Flattening Waterstones

[Denis Tranchemontagne]

I have a couple waterstones and have never flattened them.
Typically I use a combination scary sharp on a piece of granite tile andwaterstones to sharpen planes and chisels.

I was wonder what people use to flatten their stones.

Thanks

Denis

[Danny Thompson]

I use this Norton Flattening Stone.

http://www.woodcraft.com/family.aspx?FamilyID=5775

[Mike Henderson]

I use this Norton Flattening Stone.

http://www.woodcraft.com/family.aspx?FamilyID=5775
My experience with that Norton flattening stone has not been good. The problem is that the flattening stone must be kept flat or it transfers its non-flat shape to the working stones.

I use a DMT extra coarse diamond stone for flattening my working stones.

Mike

[Eddie Darby]

If you have a piece of granite already then you can use the surface plate to flatten your stones.

You should be flattening them quite frequently.

The fast cutting waterstones act fast because they wear so easily, producing fresh cutting compound in the process. The downside to this desirable fast performance is that they dish fast as well.

I have a DMT diamond stone, x-coarse/coarse, that I use, even though I have a granite surface plate which is much flatter, for convenience sake, because I can take the diamond stone to the waterstone, and do a quick touch-up very easily in between tools.

[Sam Yerardi]

Another option that I've heard of and read about in FWW (I've never tried it myself) is to use one stone to flatten the other. Place them together with a small amount of water, and rub across each other. Don't remove the paste that develops. Eventually they will flatten each other. If I can find the article I read I'll post the issue #.

[Danny Thompson]

To Mike's earlier point, the instructions that came with the Norton Flattening Stone say to periodically flatten it with a diamond stone.

[Gary Benson]

I also use the DMT x-corse diamond stone. I find that I need it to initially flatten older blades and chisels anyway, so it gets double duty. I have not had good luck using stones to flatten other stones due to differences in hardness. If you had 2 that were the same it would likely work well. I just use the diamond stone to flatten all of them.

[Thomas Knighton]

I'm trying to remember where I saw this, but there is at least one person who uses a cement block to flatten his stones. I haven't tried it myself, since my water stones haven't gotten here yet, so take this with a grain of salt!

Tom

[Greg Funk]

I've flattened waterstones with a piece of wet/dry sandpaper and any flat surface like a tablesaw top. It is not difficult.

Greg

[Mike Henderson]

Another option that I've heard of and read about in FWW (I've never tried it myself) is to use one stone to flatten the other. Place them together with a small amount of water, and rub across each other. Don't remove the paste that develops. Eventually they will flatten each other. If I can find the article I read I'll post the issue #.
This point has been discussed quite a bit before. If you rub two surfaces together, you get two conforming surfaces - not necessarily two flat surfaces (two flat surfaces are one possibily since they are conforming). The most likely outcome, however, is that one surface becomes convex while the other becomes concave.

Mike

[Christoph Schmitz]

Hi,

there is one (low-cost, I might add) technique that has been popularized in the German handtool community by Friedrich Kollenrott. He proposes to flatten your waterstones on bricks. In order to keep the bricks flat, you employ a technique that is well known in other areas (he quotes the making of precision surfaces in optics).

The key idea is to maintain three bricks and get these flat by rubbing them on one another in a cyclic fashion. If you number the bricks 1-2-3, the order would be: 2 on 1, 3 on 1, 1 on 2, 3 on 2, 1 on 3, 2 on 3. With this technique, you cancel out the effect of one brick becoming concave and the other one convex.

You can add grooves to the bricks to take away the swarf, and use silicon carbide powder to speed up the flattening of the bricks.

Those who speak German or want to take a look at his pictures, see http://www.woodworking.de/schaerfprojekt/schaerf2.html.

Best regards,
Christoph

[Sam Yerardi]

Mike,

It's good to know that. Like I said I've never tried it. Thanks!

[Bill White]

Another option that I've heard of and read about in FWW (I've never tried it myself) is to use one stone to flatten the other. Place them together with a small amount of water, and rub across each other. Don't remove the paste that develops. Eventually they will flatten each other. If I can find the article I read I'll post the issue #.

I agree w/ Sam. Been doin' this for years w/ good results.
Bill

[Sam Yerardi]

What makes me think this is worth trying is it does make sense. I don't remember the author's name in FWW but he even went so far as to suggest having an extra stone for each one just for this purpose.

[Larry Heflin]

Rob Cosman demonstrates and uses this technique in one of his videos.



