View Full Version : Waterstones & Sharpening...

04-12-03, 10:54 PM


The use of natural stones for shaping and sharpening tools goes back to the beginning of mankind. Today craftsmen still rely on these traditional abrasive materials to hone their modern edge tools. Both waterstones and oilstones are mined and sold throughout the world as premium sharpening materials. But as the veins of this material slowly run out, the availability of natural stones decreases, and the cost per stone increases accordingly (some natural polishing stones in Japan cost over $2,000.00!). To combat this inevitable supply-and-demand trend, man-made synthetic abrasives have been developed with the help of modern technology. Duplicating and advancing upon the benefits of natural stones, the new synthetic abrasives give craftsmen superb sharpening performance with consistent grain/ grit composition, sizing availability, and at a reasonable cost. When comparing stone grits, it should be noted that the American grading system varies from the Japanese system. Both are based on measuring the abrasive particles in microns, a unit of length equal to one millionth of a meter. The final scale used to equate a measurement is different however. For example, a stone averaging particle sizes of 37 microns would be classified as about 320 grit on the American scale, 500 grit on the Japanese. The chart below gives an approximation of this relationship.


Japanese waterstone grades fall under three major groups: very coarse grits for fast removal of metal; medium coarse grits for refining the edge and removing the burr; and finish stones for the final honing and polish. These grades cover a range of 150 to 8000, and they don't exactly match up with U.S. grades. For example, the abrasive action of a 1000 grit Japanese stone is the equivalent of US 500; and the Japanese 4000, a US 1000.

Waterstones sharpen with great efficiency because of the nature of their construction. They are made by fusing together very sharp abrasive particles (aluminum oxide, silicon carbide) with a porous bonding agent designed to break down with use. As the "dull" grit particles are broken off, fresh sharp particle edges are exposed to the edge being honed. For this reason, waterstones will wear more quickly than other stones, but they are easily dressed to restore their original flatness or to shape them to a desired contour. This makes them ideal for sharpening all types of flat and curved cutting tools.

Using Waterstones
The techniques for sharpening and honing with a waterstone are essentially the same as those used with oilstones. To allow the surface to wear evenly, your honing motion should utilize as much of the surface as possible. While the pattern will differ according to the tool, a figure eight motion proves efficient (Figure 1). This is especially important for very narrow tool edges, which can quickly wear a groove in a stone's surface. The motion for chisel or plane blades, the width of which approaches the width of the stone's surface, should utilize the full length of the stone (Figure 2). As with oilstones, a liquid must used during honing to facilitate the process and to keep the stone from "loading" (having the pores clogged with metal particles). Waterstones should be soaked in a shallow container of water for a few minutes prior to use. The time required will vary based on the stone's porosity. A fine polishing stone will take 15 or 20 minutes to soak, while a coarse stone will become saturated more quickly. During the honing process, the stone's should also be kept moist.


As the tool edge is sharpened small metal particles combine with loosened grit particles and the water wash to form a "slurry". This fine compound actually hastens the sharpening) process and helps produce a finer finished cutting edge. For fine polishing waterstones (6,000-8.000 grit), the formation of the slurry may be accelerated by the use of a Nagura stone.


This special dressing stone is simply rubbed over the surface of the honing scone to wear off abrasive particles and suspend them in the water lubricant prior to actual honing. The Nagura can also be used to flatten small areas or rub out embedded metal particles that may appear in a stone. When honing is complete, the slurry is simply cleaned from the surface to assure a fresh, sharp start for your next honing. Tools being should also be wiped free of stone residue when changing stones. This ensures that the finer stones are not contaminated with coarser grit particles. A used waterstone should be flushed clean with water or left suspended in a water bath for a time to allow any leftover particulate matter to work free. Waterstones do not require storage in water, and care should be taken not to leave a waterstone in water when freezing conditions may occur.

