# DuoSharp 10" Not Flat



## TheWoodRaccoon (Nov 9, 2015)

Clean the stone thoroughly with water and pat dry. Lay a reliable straightedge across the stone length wise and across. Shine a small flashlight along the seam where the straightedge and stone meet. If the stone isn't flat, you should be able to see light between the straightedge and the stone from the other side, in the center or on the edges, depending if it's concave or cupped. If there is indeed a gap and it's as bad as you make it seem, you should be able to see it clearly without the use of a feeler gauge.

If you can't detect any gaps by eye, Its most likely fine.


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## Ocelot (Mar 6, 2011)

Racoon,

I have washed scrubbed, dried the stone and done as you say.

Because of the holes in the steel, you can always see light - also the grit on the stone makes it impossible to have the straightedge down hard on the steel.

If the stone is fine, how does it produce the cupping that I see in the plane sole? If I have used the wrong procedure, somebody please show me the right way!

-Paul


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## OSU55 (Dec 14, 2012)

You dont say whether you checked the plane sole for flatness with a straightedge. Its possible the sole is that far out and the stone is fine.


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## Ocelot (Mar 6, 2011)

OSUSS,

I did check the plane sole with a straight edge. I should have said that.

In any case, since I worked the plane first on one side of the stone and then on the other, the difference between the two sides is clearly revealed by the scratch marks made on the plane. If the plane sole was flat (except for extra-coarse scratches), then working it on the other side (Coarse side) of the stone should create scratches all over the sole immediately. The pattern shown in the photos makes clear that the area of contact is limited to the central part of the sole, indicating that either the sole or the stone or both are not flat…. *after* being thoroughly worked over on the extra-coarse side of the stone.

-Paul


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## Ocelot (Mar 6, 2011)

Here is an annotated version of the photo. Sorry the web site shrank it when I uploaded, but I believe the text can still be read.


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## TheWoodRaccoon (Nov 9, 2015)

> Racoon,
> 
> I have washed scrubbed, dried the stone and done as you say.
> 
> ...


You're not supposed to press hard with the straightedge, just laying it on the surface is fine.
How coarse is it? To me it sounds like you have a surface akin to the gravel in a driveway.


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## Ocelot (Mar 6, 2011)

DMT calls it 220 grit, but apparently diamond grit sizes are calculated differently than other abrasives, so it seems *much* more abrasive than normal 220 grit sandpaper.

-Paul


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## TheWoodRaccoon (Nov 9, 2015)

> DMT calls it 220 grit, but apparently diamond grit sizes are calculated differently than other abrasives, so it seems *much* more abrasive than normal 220 grit sandpaper.
> 
> -Paul
> 
> - Ocelot


You should be able to lay a straightedge flat even on something even as coarse as 80 grit! Im really having a hard time understanding the problem you're having with the straightedge method. Also, what "holes" are you referring to? There shouldn't be any. Maybe you can take some pictures of the stone?


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## Ocelot (Mar 6, 2011)

Raccoon,

I didn't realize you were unfamiliar with the product. I should have posted a product photo.

Here's a picture and video from the manufacturer.















And DMT's web page for this product. https://dmtsharp.com/sharpeners/bench-stones/duosharp/


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## MrRon (Jul 9, 2009)

There is a good chance the plane soles are not flat. In the first place, I wouldn't use diamond to flatten a large area like a plane sole. You will be prematurely wearing down the diamond. I would use silicon, paper backed abrasive sheets on a flat surface (table saw table, etc) and save the diamond for small jobs. Personally, I don't like DMT stones. I prefer the stones that are fully coated with diamond dust (no holes). EZE-lap stones are the ones I use.


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## Ocelot (Mar 6, 2011)

MrRon,

I'm not sure I understand your comment. My goal was to flatten the plane sole, so yes, it is not flat.

Wearing an abrasive surface is just part of the cost of using it. It was my aim to save time by using diamond rather than using sandpaper on my granite surface plate. Even if time is not money, time is life and life may be too short to flatten many planes on sandpaper. I did one number 4 bench plane and used I think 8 hours of my life. I'm sure I've wasted more time doing less important things, but still, I'm willing to wear down the diamonds to save life (time).

The holes, in theory, capture the "fines" as they call them, that is the ground iron - so that your plane sole isn't floating on a layer of ground iron but instead is down on the diamonds. In theory…

-Paul


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## ssnvet (Jan 10, 2012)

I've found that a set of feeler gages and a known good reference surface (granite plate or known flat plate of thick glass, etc…) are the best way to check the flatness of surfaces.

The DMT "stones" will flex, as will the plastic mounting bases. So if you're applying downward pressure while stroking the plane back and forth, I suspect that is what may be causing your problems.

Try using them on a flat surface and clamp a couple strips of wood down to prevent them sliding about and see if that doesn't help you out.


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## Ocelot (Mar 6, 2011)

Matt,

I do have a granite surface plate, but I was working on my table saw table (cast iron) not using the plastic base, but with the "anti-skid" mat (supplied with the stone) under the stone.