Another option that I've heard of and read about in FWW (I've never tried it myself) is to use one stone to flatten the other. Place them together with a small amount of water, and rub across each other. Don't remove the paste that develops. Eventually they will flatten each other. If I can find the article I read I'll post the issue #.

[Mike Henderson]

Rob Cosman demonstrates and uses this technique in one of his videos.
I believe Rob Cosman uses THREE stones. If you do some research on the web or even do some research on your own with two surfaces you'll see that two surfaces will not (in general) produce a flat surface.

In fact, when hobbyist grind their small telescope mirrors they use a mirror blank and a glass tool. Both are flat to start but the blank quickly becomes concave. They just rub them together with a grinding compound between them.

Mike

[added note] There is a known technique for producing a flat surface by rubbing three surfaces together but not for using just two surfaces.

[Denis Tranchemontagne]

Thanks for all the opinions.

I will probably go with wet/dry sandpaper approach. Which grit/grits do you recommend and does it differ for fine/coarse stones.

Thanks again

Denis

[Cliff Rohrabacher]

My experience with that Norton flattening stone has not been good. The problem is that the flattening stone must be kept flat or it transfers its non-flat shape to the working stones.

I had a job run some many many years ago that required that I hand lap my parts to a flatness spec that was just a couple light bands (nanometers).

I used lapping compound and an old cast iron lapping table that was most assuredly not flat.

The trick is never to have any repeat motion. Random is the key: random pressure, random rotation, random stroking. It's a skill that is only good for hand lapping and applies just about nowhere else.

[Sam Yerardi]

Not trying to start a war :) but I'm finding a ton of stuff on the net (a lot of which is from reputable sources) that rubbing two stones together does work:

http://woodblock.com/encyclopedia/entries/014_02/014_02.html (http://woodblock.com/encyclopedia/entries/014_02/014_02.html)
http://www.imcclains.com/productinfo/documents/UsingJapaneseWaterstones.pdf (http://www.imcclains.com/productinfo/documents/UsingJapaneseWaterstones.pdf)
http://www.ezesharp.com.au/bladesharpener_manual.pdf (http://www.ezesharp.com.au/bladesharpener_manual.pdf)
http://www.woodworkforums.com/archive/index.php/t-10750.html (http://www.woodworkforums.com/archive/index.php/t-10750.html)


I gave up finding more because there were too many hits supporting the idea.

[Sam Yerardi]

Denis,
What I have always done (and others will have their methods that will work just as well if not better) is to use the same grade as the stone you're trying to surface. I've always understood that a particular grade abrasive will put scratches commensurate with its own grit size on a surface. Therefore that supports what I have always heard in that you wouldn't want to create scratch patterns the size of say, 600 in an 8000 stone. Understanding though, that the numbers for Japanese stones aren't directly related to grit size as they are with oilstones.

[Mark Bergman]

I generally flatten the four stones that I use most often on each other. Occasionally, I will use a piece of drywall mesh screen (used for sanding joint compound) placed on a half block solid cinder block to flatten my coarsest stone. I believe the screen is 100 grit, but it may be 150.

I did initially try to use the cinder block by itself to flatten a stone, but found that in no time at all it clogged up and became far too smooth to abrade anything. I've often read that people know people who do this, but I've yet to read a post by somebody who successfully uses this method himself (or herself).

My guess is that it would work if you were an intinerant carpenter and have plenty of sidewalks and such to choose from. (Like maybe traditional doormakers in Japan.)

[Bruce Haugen]

Denis,
You might also consider a piece of drywall sanding screen laid on a piece of glass. Lots of water, and it will take care of your problem forthwith.

Bruce

[Grant Lasson]

Sorry to hear about the problems with Norton flattening stone...mine should arrive in a few days. To this point, I've relied on wet/dry sandpaper and a machined granite block. I can recommend it but it takes a little cleanup to put it away, etc.

[Greg Funk]

Thanks for all the opinions.

I will probably go with wet/dry sandpaper approach. Which grit/grits do you recommend and does it differ for fine/coarse stones.

Thanks again

Denis
I don't recall exactly what I used but it was in the 220 to 600 grit range. You might need to experiment a little depending on how bad your stone is. You don't need superfine sandpaper as the fine scratches the paper makes in your stone will not be transferred to your blade/iron when sharpening.

