DMT Dia Stones Warranty?

Ulf Krogstad

Ulf Krogstad

Joined
Nov 19, 2013
Messages
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Just wondering if anybody knows if DMT has a warranty on their stones? I have bought 3 new ones in less than a year and all have more or less worn out. Coarse stones that I really need to be coarse. Could I send them in and have them fix them? May be the last time I buy DMT stones, or maybe it's time for a grinder and just use the stones for touch ups.
 
I don't know what you are doing with your hones, or how often you are using them, but perhaps you are pressing the blades down too hard.

I have two DMT Diasharp hones (coarse and fine) that I have been using for around a decade for regular sharpening and touch-ups on my daily work knives, and they still work (I just used one today).

Also, I don't know if you are cleaning them, but diamond hones need to be cleaned once in awhile. I use Comet kitchen cleaning powder, hot water, and scrub gently with a plastic bristle brush.

I don't believe that DMT has a return policy for used hones, or that they offer any refurbishing service. Once a diamond hone is worn out, it's finished.

If you need to remove a lot of metal from a blade (you mentioned using a grinder) DMT also makes extra coarse and extra-extra coarse hones.
 
Haven't done anything crazy with any of them, have had to use QUITE a bit though. Clean them regularly. Have used for heavy reprofiling plenty. Will probably see if the extra coarse lasts longer. All my coarses are like fine or extra fine now. They still work fine for touch ups but that's it.

Going to get something else for heavy duty sharpening.
 
None of my DMT stones have worn out, and a few of them are at least 5 years old and have been used many times. I'm not certain what "heavy reprofiling" constitutes though, but perhaps that's the issue; I use mine strictly for sharping. Perhaps you need to consider an electric grinder instead.
 
My DMT stones did about a dozen knives before they were shot. $200 down the drain.
 
I've had the same DMT coarse since the Autumn of 1984 and have used it a gazillion times. Almost weekly. That's nearly 32 years. No issues. I've never seen a DMT fail. I imagine DMT will replace yours if they failed within a few months unless you've done something insane with them.
 
The coarser grades of DMT stones don't seem to tolerate very much pressure. The larger diamonds break off easily.
 
Have you called them? I had one of their two sided stones which was scratching shiny blades - a nice lady promptly mailed me a brand new one, no questions and she did not even want the old one back. More than reasonable.
 
I have a coarse that is going to turn 30 in a couple years. It has re-profiled hundreds of blades.

They all lose that initial drag that they come with, but I would not call that worn out. I have an Extra Coarse that I was used improperly (too much pressure) and it was practically destroyed in a few weeks time. If you use too much pressure, you will destroy them. They may take care of you under "warranty" but, let's be honest here, it is not a defect if you use the hone improperly (and your replacements will behave the same way).

I cannot speak for all brands/makes, but if you are killing DMTs, you will likely have similar results with others (assuming you are bearing down too much).

One last preach then I will shut up. For the sake of the blade AND the hones, you will get much better results with VERY light pressure. Some might argue that stock removal wiht pressure is fine, but I doubt anyone wouold contest that a light hand for final edges is best.
 
DeadboxHero said:
That's normal.

They wear out quick
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At the price of their duo bench stones, (large size), this is un-exceptable. I think when I first started using one, I pressed down too hard thinking pressing down would make sharpening quicker.
 
22-rimfire said:
At the price of their duo bench stones, (large size), this is un-exceptable. I think when I first started using one, I pressed down too hard thinking pressing down would make sharpening quicker.
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I disagree. If used properly, they last a long time and are quite a value.

Applying too much pressure and destroying the hone, then claiming unacceptable at that price, is similar logic to breaking a straight razor while trying to use it to process fire wood, then claiming that it is unacceptable at that price.

No offense to you. Just realize that it is NOT normal if the product is used properly. Further, if you use them properly and they fail (unlikely) they have a warranty:

"The DMT® Commitment: Since 1976, DMT has been committed to innovate and produce the world’s finest diamond knife and tool sharpeners. All DMT products are made using the highest quality materials and workmanship and are guaranteed to be free of defects. Any product found to be defective will be replaced free of charge – it’s that simple!"
 
