How to use Nagura stones

[Andrew Pitonyak]

I saw a comment by Mr. Holcombe that gave me pause.


I like using the Nagura stones that come with the chosera's. I soak them with the stones and they work really nicely without stick-tion.

I did not want to hijack the thread:
http://www.sawmillcreek.org/showthread.php?229469-Water-stone-maintainance&p=2398811#post2398811

I realized that I don't really understand how to use a Nagura stone. It had not occurred to me that you should soak these stones. My vague understanding is that you:

rub the Nagura on your stone, which builds some "swarf" (is that the correct term).

When do you wipe that stuff off and start fresh? Does it increase or decrease stiction? (is stiction the correct word when the tool sticks to the stone?)

Any general information you have is much appreciated.

[Malcolm Schweizer]

Good day Andrew,
The Chosera naguras are a different breed. They are very porous and they almost seem to change character when you soak them. Soaking is not a necessity for all naguras. I would say try it and see which way works better for your stone.

The Nagura is used to build up the slurry as you said, and I do not wipe off the slurry, but do spritz it to ensure it stays wet. Any extra should run off.

[Jessica Pierce-LaRose]

I've never used a nagura, but my Cho 3K came with one. I've been meaning to play with it. Is it fine to use the nagura with multiple stones, with some rinsing between to keep cross contamination to a minimum? Or is the nagura different for each grit of stone? (I.e., is the natural with a 3K too coarse for my 8K stone?)

[Brian Holcombe]

I am actually not sure if the specific purpose is to keep the stone flat, so I should clarify my post. I flatten my stones with the diamond plate, but rather than continue to flatten as I use them I have taken to using the nagura. It clears off the shiny build up and maintains a good flat across the width of the stone and leaves a good worthwhile slurry. I use it evenly and minimize how often i need to aggressively flatten the stone.

[Malcolm Schweizer]

The Chosera naguras are all 600 grit. Personally I do not like them for use over 1000. They abrade easily and leave brown in the slurry. Not a big deal for a 1k, but higher than that I find the 600 to be too coarse and at the same time too soft. I bought a really nice natural nagura that I love for finer grits. Also chefknivestogo sells offcuts of stones they cut down for sharpening jigs. It is a random bag, but mine included a nice natural piece and a 1k Chosera piece. I also bought a broken 10k Chosera on eBay to use for the 10k that I am about to purchase. That way my slurry is pure 10k and if I need to I can hit it with the diamond stone to clean it.

...which brings up another point. If you have a diamond stone you can use it in lieu of a nagura, but I like to use a fine nagura matched to the stone.

[Simon MacGowen]

The Chosera naguras are all 600 grit. Personally I do not like them for use over 1000.

What are we talking here? This kind of stone? http://www.leevalley.com/US/wood/page.aspx?p=51961&cat=1,43072,43071,51961

If so, it is meant for use with stones over 1000 grit. That's 4,000 and up. No need to soak it beforehand.

Simon

[Malcolm Schweizer]

What are we talking here? This kind of stone? http://www.leevalley.com/US/wood/page.aspx?p=51961&cat=1,43072,43071,51961

If so, it is meant for use with stones over 1000 grit. That's 4,000 and up. No need to soak it beforehand.

Simon

No- the Chosera stones came with a nagura stone until they changed to "Professional Stones" and quit including the nagura. When they were called "Chosera" they included a nagura with each stone you bought, but it was the same 600 grit stone. It is a bit soft and coarse for the higher grits (my opinion). I suspect that may be why they quit including them. ...that and cost cutting.

The one you linked to is a finer grit than the Choseras came with. A nagura stone is any stone used to make a slurry- it is not a name brand or specific to any one stone.

[Winton Applegate]

Alllllrighty then,
As far as the nagura that you have follow the manufacturers recommendation on soaking and use. I only use the natural nagura, because that is the first one I ever bought, and it does not require soaking. It is like a solid of very fine silt as opposed to my other "nagura" which came with my Ice Bear brand 10,000 grit stone which I never use that nagura and it is vastly different, white synthetic looking and coarser more like a 4000 stone.


"swarf" (is that the correct term)
I can see how you might get that idea because the stuff rubbed off a blade onto a stone is swarf. The stuff rubbed up from a nagura is called slurry. Even if it has some blade swarf in it as long as it is abrasive rubbed off the stone and has water in it it is slurry.

My practice, developed from much experimentation and trying every combination possible is :
I only use my silt like natural nagura on the finer stones 4000 and up.
I ONLY use the nagura to remove swarf (metal of the blade) OFF of the stone. I use it with water and like one uses an eraser to help pull the metal out of the pores of the stone. I NEVER TRY TO MAKE SLURRY TO USE TO SHARPEN WITH. I think that is a mistake and a waste of time and motion. The well cleaned and flattened stone with a little water on it cuts much faster than the same stone with roly poly rounded loose grit and metal particles on it (the slurry).

I don't wipe the slurry off I wash it off under a flowing water tap.

Stiction
Yes stiction.
More water on the stone and no nagura is the best to prevent stiction.
My natural nagura is in the first photo and is in the second photo for size comparison just bellow the green Shapton stone.
That is an old photo and I use all Shaptons now but I still use the nagura on them

[Andrew Pitonyak]

Ah, yes, slurry. Sometimes the words escape me!

lots of good information; thanks!