Diamonds Aren't Forever

Unkldave

Unkldave

Joined
Jul 12, 2016
Messages
33
I need to hear what everyone else thinks about diamond stones. Do they seem to wear slick real quick? My Lansky XCoarse and coarse stones just seem to rumble across the blade, same thing with THE BEAST XXC from KME, as well as the 100 grit, 140 grit, ad nauseum. The stones are just enjoying the ride. I know not to bear down too forcefully, clean them with a toothbrush & dish soap. They do have a bit of use, though nothing excessive as I've only had the KME for @ 2-3 years. And I've had great results but now I grind for hours and can't get a burr. I'm provoked! Might go back to Arkansas. What's your experience?
 
You can think of diamond stones as super high-tech sandpaper. Because you only have the one layer of abrasive grains, when they wear or fracture, that's it. So yes, contrary to what many think, diamond stones can and do wear out in normal use.
 
The coarser Lansky diamond hones, in particular, are prone to clogging pretty fast (or very fast). Some stainless steels will aggravate that even more. I noticed the same 'rumbling across the blade' tendency with mine, and it usually showed up more often after sharpening/grinding on simpler stainless steels (420HC, 440A and similar variants, such as seen in stainless kitchen knives). Before tossing them out, you might consider scrubbing them with a stiff brush with the help of a fairly aggressive powdered cleanser like Bar Keepers Friend with water.

The tiny size of Lansky hones (4" x 1/2") means the small surface area has to do a lot more work, and 'absorb' a much higher concentration of removed swarf. So they need more work to keep them clean and cutting consistently.


David
 
Yes, they wear out in a few years. They will clog when rebeveling. They do stay flat & will cut any steel (their strong suit). The amount of grit material is very thin when compared to many other stones. Which is were the economy is less than with thicker stones. More material in the beginning equals longer cutting life. Even if you have to level the other one. DM
 
I was reading a review, the guy said cheap diamond sharpeners the diamonds are glued to the surface of the metal, on the more expensive ones the diamonds are embedded in the metal, also he said not to use water as it can get under the diamonds and corrode the metal causing the diamonds to fall out, so use oil if you want to use anything or make sure the sharpener is really dry after using water.

John.
 
The working life of diamond is directly related to how much pressure you apply.

Lite pressure will cut the steel just as fast as a heavy hand which will prematurely remove and fracture the diamonds.
There is a break in period which will smooth and level out the diamonds, some think this is early wear but is normal and the DMT will settle down for a very long life time with excellent results.

I have a very old set of DMT about 30 years old in my wood shop, they are still going strong.

One newer DMT extra coarse is well worn from trying to flatten cast iron wood planes,, the soft cast iron dragged the diamonds out of the nickel plating. Not advised for using on soft steel/iron.

I originally used water which is DMT recommended however, the ugly rust stains were annoying and I changed to lite mineral oil which is great.

Regards,
FK
 
John Stubley said:
I was reading a review, the guy said cheap diamond sharpeners the diamonds are glued to the surface of the metal, on the more expensive ones the diamonds are embedded in the metal, also he said not to use water as it can get under the diamonds and corrode the metal causing the diamonds to fall out, so use oil if you want to use anything or make sure the sharpener is really dry after using water.

John.
Click to expand...

Quite frankly that guy didn't know what he was talking about.
 
In my experience it is almost the luck of the draw when it comes to longevity. I have a fine DMT tapered rod that is close to 20 years old, has been used to create serrations on plain blades and has touched up countless knives. The thing still cuts like new.

I have an EF interrupted surface hone that is dying even though it was used only occasionally for a handful of years. My XXC is all but dead from pretty normal usage - didn't even lap very many waterstones with it. Some of my DMT plates seem impervious to wear and others just seem to croak with what I would consider a bare minimum of use.

The same goes for my Smith's. I have a pair of the 6" hones and a fine grit oval 'steel' that are still in good shape after close on 20 years. I bought a double sided larger version a number of years back and it died in under a year, again from what I would have considered normal use.

I've used water and mineral oil. Lately I find water with a rub down of red oak till it forms a thin sludge makes a nice surface carrier that keeps the plate from loading and gives good feedback.
 
I have a small fordable double sided DMT for over 10 years, while the metal is stained it still sharpens fine.

John.
 
I wore out a lansky extra course diamond stone for my guided shaprener. I think i was apply too much pressure. Something that works for me is when using my extra course and course diamond stones i apply a little honing oil. Also the worn out diamond stone still works but more like a meduim grit
 
No complaints on 2 large (3 x 10?) DMT interrupted surface whet stones — coarse and fine. Used 30, 15 years respectively with water on stainless. I see they are ~$106 ea. on DMT website.

Lansky small stones sucked— went bald in no time, useless.
 
bgentry said:
You could try the glass test. Rub your diamond plates on a plate of glass. If it scratches and "frosts" the glass, there are diamonds left on the plate. If not...