Greg

[Don C Peterson]

OK, we've established that you can indeed flatten a surface using another surface (or two), providing you've got the patience, skill and luck, but good grief, why? The idea that you have to flatten your flattening stone is totally ridiculous, to me at any rate. Three years ago I bought a DMT extra coarse/coarse bench stone. It's flat, it works fast, it's not close to wearing out, and I never have to go through all the fuss an bother of flattening my flattening stone...

Actually, I've largely switched over to using the Spiderco ceramic bench stones and a Hard Black Arkansas stone so my DMT plate now spends more time flattening the backs of chisels and plane irons than it does flattening waterstones.

[Mike Henderson]

If anyone has a technique which will guarantee to flatten two surfaces by rubbing two surfaces together (without feedback) run to the patent office and file a patent on it. You'll get rich.

If you visualize two surfaces rubbing together, there are an infinite number of conforming surfaces which will work to bring the two surfaces in full contact. Only one is a flat surface. And nothing about rubbing two surfaces together will lead to that one particular outcome. In other words, nothing favors a two flat surface result. Because of that, the most likely outcome will be that one surface will become concave and the other convex.

The fact that this myth is so widely believed indicates that you don't have to have your working stones perfectly flat to get a good edge on your tools.

Mike

[note: "feedback" means that you stop rubbing every so often and measure the surfaces. Based on that measurement, you might change how you move the two surfaces in order to correct the non-flatness. But if all you do is rub two surfaces together, you cannot guarantee that they will wind up flat.)

[Eddie Darby]

Having read the talk about flattening stones, I went to an expert optical lens maker that has made lenses for high tech satellites in earth orbit.

Question: Do you need three stones?

Answer: No.
If you put the concave stone on the bottom, and move the flat stone on the top only.
You need three stones if you want to use one as a reference surface only. Hold the reference stone and the stone you are flattening together up to the light, and see if any comes through.

So Rob Cosman's method works if he advocates the concave stone on the bottom, and the flat one on the top, with the flat stone only being moved.

Please note that this system uses one stone that is already flat.

================================================== ================================================== =========

Last time I saw a demo being given by Rob Cosman ( 2 months ago ) he was using a Shapton Diamond plate for flattening his Shapton GlassStones. He was using the 1,000x , 8,000x and 16,000x glass-stones.

The plate he was using was called "Diamond on Glass Lapping Plate", not to be confused with the more expensive "Diamond Reference Lapping Plate"

[Mike Henderson]

If you rub two stones together, both will abrade.

If one is flat and one is concave, you must find some sequence of motions that causes the entire surface of the flat stone to be abraded evenly. If you use a motion that causes the center of the "flat" stone to get less wear, that stone will become convex.

It's unlikely that someone rubbing two stones together in a haphazard manner will fulfill that above requirement which will lead to a convex stone and a concave stone.

It is *possible* to produce two flat surfaces, but unlikely when no particular process is used.

Mike

Also, which stone you hold on top is essentially meaningless. It is the relative motion between the two stones which causes the abrasion. It doesn't matter if you hold them "right side up" or "upside down" of "sideways". Those descriptions are relative to gravity which plays no part here.

[Bill Brehme]

The DMT Diamond stone makes the most sense to me because of the relative hardness of the diamond stone compared to the much softer water stone. The water stone will conform to the much harder diamond surface.
Also, the sandpaper on glass method also holds water (heh, pun):D because of the predictable hardness and flatness of the glass:cool:

[Joe Cipriano]

If you rub two stones together, both will abrade.

If one is flat and one is concave, you must find some sequence of motions that causes the entire surface of the flat stone to be abraded evenly. If you use a motion that causes the center of the "flat" stone to get less wear, that stone will become convex.

It's unlikely that someone rubbing two stones together in a haphazard manner will fulfill that above requirement which will lead to a convex stone and a concave stone.

It is *possible* to produce two flat surfaces, but unlikely when no particular process is used.

Mike

Also, which stone you hold on top is essentially meaningless. It is the relative motion between the two stones which causes the abrasion. It doesn't matter if you hold them "right side up" or "upside down" of "sideways". Those descriptions are relative to gravity which plays no part here.

I use two stones.

One of them is a granite surface plate, which is technically a stone...;)

As the plate cost less than most of my sharpening stones, and should not wear out of true during my lifetime, I figured it was a good deal. I just place a sheet of 220 wet/dry paper on the plate; it only takes a few strokes, depending on how far out-of-true your stone is - although my King 800 took almost 5 minutes to remove the pencil line grid. OTOH, the Norton 220 took about 8 strokes total out of the box.

If you can afford it, use the big DMT to flatten. If not, get a surface plate (both LV and Woodcraft carry them for around $30).

