Flattening waterstones
#21
I think the main thing is as stated to learn to use the whole stone so it does not get too much out of flat.  But occasionally you will want to flatten a stone, like the oilstones you find at a garage sale that are severely dished.  Gluing some sandpaper down to glass or any flat surface is a start, but would wear out before much flattening was done.  However, sprinkling some loose grit on the sandpaper makes it cut better than new, so I just start with dull sandpaper of any grit.  The purpose of the sandpaper is primarily to keep you from wearing out your reference surface, and secondarily to provide a bit more friction so the grit does not slip off too easily.  Loose silicon carbide grit sold for rock tumblers is available in a whole range of grits at significantly less cost than sandpaper.

So why loose grit?  It's cheaper and cuts faster.

As to whether the surface you get is flat, no it's not flat to 1/4 wavelength of light as you would want for optical purposes.  But if the flat reference surface is large enough that your work does not hang over the edge at either side, and you make sure to not rock the work as it moves, it will be flat enough.  If you invert so as to rub the larger flat over the work so it overhangs on each side, it is much harder to keep from grinding the work convex, but it can be done well that way with care.
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#22
(09-14-2018, 04:35 PM)Alan S Wrote: I think the main thing is as stated to learn to use the whole stone so it does not get too much out of flat.  But occasionally you will want to flatten a stone, like the oilstones you find at a garage sale that are severely dished.  Gluing some sandpaper down to glass or any flat surface is a start, but would wear out before much flattening was done.  However, sprinkling some loose grit on the sandpaper makes it cut better than new, so I just start with dull sandpaper of any grit.  The purpose of the sandpaper is primarily to keep you from wearing out your reference surface, and secondarily to provide a bit more friction so the grit does not slip off too easily.  Loose silicon carbide grit sold for rock tumblers is available in a whole range of grits at significantly less cost than sandpaper.

So why loose grit?  It's cheaper and cuts faster.

As to whether the surface you get is flat, no it's not flat to 1/4 wavelength of light as you would want for optical purposes.  But if the flat reference surface is large enough that your work does not hang over the edge at either side, and you make sure to not rock the work as it moves, it will be flat enough.  If you invert so as to rub the larger flat over the work so it overhangs on each side, it is much harder to keep from grinding the work convex, but it can be done well that way with care.
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I just hold those old hollowed oilstones on the platen of my 6X48 belt sander and step on the foot switch...and the hollow disappears....
Big Grin
Often Tested.    Always Faithful.      Brothers Forever

Jack Edgar, Sgt. U.S. Marines, Korea, America's Forgotten War
Get off my lawn !
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#23
That will work.

You can also use a flattening stone like the one Norton sells, but make sure you check it for flat itself.  ;-)

It can be corrected using coarse sandpaper.
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#24
(09-13-2018, 10:08 PM)Elijah A. Wrote: Hey, I am trying to come up with a flattening solution for my new 1000/6000 water stones. I have never used water stones before and I am excited to give them a try. I love the dia-flat plate but at $200 I'm gonna have to wait on that. So I have a piece of granite and some 120 grit wet/dry sand paper. Is this the best option for a low budget solution? I also came across this lapping plate on Amazon and I'm curious if any of you have used it?

https://www.amazon.com/gp/aw/d/B07BW52DZ...op?ie=UTF8

Wondering if this would be better than buying so much sand paper... Look forward to hearing your thoughts!

Eli

Eli,  I've not tried the plate your looking at. Low number of reviews. But should you give it a go let us know how it works out. For the bucks I think it would be worth a try.

I used the sand paper for sharpening and later for flattening my water stones and ended up with oil stones. For me on a low budget $34 bought a lot of sand paper.



Now that I'm down to just
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#25
(09-17-2018, 03:46 PM)Laid-Back Wrote: Eli,  I've not tried the plate your looking at. Low number of reviews. But should you give it a go let us know how it works out. For the bucks I think it would be worth a try.

I used the sand paper for sharpening and later for flattening my water stones and ended up with oil stones. For me on a low budget $34 bought a lot of sand paper.



Now that I'm down to just


I ordered one recently. Not even close to flat. Useless to flatten water stones on. Worth a try for the money, but had to be returned.
John
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#26
Eli, you might want to look at the Atoma plates on Amazon. I have the 400 grit and have been using it for several years now . It was about $50 last time I checked. They also offer a 120 grit which would be faster.
Currently a smarta$$ but hoping to one day graduate to wisea$$
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#27
(09-14-2018, 12:08 PM)adamcherubini Wrote: I'd like to see a study showing what really happens when you rub 2 similarly sized stones together. Pretty sure you won't be left with 2 flat surfaces or 2 mating surfaces.  Pretty sure this is a woodworking myth started by sellers of Japanese water stones.

