New waterstones and a question

[Brian Hale]

Well i picked up a set of two sided waterstones from the WW Show on Saturday and my first question is... Is it bad to store these in water or give them a quick soak before use.

Set consists of 220/1000 combo, 4000/8000 combo, Norton flattening stone and a Norton Prep Stone (to be used like a Nargua stone) The blue plastic tray was an added freebie.

Brian :)

[Mark Singer]

Brian,
You may want to ask Norton. I think the impurities in the water will clog the stone and fill the abrasive tooth...
The truing stone is a stone and will also need to be trued in a short time. So in my mind you are better off with sandpaper on a flat granite plate or a truing plate which is metal and usually diamond and is more $$$
If the truing stone is to truly flatten the other stones it needs to be extremely flat....otherwise it is deforming the other stones.

[Ken Werner]

You've made an excellent start on the journey to THE edge you seek.

I keep my Norton 4K/8K dry in its case. A 10 minute soak is all the 4K needs, and a spritz is good for the 8K.

I keep my other stones in water, but given the case you have for the 220/1K, I'd be tempted to store it dry and soak for a bit just before use.

Remember, don't let them freeze.

Happy honing.

Ken

[Brian Hale]

Thanks Guys!!

The paper that came with the stones said to soak them for 10 minutes before use but said nothing about long term soaking.

The guy doing the demostration said to store them dry.

One guy standing next to me said his have been in water for over a year now but another guy said to only let them soak for a couple weeks.

:confused: :confused: :confused:

Brian :)

[Michael Gibbons]

Brian, I keep all four stones in a water bath at all times with no ill effects. Just don't let them freeze as a previous post suggests.

...Mike

[Roy Wall]

Brian,

I have 2 - 1k nortons and a 8k norton..

I just soak the 1k's about 10-20 before use and spritz the 8k.

I have left them all in water overnight but couldn't tell a difference.

You will like those stones!

[Mark Stutz]

I've done both and can't tell a difference. That little blue tray may be the best thing ou picked up:D . I've been looking for something like that since I started using waterstones.

Mark

[Richard Keller]

Brian,

I have kept my stones in water for at least the last five years with no problems (Not Norton stones though - not sure if that matters) I find that there is no cutting difference between leaving them in and just a ten minute soak. I have a 220/1200x combo, an 800, 4000, and 8000. The only thing that leaving them in has over the pre-soak is that they are ready to go when you are. I find that when I am working, all of a sudden I will have the urge to sharpen something. If I wait ten minutes, the urge goes away, which means that nothing gets sharpened.

One recommendation though - change the water often - monthly or more depending on use. --- AND ---- if your not in a heated shop --- make sure you bring them in the house! Freezing is very bad. I also have heard bad things about guys putting anti-freeze in the water, so I wouldn't recommend it. Apparently that can cause the stones to dissolve!

Richard.

[Mike Henderson]

Let me suggest that you return that flattening stone. While it sounds good, the problem you run into is that it doesn't stay flat. So what you wind up doing is making your sharpening stones other than flat. You'd have to have something to flatten the flattening stone before you use it to flatten your working stones.

Rather than do that, return the flattening stone and buy a DMT coarse/extra coarse diamond stone. The diamond stone cuts quickly, stays flat, and can be used to flatten the backs of chisels and plane blades.

While I like Norton water stones, I think that flattening stone is a rip off.

Mike

[Rob Blaustein]

Rather than do that, return the flattening stone and buy a DMT coarse/extra coarse diamond stone. The diamond stone cuts quickly, stays flat, and can be used to flatten the backs of chisels and plane blades.
Mike Mike,
Is this (http://www.amazon.com/Machining-Technology-W250CXNB-DuoSharp-Extra-Coarse/dp/B00004WFUL) what you are referring to? Is that the right length? A few months ago I picked up a LV Veritas Mk II jig for sharpening and a 1000/4000 Japanese waterstone from them as well. I didn't realize I needed something else too. I admit I've been intimidated by the sharpening process and so haven't given them a try but I'm about to take a dovetail class and wanted to sharpen my chisels. Is the idea that the 1000/4000 stones get worn from use and need to be flattened periodically? Would they be fine initially right from the box? Will those stones plus jig plus flattening stone suffice for sharpening chisels and tuning up handplanes? Thanks, and sorry for bombarding you with questions.
--Rob

