bevel is OK and even desired by some.

In another thread someone is playing with diamond dust on
his rock rather than using a nagura to worry up a slurry. While
a waste of rock and diamond you might try a spray of sub micron
diamond to see how it works.

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, :D

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...

Quote:

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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?

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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.

:)