How to flatten a water stone without a diamond lapping plate?


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I have a couple thin water stones i want to flatten.  They are for a knife sharpening system called the Edge Pro.   i have noticed the stones are starting to dish out a bit.  Other than a DMT lapping plate or the like, what's the best way to flatten these water stones?  Can i do it with plate glass and sand paper?

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each fine stone can be flattened with the lower grit. but of course if you have them all in need, something must be done. There's also a open grain sand paper that's made specifically for flattening. The edge pro is great. A friend has one and loves it. don't think he's had this issue yet. 

 

make sure your stones are dry tho! if at all wet,the paper gunks up, and you'll be at it for ever!

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==>Just hit it with the random orbit.  :D

Funny, but you've got to be careful with advice like that... Someone may actually try it... :)
 
==>I have a couple thin water stones i want to flatten.
I usually use the DMT... It's expensive, but works well...
 
If you don't want the expense of a DMT, you can also use wet/dry paper (anything in the 120 - 240 range works well) on a flat surface. Two 'flat' surfaces in my shop: a slab of 1/2" float glass and a granite reference surface. If you hunt around, you can still get float glass... Granite reference surfaces are quite expensive, but if you've got other uses for a machinist's surface, they are hard to beat. I also have a machinist's lapping plate, but don't use it for waterstones... Some folks have reported luck with granite counter top off-cuts, I've never used one, so can't comment on their actual flatness.
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Coarse silicon carbide is better than sandpaper.  It's faster, exactly as flat as the surface you put it on (which may or may not be true of sandpaper), is cheaper, doesn't wear unevenly the way sandpaper does, and doesn't have the potential to come apart on the more modern harder ceramic waterstones.   Sandpaper does work, particularly on things like Nortons and Kings, but SiC is superior. The one drawback is it can theoretically wear your substrate over time so you wouldn't want to put it on bare precision ground granite plate.

 

Go to ebay and type in Silicon Carbide.  Mine is 100 grit...I'm sure anything in the 90-220 grit range would work fine.  You can get a bag for less than $10 that will last you a LONG time and an even bigger bag for a little more.

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==>^^^

Great suggestion and good advice, but would like to qualify it a bit...

 

==>Coarse silicon carbide is better than sandpaper

Certainly faster and will cut harder stones... but with a qualifier -- depends on your lapping surface...

 

==>The one drawback is it can theoretically wear your substrate over time so you wouldn't want to put it on bare precision ground granite plate

That's the drawback... and it's more than theoretically possible, it indeed does wear what many would use for a lapping surface...

 

Actually Chris Schwarz used this method until he dished all his irons when the granite was eroded by the SiC.

 

I use SiC and diamond lapping paste on a machinist's lapping plate... But a proper lapping plate is quite expensive...

 

Most granite is too soft for this method -- woodworkers tend to use counter-top cutoffs or inexpensive machinist's surfaces.. There are sources for granite that gets used for high-end surfaces (think Starrett), but that's expensive... In the spirit of the Olympics -- it's the same granite used to make curling stones and mined in Scotland...

 

I just did a quick eBay query, there are numerous Starrett plates selling for pennies on the dollar (obviously, a casualty of machine shops closing their doors). They are no longer in cal, but who cares. You can get a $1K Starrett reference surface for $75 + about $50 in shipping...

 

For the bargain hunter:

http://www.ebay.com/itm/12-x-18-x-3-ACE-GRANITE-GRADE-AA-SURFACE-PLATE-TWO-2-LEDGE-/281268633263

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True. I'm not sure why I said theoretically.  You're correct it WILL.  You want either something cheap & sacrificial (thick glass) or something you can reflatten  somehow...mild steel/a kanneban(sp).

 

For the qualifier...I would say depends on what you're flattening more than depends on your lapping surface...though again, I wouldn't want to use it on something that I want to STAY flat eternally.  Nortons, Kings, Suihiros, and softer waterstone do well with sandpaper and that may be preferable for some folks (though I'd still rather use SiC)

 

Modern ceramics....I'd say SiC is definitely better...sandpaper won't do jack to some of them.

 

Oil stones...well they laugh at sandpaper....they even laugh ZirC sanding belts.  Loose Sic or diamond is in my experience (which everyone should feel free to take with a GRAIN OF SALT) by far the most effective way to flatten those. 