[Mike Henderson]

Mike,
Is this (http://www.amazon.com/Machining-Technology-W250CXNB-DuoSharp-Extra-Coarse/dp/B00004WFUL) what you are referring to? Is that the right length? A few months ago I picked up a LV Veritas Mk II jig for sharpening and a 1000/4000 Japanese waterstone from them as well. I didn't realize I needed something else too. I admit I've been intimidated by the sharpening process and so haven't given them a try but I'm about to take a dovetail class and wanted to sharpen my chisels. Is the idea that the 1000/4000 stones get worn from use and need to be flattened periodically? Would they be fine initially right from the box? Will those stones plus jig plus flattening stone suffice for sharpening chisels and tuning up handplanes? Thanks, and sorry for bombarding you with questions.
--Rob
Yes, that's the DMT stone that I purchased. Let me say that there are other ways to flatten a water stone. One alternative is wet-or-dry sandpaper on glass or other flat surface. But if you can afford it, the diamond stone is fast and easy to use.

To your other question, yes, water stones wear and get dished, usually in the center-middle. If you sharpen a chisel or plane blade on a non-flat stone, your edge will be curved rather than straight across. And if you try to flatten the back of a chisel or plane blade on a non-flat stone, it won't work.

The 1000/4000 will work for sharpening your chisels and plane blades. It'd be nice to have an additional stone in a higher grit, but you'll get acceptable results with what you have.

Generally, water stones are flat when shipped to you.

If you're just getting started, you might wait on the diamond stone and do your flattening with sandpaper on some flat surface. But if you're sure you're going to stay with it, the diamond stone is a good investment IMO.

Mike

[Rob Blaustein]

Thanks Mike. What is the appropriate grit of sandpaper for flattening a 1000/4000 stone? Do you use some sort of adhesive to attach it to a sheet of glass or say an unused piece of marble or granite?

[Ken Bryant]

If the truing stone is to truly flatten the other stones it needs to be extremely flat....otherwise it is deforming the other stones.

Well, not really. If you rub the two stones together so the bumps on one slide around and the bumps on the other slide around, pretty soon all the bumps on both are worn off...and both stones are flat. This is the recommendation of Rob Cosman of Lie-Nielsen (see any of his videos). He recommended to me on the phone that I keep two 1000 grit stones, rub them together to flatten both, and then use them both to flatten the finer stones. It works fine, every time. The diamond stone might cut faster, though.

Again, the trick in the two-stones approach is that BOTH stones have to be wearing away at once, along an intersection plane that's already more or less flat. If you had a lopsided diamond stone (which would not wear down), and tried to true a softer stone with it, THAT would be bad news.

[Richard Keller]

I use silicon-carbide powder from LV -- about 120x. I do this on my granite surface plate (with a sheet of self-stick mylar on it) and a little water. I would think that sandpaper would work fine, but use wet-dry and a little water. Also, I would highly recommend investing in a good 8000x water stone. Makes and edge MUCH noticeably sharper than 4000x.

Richard.

[Dan Forman]

The Norton flattening stone is worthless. Return it, it's an exercise in frustaration. 120 or 180 grit drywall screen works great, and can be flipped when worn, which doesn't take long.

Dan

[Mike Henderson]

Well, not really. If you rub the two stones together so the bumps on one slide around and the bumps on the other slide around, pretty soon all the bumps on both are worn off...and both stones are flat. This is the recommendation of Rob Cosman of Lie-Nielsen (see any of his videos). He recommended to me on the phone that I keep two 1000 grit stones, rub them together to flatten both, and then use them both to flatten the finer stones. It works fine, every time. The diamond stone might cut faster, though.

Again, the trick in the two-stones approach is that BOTH stones have to be wearing away at once, along an intersection plane that's already more or less flat. If you had a lopsided diamond stone (which would not wear down), and tried to true a softer stone with it, THAT would be bad news.
I'm afraid that rubbing two stones together will NOT give you a flat surface. It will give you two surfaces that fit together. For example, one surface may be concave and the other convex and they'll fit together very well.

People who grind their own telescope mirrors know this. They have a glass tool and a mirror blank and by rubbing them together with grinding compound between them, they create a spherical concave mirror (which is converted to parabolic in the final steps).

