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Sharpening stones


Doug Sanders

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I looked through the archived topics and we've discussed sharpening, but not stones per se. I write because I have a man-made waterstone, 4000 grit. On certain blades- be they kitchen knives, chisels, carving scrapers, etc- the stone tends to glazed over in no time. I'm soaking the stone in water for 15-20 minutes before use, and keep it moist while sharpening. The glazing is a dark grey shiny appearance- sometimes it's a kind of dappled deposit- on the stone surface. When it happens, the slurry doesn't develop and I have to take another spare, small 4000 grit stone and rub it over, re-charging the surface and removing the glaze.

 

I thought that maybe residual camelia oil that I wipe on tools to prevent corrosion is the culprit, but I can't be sure. The glazing seems to happen more with shiny blades- dockyard chisels, Henkel's chef knife- than high carbon metals like my Michi carving chisels and a french Opinel pocket knife.

 

All opinions welcomed-

 

-Doug

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Hi Doug

 

I have a couple of fine stones I use for wood chisels etc, quite often when the finest stone 'glazes over' gets clogged up, I simply wash it with liquid soap (the kind used for washing dishes), this seems to do the trick for me...

 

Hope it helps

 

Regards

 

Mike Mc

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The answer is: Nagura Stone

 

The Nagura Stone is used to build up a slurry of paste on a waterstone for final polishing. I keep my whet stones in water all the time, in a covered container, and the nagura is dry. When ready to use the stone, move the nagura stone back and forth to work up a slurry on the stone's surface. The abraded metal will not build up, and if it does the nagura stone will remove it.

 

When I bought my Japanese stones from Rockler Woodworking, the Nagura Stone was right there with the sharpening stones.

 

Excerpt from http://www.japanwoodworker.com/page.asp?content_id=2817:

 

Nagura Stones

 

The incredible polishing action of a finish stones results from the mud” which builds up on the surface of the stone during honing. Nagura Stones create this “mud” before honing begins, thus speeding up the polishing process. In addition, the Nagura Stone makes the stone surface slippier, keeping the tool from sticking. Nagura Stones are small pieces of very fine chalky natural stone, specially mined for this purpose.

 

A Nagura Stone is easy to use. Simply rub it in a circular motion on the full surface of a finish stone until a paste or “mud” develops. If the stone surface is too dry the Nagura Stone will stick To alleviate this problem, add a few drops of water. Generally speaking, the more paste, the better the honing action.

 

--

 

So, Google "Nagura Stone" and see what you can find, and look for it where you purchased the Japanese stones, it might be available there.

 

Janel

 

PS in a pinch, I wonder if using a plaster of paris chunk or a piece of chalk might do? It may be the wrong thing altogether, but... I have not tried it...

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Hi Doug,

 

I have been using Japanese water stones for over 20 years years, and own about a dozen, from a 300 grit to 4000. I store them in water all the time, and use them dripping wet. I am familiar with the nagura stones, but have never needed one. They are available at Lee Valley Tools Artificial Nagura for a reasonable price, and as Janel suggests, this may be your answer. I have noticed that the 4000 stone clogs readily, unless used really wet. The extra water on the surface helps build a slurrey faster, and keeps the surface lubricated. Mark's and Mike's soap suggestion is also excellent, and will help also, but I just use water.

 

I rarely use the 4000 stone, unless working with exceptionally soft materials, as the 2000 grit will readily hone an edge that has been prepared with the 800 stone to a razor edge, and do it more quickly. I am also a big fan of stropping to refine and maintain an edge after the water stones. A tool sharpened first with 800, then 2000, then stropped with a little chromium oxide buffing compound, will shave the hair off of your arm faster than a razor.

 

Ocasionally, I use these stones on Kitchen knives, but find that a razor edge is not really necessary, or desirable, to cut cucumbers, and leave it at 800.

 

I know of no reason why different steels would have an effect on clogging in this situation, unless there was oil involved.

 

Phil

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  • 4 months later...

What stones do most of you use and in what grades? I haven't done much sharpening but generally go from 800 to 1200 to 6000 - all with King water stones and a little nagura for slurry when needed.

 

I need to flatten the stones now and was wondering what methods most of you use. Or is this less of an issue with small tools?

 

I was thinking of either flattening against a coarse diamond stone (maybe 240 grit or 400 grit) or getting some float glass (12mm) and flattening on wet and dry paper. Any thoughts?