Surface flattening
To flatten a worn waterstone, simply place a sheet of wet-dry sandpaper on a flat surface such as a bench top, piece of glass, tablesaw top, or flat cement floor. Use a paper with a grit appropriate to the stone being restored: a coarse water stone of 250 to 1,000 grit should be resurfaced with 180 to 220 grit paper; a polishing stone of 8,000 grit should be worked with at least a 400 grit paper. Rub the stone on the sanding surface in a circular motion to wear down tile high spots, taking care to keep the stone flat during resurfacing so the body of the stone wears evenly. A water wash can be utilizes) or the paper can be used dry. In order to maintain their grit integrity, waterstones of different grits should not be flattened on the same piece of paper. An increasingly popular method for resurfacing medium to coarse waterstones, especially larger stones such as those on the motorized grinders, is with the use of diamond honing stones. Diamond stones remain truly flat with use, providing a conveniently flat, abrasive surface to work waterstones in place. For owners of motorized waterstone grinders, a diamond stone may simply be held atop a rotating waterstone on the grinder to quickly renew a level honing surface. Again, use an appropriate diamond grit on your waterstone, as diamonds are extremely aggressive. A coarse diamond stone will chew up an 8,000 grit polishing stone in a hurry! When resurfacing is completed be certain to flush the slurry off both the waterstone and diamond stone.

Here are some tips for buying Japanese waterstones.

If you need to remove a lot of metal fast, restore the damaged edge of a tool, or change the bevel on a blade, you'll want a stone in the 80 to 400 range.
For general purpose sharpening, a stone between 700 to 2000 will do the job. The finer stones, 1200 and 2000, are preferable if your tools don't have an nicks or other defects. The 800 is an good all-around choice if you sometimes need to sharpen nicked or heavily used edges.
For honing and polishing an edge, choose a stone in the 3000 to 8000 range.
Often you can get by with just a pair of stones: a medium grit stone (800, 1000, or 1200), and a finish stone (6000, 7000, or 8000). If you have to deal with damaged blades a lot, toss in a more aggressive coarse grit stone (240, 280, or 360).

If you put oil on a waterstone, you will ruin it!

If you live in a cold environment take care not to store your wet stones where they can freeze. If they freeze they will be reduced to a pile of useless rubble. You'll find that your stones might take a few days to completely dry, so during that time, they should be stored in a warm environment to prevent freezing.

Hope you find this useful.

04-12-03, 10:55 PM
Please feel free to add any tips specific to knife blades. How do you do it?

04-12-03, 11:33 PM
Martyn you're a godsend. The American equivelant to Japanese sharpening stone numbers has been driving me insane. Reading articles on American sites about sharpening but not understanding the coarsness of what they were talking about. :yikes:


05-12-03, 03:48 AM
You're welcome Jon. I think I'll make this a sticky. ;)

05-12-03, 08:40 PM
A damn good article.

Thanks Martyn :biggthump

06-12-03, 09:47 AM
Thanks Martyn, that's really helpful! Definately a sticky.


I found this whilst looking for something on Arkansas stones


The whole site (www.antiquetools.com) is fascinating and the sharpening stuff is well laid out and interesting. The museum it belongs to sounds like an ideal place to spend a rainy afternoon.



06-12-03, 03:35 PM

thanks for that Martyn.. great stuff.. more information for journeying to the dark side of sharpening.. :biggthump


07-12-03, 10:27 PM
Martyn, a question.
The numbers on wet & dry paper or sandpaper that I see in B&Q etc here in the UK, is that American grading, Japanese grading or is there a special British Imperial grading system ? :confused:
I just know your going to tell me its another system I have to get my head around. :banghead:


07-12-03, 11:50 PM
Martyn, a question.
The numbers on wet & dry paper or sandpaper that I see in B&Q etc here in the UK, is that American grading, Japanese grading or is there a special British Imperial grading system ? :confused:
I just know your going to tell me its another system I have to get my head around. :banghead:


As far as I know Jon, the british grits are comparable to American. Most of the stuff is the same 3M etc - it's the same international company. Certainly in terms of belts for belt grinders, Brit/US values are the same. The Japanese stuff is out there on it's own AFAIK. At least that's my experience/take on it - anyone have any different info, I'd love to be corrected.

08-12-03, 07:19 PM
:thanks: Martyn

08-12-03, 07:47 PM
Er - not to contradict, but... AIUI, US grits track European more or less up to about 300 or so. After that, they diverge.

http://www.ameritech.net/users/knives/grits.htm for example.