Mike

[Mike Henderson]

Thanks Mike. What is the appropriate grit of sandpaper for flattening a 1000/4000 stone? Do you use some sort of adhesive to attach it to a sheet of glass or say an unused piece of marble or granite?
When I used sandpaper for flattening water stones, I wasn't very particular - I used what I had handy. That said, I wouldn't use too fine a grit because it takes too long and I wouldn't use too rough a grit because it leaves big scratches in the stones. Maybe 100 to 150 grit. Maybe someone else can give an opinion.

Mike

[Brian Hale]

The flattening stone and tray was part of the group price and that was cheaper than just the 2 stones by themselves so returning it isn't an option. However the back of it might be used as an extra course stone? :confused:

As a side note, precision granet inspection plates for the machining trade are made by rubbing a combination of 3 plates against each other with a lapping compound between them. I'd think that using just 2 stones would create concave surfaces but perhaps using the 3 stone method would work provided they all were of equal abrasiveness. Maybe.

Brian :)

[Rob Blaustein]

I'm afraid that rubbing two stones together will NOT give you a flat surface. It will give you two surfaces that fit together. For example, one surface may be concave and the other convex and they'll fit together very well.

People who grind their own telescope mirrors know this. They have a glass tool and a mirror blank and by rubbing them together with grinding compound between them, they create a spherical concave mirror (which is converted to parabolic in the final steps).

Mike

If you rub along several axes shouldn't that help? I can see where rubbing two stones together along only one axis can give rise to what you describe, but would that also occur if you switched directions often?

[Mike Henderson]

If you rub along several axes shouldn't that help? I can see where rubbing two stones together along only one axis can give rise to what you describe, but would that also occur if you switched directions often?
Nope - if all you use is two surfaces, all you get is two surfaces that fit together - not two flat surfaces. As Brian mentioned, it is possible to get a flat surface by using three surfaces, but I don't know the sequence or other requirements.

But I can guarantee that two surfaces will only give you two conforming surfaces, not two flat surfaces.

Mike

[Ken Bryant]

Your two 1000 grit stones, after wearing through similar sharpening, will be worn in similar ways -- i.e., both convex or both concave. Empirically, if you rub them in a more or less circular fashion, all the high spots are hit, and they come out quite flat. I will agree, though, that if you had a convex stone and a concave stone, and carefully (and perversely!) rubbed them together along the axis, you'd only make the problem worse.

Again, see Rob Cosman's videos. This wasn't my creation, but his.

[Rob Blaustein]

Maybe the answer is that the two surfaces will be flat enough--not good enough for optics, but maybe good enough for sharpening something small like a chisel where a very small deviation from flat would be ok.

[Mike Henderson]

Not to beat this to death, but let me give you an example. First, why does your working stone wear more in the middle-center than around the outside? It's because no matter how you try, you use the middle center more than the outside.

Now, suppose you take two stones that aren't concave the same amount. For purposes of illustration, let's assume that one of them is actually flat, while the other has a concave in the middle-center, and you begin rubbing them together. No matter how you try, you will abrade the outside of the flat stone more than the center because the outside will be making contact while the center is not. Eventually, the stones will make full contact but the flat stone will now be convex while the originally concave stone will continue to be concave. Using only two stones it is simply not possible to guarantee that the two stones are flat - in fact, it's more likely that they will not be flat.

If you use these stones to flatten other stones, you will transfer the shape of one stone to the other. So if you use the convex stone on a concave working stone you will absolutely not flatten it - it will continue to be concave. And if you use the concave stone on another concave stone, the one that is less concave will become convex.

You can use two stones you rub together, but don't try to fool yourself into thinking they are flat.

Mike

[Rob Blaustein]

For purposes of illustration, let's assume that one of them is actually flat, while the other has a concave in the middle-center, and you begin rubbing them together. No matter how you try, you will abrade the outside of the flat stone more than the center because the outside will be making contact while the center is not.

Mike--I envisioned a different sort of movement that I think would not lead to what you are proposing. What if you started rubbing your concave stone against the flat stone but orient them, at least initially, 90 deg to each other, as in the attached photo. Moving the concave one (the upper one) side to side will remove material uniformly from the flat one, and also remove the material from the upper one too, and evenly if that one is also allowed to move. Does that make sense?
54609

[Alan Turner]

Brian,
We use 180 grit wet/dry black SC paper, on a granite sink cut out, and it is pretty quick for our Nortons at PFW. We leave all three in water all the time. The 220 is not a great stone as it dishes pretty quick, and is difficult to re-flatten.