Also interested in how flat our "flattened" stones and plane irons really are.  I'm guessing not very.

Machinists don't flatten stuff by rubbing it on something flat.  That doesn't result in flat.

I think its worse if the thing you are rubbing on (the flattening stone) is sized such that the water stone over hangs the flattening stone during the process. When I flatten the back of a chisel, the steel never leaves the surface of the stone. But chisel backs are rarely flat.  They are flat-ish.

My sense is that the process we use doesn't produce flatness. So the thing we use to flatten, doesn't have to be perfectly flat. I think I recall hearing some old time Japanese craftsmen flattened their water stones on cinder blocks.  I would start there and see how it works.
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What Adam said.....
Winkgrin ...Nothing is ever "flat".....Flat "enough", maybe....Aluminum oxide or silicon carbide grit on a large floor tile will suffice for "flat enough".....get it from amazon or at a local rock shop.
Often Tested.    Always Faithful.      Brothers Forever

Jack Edgar, Sgt. U.S. Marines, Korea, America's Forgotten War
Get off my lawn !
Upset





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#28
100 grit drywall sanding screens on a flat surface.  Works for me.  You can flip them over too.

https://www.homedepot.com/p/3M-4-3-16-in.../100321141
Credo Elvem ipsum etiam vivere
Non impediti ratione cogitationis
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#29
I'm going to be the Grinch here. I love the way water stones cut, but they are a mess and a hassle even under the best of circumstances. Flattening them is necessary, and most (all?) flattening operations are messy and add to the hassle. Some flattening operations are messier and more aggravating than others. Sand paper on glass or granite works but it's really messy and the sandpaper wears out quickly or tears and has to be replaced often. It's a continuing expense. Drywall screen is only marginally neater and it can be used dry. I've never been a fan of loose grit abrasives, probably just me, but I find them to be excessively messy too, and the grit escapes and contaminates other media and my shop in general. Rubbing stones together doesn't work well for reasons already discussed. Rubbing stones on concrete blocks, sidewalks, pavement or any other architectural surface is even less satisfactory. I've tried and discarded all these methods and finally bit the bullet and bought a large DMT Duo Sharp coarse/extra coarse diamond stone for about $100 (https://www.amazon.com/DMT-W250CXNB-10-I...ing+stones).
It works fine, lasts forever if you don't abuse it and is reasonably tidy.
I eventually abandoned water stones (except for my Japanese edge tools) because of the mess and hassle, and have ended up with oil stones - back where I started 60 years ago.
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#30
(10-24-2018, 11:46 AM)Hank Knight Wrote: I'm going to be the Grinch here. I love the way water stones cut, but they are a mess and a hassle even under the best of circumstances. Flattening them is necessary, and most (all?) flattening operations are messy and add to the hassle. Some flattening operations are messier and more aggravating than others. Sand paper on glass or granite works but it's really messy and the sandpaper wears out quickly or tears and has to be replaced often. It's a continuing expense. Drywall screen is only marginally neater and it can be used dry. I've never been a fan of loose grit abrasives, probably just me, but I find them to be excessively messy too, and the grit escapes and contaminates other media and my shop in general. Rubbing stones together doesn't work well for reasons already discussed. Rubbing stones on concrete blocks, sidewalks, pavement or any other architectural surface is even less satisfactory. I've tried and discarded all these methods and finally bit the bullet and bought a large DMT Duo Sharp coarse/extra coarse diamond stone for about $100 (https://www.amazon.com/DMT-W250CXNB-10-I...ing+stones).
It works fine, lasts forever if you don't abuse it and is reasonably tidy.
I eventually abandoned water stones (except for my Japanese edge tools) because of the mess and hassle, and have ended up with oil stones - back where I started 60 years ago.
............................
I eventually abandoned water stones (except for my Japanese edge tools) because of the mess and hassle, and have ended up with oil stones - back where I started 60 years ago.

And there's nothing wrong with that, Hank..I like 'em too !!!!!! I do not have waterstones....for rough work, I use a Norton Carborundum...They are cheap, they cut and they cut fast...maybe not too flat tho...but I am not a member of the "flat tool society".....
Big Grin
Often Tested.    Always Faithful.      Brothers Forever

Jack Edgar, Sgt. U.S. Marines, Korea, America's Forgotten War
Get off my lawn !
Upset





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