We only stock them for ceramic knives. I have tested every diamond on the market and not one of them lasted much over a couple of hours and most of them much less.
What was he doing wrong? So in total frustration I was telling a engineer friend of my dilemma and he suggested I call a tool company that specializes in diamond tools for industry, to get the straight story.
Which company did he call? So I did. I asked them if they would build me a tool to use on 58 Rockwell high carbon stainless. They said NO. They said that diamonds should never be used on steel and if they built me the tool, it would not last 10 minutes.
Why is it that so many users here manage to make them work for hours at a time, if it is impossible? Here is what happens
when you use excessive pressure. The diamonds sink into the steel, the steel surrounds the diamonds and pulls them off the plates. However if you are using a diamond on ceramic or carbide, the material is way to hard for the diamonds to sink in so they ride along on the points undisturbed. Now I know everyone sells diamonds for knife sharpening and here is why I think they get away with it and I can't. You buy a Gatco or Lansky Diamond, you get it out a few times a year and sharpen a few knives. The diamonds last a few years and you order a new set, thinking that was just fine. I sell a lot of Edge-Pro's to customers going into the sharpening business. These people are sharpening over 100 knives a day. Under these conditions a diamond won't make it to lunch.
I can add from my experience that diamond stone longevity sadly isn't comparable to waterstones. All major diamond sharpening stone manufacturers, including DMT, EzLap, etc, do warn you not to apply excessive pressure when using the stones, exactly because of the reason stated above, diamonds sink into the soft metal and when you push the metal it simply rips diamond crystals out of the base. It makes sense on the physical level. For large amounts of knives, even light pressure won't help.
And we know this because? Especially, when you are using higher grit, i.e. bigger crystals. Also, when using the Edge-pro most of the people I have seen live or on videos, tend to apply quite a bit of a pressure, me too
Makes work faster after all. On the bench stone, it's the opposite, you hold the knife, stone is stationary and unless you are focusing, or if you apply excessive pressure you will loose edge control easily. So, you are being more careful, or alternatively, unsuccessful in sharpening.
You are being unsuccessful in sharpening if you are using your tools properly?
I understood that last part differently when I read it the first time. I didn't meant to imply that excessive pressure was important, in fact, it appears that that portion of my response had nothing to do with anything...