The new steel: waterstones, or diamonds all the way?

Crayola

Crayola

Joined
Sep 23, 1999
Messages
3,831
Hello everyone.

I believe I have asked this question in one form or another in the past, but it is time for me to ask it again!

From what I have read and from the actual experience I have had, Japanese waterstones seem to be incredible sharpening tools. But one worry I have about them is newer steels like the CMP variety. With the large amount of really hard carbides in them (like the vanadium carbides), can a man made waterstone (I believe they are made of aluminum oxide) do an appropriate job on them? I have no doubt that waterstones can tackle ATS-34 or 440-C or O1. But what about CMP S30V? Are diamons not only CMP steel's best friend, but their ONLY friend?

Thanks all.
 
For the high vanadium CPM steels, those waterstones will work, but you sure wont be taking off any significant amounts of steel quickly. The waterstones will work great for the final edges and touch ups, but you are going to need the diamond stones to do any profiling and heavy metal removal. I, myself, use strictly diamond stones. I start with the DMT blue(coarse), work up to the red(fine) and finish with the green(ultrafine). The blue stone will give you a good working edge, the red leaves a great finer edge, and the green polishes a super fine edge. Actually, I rarely see the need to use the green stone, as I prefer the grabbier edge of the red stone.
 
Danbo, as always you are a helpful guy!

So, I'm going to pick your brains a bit more. Would you say then that a set of waterstones with the coarse stone replaced with a DMT stone for fast removal would make a better set for a variety of steels than just the water stones alone?
 
While Diamond hones will cut faster than Waterstones under low pressure, press down hard and the waterstones will leap ahead. For heavy reprofiling I use a 220 grit SiC waterstone, and usually start with a sprinkle of 80 grit lapping compound. This is many to one times faster than an x-coarse DMT hone.

I finish with Diamond hones because they have the ability to cut at very low force which is essential for preventing excessive burr formation. As well since they have the ability to cut the carbides, even the harder ones, this insures that you get the maximal edge aggression as the carbides faces are not rounded out.

-Cliff
 
Thanks Cliff.

Does this method only apply to the super steels though? If you had a knife of 1095, would you use the same procedure, or would the waterstones be fine?

Thanks.
 
Yes, it is only a real concern with the high carbide CPM's (or anything similar). A real problem is that people are making such steels soft and when you combine a weak matrix with hard carbides, the edge resists machining because of the carbides so you have to press hard, and then because it is weak it just bends, Spyderco's ~55 RC 440V for example.

I use a 4000 grit waterstone as the finishing hone on a lot of knives, plain carbon, 5160 and the like, and after a little stropping on CrO (just a few passes), the edge will almost pop hair (or can depending on how sloppy I was). On the high carbide steels I finish with a 1200 grit DMT plate. The only reason I use 4000 instead of 6000 or 8000 is that I could not get them in the size I wanted (1"x4").

-Cliff
 
Thanks Danbo and Cliff, I have noted that the water stones alone require quite a bit more pressure in order to be effective with these steels. My only problem with using the diamond hones is with my knives that have convex ground edges that rise all the way to the spine. THe diamond is too aggressive in this case because it leaves the side of the knife badly scored. For all of my other knives the diamond hones that I have used are great for their speed and ease of use.
By the way Cliff, do you use 80 grit compound on the stone as part of the slurry or do you simply use the stone as a base to hold the compound?
 
It becomes part of the slurry. I tried using it just on glass but it wasn't nearly as effective.

-Cliff
 
You must log in or register to reply here.
Back
Top