07-01-04, 11:16 PM
I would like to get a set of waterstones and advice on where to go would be great. Also any viable alternatives would be interesting as long as they won't break the bank. I'd be looking to pay around 15 a stone...

Also mention anywhere you might know of in London as that is where i'm based.

07-01-04, 11:28 PM
I'd probably go for http://www.axminster.co.uk

07-01-04, 11:45 PM
Thanks Martyn and well timed!!!
I just returned from a shooping trip with a handful of japanese stones....250, dual 800/4000 and 8000 then saw your post :)

08-01-04, 04:56 AM
Great, I always wondered how the oil/water worked.

I still have several questions:

(1) I've read several articles, instruction leaflets and the Razor Edge sharpening book and seen the Sharpmaker video and they all advise a different pattern of honing.

Circular to the tip
Circular away from the tip
Linear across the edge, up
Linear across the edge, down
Linear across the edge, down then finish with up
Pull draw along the edge
Figure eights
Same sides
Alternate sides
Same then alternate sides
Using the stone's flat
Using the edge then the flat
Using a flat action
Using a curved action

(1a) Does it really make a difference?

(1b) Are some techniques specific to a diamond/ oilstone/ whetstone?

(2) I'm careful to avoid applying too much pressure, but both my flat diamond hone and my diamond sharpmaker sticks are shedding sparklies and are beginning to develop bald spots. What am I probably doing wrong?

(3) Everyone recommends a guide to lock in the edge angle. Yet the hand finished, convex edge on the CRK blades is beautifully sharp.

(3a) There is no efidence that the final-final edge is guided, so how is it so sharp?

(3b) How can they get a perfect 2mm polished with to the edge without marking the gun-kote?

(3c) What can I do to duplicate it? (Other than return it to CRK).

08-01-04, 05:41 AM
A few tips that I've come across in my sharpening research and tribulations:

You can't hone a good edge out of crappy steel. My old kitchen knives keep developing rust pocks. I hone the edge back to get rid of one and then hit another pock. Some knives won't take an edge, others won't hold it. I've found it's not so much the steel formula or the manufacturer - some knives by the same manufacturer in the same steel differ tremendously. If I can't get and maintain an edge, on a knife I won't kill myself trying to 'get it right'.

Use a guide It's almost impossible to hone a decent edge unless there's a decent (very acute) back bevel. Sometimes achieving that will ruin the appearance of the blade. Juranich recommends that you ignore finish to get the perfect working edge. As a collector, I find that's unacceptable. Therefore, always use a guide on a knife that requires a precision edge - either working knives or ones that you can't risk scuffing the blade face.

Guides basically fit the fixed blade and guided hone (Edge Pro/ Lansky), or the clip on (Razor Edge Systems), or the hand-eye (Spyderco Sharpmaker) categories. I get better results with the mechanical systems, both in finish and function.

If I must sharpen freehand on a collectible, I mask off the blade face with masking tape. It's not foolproof, but it helps. I tried recontouring my Benchmade without such protection and let's just say I'm sending it off to Colin for him to revive it.

The most critical moment is the final edge finish. On the very finest polishing stone I own, I'll slowly lower the knife back/ guide and rotate the edge onto the stone. Touching edge first will ruin the edge. Then I'll hone alternate sides in the direction with the edge in front. The final strokes are very, very light indeed. I try to use less than the weight of the blade.

You want to end up with a microscopically fine edge. In the Sharpmaker video, Sal shows how the straight razor is sharpened to draw out a fine burr with a strop, but he also explains that it's an incredibly delicate edge. Pushing the edge like I described above in the final strokes destroys gives a clean edge that is a little more robust.

A grinding wheel works well for initial work on the back bevel, assuming you can get a fine enough wheel. The tricks are:

never sharpen double edged knife blades on a wheel and never use a rag polisher
the wheel spins towards you and the edge faces away
use a guide at the base of the blade where it contacts the back of the blade. The angle should allow for the hollow grinding effect and not allow the wheel to contact too near the edge
the edge should make contact with the wheel last, after the back has been seated on the guide, or you'll ruin the back bevel
use a really slow speed (max 1,000 rpm) and very light pressure on the wheel

BTW, Never use a dremmel, like you see on the dremmel box illustrations, except for on large serrations.