 

Personally, I use an Atoma 400 to keep watestones flat finding a diamond plate to be the most convenient way to get the job done.  For oil stones I have a worn out diamond stone that I sprinkle SiC on and use as a lapping plate.  I almost never flatten those so I don't really worry about it going out of flat quickly.  When it does...I'll get something else sacrificial. 

 

Anyway, great info HHH...thanks for the clarifications.  "Theoretically" was really not the best word choice for this topic.

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If you are really desperate, you can do what they did before they had flattening stones, which is rub it on a concrete floor.

Granpa used to flatten his stones by rubbing them face to face. The coarser will remove more material than the finer, but they will still get flat. For sharpening knives, I never use a jig. Most blades have a curved edge, and it just seems easier to freehand. Doing it that way, a little dishing really isn't a big deal.

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==>I would say depends on what you're flattening more than depends on your lapping surface...though again, I wouldn't want to use it on something that I want to STAY flat eternally.  Nortons, Kings, Suihiros, and softer waterstone do well with sandpaper and that may be preferable for some folks (though I'd still rather use SiC)

 

That's a very good qualifier on my qualifier... Ceramics are indeed a different animal --- and even within ceramics, there is a hierarchy... When I made my switch to Naniwa Choseras, my flattening method had to change as well... I used to use sandpaper on a plate with clay-matrix stones, but the magnesium-oxide stones just killed that method...

 

What folks don't realize is that many of the harder ceramic stones will kill most diamond lapping plates very quickly. There was a survey of diamond plates on Hock's blog -- actually Chris Schwarz contributed some of it. At the time, Chris was spending a fortune buying several lapping plates per year -- especially after ceramics came into the market... After trying quite a few plates, Chris found that only the DMT Dia-Flat held-up over extended use (yea, it's $200, but it beats purchasing several $150 plates per year).

 

Note: not all ceramics stones are the same -- some are considerably harder than others... What was ironic, the ridiculously-priced Shapton plate ($375) was killed faster than most bargain plates (assuming you think $100 is a bargain). If you read the fine print, Shapton's plate warranty only holds if you only use it on Shapton stones -- and not all their stones to boot...

 

I agree that if you don't want to invest in a diamond plate, then a throw-away surface is a viable option... I think the other value-solution would be a decent plate from eBay.

 

Note: the DMT isn't perfect -- you do kill it over time, just not as fast as other plates... If you want a truly long-lasting plate, you need to look at 3M's line of industrial diamond lapping plates -- but those are ludicrously expensive and made for 24/7 production use...

 

==>Granpa used to flatten his stones by rubbing them face to face. 

Yea that can work (for a while), but with more and more folks getting ceramic stones that method passed into the sunset.... The actual result of the 'two stone method' is two un-flat stones. The old-timers got away with this because the hard Arkansas stone was their reference and those stones are super hard and really tough... But in the end, they dish just like anything else.

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You can not make anything flat with only 2 surfaces if you do not have a reference flat surface to start with. You can mate a bowling ball to a flat plate, they will fit together perfectly but neither will be flat. It takes 3 surfaces, all working one into the next to eventually wind up with a flat surface so just using one stone against another will not give you 2 flat stones, you will have 2 stones that mate to each other.

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I use 100 grit wet-or-dry sandpaper, on a $35 granite surface plate, under running water.  Make sure to use a brand name paper like Norton or 3M.  The offbrand stuff lets go of the abrasives too easily.  Rinse the sandpaper, and let it dry until the next use.  I've been using the same sheet for about a year on Norton stones.  I've heard this doesn't work too well on the high dollar glass stones, but it works great on these.

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==>Make sure to use a brand name paper like Norton or 3M.  The offbrand stuff lets go of the abrasives too easily.  

You know, if you really get into S-Sharp, you should look at production sanding belts -- They are more robustly made and the grit stays on longer. Just buy the 37x60 belts and cut them yourself. Save a bunch of $$ because the belt lasts at least 3x over sheet paper. Just an idea...

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Like I said, one sheet of 100 has lasted me over a year. I just rinse it off, and let it dry until the next time. That one sheet is only used for flattening water stones.

