Question for Joe T (and others): Diamond stones

Crayola

Crayola

Joined
Sep 23, 1999
Messages
3,831
Hello Joe. As you have thought about and experimented with sharpening more than a zillion times, I'd like you to clear up a question I have about diamond hones that I have only recently discovered. On a post about diamond hones and the Edge Pro system, the Edge Pro guy said that diamond hones wear FAST using their gear as the diamonds embed themselves in the relatively soft steel and tear off the base, leaving a worn and useless stone. Now there is a post going on where someone (sorry, I forget your name) wants advice on sharpening stones for freehand use. There are some who posted on that question that they found their diamond stones to wear out quickly as well. Now, if diamond stones retain their cutting ability for years and years they seem to be the natural choice for a coarse stone: They don't dish, they can be used dry, they cut quickly and they will do an efficient job on even the high vanadium steels. But, why the heck should we get them if they wear out so fast? Have you found this to happen with your stones? Have you ever heard of this happenning?

I had been pondering the idea of getting an extra coarse DMT stone for a while, especially due to your recommendations but hearing these problems stopped me from thinking further and made me appreciate my Razor's Edge stone more. I'd like to hear more about diamond stones and I'm sure others would too.

Thanks very much.

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"Come What May..."
 
I have diamond Lansky stones.

What might be confusing some people is that diamond stones show up pretty rough on the surface. That rough surface wears down pretty quickly, as those diamonds protruding above the metal base seem to shear off quickly. HOWEVER, the industrial diamonds below the original "rough" surface are embedded in the steel matrix. The stones soon feel "smooth" to the touch, but believe me, they still cut steel, and much faster than regular "stone" stones.

I sharpen all my stuff with diamond, from the easy (AUS-8) to the very difficult (hard D2, CPM 440V, 420V, and Stellite), and these "smooth" diamond stones are all I'll use...they work and minimize my effort.

If the diamond actually wore away, there is no earthly way I could get an edge on something like 420V or Stellite.
 
I am concerned about wear on my diamond hones because I am an unusually heavy user. There are frequent intervals where I sharpen an extremely dull knife every night for weeks on end. I buy scores of knives at thrift stores and sharpen them all by hand to get the feel of the alloys and blade design. If I had a practical need to sharpen this many knives I would get a belt sander. Since I'm sharpening the knives as experiments, for practise, and for fun, I do it "the hard way".

I use diamond hones because they do the best job and I am a perfectionist when it comes to sharpening. I also use diamond hones because they are the fastest manual way to sharpen knives. The diamond hones last long enough, even with my intense use to give me value for my money. I expect to wear out hones faster than I wear out knives. I've warn out plenty of aluminum oxide and silicon carbide hones over the years. My worn diamond hones still work, they just have become finer gritted as time wears on.

By the way. Although you can use diamond hones dry, I mostly don't. I like to use my hones under running tap water. This keeps the hone from loading up with metal and minimises wear from loose diamonds.
 
I agree with the others on the diamond hones/benchstones. They do wear, and end up as finer grits as time goes on, but I have never heard of anyone wearing one out. DMT has a lifetime warranty on their bench stones (not sure about the hand hones), so if I ever wearr them out, which is highly unlikely, I'll send them in for replacement.
 
The Edge Pro encourages the use of force when sharpening, it is not an enviroment friendly to diamond hones.

-Cliff
 
I've used diamond hones for almost 15 years. I still have the first one I ever bought at a Mall outlet in Dallas, TX. I like the balisong style from DMT. I bought the red (fine) one and still use it when I need a really fine edge. Yes, they do seam to wear down to the point that they seem to be worn out, but they still put on an edge faster than a regular stone.

DMT just came out with the double sided balisong style of pocket sharpener. I've got one on order. I don't use a bench sharpener. I use a four step felt-wheeled line shaft for that. You can't go wrong with diamond hones as long as you get a good one. Expect to pay no less than $20.00 for one though.
 
It still sounds like most diamond stones are a product in need of more development, considering the cost and fairly rapid wear. On my own credit card sized stones I now have a smooth surface in the middle of the stone and coarser edges, and the medium and fine stones appear to be working about the same. Some sort of vitrified stone, maybe mixing diamond with silicon carbide or some other material, seems like it might offer a good balance of properties between wear, cutting rate, and grit size.
 
There's a few things going on here.

First, as others have pointed out, there's a quick break-in period for diamond hones. Even after the break-in period, though, diamond hones cut fast.

Second, not all diamond hones are created equal. My 6"x2" DMT hones have lasted through years of use! Other brands may or may not last as long. Above, johno mentions that he has a diamond card that has a bald spot. For what it's worth, my worst experience with diamond hones has been with cards and other little sharpening doodads. My worst experience was with an EZE-LAP diamond-coated "steel", which lost its diamonds very quickly. Use a good quality hone, and it will provide years of use, and cut better than anything out there.

Lastly, there is the question of pressure. No matter how good the diamond bonding is, if you scrape hard enough with the blade, the diamonds will come off. Use easy pressure and let the diamonds do the work. If, as Cliff points out, people using the Edge Pro tend to use harder pressure, that would partially explain why diamond stones are so unsuccessful for Edge Pro but so successful for DMT.