Just my $0.02 - and worth every cent...;)

[Mark Roderick]

There are a zillion possibilities.

I used to use a piece of wet-dry sandpaper on glass, but the sandpaper was getting expensive.

I still use the glass, but instead of sandpaper I now use a sheet of kevlar (I think that's what it is) that you can buy very inexpensively from Lee Valley. I sprinkle some lapping compound onto the kevlar (the lapping compound is inexpensive almost to the point of being free, also from Lee Valley), add a few drops of water, and rub the stone in a circular motion.

Like everything having to do with sharpening, you can go crazy flattening your waterstones.

[Sam Yerardi]

Great discussion! The biggest thing I have learned from this is that there are a lot of different ways to do something. Everyone has made good points about it working/not working and I know I've learned some new things from this discussion. Actually I don't use the two stone method and have no plans to do so because it means I gotta get another stone for each one I've got :). Not a big issue but so far the methods I've used seem to work. You can always find a better way to do something. Especially when it comes to sharpening. Is it sharp enough? Can I make it sharper? Oilstone vs. waterstone? I found a new one (to me anyway) I'd never heard of the other day - Belgian stones. Touted as being the best. Who knows? I'm always wondering that. I can hone to an edge that gives me good results but I'm still asking myself should I spend a few more minutes and try to make it even better? Try a different method? What works for me might not work for you, and vice versa. But I try to learn something from everyone.

[steve swantee]

I use a concrete cinderblock to flatten my waterstones. I have been using the same one for a couple of years, and it is beginning to get pretty smooth now, so I will likely replace it soon, but it works great. I do it outside because it is messy- just splash some water on the block and start rubbing. They're cheap and easy to replace and you don't have to flatten them. They do leave a few scratches in the stones, but I haven't found it to be a problem.

Steve

[Alex Berkovsky]

...the instructions that came with the Norton Flattening Stone say to periodically flatten it with a diamond stone.:eek: Then why bother buying Norton flattening stone? Just use the diamond stone to flatten the waterstones. :confused:

[Thom Sturgill]

Mike, while you do grind telescope mirrors by starting with two plates, it is not easy and requires specific motion.
With two stones I get 4 surfaces to flatten with not two. That said, I probably will buy a diamond stone just for flattening, as I still need to flatten the single 8000 grit stone.

[Dan Racette]

I think that what Mike Henderson is saying has very valuable merit. If you look to the machinist's trade, that practice would not be used for the reason he is saying.

Joe C also makes an excellent point that a Grade B Granite Surface Plate is much less expensive than another waterstone and by the way, doesn't wear out. (Maybe less than $30 at the high end)

I, personally, do not accept glass or stones for my back flattening, only granite, but that is a personal preference.

It seems much more logical to me to get a granite surface plate since it is less costly and most assuredly flatter and use that for flattening stones. It is the best of both worlds, economics and high tolerances. Plus a piece of 120 grit paper just soak sticks to it with water adhesion, so it is also easy. Somebody bump me in the head and tell me I'm not being logical. That is not that any other system wouldn't work well, that is just my choice.

Dan

[Mike Henderson]

Mike, while you do grind telescope mirrors by starting with two plates, it is not easy and requires specific motion.
With two stones I get 4 surfaces to flatten with not two. That said, I probably will buy a diamond stone just for flattening, as I still need to flatten the single 8000 grit stone.
Thom - you're correct about the telescope mirror. To tell a personal tale, when I was a young man and broke, I made my first telescope mirror (a 6 inch). At that time, a kit was a lot less expensive than a finished mirror. Today, small mirrors are pretty inexpensive and it's not really worth while to grind your own unless you just want to learn how it's done.

Anyway, while there are specific strokes you use to deepen the concave on the blank, they're not really extreme. My guess is that our ancestors discovered the process by rubbing two surfaces together without any special strokes.

The point I was trying to make is that, when you rub two surfaces together, there's nothing that guarantees that two flat surfaces will result. In other words, the outcome is pretty much random - there's nothing in the process that will encourage "flatness". Since the outcome will be two surfaces that conform, and there are an infinite number of such surfaces, the likely result will be two surfaces that are not flat.

You can guarantee flatness with three surfaces, and the proper sequence, as Christoph Schmitz has pointed out in his post above. And as you pointed out, with two stones, you have four surfaces so if you use the proper sequence, you can guarantee flat stones.