I was just making the comment on off brand paper from past experience in getting some from an auto parts store in a pinch. Since then, I have ordered and stocked up on good wet-or-dry. I use it mostly for working on fiberglass boats now that all my planes have been flattened.

I think a lot of people try to over think this stuff. This cheap system has served me well for a long time.

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So I tried sandpaper on a granite slab first. My stones murdered dry 80 grit norton paper in seconds. Next, I tried wet dry paper with water. This was a bit better bit still wasn't really making a dent. Finally, I ordered some silicon carbide powder and sprinkled that onto a granite slab with water. This did the trick. The only downside was that it dished my granite out. It was a cheap cutoff so no big deal. I need to find some 1/2" plate glass. I think it will be more durable.

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==>Like I said, one sheet of 100 has lasted me over a year. I just rinse it off, and let it dry until the next time. That one sheet is only used for flattening water stones. 

???

 

​I read that in the original post, but figured you were kidding... That's why I didn't comment.

 

I'm not sure what type of stones you flatten or how often, but the general rule of thumb is a sheet will work for a total of ten flattenings of soft clay-matrix stones (think King) or a single flattening of hard-ceramics (think Chosera). The flattening process consumes the paper's abrasive -- there is no magic here, that's just the way it works...

 

When I was using 3M and/or Norton wet/dry on a reference surface, I'd usually go through 5 to 10 sheets in an afternoon -- that's typical consumption for this method and in-line with what others report.

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I went through a number of sheets flattening plane bottoms, but the Norton stones flatten right out quickly with 100 grit.http://www.multitechproducts.com/100-grit-carborundum-silicon-carbide-diamond-grit-wet-or-dry-sandpaper/

Under running water might make a difference. How much water were you using, and what grit paper when it went through so many for stone flattening? I bought an old porcelain sink with drain board, and leave a 9x12 granite surface plate in the sink, except when I'm washing out spray guns. Anything less than 100 grit cuts too slow for me, and does load up a lot quicker.

Wet-or-dry paper stays right in place on the plate with just a splash of water under it, even under running water. I would think a sanding belt wouldn't do that.

I will admit that since I started using the Diamond Lapping Film on another surface plate that water stones aren't used that often any more. I do my honing by hand on the film when I'm in the middle of a job. The water stones do get flattened after every session with them, but I'd have a hard time saying how often that is. if one gets a small nick in it, that is not so much worried about, but the whole surface gets cut down to a whole clean face.

Another factor might be that we don't use any hard steel chisels or irons. when we do use a stone, nothing stays on it very long, so wear to the stone, especially using the whole face of a stone, puts minimum wear on one to have to flatten.

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  • 7 years later...
On 2/28/2014 at 11:28 AM, calblacksmith said:

You can not make anything flat with only 2 surfaces if you do not have a reference flat surface to start with. You can mate a bowling ball to a flat plate, they will fit together perfectly but neither will be flat. It takes 3 surfaces, all working one into the next to eventually wind up with a flat surface so just using one stone against another will not give you 2 flat stones, you will have 2 stones that mate to each other.

that is correct.  furniture and cabinet maker here (CR/Krenov School), and i can say that nearly every craftsperson in existence that needs flat stones uses a reference surface that's accurate/within ≈.0001-.0005 of flat.  that said, flattening the sole of a plane, chisel or other precision steels that must then become their own reference surfaces makes this kind of accuracy important.  once a person is experienced with hand sharpening of most field knives they may be able to follow the wear or dishing of the stone a bit without needing such reliable accuracy...regardless, diamond honing plates, granite surface plates, etc.  are probably best.  glass is a liquid, and large panes left on factory shelves for 50 years without proper support bow and warp even at large thicknesses, but for rough applications, a good 3/8-1/2" glass plate should be fine for flattening--preferably polymerized or further engineered--but decent glass ain't cheap either.  Lee Valley used to sell .0005 granite surface plates for ~$30, but this appears to be their only one now (.0001) for ~$60: 

leevalley dot com/en-us/shop/tools/hand-tools/marking-and-measuring/32526-granite-surface-plate?item=88N8501

check out videos of togishi sharpening katana sometime, and try to wrap your mind around some of those crazy water stones  xD

88N8501-granite-surface-plate-f-0033.jpg

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