[Mike Henderson]

Mike--I envisioned a different sort of movement that I think would not lead to what you are proposing. What if you started rubbing your concave stone against the flat stone but orient them, at least initially, 90 deg to each other, as in the attached photo. Moving the concave one (the upper one) side to side will remove material uniformly from the flat one, and also remove the material from the upper one too, and evenly if that one is also allowed to move. Does that make sense?
54609
Rob, the point I was trying to make is that you cannot gurantee flatness with only two stones. I cannot see any technique which will allow you to say with confidence that the surfaces are flat.

If what you are doing works for you - if you have used it and tested the surfaces after using it and they are always flat - I would say continue to use it.

Mike

[Roy Wall]

Thanks Mike. What is the appropriate grit of sandpaper for flattening a 1000/4000 stone? Do you use some sort of adhesive to attach it to a sheet of glass or say an unused piece of marble or granite?

Rob - I do what LN taught me......

I bought a 12x12 granite plate from Woodcraft.....good to .00005 flat or something crazy.... wet a sheet of 120 sandpaper and stick it to the granite...then run each stone over to flatten.

[Ken Bryant]

works for me. works for Rob Cosman.

[Dave Burnard]

If you rub two surfaces together, like abrasive stones or glass plates and abrasive, and orient them randomly (mathematically speaking) - what you get are spherical sections. So you might get two flat surfaces since that's a special case of spherical sections but you're much more likely to get some form of concave/convex pair. This is how you do the initial grinding when making a telescope mirror or glass lens

However if you do the same thing with three surfaces and also randomly switch which two you are rubbing together - you can only end up with a planar surface. That's how optical flats (or telescope diagonal mirrors) used to be made.

So you can do it with three (similar) stones, and I've heard of some folks doing this. You just need a bigger stone pond ;)

[Monte Milanuk]

This topic is of interest to me as I just ordered my first waterstone (Norton combination 1000/4000 grit) and figured I'd try the drywall screen or coarse sanding belt as shown in one of Frank Klausz's videos.

On the two stones vs. three stones for flattening each other... I've seen Rob Crosman's video on hand planes where he flattens the stones against each other (two stones), but I also understand the concept of three independent surfaces normally being required to guarantee that any one is perfectly flat. The question that comes to mind is if this changes materially by rubbing in a circular or figure-eight pattern such as some people appear to use when flattening stones, vs. a more linear forward and back motion?

[Mike Henderson]

This topic is of interest to me as I just ordered my first waterstone (Norton combination 1000/4000 grit) and figured I'd try the drywall screen or coarse sanding belt as shown in one of Frank Klausz's videos.

On the two stones vs. three stones for flattening each other... I've seen Rob Crosman's video on hand planes where he flattens the stones against each other (two stones), but I also understand the concept of three independent surfaces normally being required to guarantee that any one is perfectly flat. The question that comes to mind is if this changes materially by rubbing in a circular or figure-eight pattern such as some people appear to use when flattening stones, vs. a more linear forward and back motion?
For me, the problem is that you cannot guarantee that you will get a flat surface when you only use two stones. You might, and again, you might not. It's possible that you could find some sequence of motions that would provide you with a relatively flat surface but you'd have to verify that the surface is flat by some testing method, and you'd have to follow that particular sequence every time - or repeat the flatness testing. And you might need different motions depending upon the wear pattern on the stones.

I chose to use a diamond stone to flatten my water stones because I could depend upon repeatable results.

Mike

[Rob Blaustein]

On the two stones vs. three stones for flattening each other... I've seen Rob Crosman's video on hand planes where he flattens the stones against each other (two stones), but I also understand the concept of three independent surfaces normally being required to guarantee that any one is perfectly flat. The question that comes to mind is if this changes materially by rubbing in a circular or figure-eight pattern such as some people appear to use when flattening stones, vs. a more linear forward and back motion?
Well, I picked up a few Rob Cosman DVDs including the one where he discusses and demonstrates sharpening. Just to clarify, as Ken pointed out earlier, Rob actually does use a 3 stone system for keeping his stones flat--he doesn't only rub the two 1000 grit stones together, he also uses one of the 1000 stones on his 8000 stone.