08-01-04, 07:02 PM
BTW, if i am going to get some japanese Waterstones, what would be a good set?

I am considering getting an 800, a 1200 and a 6000 as it seems a good spread but if anyone has any ideas other, let me know.

09-01-04, 03:10 PM
Depends what you want to achieve.

In terms of sharpness, you can never have too fine a stone, but Japanese swordsmiths would work up in very fine increments.

Your choice should be adequate, though. You could even get a 800/1200 combi and a single 6000 (very high grit waterstones don't seem to come in double sided, unless they're adhered).

Chris Barry
11-02-04, 08:00 PM
What are the differences between a waterstone and an oilstone?

As I understand it you put oil on one, water on the other and the waterstone forms a slurry that speeds up the cutting of the metal. Any other differences?

10-03-04, 06:45 PM
Excellent article Martyn,well done!

10-03-04, 09:52 PM
As with any abrasive the quality of the final finish, ie the sharpness in the case of a knife will depend on how fine the final grit you use is. Having a wider range of grits will speed up the process since it is, for example, a lot easier to remove the scratches from a 250 grit stone with a 1000 grit stone than a 6000 grit stone. If that makes sense.

It is possible to sharpen a blade with a 8000 grit stone only. It's just that is will take ages.

The use of a leather strop and very fine abrasive paste is a good way to get that final razor edge, and if your knife is made of good steel you should be able to maintain it with by stropping for quite a while before you need to take a stone to it. The trick is to sharpen it little and often. Give it a quick touch up every time you use it.

The great advantage of a strop is that it is so much easier to carry around with you than a stone ( I use the inside of my leather belt, it keeps my trousers up as well ). lets face it who wants to carry around what is bascially a big rock with them in the field

axminster is indeed a great shop, also check out Cromwell tools, they stock a huge range of oil stones in various shapes and sizes. Good for those hard to reach places and also handy for polishing blades, especially funny shaped ones.

I have also noticed that if you use a water stone to polish the back opf a blade it turns it quite an attractive matt grey, quite unlike the shiney finish from an equivalent grit abrasive paper. I hav eno idea what the physics behind this is but I think its quite a cool finish.

13-04-04, 08:34 PM
I am looking for waterstones to sharpen my ws woodlore knife.
I know how to sharpen my folding knife with a lansky set but i never
have used waterstones.
Can anyone tell me if this a good set for a starter with waterstones.
Also i saw these DMT stones i like the size and was thinking to put the knife
in a holder and work with the stone in the hand (good thinking or bad) :confused:

13-04-04, 08:42 PM
for waterstones that is a good starter kit ... i've got that and added some further stones to it.
The DMT stones I find a bit coarse and prefer the spyderco alumina ceramic stones
there are 2 schools of though about working the blade on the stone and the stone on the blade ....... I prefer the former as I find it easier to control

14-04-04, 12:09 AM
for waterstones that is a good starter kit ... i've got that and added some further stones to it.
The DMT stones I find a bit coarse and prefer the spyderco alumina ceramic stones
there are 2 schools of though about working the blade on the stone and the stone on the blade ....... I prefer the former as I find it easier to controlI looked at those spyderco alumina ceramic stones and they look
good to me.
I have not decided what to buy but i will keep those in mind.
i think a starter kit en those spyderco alumina ceramic stones wil do for me to learn.
All i need now is a old knife to practice on :biggthump

14-04-04, 08:40 PM
Saw this on the http://raymears.co.uk site http://raymears.co.uk/pictures/wet.jpg
Newly developed combination whetstone, where one side is a fine diamond whetstone (25 micron) the other is a fine ceramic whetstone.
The diamond whetstone restores the wedge form of the blade edge and the ceramic whetstone smoothes the edge to obtain long-term sharpness.

They can be used dry, withstand all types of steel, do not become deformed and come with a leather case. Size 27 x 77mm

Anybody a opinion about these stones :confused:
I like to here :thanks:

14-04-04, 08:47 PM
I am tempted to get some (to add to my burgeoning sharpening stone collection :D ) to try but my last experience with diamond stones is putting me off. If I cave in and get them I'll post a review.

I can see them being, potentially, very good for axes in the field.

