Another thread on Flattening Stones: DMT DiaSharp XCoarse... too coarse?

[Augusto Orosco]

A while ago, I got the DMT D8X Dia-Sharp Extra Coarse for flattening waterstones. It works but it feels a bit too coarse to the point that the circular motion I use to flatten clearly leaves a circular scratch pattern in the stones. I don't expect the stones to end up absolutely smooth, but the scratches look a bit excessive to me. Would I expect better results with just a Coarse stone, or with something else? I am a bit confused by all the choices with DMT (Dia Sharp, Dia Flat, etc) plus the other options available; such as the Atoma 400, Shapton lapping ($$$!), etc.

In short, I am happy with the flatness level I achieve with the DMT, but am concerned that the scratches are excessive. I just got some new Sigma Select Power II Ceramic Stones from my wife (stealth gloat: 9th year anniversary = ceramic, for you non romantics!) and I don't want to take them to the DMT if they are going to suffer unnecessarily!

Any thoughts?

[David Weaver]

The x coarse is 220 grit, right? I wouldn't worry about it on friable stones like the SP IIs.

A nice middle ground compromise for all stone is a DMT 325 from a duosharp (the plastic cored stone, in my experience they are flat consistently - but you have to go to ebay or amazon to get a good deal, avoid woodworking retailers for anything DMT) or an Atoma 400, which is a little nicer to use because there's more space between the diamonds.

The shapton lapping plate is excessively priced for what you get, it makes no sense to me. The diasharp is coarse, bigger than it needs to be and expensive. If they made a small version of the same thing for $90 and with 325 grit, it might be the best option.

There are two things to be concerned about with large scratches:
1) if you're hogging off too much in terms of shortening stone live
2) if the stones are fairly hard, scratches all over the surface can yield an edge that's not quite as good, though how different the edge is depends on the circumstances (for instance, on a translucent or black arkansas stone it can make a huge difference, on a king 8000 not much). For this reason, a lot of razor sharpeners will go way up in grit with their flattening routine, sometimes ending with rubbing two fine stones together as a final step, or using automotive wet and dry.

If you're satisfied with your edges, I wouldn't worry too much or buy anything unless you're worried about hogging away stones.

[Augusto Orosco]

The x coarse is 220 grit, right? I wouldn't worry about it on friable stones like the SP IIs.

A nice middle ground compromise for all stone is a DMT 325 from a duosharp (the plastic cored stone, in my experience they are flat consistently - but you have to go to ebay or amazon to get a good deal, avoid woodworking retailers for anything DMT) or an Atoma 400, which is a little nicer to use because there's more space between the diamonds.

The shapton lapping plate is excessively priced for what you get, it makes no sense to me. The diasharp is coarse, bigger than it needs to be and expensive. If they made a small version of the same thing for $90 and with 325 grit, it might be the best option.

There are two things to be concerned about with large scratches:
1) if you're hogging off too much in terms of shortening stone live
2) if the stones are fairly hard, scratches all over the surface can yield an edge that's not quite as good, though how different the edge is depends on the circumstances (for instance, on a translucent or black arkansas stone it can make a huge difference, on a king 8000 not much). For this reason, a lot of razor sharpeners will go way up in grit with their flattening routine, sometimes ending with rubbing two fine stones together as a final step, or using automotive wet and dry.

If you're satisfied with your edges, I wouldn't worry too much or buy anything unless you're worried about hogging away stones.

Thanks, David!

When you said the DiaSharp is coarse, bigger and expensive you actually meant the DiaFlat, right? That's the one that goes for $200 or so and is quite large, The DiaSharp XCoarse can be found under $60. DMT should choose less similar names for their products. It gets quite confusing.


And yes, I am (mostly) satisfied with my edges. My main concern is hogging away my stones (and also the scratch pattern drives me crazy, but that's jut me being obsessive)

[Don Dorn]

Just curious, but if you are using a diamond stone to flatten the waterstone, why not use the diamond stones and stop there? My theory may be flawed, but that is the conclusion I came to a couple of years ago and don't see going back to waterstones. A spritz of glass cleaner or soapy water and you're good to go regardless of the courseness. They stay flat and if used strictly for honing plane irons and chisels, they'll last much longer than the water stones they flatten.

[Augusto Orosco]

Just curious, but if you are using a diamond stone to flatten the waterstone, why not use the diamond stones and stop there? My theory may be flawed, but that is the conclusion I came to a couple of years ago and don't see going back to waterstones. A spritz of glass cleaner or soapy water and you're good to go regardless of the courseness. They stay flat and if used strictly for honing plane irons and chisels, they'll last much longer than the water stones they flatten.

Nothing against sharpening with Diamonds; I am sure they are just as good. In my case, it's a personal preference: I don't like the feedback I get from them. Besides, you missed a key point in my argument: wedding anniversary present! :D Those ceramic stones will be cherished!

[Don Dorn]

I'll give you the feedback argument, it does seem like you can "feel" an iron sharpeneing with them. Actually, I did miss the anniversary present - afraid age is starting it's cruelty.

[Tony Shea]

I personally really enjoy working with water stones. Switching to strictly diamonds would not b my preference therefore am in agreement with the OP.

I think what your flattening setup is now is perfectly fine. You do not need to go out and spend any more $. Those scratches should b of no concern to your edges and they will eventually get smaller and smaller the more you use the diamond stone, especially the dia sharp. In my experience the duo's stay sharper a bit longer, which really is a long time. Point being is that ur setup now seems fine, especially using the sigma select II's.

[David Weaver]

Thanks, David!

When you said the DiaSharp is coarse, bigger and expensive you actually meant the DiaFlat, right? That's the one that goes for $200 or so and is quite large, The DiaSharp XCoarse can be found under $60. DMT should choose less similar names for their products. It gets quite confusing.


And yes, I am (mostly) satisfied with my edges. My main concern is hogging away my stones (and also the scratch pattern drives me crazy, but that's jut me being obsessive)

Yeah, sorry, the diaflat. I saw one of those for about 15 minutes a couple of weeks ago and then put it in a box and shipped it to japan. It looked like a reasonably nice piece of gear, but it'd make more sense at 60% of the size (in area), 60% of the price and double the grit.

[Jack Curtis]

Yeah, sorry, the diaflat. I saw one of those for about 15 minutes a couple of weeks ago and then put it in a box and shipped it to japan. It looked like a reasonably nice piece of gear, but it'd make more sense at 60% of the size (in area), 60% of the price and double the grit.

The theory being the Japanese need examples of diamond stones that are too large, too expensive, and too coarse?

[David Weaver]

No, I shipped it to stu tierney. We have sort of an exchange of goods where sometimes I send him stuff he can't get there, and sometimes he sends me stuff I can't get here. Sort of an indirect barter.

There's no DMT stuff sold in japan, and there are aggressive stones that are hard on regular electroplate hones, but DMT says the coating is a lot harder. The only way to figure out how much tougher it is is to find out hands on.

[Augusto Orosco]

Thanks for all the advice, it's very helpful.

One more question regarding the Power Select Sigma IIs. LV recommends a 10 minute soak before use. Is it not advisable to keep them permanently submerged?