The thing is, if it were flexing, I would expect it to flex both ways - that is, that the coarse and extra-coarse sides would both be convex, but that's not what's happening.

I intend to call and talk to them. They do have telephone hours, but only when I'm supposed to be at work.

-Paul


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## TheWoodRaccoon (Nov 9, 2015)

> Raccoon,
> 
> I didn t realize you were unfamiliar with the product. I should have posted a product photo.
> 
> ...


Oh THATS what you have? LOL! I thought you had the ones that are 1/4 inch thick solid nickel alloy, like my 6" DMT stone!


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## Ocelot (Mar 6, 2011)

... and until today I didn't know they make a solid nickel alloy version.

:-o

In any case, since they recommend flattening plane soles and even waterstones with this thing, it should be flat.

-Paul


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## Grumpymike (Jan 23, 2012)

Ocelot, you might want to talk with Don on this site, he's kind of the plane restoration guru …
I never use a stone that can flex as you are restoring the sole. I use some PSA sandpaper stuck to a piece of marble that I picked up from a countertop guy 'cause it had a chipped corner.
I have also used the table saw's flat surface and the PSA sandpaper.
Some of these old planes are just not true by nature, and the abuse they've seen over the years, like the grandkids hammering on them 'cause they were to hard to push etc.
I had a neighbor years ago that placed a beautiful #7 between his car frame and the jack, yep these things happen, and that #7 had a pot belly sole to it … (boat anchor)
So, before you condemn the stone, place the sandpaper on a known dead flat solid surface, then mark up the sole and take a few strokes and see where the wear pattern is.
Also be sure that you are not pressing so hard in the middle that the plane body it self is flexing; you must use even pressure from toe to heel.
If you have done all that, then I would say that the plane is that far out of being true and will make a great paperweight. And as you stated that the #4 and other planes lapped in ok, I'd tend to believe that the plane really is that far off of true.
I have a #5 Stanley of about the 1950 era that I scrubbed on a 220 surface for 4-1/2 hours before all three sides came back into true. 
Bottom line: Use a solid known flat surface and PSA sandpaper to lap the plane sole and use the diamond stones for sharpening the iron.


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## TheFridge (May 1, 2014)

I have 2 diamond stones. A dmt and an eze lap.

One isn't flat. Blatantly obvious to me so I feel your pain. Send it back. They'll send you another. I sent a dmt back because I wore it out somehow. The new one is fairing much better.


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## Ocelot (Mar 6, 2011)

Thanks for your comments Grumpy and Fridge.

I think I'm not flexing the stone in use. I'm using reasonably light pressure and the stone itself is quite stiff. The "plastic" between the two steel plates is actually something like epoxy resin. Also, the extra coarse side seems to be convex while the coarse side is concave, which is not what I would expect if the stone were flexing.

I do plan to call DMT and I feel confident that they will exchange my stone. They have not responded to my email questions for over a week. Their telephone hours are the same as my work hours so I don't want to get tied up for a long phone consultation when I'm supposed to be working, but I'll do it sometime in the next few days.

-Paul


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## bbasiaga (Dec 8, 2012)

Seieng your photo and re-reading your description, am I right that you ran the plane sideways across the stone (i.e. left to right instead of along the sole in the direction of normal use? If so, I doubt you had the whole plane on the stone at the same time. If you are trying to flatten something, it would be best to have the entire surface on the flattening stone at the same time. Otherwise you risk rocking or twisting the base.

Is it possible you made the out-of-flat worse by going bi-directional with the stones?

-Brian


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## Ocelot (Mar 6, 2011)

bbasiaga,

You know, I'm not very good at reviews or describing things. sigh.

Yes, on the first pass, on the extra-coarse side, I went side-to-side, but I was careful to stay on the stone. The stone is 4 inches wide and the plane is 2 inches wide, so it's about a 2 inch stroke.

Then, after flipping the stone, I went the long way on the "Coarse" side, keeping the plane on the stone, which allows about a 3 inch stroke because the stone is 10 inches long while the plane is 7 inches. Of course, I might have occasionally gone off the edge and doing so could lead, I would think to making a not-so-flat sole.

I was hoping that someone would post that they have done the same thing with the same stone, and there is some technique that I should use that will work, but I'm now fairly confident that the stone is not flat.

-Paul


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## Grumpymike (Jan 23, 2012)

Hmmm, I just went back and reread this posting from the beginning and noticed something.
No matter what advise those who were trying to help you gave, your answer was always "I did that" or "I use that" and ("there is nothing that I did wrong").
You say that you used a straight edge to inspect the plane sole before you started … It must have been convex before you started. If it was flat why lap it in the first place?
You said that you have a 'granite surface plate' ... Why are you not using the correct tool for this job? 
I apologize for wasting your time with our feeble attempt to help you. 
Have a nice life.


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## Ocelot (Mar 6, 2011)

Grumpymike,

I noticed that pattern myself. I certainly didn't intend to offend anybody, or to be ungrateful for the time anybody spent considering my problem.