[Terek Johnson]

Let me suggest that you return that flattening stone. While it sounds good, the problem you run into is that it doesn't stay flat. So what you wind up doing is making your sharpening stones other than flat. You'd have to have something to flatten the flattening stone before you use it to flatten your working stones.

Rather than do that, return the flattening stone and buy a DMT coarse/extra coarse diamond stone. The diamond stone cuts quickly, stays flat, and can be used to flatten the backs of chisels and plane blades.

While I like Norton water stones, I think that flattening stone is a rip off.

Mike
I'm with Mike on this one. I use Norton waterstones, and I bought one of their flattening stones at the W.W. show last fall. Hate to say it, but it doesn't make the stones truely flat. I can use a stone that I just "flattened" on it, and the stone will cut a noticable camber on the blade. I like the sandpaper on granite idea, have to give that a try.
As for leaving waterstones in water, I leave mine in water and haven't had any noticable problems with them. But while at a woodworking show was told by a Lie Nielsen rep that if you leave fine grit stones in water all the time, you risk softening them excessively. Good luck.

[Derek Cohen]

For the past few years I have used 220 grit drywall screen to flatten my King waterstones. This has a number of positive attributes, such as the mesh does not load up like sandpaper.

I have had a growing unease for some time, however, that both drywall screen and sandpaper have a major negative attribute, this being that these wear unevenly, and this uneven wear is transfered to the surface of the waterstone. For example, if the centre section wears more, then this can create a camber on the blade. It can be circumvented by using fresh sandpaper or mesh, but this is expensive and inconvenient.

So - like Mike - I am going back to using a diamond stone to level my waterstones. This retains the same surface characteristics and puts my obsessive compulsive side to rest.

Regards from Perth

Derek

[Eddie Darby]

Having read the talk about flattening stones, I went to an expert optical lense maker that has made lenses for high tech satellities 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.

[Andrew Homan]

Eddie,
I think the important factor is that one is always flat and that the other only ever becomes concave, never convex. If a stone is becoming convex, it will make the other stone concave. This is where you would need a third stone, or a surface that stays true, like a diamond stone or concrete block.

That is, if I am visualizing correctly. ;)
I use Cosman's method. Note that you must work on the stones before going to the next grit!
-Andy

[Eddie Darby]

Eddie,
I think the important factor is that one is always flat and that the other only ever becomes concave, never convex. If a stone is becoming convex, it will make the other stone concave. This is where you would need a third stone, or a surface that stays true, like a diamond stone or concrete block.

That is, if I am visualizing correctly. ;)
I use Cosman's method. Note that you must work on the stones before going to the next grit!
-Andy
I have yet to get a stone that is convex in 3 decades of sharpening. Maybe you do?
The goal in sharpening is to never ever ever go over the edge of the stone, so most of the wearing down takes place in the center of the stone.
To track the progress of a stone, use a pencil to put hash lines across the surface. You will see that the last hash lines to disappear during flattening, are the ones in the center.

So when Rob Cosman sells you two 1000x stones, he is selling you a viable method. I have a DMT X-coarse stone that I use for flattening stones, so I only have 1 stone at 1000x. My thinking is that I can use this diamond stone for lapping flat the back of blades as well as flatten stones.

[Andrew Homan]

I have yet to get a stone that is convex in 3 decades of sharpening. Maybe you do?

No, I don't, but it does happen to people, particularly if the aren't careful about the way they work on chisels toward the sides of the stone.

Anyhow, I thought I was supporting what you said, not opposing it. I have some questions, since you sound like you have a lot of experience. When you mention three decades of sharpening (that's a lot), were you using waterstones all that time? And how long did you use the waterstone-on-waterstone method before switching to DMT?
-Andy

[Eddie Darby]

I started out using waterstones when Lee Valley Tools started to sell waterstones back in the early 80's. Before that I had a couple oil stones.

I asked if you get convex stones because someone who does only knives will get a convex stone, or as you pointed out, someone with bad technique. I am sorry if I was a little too direct with the question.

Rob is mostly doing plane blades, and so the stone will dish out, to end up concave.

I use to use the glass plate that Lee Valley Tools sells with silicon carbide. I now use the DMT and a granite surface plate. Whatever is handy at the time.