Mike

[Matt Z Wilson]

So I don't really subscribe to the whole waterstone idea, I prefer oilstones, but I've been using a system for flattening chisel backs and plane soles for quite a while that works pretty well. I went to a scrap yard and found a piece of 5 x 8 cast iron that was about 1 inch thick (who knows what it was in a previous life) Cost: $16. Then I took it to a machine shop and had it surface machined on one side to flatness to .0005. Cost $5. Or if you're really ambitious you can have them machine grooves in it like a real lapping plate but that's more expensive. Now you can use the abrasive of choice for the lapping grit. Being cast iron and unhardened, the grit sticks into the surface of the plate and wears on whatever you are flattening. Diamond grit works very well, but other compounds work equally as well for less money. Now jut mix up a slurry of honing oil (or water) and the grit and you're in business. The plate hasn't been dressed in at least 5 years and yet is still flat to within .005. And it can be reflattened at the machine shop and being very thick will last long past my use for it. I suppose it would work just as well for waterstones, just make your lapping slurry out of water instead of oil and be sure to clean the plate thoroughly when you're done.

[Dan Racette]

Matt Wilson.

Looks like your first post on the Creek Matt. Welcome!

Dan

[Greg Cole]

I use an Arkansas Hard Stone on mine..... no other reason than it was what I found rummaging in the shop when I needed to flatten the stones the first time.
Works well for me anyway.... I have yet to break down and buy one of diamond stones. Something about buying anything related to diamonds makes me feel like I should be buying LOML something.:confused:

Works for me, as someone said... there's a zillion possibilities.

Greg

[Matt Z Wilson]

Thanks Dan, been around for a few weeks, just didn't have any contributions. I enjoy the conversation though.

[Alex Yeilding]

Thanks for all the opinions.

I will probably go with wet/dry sandpaper approach. Which grit/grits do you recommend and does it differ for fine/coarse stones.

Thanks again

Denis
Allow me to mention one variation of this approach. Drywall sanding screens work very well for this purpose. I like the 120 screens, but the finer ones work, too. the swarf drops through the screen, allowing much more efficient flattening. Used dry.

I understand some have had bad luck with the Norton flattening stone. I haven't. But for the heck of it, I used a friend's DMT extra course to "flatten" it. From the early abrasion patterns, it looked like my norton stone had gotten dished. After flattening, I took it home and held it up to the light with a straightedge and found a noticeable crown:( Don't know whether it was my technique or his diamond stone, but that was the result.

[Alex Yeilding]

If anyone has a technique which will guarantee to flatten two surfaces by rubbing two surfaces together (without feedback) run to the patent office and file a patent on it. You'll get rich.

<snip>

The fact that this myth is so widely believed indicates that you don't have to have your working stones perfectly flat to get a good edge on your tools.

Mike, I agree with the points you have been making about the two stone approach, at least in theory, but I think that in this post you hit on two important "real world" considerations.

We can't achieve a perfectly random pattern of rubbing two soft abrading stones together, or a soft and hard stone together, so any approach needs feedback or technique informed by prior feedback. I mention in another note my own negative experience of flattening on a DMT duosharp. I know some people have had problems with the flatness of those stones, but I believe the problem is just as likely to have been my technique.

And, yes, maybe the nth degree of flatness isn't necessary. Particularly if you are sharpening plane irons and putting on a slight camber.

[Ron Brese]

I was flattening my water stones yesterday, used a piece of 150 grit paper on top of my table saw to start. When I got them almost flat I changed to a piece of 220 grit paper. We are human and we will tend to take more off on the front end as we push the stone so rotate the stone every couple of strokes. I do all three stones in the same exact spot on the table so that they are all the same shape. When finished I re-soaked the stones and honed up a 1/4" thick 1 3/4" wide 0-1 iron popped it into a plane, made a few adjustments and pulled a fluffy full width shaving off of my set up board.

The moral of this story is "When you find a method that works, stick with it and don't over analyze it unless it stops working".

Ron

[Don Dorn]

Between the mess of the water stones and the hassle of keeping them flat, I took the easy road and changed to a Jet wet shapener and then like Don Petersen, a Syperco ceramic stone. I can get them sharp enogh with initial griding, then the leather strop - but then I hone with the 1800 g ceramic bench stone and also use it for touchups. I don't have to worry about wear or flatness. When I discovered that my left forearm was essentially hairless, I figured I had it right.

[Greg Crawford]

A couple of people have mentioned drywall sanding screens. You may want to take a look at this setup

http://www.woodworkforums.ubeaut.com.au/showpost.php?p=261326&postcount=1