 

I don't know how far many of you go but I saw a Spyderco saphire ceramic stone of about 10,000 grit. Any other obsessionals out there ?! :unsure: (http://www.spyderco.com/catalog/details.php?product=81)

 

Cheers Ed

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Guest ford hallam

Hi there Ed,

 

there are two general ways of restoring the surface of your Japanese wet stones. You can rub the faces of two similar grit stones against each other or use a coarse wet and dry emery paper on a sheet of glass, as you yourself suggested. I tend to use the "wet and dry" option first and then finish with a bit of stone to stone lapping. For general woodwork I use 700/800; 1200; and 4000. Occasionally I'll go up to 12000 on a Japanese plane blade, 'cos it's fun! :unsure::D I only use Japanese water stones for Japanese chisels and they are all pretty much standard size not for small scale work at all. I'd think small tips would make a bit of a gouge in soft water stones.

 

I don't carve wood but metal and my chisels are as small as you'd find. I used to use a coarse Arkansas stone to shape and then finish off with a very fine white Arkansas, all used with oil. Recently though ( after a recommendation from one of our members, Robert Weinstock I think it was ) I've been converted to these diamond sharpening "stones" here's a link to the items I use.

 

I introduced my teacher in Japan to them too, he loves them, as do his friends. The technical info on the site I've linked to is worth a read because in this case it does actually seem as though there really is a big difference in the various diamond sharpening systems available.

 

Another useful aspect here is that the surface remains flat and true, this is obviously especially important when trying to sharpen very small chisels and blades. They do cut beautifully as well, and use water to help prevent the cutting surface becoming clogged.

 

I like the slightly matt finish the "very fine" leaves as it helps keep the glare down on the cut surface of my work and is less slippery. For wood, etc, you could apply a final polish with a very fine Arkansas.

 

hope this is of some use,

 

Namaste, Ford B)

 

p.s. it ain't half hot here, down at the very tip of Africa :blink:

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Hi,

 

You are right, Ford, about the small tools making a gouge into softer Japanese stones. :unsure: Thanks for the diamond sharpening "stones" link. They look nice. I have some cheap diamond sharpeners, but the surfaces seem a little irregular, so I don't choose them by first choice.

 

A while back in warmer weather, when I needed to do an aggressive re-flattening on a soft, too worn and gouged stone, (I put off taking care of that one too long I'll admit :blink: ) Outside, I turned on the hose, found a flat and fairly smooth area of pavement on the side walk by the studio, and quickly took away the high parts. Then, indoors, with a true, flat surface, I used wet-dry sand papers and plenty of water to finish the surface. I am more attentive now.

 

Janel

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I don't know how far many of you go but I saw a Spyderco saphire ceramic stone of about 10,000 grit. Any other obsessionals out there ?! :unsure: (http://www.spyderco.com/catalog/details.php?product=81)

 

Cheers Ed

 

I've used this Spyderco ceramic stone for a number of years now (I bought it when it was $40, now it's $79, just to put it in perspective). Excluding the wife and child, this might be the thing I'd most miss. Once the first edge is established using oil stones, I use a fine hard black Arkansas stone, followed by this ceramic stone, and it's so fine a texture I have no need to strop.

 

The best part is you use this stone dry, and when it gets dirty simply use water and an abrasive kitchen cleaner until it's white again. It's so hard, I've not seen any wear even from my smallest blades. When a blade gets dull, I just wipe it against the ceramic stone a few times and I'm back in the carving business - of course, eventually you have to go back to the coarser stones and re-establish the proper edge angles; for me, maybe twice a year. I've tried the Japanese water stones, but my system works much better for me, with an order of magnitude less fuss - no soft stones to wear out of flat.

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I don't know how far many of you go but I saw a Spyderco saphire ceramic stone of about 10,000 grit. Any other obsessionals out there ?! :unsure: (http://www.spyderco.com/catalog/details.php?product=81)

 

Cheers Ed

 

Ed, I also use Spyderco ceramic stones to finish the edges on my knives. I grind the edge with 220, then 600 grit belts on my belt grinder, then run them across the ceramic. I don't have the flat bench stones. I have the ProFile sticks in medium and fine grits. I get an outstanding edge with them, and as Tom says they don't wear out.

 

Never have used water stones.

