Perfect stone for grinding and flattening tools and other stones.

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Review by Dan posted 02-07-2012 09:03 PM 9218 views 3 times favorited 13 comments Add to Favorites Watch
Perfect stone for grinding and flattening tools and other stones. Perfect stone for grinding and flattening tools and other stones. No-picture-s Click the pictures to enlarge them

For the past couple years I have been sharpening my tools using the Scary Sharp method. To grind a new bevel on a plane iron or chisel I would use a grit anywhere from 80-120 grit sheets. The paper cuts fast but it also wears fast. Another problem with the paper is it clogged up quickly. With all the irons that I sharpen I was just going through a ton of paper so I started looking into coarse diamond stones.

DMT sell two different types of bench stones. They have the DiaSharp which are a single grit stone and they have the DuoSharp which are a combination of two grits. The DuoSharp also have the holes all over to help prevent clogging. I spent a lot of time researching both types of DMT stone and I ultimately decided to go with the DuoSharp Coarse/Extra Coarse 10” stone.

This stone was not cheap, the price tag on it through Woodcraft is 124.00 but its a big stone, much larger then a standard sharpening stone and you also get two different grits.

To test it out I decided to use my thickest A2 steel iron which is my Pinnacle/Cossman iron. The A2 irons I have are really tough to grind using sandpaper. The A2 wears the paper out twice as fast as my O1 irons so I was curious to find out how the DMT stone would work on them. Using the coarse side of the stone I was able to shape a new primary bevel on the Pinnacle iron in less then 10 min. I also tend to work a little slow when sharpening so I bet it could be done even quicker.

The 2 big advantages that I found with the DMT stone vs Sandpaper are-

1. The stone does not wear like the paper does. While a fresh sheet of 80 grit paper will cut extremely fast for the first few passes, it will dull very quick, especially when using it on A2 steel. Previously I would wear out a full sheet of sandpaper each time I had to shape a new bevel.

2. The DMT stone did not clog at all during the whole time that I was grinding a new bevel. A few sprays of water was all that was needed before I started. With the sandpaper it would start to clog after the first few strokes so I would often have to stop to clean the paper off.

The DMT Coarse grit does not cut super fast but considering it does not wear or clog I think it takes less time over all to put a new bevel on an iron or chisel then it does with the paper.

I have also used the coarse side to flatten my Shapton glass stones and it works great for that.

-- Dan - "Collector of Hand Planes"

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3653 posts in 3687 days

13 comments so far

View Don W's profile

Don W

19652 posts in 3374 days

#1 posted 02-07-2012 09:09 PM

I just purchased a set of DiaSharp stones used off ebay. It was kind of an impulse buy, but I can use the course to flatten my oil stones, and may wind up just sharpening with the DMT’s. We will have to compare notes and see what the difference really is.

-- - Collecting is an investment in the past, and the future.

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3653 posts in 3687 days

#2 posted 02-07-2012 09:27 PM

Don, I have read that the DiaSharp stones cut a little faster then the one I have which is the DuoSharp. The DiaSharp stones don’t have all the holes to prevent the clogging so you actually have more diamonds on the surface of the stone.

I think you will like the coarse stones for flattening backs of your irons and repairing an edge. The coarse one should work well on the oil stone as well.

I am thinking of picking up the fine and extra fine Duosharp sometime in the future.

-- Dan - "Collector of Hand Planes"

View lj61673's profile


271 posts in 3205 days

#3 posted 02-07-2012 09:41 PM

Nice pick up Dan. I too have the 10” coarse/extra coarse DuoSharp. I use the extra coarse side for shaping new bevels and the coarse side for flattening my Shapton glass stones. Works great.

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10153 posts in 3246 days

#4 posted 02-07-2012 09:58 PM

I am glad to hear the DMT stones fit the bill. I am eager to know how they well they last with regular use.

Thanks for the review Dan.

-- ~Tony

View Dennisgrosen's profile


10880 posts in 3921 days

#5 posted 02-07-2012 11:50 PM

thanks for the rewiew Dan :-)

can you tell me the wide and length it is in cm


View ShaneA's profile


7085 posts in 3405 days

#6 posted 02-08-2012 12:18 AM

Thanks for posting, the size sounds like a real plus. I may put one of these on next yrs christmas list.

View Roger's profile


21030 posts in 3610 days

#7 posted 02-08-2012 12:43 AM

thnx for the review. very good

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed. [email protected]

View Dan's profile


3653 posts in 3687 days

#8 posted 02-09-2012 02:49 PM

Dennis, The stone is 3in x 10in I have no idea how many cm that is but you can probably figure it out based on the inches?

-- Dan - "Collector of Hand Planes"

View Bertha's profile


13588 posts in 3499 days

#9 posted 02-09-2012 02:50 PM

Dammit, Dan. Now I’ve got to have this.

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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10880 posts in 3921 days

#10 posted 02-09-2012 08:48 PM

thank´s Dan
it was the first picture that is looking a little werd when you come up with the meassurment
1 imperial UK inch = 2,54 cm (not to confuse it with the nordich inch´s …LOL ) (you can see the different
in one of swirts blogs )
so its 7,62 cm X 25,40 cm


View stefang's profile


17039 posts in 4140 days

#11 posted 02-15-2012 09:09 PM

I’ve been using the DMT duo sharp plate for several years with 600 grit on one side and 1200 on the other.

-- Mike, an American living in Norway.

View Karson's profile


35224 posts in 5207 days

#12 posted 02-16-2012 08:22 PM

I have the DiaSharp in the extra extra fine I think it’s 3 micron and 8000 grit. It is a nice stone to do the final work.

I’ve also got a course and mdeium and fine in the dia stones, but the new one is the extra/extra fine.

I carry around a fine 1200 grit (credit card size) in my pocket for the quick touch up of knives and Forster bits at the toy workshop.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

View Don W's profile

Don W

19652 posts in 3374 days

#13 posted 02-26-2012 06:16 PM

I’m beginning to like my diamond stones. I took another swipe at sharpening my krenov style smoother. I like the DMT’s for flattening the back of the irons better to, they seem to cut a little quicker, and they are 3” wide. I know some of it is the fact I’ve just gotten better at sharpening, but the DMT’s are quickly growing on me.

I can see where the DuoSharp would be worth a little extra. The hole through out the stone would be beneficial. With Thats said, I’m sure I’ll be happy with mine for a while.

-- - Collecting is an investment in the past, and the future.

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