Diamond Machining Technology (DMT), 8-in. Diamond Dia-Sharp Whetsone Bench Stone, Medium Extra Fine Grit Sharpener (D8ME)

I've been using DMT products since the '80s. These Dia-Sharp 8" are my mainstays. Once broken in, they grade fairly and just don't require the maintenance of other stones. If you have the range (after the Medium-Extra-Fine I have them all) you can tackle anything. The 4000 (6 micron) has been a hole in this line for a while, it's nice to see it has been filled.As delivered, these stones have a lot of manufacturing "gunk" on them, and when new can be pretty sharp, i.e. grading lower (coarser) than marked. The stones break-in with use, and I actually break them in before using on anything of any significance.To break these stones in and clean them up, spray with 50/50 solution of Simple Green and Water. Use this as a lube for the stones all the time, it just works better than water or dry. Take a hardened piece (nice if it is the width of the stone) of 440C (I use a old knife tang) and run it up and down the stone, in circles or whatever, but try to cover the whole area. Keep adding Simple Green as needed, wipe the stone and steel off when it gets dirty (it will) and you should start to feel the stone smoothing out. There are little pieces of dirt and manufacturing eccentricities in the coating they put on them and you need to work that off. Once that is off, the stone will exhibit a much more uniform texture that you would expect. At the point that the surface is uniform, the stone will still grade a little rough, but will smooth out with use. Keep using the Simple Green solution to keep the stone and work clean. When breaking-in, pay significant attention to working the edges of the stone, this is important as this area can be a little rough. Even using the Dia-Lap 120 to chamfer the edges doesn't work all that well. If you are lucky enough to have a stone that they didn't get coated all the way to the edges, don't send it back; I wish they made them all that way. The stone should exhibit a uniform gray/silver appearance when properly cleaned and broken-in.

I've been using various diamond stones, including DMT stones for about a decade. DMT used to be of the best quality, but lately I have noticed that their quality has been going downhill. When I received this stone, it had several small dimples on the diamond surface of the stone which caused the blade to catch as it was run across. I figured a good break-in would take care of it, but I was wrong. I found at least a couple of more spots on the stone which caused the blade edge to catch during sharpening, and resulted in actual damage to the edge. I sent it back to DMT, and the replacement was a little better, but still flawed. I got a refund, and decide to go back to water stones and Arkansas Stones. Boy, I forgot what I was missing. Yes, the diamond stones cut faster, but they leave deep gouges on the edge preventing a fine edge polish. A fine edge polish on any steel will literally double the longevity of its edge versus the toothy, micro-serrations of a diamond stone edge. I started putting razor edges on knives 30 years ago, and I have found that all types of bench stones have their place. I will save my DMT diamond stones for major profiling and steel shaping, water stones for most other edge refining tasks, and Arkansas Stones for extreme edge polishing so that it will shave the free standing hair off your arm without having to even press the edge against your skin to make the hair catch on the edge. So, in summary I do not recommend this stone. If you want the best overall sharpening system, get a coarse rated diamond stone for profiling work, a good water stone kit, a black surgical or translucent Arkansas Stone for an ultra edge polish, and then a good strop for final edge refinement. If I could only choose one system to save money, I would get a water stone kit and a good strop which will total less that $100..

I have 2 already and love them. Purchased a coarse it showed with out damage.medium fine & extra extra fine showed with a lot of damage to the surface. Return came before I sent the old one. The return is better than the first one received but still has minor scratches I feel them when I drag my knife on it. I am still awaiting the Extra extra fine that is dinged. If I see any flaws on that one I will return as soon as I get it, and Switch to another cheaper Non American company since American quality does not seem to be a selling point any more.

I get my japanese kitchen knives wicked sharp in no time with diamond stones. Used to jump from 1200 grit to 8000 grit and it just didn't do it. Now with the 4000 grit, sharpening with the three stones is better, faster and I often just use the 4000 and 8000. Plus water stones are less of a mess in the kitchen.

I just went through this same situation with their extra extra fine! . I was excited for their medium extra fine, It came in original packaging and all scratched. Again I thought ok maybe it’s the nickel that’s all banged up and this is still very small 6 microns? And again I Ran my nail through the plate and yet again my nail was getting caught. There was no point in breaking it in. This looks a bit better than my extra extra fine but still appears used! This is straight form the original box! What’s happening with quality control?? I do not want to try again for this extra extra fine. I should have listened to the other reviews one here. Looks like getting a perfect one is near impossible. I wish people with 5 stars would share pix to compare for this as well as the extra extra fine. I can’t recommend these.

En verdad estas placas diamantadas son una maravilla, ayudan enormemente en el afilado de las cuchillas y formones. Por fin mis herramientas están con el filo adecuado, al usarlas se nota la diferencia.Esta placa la uso para pasar a una piedra de agua más fina, pero si no tuviera la piedra, bastaría solo asentar el filo un poco y a cortar.

Prompt delivery and exactly as advertised.