I don't recall DMT stating not to press down when sharpening. I believe they say something like "light pressure or light even pressure" whatever that means when talking to the DMT folks at Blade. In my opinion, they should say something to the effect that pressing down does not increase the sharpening rate or abrasiveness of the stone on the knife, rather it potentially breaks diamonds loose. That is not to say that I ever tried to get anything from them via a warranty or even brought it up. I figure in most things, you're on your own unless it is an obvious defect and that seldom happens. I like their bench stones and bought another one this past year.

Plan on getting one of their extra coarse for profiling in the future. I have coarse, fine, extra fine now.
 
22-rimfire said:
I don't recall DMT stating not to press down when sharpening. I believe they say something like "light pressure or light even pressure" whatever that means when talking to the DMT folks at Blade. In my opinion, they should say something to the effect that pressing down does not increase the sharpening rate or abrasiveness of the stone on the knife, rather it potentially breaks diamonds loose. That is not to say that I ever tried to get anything from them via a warranty or even brought it up. I figure in most things, you're on your own unless it is an obvious defect and that seldom happens. I like their bench stones and bought another one this past year.

Plan on getting one of their extra coarse for profiling in the future. I have coarse, fine, extra fine now.
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I think it's a balance. On one end, you put no pressure and the blade surface just slides roughly over the stones. This will take a whole not of back and forth motion with minimal results. On the other end, bearing down the blade against the stone and you're more liable to knock loose some diamond. I imagine also that it's possible that the sharp edges on the diamonds get knocked down with heavy pressure? I suppose the optimal pressure which is closer to "light" than "heavy" is enough pressure to have maximum abrasive contact without knocking loose any diamond.
 
Ulf Krogstad said:
Haven't done anything crazy with any of them, have had to use QUITE a bit though. Clean them regularly. Have used for heavy reprofiling plenty. Will probably see if the extra coarse lasts longer. All my coarses are like fine or extra fine now. They still work fine for touch ups but that's it.

Going to get something else for heavy duty sharpening.
Click to expand...

Heavy reprofiling/work = XXC in my book. If you want to stick with diamonds... best tool for the job.
 
I have their 3-hone set of the 6" diamond whetstones (red, green, blue polka dot). Have had them for about three years. I haven't used them heavily and only on relatively soft steels like 1095 and 420/440, with the exception of a couple Queen D2 folders.

The coarse and extra fine are still in good shape, but the fine is worn out in sections over maybe 1/3 of the surface. I attribute that to perhaps spending too much time on the fine and maybe too much pressure trying to reprofile the D2 blades.

Still, it wasn't THAT much pressure. So my takeaway from that is that they are somewhat fragile and require very light pressure. I also decided to use SiC stones for reprofiling D2 which works better for me. I don't use the DMTs often now.
 
Like any other abrasive, diamonds do wear. They are the hardest known natural substance, but they aren't invincible. The hones as they come are the sharpest they will ever be. During use, high diamond points will get chipped away, diamonds will pull free of the nickel bond, and diamonds will wear to a flattened/rounded profile. The lighter the pressure used, the longer this will all take. The diamond will keep cutting as long as it's attached to the plate. Over time, the speed will drop off and so will the depth of the scratches. I have a well worn decade old DMT C that can put a shaving edge on a straight razor with very light pressure! (Yes, I've shaved with it - no irritation whatsoever!) The same stone used with ½ pound of pressure will still rip steel off a knife PDQ. I have a feeling that the standard DMT reply will be to test the hone on glass - if it still cuts they'll consider it to be in working order.
 
Ben Dale, inventor and owner of Edge Pro, has always said that diamonds are incompatible with steel... should never be used to sharpen. He said the diamonds sink into the steel and are pulled out. They (Edgeproinc.com) don't recommend their diamond plates be used on regular steels- just for ceramics and really hard steels.
 
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