Nagura stone grit

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Bo-dacious

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Aug 13, 2016
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Hi guys. I recently came I to a small amount of disposable income so I bought some decent sharpening stones. I bought a diamond one with 4 grits under 1000 (I know that's unnecessary but it was a good deal and had a nice base for grip on my table), a combo 1000/4000 grit waterstone, a 10,000# grit water stone (I'm not very proficient yet so that's for when I get really good) and a 400 grit (if I recall correctly) flattening stone all for under $100. Now I'm looking at a nagura stone. My question is what grit do I want the nagura stone to be? Should it be the same grit as my finest stone (10,000#)? Should I have one for each grit?

Please let me know what you guys think!

Thanks,

BO-DACIOUS
 
I'm using the Naniwa nagura stone for all my artificial stones. It's 600 grit and if the color doesn't bother you, you can use it bofore sharpening on all stones up to J6000. All stones with higher grit can be cleaned with it after sharpening.

If you use a King Nagura it's most likely the 8000 grid one, it won't help refreshing the 1000 and 4000 and you can use it on the 10000 after sharpeing.
 
Okay, thanks man. I bought the ngr-50 which is 5000#.so I guess I use that on the 10000# stone only, correct?

Thanks!

BO-DACIOUS
 
Synthetic Nagura stones are for cleaning and leveling only. The Naniwa as example above is one of the best but it should not be used for making a slurry, it will contaminate the slurry and cause unwanted scratching.

Natural Nagura stones are a soft chalk stone that is used with hard natural finishing stones that don't like to make mud on there own. They average 4000 grit and should only be used on stones of that grit rating or less. Tomo-Nagura or "stone of stone" nagura are a chunk of the stone you are using. This can be good because it keeps the slurry consistent but it does not always work as expected... especially with very hard stones.

FYI, I use a wide range of waterstones daily, I hardly ever use a Nagura stone of any kind.
 
Okay... I got a "suehiro nagura toishi" stone which says "for touch up and slurry". It also says it's for 5000#-8000#. So I'm kind of confused. I apologize as I'm new to knife sharpening. So what should this stone be used for? Touching up and creating a slurry in the said grits? Can I get away with my 10000#? I didn't see one that said it was specifically for 10000#.
Thank you so much for your help guys, I really appreciate it!!!

BO-DACIOUS
 
It's something that is lost in translation... and a bit of marketing. Instructions in Japanese don't always translate correctly into english and you end up with a very generalized explanation of how to use something.

Truthfully, you have almost no need for a Nagura. If it's not a Natural Stone then you SHOULD NOT BE MAKING A SLURRY WITH IT. Even then, it should be a matched Nagura to a Natural Sharpening Stone, not a synthetic.

Synthetic Nagura stones are for cleaning and leveling only, once done cleaning and leveling the stone surface should be flushed with fresh water. Do not use the slurry from this Nagura.

Slurry formation is something you control and make in the sharpening 99% of the time. It's very rare you would start with a pre-made slurry, it would rush the surface polish before the stone had a chance to convert the coarser scratches of the previous stone. Only makes the sharpening harder on you.
 
For artificial stones you might use a nagura for:
  • cleaning after sharpening
  • refreshing the surface of your whetstone
  • put on nagura before sharpening to prevent clogging during sharpening
  • smoothing the surface to make the stone work in the designated grid range
  • put on nagura before sharpening to aim for some minor changes during finishing
Leveling your whetstone regularly with a diamnond plate takes care of the first two items and makes the third item pointless. Item five is experimental for experienced users, play with it when you consider yourself one. ;) Item four is taken care of if you use a diamond plate for maintenance that is not too coarse. Most users have no issues using a DMT 325 grid plate even for the highest grid whetstones. What a nagura might do for you depends on the kind of stone you use, most whetstones a far easier to figure out without tricky nagura issues. Try everything you want, but try to learn the simplest way first. :)

The purposes for nagura on natural stones is a completely different and complicated discussion. Let's come to these complicated questions when they appear. Have fun learning! :D
 
Okay, thanks guys. I've learned a lot about the nagura stone. But my final thing I'm still unsure of is if I can use a nagura 50 (#5000 which is meant for #5000-#8000 stones) on a #10 000 stone. I won't use it for slurry for now but for cleaning the black marks at least. I also have a #300 something levelling stone. Can I use that to level any grit, or will the granules contaminate the higher grit stones? If so, what grit levelling stone should I use?

Thanks,

BO-DACIOUS
 
You can use any other stone to flatten or clean your 10000 stone as long as you clean the 10000 afterwards to minimize the risk of contamination with bigger grid size particles.

Any leveling stone and of course any diamond plate should have a much harder binding than your sharpening stones. So the abrasive from the leveling stone will not interfere with normal sharpening. You will do your leveling maintainance mainly under running water or at least wash the stones after leveling so that will not become an issue. Most users have no problems using a 325 DMT diamond plate to level even their 10K stones or higher. If you want to make sure, that the surface of your 10000 stone ist smooth enough, use your next lower grid sharpening stone (8K, 6K or 5K depending on your setup) and make a few laps with it on the 10000, clean both afterwards and your perfectly ready for the next sharpening session! :D
 
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