My recommendation regarding diamond hones is specifically for the hone that I've had good luck with (DMT 6"x2" or 4"x1"), using easy pressure. This just plain outcuts any other hone, for me.

Joe

[This message has been edited by Joe Talmadge (edited 09-07-2000).]
 
Based upon the comments so far all of the diamond stones, even the DMT stones, wear fairly quickly during what some are calling a 'break in'. This means that wear will tend to be uneven as it is not common for all of the surface to be used on a consistent basis. It is being acknowledged that the diamonds are not bonded very well and that light pressure is needed to minimize wear. It is difficult to apply light pressure in some cases, such as when dealing with nicked or rolled edges, as what is perceived to be light pressure applied over a small area can still produce high pressures. As I mentioned previously it seems that more development work is needed. Does anyone have experience with the 3M or Norton diamond stones ? Do they wear any better ?
 
I have used DMT diamond stones for around eight years now -- coarse, medium and fine -- and have not noticed any reduction in cutting efficiency, or any wear other than cosmetic.
 
When I discussed diamond abrasives with Ben Dale I think I recall him mentioning that he used 3M products but I can't be positive, just might want to drop him an email.

About the break-in period, I would assume that this frees up "loose" bits. I guess the bonding in random in nature and that there are some bits not well secured so you lose this fast initially.

As for the DMT products, they are guaranted against wear after the initial loss. As with anything else of course there is room for improvement.


-Cliff
 
Some steels just about cannot be sharpened without diamond stones. Most of the stainless steels out today, and the CPM stuff is VERY wear resistant. I wouldnt even like to think about trying to sharpen a CPM420V blade with a soft wa****a stone! As for the DMT and Ezlap stones, if you were to take one of each of the same grit and rub them together, the DMT would be smooth a lot sooner. I dont know about the Ezlap wearing out sooner either. I have never worn out any of them. They(all diamond hones)seem to get smoother, but they still cut the metal.

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Danbo, soul brother of Rambo


[This message has been edited by Danbo (edited 09-07-2000).]
 
Just curious, but why did this forum edit out the word wa****a?

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Danbo, soul brother of Rambo
 
Danbo, why do you think an EZLap would wear down a DMT? DMT's are supposed to be monocrystaline for greater partical strength. I like my 12" long EZLap hones, but they seem to wear faster than my DMT's.

PS. The profanity filter takes the s-h-i-t out of the middle of washeeta if spelled correctly.


[This message has been edited by Jeff Clark (edited 09-07-2000).]
 
Ahh.. thanks for the info! I now come to the following conclusions:

1) Non-doodad (Joe T's technical word) DMT diamond stones, due to their use of monocrystaline diamonds, superior hardness, lack of "dishing out" and lifetime warranty, are probably the best chouce for rough or initial sharpening unless one has a belt sander.

2) The use of rigs and jigs can increase the pressure placed on stones dramatically, but when learning freehand sharpening, this point does not come up.

3) Given point 1, even though DMT stones require a comparatively high initial layout of hard earned cash since they work faster and cut longer than other stones dollar for dollar they offer the most bang for the buck.

4) Other stones work just fine too.


belt sanders aside, I wonder then if we can come up with an ultimate list of hones for the freehand sharpener! Lets all ring in and see what we can come up with.

1) Large DMT diamond stone, extra coarse or coarse (which is better?) for fixing edges and setting the initial bevels

2) I guess spyderco medium bench stone for getting a hair scraping/shaving toothy edge

3) I guess spyderco fine bench stone for hair shaving, micro tooth, push-type cutting edge

4) 8000 grit waterstone with nagura stone for the ultimate in a polished edge (if required)

5) Smooth steel (razor's edge)

I don't know whether a strop is needed if you have 1-5. Well, what do others think? What is the ultimate set of sharpening gear for freehand sharpeners? hey, maybe 1SKS could make up sharpening gear packages.....

------------------
"Come What May..."
 
Well, I'm particularly impressed with your list, since it's exactly the setup I use
smile.gif
I *do* have a strop, and consider it an important addition. For re-profiling, there's nothing like the x-coarse DMT, I swear by it.

The least important of the list, for me, is the waterstone. I rarely razor polish my edges, so I rarely break out that waterstone.

I use the strop when 1) I do want a razor polished edge, or 2) I want to really make sure the edge is clean and burr-free (sometimes I rough it back up on the medium hone afterwards).

Joe
 
So maybe I should change my username to Little Joe T
biggrin.gif


I guess one benefit of the strop is that is is cheaper than an 8000 grit water stone. I assume the green buffing compound adorns your strop Joe?

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"Come What May..."
 
I believe "non-doodad" means not those little credit card, clip to your key ring, fits in your kid's pocked, perfect for 1" blade type of sharpeners. If it ain't a bench stone or a diafold, it is a doodad.

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"Come What May..."
 
Joe,
I think I know this answer but would like a reconfirmation. Do I need to use water on the diamond for lubrication? If I don't (and I don't) can I still clean it with a impregnated SOS pad & water (I do)?

Thanks,

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~Greg Mete~
Kodiak Alaska
 
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