Breaking in DMT Dia-Sharp Benchstone

[VTer]

I've got a new 8" Dia-Sharp Fine benchstone that I plan to use to learn freehand sharpening (I've previously been using a Lansky guided system). Last night I practiced by sharpening, dulling, and resharpening an inexpensive chef's knife several times for practice, and it worked well enough: it quickly raised a burr that I was able to remove with my 3 micron strop for a decent edge. The stone feels really coarse, though (similar to my Lansky system's 280 grit stone), and the edges it creates have pretty deep scratches in them. Is this normal for a DMT stone that hasn't been broken in? What's the best way to break it in so that I can feel comfortable using it on my more expensive knives? How long does it usually take? Any advice would be appreciated.

 

[bmo419]

Doing what you're already doing is a good way to break in a diamond plate. Diamond plates will always be more aggressive than a natural/synthetic stone or a resin bonded stone by virtue of how they're constructed. The abrasives are adhered to the top of the surface with a diamond plate, hence the deeper scratches.

Your experience sounds perfectly normal for any diamond plate. I own a bunch of different brands of diamond plates and I don't know if it's the best way to break them in, but just using them will break them in. There's not really any hard and fast rule as to how long it takes. You'll just start to notice the surface of the plate feels a little smoother to the touch as the diamonds wear in, instead of the jagged feeling when brand new. It also won't cut quite as aggressively as when you first got them, though it'll still leave deeper scratches relative to other types of whetstones. If you want something that doesn't leave deep scratches, a water stone or bonded stone are what you want.

 

[Obsessed with Edges]

Good advice above.^

As mentioned, a plated diamond hone will always produce deeper scratches for a given grit rating, even after they're broken in. The Fine DMT is rated at 600 mesh (25 micron). And after it's broken in, the scratch patterns on bevels will look more like that produced on a coarser stone of another type, often around 300-400 grit or even a bit coarser. It's just the nature of how the grit protrudes above the surface of the plate and also because diamond cuts steel almost effortlessly for a given pressure used. Some steels will feel literally as soft as butter when grinding them against a diamond plate. On that note, a thumbrule I subscribe to is to use maybe 1/3rd or less of the pressure when sharpening on a diamond plate as compared to what I'd apply with any other stone. Anything heavier will just force the apex down into the plating itself and create edge-rolling / heavy burring issues. Keep the touch moderate to very light on a diamond plate and even lighter in the finishing passes for the best results. That'll also protect the plate from excessive wear over time.

 

[VTer]

Doing what you're already doing is a good way to break in a diamond plate. Diamond plates will always be more aggressive than a natural/synthetic stone or a resin bonded stone by virtue of how they're constructed. The abrasives are adhered to the top of the surface with a diamond plate, hence the deeper scratches.

Thanks for that. It makes sense. I'm not really worried about the scratches, I was just describing what I was seeing. My goal is to be able to put a sharp, functional edge on my blades not a mirror polish. I've got several in S30V that I've never been able to get sharp with the Lansky.

On that note, a thumbrule I subscribe to is to use maybe 1/3rd or less of the pressure when sharpening on a diamond plate as compared to what I'd apply with any other stone. Anything heavier will just force the apex down into the plating itself and create edge-rolling / heavy burring issues. Keep the touch moderate to very light on a diamond plate and even lighter in the finishing passes for the best results. That'll also protect the plate from excessive wear over time.

Yes, I have been using significantly less pressure.

 

[eveled]

Don’t press too hard! Let the diamonds work.

They seem to be a little coarser than I expected. The extra coarse is crazy coarse.

 

[pitonyak]

I own many of the DIA-Sharp plate stones and some break-in easier than others. One was particularly problematic, sufficiently so that I contacted their support and they said just keep running steel on it. I literally had to knock something loose and I was not happy about the issues with it. Only stone that gave me problems though.

So anyway, now I own four Naniwa Diamond Stones. have not had them long, only tried the 1000 and I was very pleased with the results.Expensive stone though.

 

[Alberta Ed]

Use light pressure; that's all you need, considering that you're abrading a very thin edge against the embedded diamonds. I use BreakFree CLP to clean my DMTs -- leave a light film on for a few minutes (or even overnight) and it lifts the swarf off. My DMT hones (coarse, fine, extra fine) have lasted for decades and are still as good as new. Soap and warm water and a nylon scrub pad are also a good way to clean diamond hones.

 

[yepimonfire]

I've got a new 8" Dia-Sharp Fine benchstone that I plan to use to learn freehand sharpening (I've previously been using a Lansky guided system). Last night I practiced by sharpening, dulling, and resharpening an inexpensive chef's knife several times for practice, and it worked well enough: it quickly raised a burr that I was able to remove with my 3 micron strop for a decent edge. The stone feels really coarse, though (similar to my Lansky system's 280 grit stone), and the edges it creates have pretty deep scratches in them. Is this normal for a DMT stone that hasn't been broken in? What's the best way to break it in so that I can feel comfortable using it on my more expensive knives? How long does it usually take? Any advice would be appreciated.

Yes. You can speed up the break in process by lapping a water stone. Don't go overboard on the fine and xfine grit, just create a small slurry and be done.