I certainly would confess that I seem to lack social graces. <sigh>

Also, my initial "review" was badly worked, incomplete and probably confusing. If I had spent more time there making clear what I had done and what product I was reviewing and why I felt there was a problem with it, it would have make it much easier for people to read and follow and possibly offer me helpful comments.

As for the flattening operation: If I knew something that I had done wrong, or somebody had persuasively pointed out something that I did wrong, I would go do it differently. I just haven't found anything yet.

I suppose I could respond to people by saying "That's a great suggestion! I'll go try that", even if I already have tried what they suggest or their suggestion doesn't fit my situation, but I find it hard to be that way.

So, I sincerely say that I meant no offense, and that I am always ready to learn from anybody who can teach me something, and I know that I don't have the social graces that others do - nor the skills that many others have. But, I am an engineer, and I like to think things through logically and don't just accept something that somebody tells me if it doesn't make sense.

-Paul


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## HokieKen (Apr 14, 2015)

Paul,

If you have a proven granite surface plate, it's a simple matter to verify whether or not the stones are flat by "printing" them. Get some machinist's layout dye and paint your surface plate. While it's still wet, lay your stone face down gently (no sliding and no pressure) then pick it straight back up. The dye will transfer only to the high spots on the stone. If it's flat, there will be dye all over it.


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## Ocelot (Mar 6, 2011)

HokieKen,

That's a great suggestion!

I'm not familiar with machinist's layout dye, but I'll see if I can find something similar.

thanks,
-Paul


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## HokieKen (Apr 14, 2015)

> HokieKen,
> 
> That s a great suggestion!
> 
> ...


Here's some at Amazon. Not sure where you would find it locally.


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## OggieOglethorpe (Aug 15, 2012)

*I m not familiar with machinist s layout dye, but I ll see if I can find something similar.
*

Sharpie ink from the fattest tip Sharpie you can find works fine… Just as well as DyKem


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## HokieKen (Apr 14, 2015)

> *I m not familiar with machinist s layout dye, but I ll see if I can find something similar.
> *
> 
> Sharpie ink from the fattest tip Sharpie you can find works fine…  Just as well as DyKem
> ...


For layout it does. I'm not sure it will stay wet long enough for printing though…


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## OggieOglethorpe (Aug 15, 2012)

*For layout it does. I'm not sure it will stay wet long enough for printing though…*

Agreed! I missed that message, thinking you were using it for lapping.


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## bbasiaga (Dec 8, 2012)

If woman in your life has, or you are not too proud to go buy, a tube of cheap lipstick you might get away with using that for printing.

I have used it as marking fluid before.

Brian


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## HokieKen (Apr 14, 2015)

> If woman in your life has, or you are not too proud to go buy, a tube of cheap lipstick you might get away with using that for printing.
> 
> I have used it as marking fluid before.
> 
> ...


Too thick for printing but it gives me an idea… you could probably dissolve some in denatured alcohol and get a good dye that's the right consistency and has a good, long wet edge.


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## Ocelot (Mar 6, 2011)

It's in my Amazon cart.

Looks like something I might find a use for later anyway.

Dollar store lipstick and alcohol sounds like a country song.

-Paul


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## HokieKen (Apr 14, 2015)

> Looks like something I might find a use for later anyway.
> 
> -Paul
> 
> - Ocelot


It's great for flattening plane soles and for sharpening anything where you want to see where you're grinding or when you're re-shaping the bevel because it won't wash off in slurry. They sell special remover for the dye but it comes off fine with denatured alcohol.


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## OSU55 (Dec 14, 2012)

So how far out of flat, concave or convex, was the plane sole when checked with a straightedge? I have attempted to use the same stone for the same thing and found sandpaper on a flat surface a superior method. The DMTs work fine for bevels but not for large surfaces if you want FLAT.


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## Ocelot (Mar 6, 2011)

OSUSS,

I just eyeballed it with a steel ruler on the plane sole. I didn't use feeler gauges. I would guess it's between 2 and 5 thousandths out of flat in the middle.

The steel ruler (PEC, made in USA) is not an item which came with a straightness tolerance spec, but I have held two steel rulers together (backlit) and see that they seem to conform very tightly, so I'd say it is straight within 1 thousandth over 6 inches at least.

The main thing was that after grinding it on the "extra coarse" side, only the center portion of the sole was being touched by the "coarse" side, even after 2000 strokes. I would expect to be able to use the more coarse "extra coarse" side first, then flip the stone and fairly quickly see contact edge-to-edge and end-to-end on the finer "coarse" side of the stone.

-Paul


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## OSU55 (Dec 14, 2012)

You didnt say if its concave or convex?


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## Ocelot (Mar 6, 2011)

Sole was convex after "flattening" with the extra coarse side.

-Paul


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## OSU55 (Dec 14, 2012)

If the sole was convex, higher in center, and with the pics you showed, it would appear the stone is doing what it should. With the sole that far out using 50-60 grit paper or belt on a flat surface would be quicker. I wore out the same duo sharp doing the same thing and decided paper/belts were the better tool.


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