 

David

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I recently got some cermaic sharpeners from the Blade Shop. They have a number of pocket stones. The one I find most useful is from Gatco. It is triangular in shape and comes in to sizes.

One feature that I like is that each corner of the sharpener has a slightly different sized curves designed for serations but useful for changing the shape of a blade.

 

 

David Callaghan

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Guest ford hallam

Hi Tom,

 

I find these diamond "stones" really convenient for small metal carving chisels, you may find them handy too, and they are relatively cheap. I've found that an edge that is too finely honed/polished on a metal carving chisel can sometimes be counter productive, it can end up being prone to chipping or slipping not to mention leaving a very reflective cut which can be a bit irritating and confusing.

 

I once had a ceramic bladed potato peeler that cut like a laser...until the rather flimsy housing broke and I nearly removed a finger! B)

 

Namaste, Ford

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I can believe the sharpness of a ceramic blade. Porcelain, a fine grained white clay mixture, when fired can be nearly glass like, and when it is fractured, can cut like broken glass.

 

Some years ago, I acquired a ceramic knife, a white and translucent glass-like ceramic, made by Ryushi, which is very sharp and hard. I have not used it much, but it does work when I need it to.

 

It is good that your finger was not attached to the potato too closely! I'll get the diamond stones and see what they can do for the tools. Thanks for emphasizing the difference between the polished to shiny and the virtues of the unshiny sharpened tools. Yet another good technique to learn about to work with towards accomplishing the look we want a piece to have.

 

Janel

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Thanks, Ford. In my searches around the Web looking for engraving information, I ran across lots of mentions about "bright cut" engraving, where one uses polished gravers, leaving a shiny cut. Bright cut mainly seems to be used in "Western" style engraving (meaning USA wild west/cowboy), but I don't find the style attractive, so I haven't been taking my gravers past a 600 grit diamond wheel. So far that seems to be working for me.

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Take this for what it is worth -

When I have mistakenly gotten oil on a water stone I use naptha and a stiff brissil brush and clean all the buildup off then I will soak it in naptha for an hour - hang it up or rap it in absorbant toweling - air dry for at least a day. Then wash it with a natural soap like castile with very hot water.

 

If the buildup returns the stone may have to be boiled or put in a double boiler, caution - the exact method depends on the stone - caution!!!!!!! Laying a towel on a cookie sheet and baking at 250 to 300 degrees for an hour is safe for all natural stones.

After an hour on one side turn it over and do the other; do the oilest side first.

 

Regards to All,

Debbie

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  • 1 month later...
I looked through the archived topics and we've discussed sharpening, but not stones per se. I write because I have a man-made waterstone, 4000 grit. On certain blades- be they kitchen knives, chisels, carving scrapers, etc- the stone tends to glazed over in no time. I'm soaking the stone in water for 15-20 minutes before use, and keep it moist while sharpening. The glazing is a dark grey shiny appearance- sometimes it's a kind of dappled deposit- on the stone surface. When it happens, the slurry doesn't develop and I have to take another spare, small 4000 grit stone and rub it over, re-charging the surface and removing the glaze.

 

I thought that maybe residual camelia oil that I wipe on tools to prevent corrosion is the culprit, but I can't be sure. The glazing seems to happen more with shiny blades- dockyard chisels, Henkel's chef knife- than high carbon metals like my Michi carving chisels and a french Opinel pocket knife.

 

All opinions welcomed-

 

-Doug

I use sewing machine oil on my stones (the japanese artificial stones are great, not cheap though), wipe it off after usage, and when they get clogged I warm them up in the oven (not hot) and wipe them with kerosene, gas or turpentine-- be careful, no open flames, and don't inhale, best to do it outside -- gets the job done -- water does not "float" the metal particles and helps rust deposits.....Ellen

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  • 3 weeks later...
I can't believe the sharpness of a ceramic blade. Porcelain, a fine grained white clay mixture, when fired can be nearly glass like, and when it is fractured, can cut like broken glass.

 

from a metallurgical standpoint carbides like iron carbide (Cementite), Tungsten Carbide, Titanium Carbide are classified as ceramics.

 

The original famous Wootz Steel\Damascus Steel circa 300BC >1400AD has iron carbide to thank for its reputation, and of course modern carbide tooling\blades again are far more closely related to ceramics than most appreciate. ;)

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