Lord Farquhar
05-07-04, 01:09 PM
I have a set of 9 toshi (water stones) at about 220, 400, 600, 2x800,2x1000, 3000 and a 6000 i think there great some are natural Japanese ones some are man made. You do need a good stone holder for them and have cloth/rags in your hands when using them as its easy to slip with them and loose your skin also your skin goes puffy and soft in the water so you can end up sharpening your hands by accident (been there done that) and its very sore.

I personally like to use them while sitting on the floor. I put them on a low surface and put a bit of carpet under my knees and I feel I can get a lot of control and weight on the blade. They are not just good for sharpening but also great for polishing especially if you some nagura to mix with the slurry.

A good set may cost you about 500 easily but they will last and last.

20-09-04, 06:29 PM
Hi Folks,

Inherited some stuff from my Dad recently, including a sharpening stone. All it says on the pack is Condor (in an eagle / condor knid of logo) Silicon Carbide Sharpening Stone - Double Surface - Fine and Course. Having never used a silicon carbide stone, what I'm not sure of is wether ALL silicon carbide stones are waterstones as all I've ever used is oil stones and recently diamond stones. I don't thinbk it's fine enough for a final edge, but would be useful for rough sharpening, so I wouldn't want to ruin it by using the wrong lubricant.

Ta in advance,


25-05-05, 01:38 PM
I got a waterstone a while ago off E Bay the trader said it should be permanently kept wet any thoughts if thats correct or not?
heres an E Bay link no idea of grit mines the same and seems v fine

Lord Farquhar
25-05-05, 01:50 PM
I got a waterstone a while ago off E Bay the trader said it should be permanently kept wet any thoughts if thats correct or not?
heres an E Bay link no idea of grit mines the same and seems v fine

I have lots of water stones i let them dry out and i have never had a problem with that. As for wetting the stone just put it in water a while before you want to use it.

26-11-09, 11:23 PM
Great Article Martyn

Just received my 600 1200 and 800 Japanese water stones and Nagura stone from a German website.


Arrived in two days, good site with good selection of tools for working with wood and metals.

This is apparently Ray Mears's preferred combination of Grades, Looking forward to seeing the end result, I'll start with an old Victorinox

28-11-09, 07:49 AM
heh, yeah, i have a combi artificial waterstone and nagura on the way from fine-tools

im getting more interested in the natural waterstones too tho

theres a complete kit u can get: http://www.namikawa-ltd.co.jp/english/shopping/polishing_kit.html

45,000yen Shipping cost is not included. bit excessive really .. but it has examples of all the gubbins

13-06-10, 06:42 PM
Sorry to restart an old thread but I was wondering whether the nagura stone is used dry - or whether it needs soaking with the 6000-grit stone? :)

14-06-10, 10:22 AM
I'd say try it dry, then you'll see why it's better soaked. :)

Dry, the nagura drags water out of the waterstone as it goes, making it difficult to build up a slurry.

14-06-10, 10:28 AM
Ahh, ok good ... there also seems to be mixed advice on whether to store stones in water or whether to dry them between uses. I'm bad at forward planning so I'd prefer to store them in the dark in a little water - then they'd be ready for use when I need them, but obviously not if it's going to ruin them over time.

11-10-11, 08:15 PM
Quite interesting - also, has anyone heard of murray carter on youtube (cant remember no i think its carter cutlery something like it), got some interesting waterstone techniques...

very useful cheers


11-10-11, 08:16 PM
Nothing likes a waterstone like a swiss ;-)


12-10-11, 04:35 PM
Ahh, ok good ... there also seems to be mixed advice on whether to store stones in water or whether to dry them between uses. I'm bad at forward planning so I'd prefer to store them in the dark in a little water - then they'd be ready for use when I need them, but obviously not if it's going to ruin them over time.

I have a friend who is a japanese carpenter. He stores his waterstones in a bucket of water under the sink.

The main risk with storing them in water is if it's in a workshop and freezes, your stones are gonners.

12-10-11, 07:35 PM
Also to note with artificial stones, there are Soakers and splash-and-go stones depending on the binder used. Some stones like the Naniwa choseras should not be soaked for long periods of time or they will start to break down. Always worth checking whether the stone is a soaker or not