When I started out as a raw beginner, I would try and put-off flattening the stones as long as possible, now I have the opposite frame of mind, and I probably flatten too often. A little flattening at the right time goes a long long way.

[Andrew Homan]

When I started out as a raw beginner, I would try and put-off flattening the stones as long as possible, now I have the opposite frame of mind, and I probably flatten too often.

Rob Cosman seems to flatten his stones about as often as I hit command-s while working on an important document! Which is to say, very often. I think that it prevents flattening from becoming a huge issue. I flatten my coarser stones often and could probably be more vigilant with my finishing stone.
-Andy

[Derek Cohen]

Rob Cosman seems to flatten his stones about as often as I hit command-s while working on an important document! Which is to say, very often. I think that it prevents flattening from becoming a huge issue. I flatten my coarser stones often and could probably be more vigilant with my finishing stone.
-Andy

As noted earlier, I currently prefer a diamond stone (over drywall screen or sandpaper) for this task. I will add that I flatten or, as Rob refers to it, "freshen up", as often as he does. Just a swipe or two inbetween stones. I still draw on a grid to check it is being surfaced evenly.

Regards from Perth

Derek

[Richard Danckaert]

I have the 1000,4000,and 8000 Norton stones.I formerly used the Rob Cosman method of flattening the stones.Now I use the same method as Roy Wall , consisting of a Granite Surface plate that I bought from LV and some 220 grit wet dry sandpaper glued to the plate.It made a world of difference in keeping my stones flat and improved my success at sharpening.I have found other uses for the granite plate which is a bonus.
I also keep my stones in water all the time with no problems.

Rich

[Jules Dominguez]

I have an old King combo stone and a coarser stone that I bought probably about 20-25 years ago. I've kept them submerged in water in a Tupperware breadbox almost since I first got them, and it hasn't changed them in any way that I can tell. I rinse the box and change the water occasionally.

Most of my plane blades are almost as wide as the stones, and I try to use the whole stone and switch ends fairly frequently when honing, which I do with a guide, and I don't find that the stones get out of flat very much. I only hone microbevels and a portion of the backs of my irons, so neither initial honing nor touchups take long or cause much wear. I check the stones for flatness before each time I use them.
I previously used a section of a belt sander belt fixed to a cast iron table to flatten them, but recently purchased the coarse Norton flattening stone with the diagonal grooves. I've used it once to resurrect my first waterstone which was fairly badly grooved and to touch up my other stones. Worked fine. I cleaned it with water and a stiff plastic scrub brush after using it. I don't expect a problem with it unless it loads up with grit to the point that I can't clean it. What problems do you guys have with it?
As a qualifier to the above information, let me say that my use of hand planes is pretty sporadic, so they don't get nearly as much wear as a hard-core Neanderthal would give them.

[Mike Henderson]

I have an old King combo stone and a coarser stone that I bought probably about 20-25 years ago. I've kept them submerged in water in a Tupperware breadbox almost since I first got them, and it hasn't changed them in any way that I can tell. I rinse the box and change the water occasionally.

Most of my plane blades are almost as wide as the stones, and I try to use the whole stone and switch ends fairly frequently when honing, which I do with a guide, and I don't find that the stones get out of flat very much. I only hone microbevels and a portion of the backs of my irons, so neither initial honing nor touchups take long or cause much wear. I check the stones for flatness before each time I use them.
I previously used a section of a belt sander belt fixed to a cast iron table to flatten them, but recently purchased the coarse Norton flattening stone with the diagonal grooves. I've used it once to resurrect my first waterstone which was fairly badly grooved and to touch up my other stones. Worked fine. I cleaned it with water and a stiff plastic scrub brush after using it. I don't expect a problem with it unless it loads up with grit to the point that I can't clean it. What problems do you guys have with it?
As a qualifier to the above information, let me say that my use of hand planes is pretty sporadic, so they don't get nearly as much wear as a hard-core Neanderthal would give them.
The problem with the Norton flattening stone is that you have to flatten it on a regular basis to make sure it's flat before you use it to flatten your working stones. If you don't, you'll be putting some non-flat profile on your working stones. Rather than use the Norton flattening stone as an intermediary, use whatever you would use to flatten the Norton flattening stone to flatten your working stones.

Mike