Brian.
Click to expand...
I was thinking the same kind of thing —grinding a zero edge on an old stainless blade. If you see the scratch pattern on the spine, it's doing something.

Then move up a grit, the scratch pattern should change. In either case, if not, you can isolate which stone is "dull."

If it works, you will have thinned the blade behind the edge —at worst making it easier to sharpen.
 
I had an EZE Lap diamond stone get left submerged in the water stone pan and not discovered for a couple weeks. A couple rust blisters smaller than dime sized formed and the nickel/diamond plating flaked off. The rest of the stone still worked fine. I mentioned it to the EZE Lap dealer when I saw him at a trade show a year or so later, and he told me it should not have happened and insisted on replacing it. So rust is possible, but that's the only time I've seen it. I've worn out a few small diamond files, mostly on ceramic, but I've not had a diamond sharpening stone get so dull it was no longer usable.
 
Obsessed with Edges said:
more often after sharpening/grinding on simpler stainless steels (420HC, 440A and similar variants, such as seen in stainless kitchen knives). Before tossing them out, you might consider scrubbing them with a stiff brush with the help of a fairly aggressive powdered cleanser like Bar Keepers Friend with water.
Click to expand...
Totally what I was thinking.
I only use mine on pretty hard high alloy stuff, I mean why use diamond when a water stone will do ?
I have never experienced the rumbling / loading up. But . . . on my oldest most used diamond plate, a DMT coarse / extra coarse about ten inches long, I use it A LOT to flatten my stones so it gets plenty of cleanser like cleaning from that I suspect. I have have never used cleanser on it.

My main point I wanted to make, well two actually :
1. Early on when I first got it I was flattening A2 blades on it and it wasn't cutting fast enough so in frustration I was putting a lot of my body weight on it; I had it down on the floor and was really putting as much weight on the blades as I could manage. Yes I read that was bad . . . let the stone do the work . . . yah but it wasn't effecting that wide surface of the blade much and the WHOLE reason I bought the plate was to do just that. I've since learned better methods . . .
anyway I didn't destroy the plate, it still sharpens edge bevels like crazy and flattens the heck out of my stones even my trans-hard-Ark.

2. I have only used water on it. I sharpen dry and rinse it and put it away wet in open air. I never dry it with a towel (I don't want the cloth fibers that would leave on the stone). I flatten stones on it wet mostly because the stones are wet when I start and I rinse the plate to get the build up of grit off it. It has some stains on it but the diamonds are in good shape and no bare patches. I don't think water has effected its structural integrity. It's a very well made plate and super flat as checked on a Starrett precision surface plate.

. . . yahhhhh stop rubbing them soft gummy blades on yours and just use it for the good stuff.
 
Last edited:
I've used the same DMT 6" bench stones for 25 years and they still cut just as good as new. I clean them from time to time with BreakFree CLP when they seem to get clogged. That lifts out the swarf and restores the cutting quality.
 
Alberta Ed said:
I've used the same DMT 6" bench stones for 25 years and they still cut just as good as new. I clean them from time to time with BreakFree CLP when they seem to get clogged. That lifts out the swarf and restores the cutting quality.
Click to expand...

That's a great point you bring up because I've also had really good long term performance out of a couple of my diamond stones over the years. Diamond stones are like any other type of abrasive stone out there>> most of the time you get what you pay for.

About 12 years ago I got two diamond stones from a vendor at the 2005 BLADE Show in Atlanta. One was made by 3M and the other was made by Norton. I still have and constantly use both stones and they still perform very well. Now I would be lying if I was to say that they are the same as they were when I bought then new but they still perform at about 85% to 90% of what they were when new.

Since then I've bought some diamond files made by 3M and they've been excellent for the work I do with them. Also all of the other Norton abrasive products I've bought over the years have really been well worth the money I paid for them. I do have a few DMT diamond tools but so far I don't like them as much as I do the 3M and Norton diamond stones I have had for all those years.
 
My KME DMT stones don't seem to cut as well as they were after they were broken in. My recurve stone actually seems to be showing bald spots, they also seems to clog fast and dry fast.
 
This is an interesting thread for a lot of reasons but one thing that comes to mind is a discussion we had a few years back on this sub-forum. There was a talk about the type of diamonds that many of the manufacturers use in their benchstones and other sharpening tools that they make with industrial grade diamonds.

During that conversation I remember one guy making the point that "monocrystalline" diamonds are truly the best ones to use for sharpening tools. I'm now wondering if some of these manufacturers are now using inferior grade diamonds in their sharpening tools to obvious save money and to widen their profit margin?

But again praising my 3M diamond benchstone I believe that they must have used a really high grade of diamonds on that tool because they are still holding up after all these years and many hours of use.
 
You must log in or register to reply here.
Back
Top