The micron rating of the particles is somewhere between 7 and 15 microns on average, but because of the way it cuts, it gives an edge more like a 12,000 grit stone. If you go here, you will see various edges under 200x magnification, the UF is about the same as the Chinese 12K, which to me, look like two of the finest edges not including the pastes (and they are the two least expensive stones too). If you want to see how a stone with such large particles can cut so fine, go here and read the posts. You can see a VERY close up picture of the surface in the last post. The particles don't look, or cut, like normal wet stones would be expected to. I own and use the Spyderco 306UF, use it dry, and have been very pleased with it. That said, I haven't owned or used any other super high grit stones, so I wouldn't be a good one to ask for comparisons. For that you will want to go to this wiki and read the posts in the "different hones explained" section to learn about the differences between high grit stones. For some reason, I can't get #16 of this section to work, but Joel had done lots of testing work and wound up rating the Spyderco UF finished on leather as an "A-", which was VERY high on his scale. I think the only thing that beat it was finishing up on CrOx then leather. I think the only reason Joel isn't an even bigger fan of the UF is because it doesn't have the feedback that some of the naturals do. I for one, like the lack of noise while using it, as my wife and I can watch TV, I can put an edge on a razor, and it's not a nuisance. I also like that you can use it without water or oil.
Last edited by PapaFish; 04-20-2011 at 02:03 PM. Reason: Changed the rating from "A" to "A-"
A few people have lapped their full range of Spyderco M F and UF, and they said that the fine after lapping doesn't behave like the UF. I heard the rumors too, but I havent read one single post here that said that he lapped his UF and F, and after lapping they were the same. It would be good if they were the same, you could buy the cheaper F and lap it, to make an UF out of it.
here that another member has lapped and polished the second side of his UF and it "gleams like glass and acts like a 40k or so hone". With that being said, the reason I didn't buy the cheaper Spyderco 302F stone and lap it up to get an UF like finish is because the Spyderco medium and fine stones don't come in the 3" wide variety, so I went with the 306UF (also I didn't want to buy lapping supplies...). I realize that I have thrown a few links around, and that's because I did a lot of research before I picked a stone to go with, and a lot more between the time I purchased the stone and the time it actually came in the mail! Everything I have read on these stones has made me extremely impressed.
I have the Spyderco ceramic fine and lapped one side creating a side as Sal G. explained the ultra fine was. I lapped mine using a fine diamond and it works very well with my razor . One can certainly tell the difference in feel and shave off that side. So, I saved the 20$ and have the same stone. Then take it to my strop loaded with .5 green slurry rouge and my razor shaves like a lazer. Possum
You are making me wanna buy a UF
Can-can scratch patterns!
There is a Spyderco 302UF (8"x2"x7/16") for sale here in the B/S/T, along with a bunch of other hones. If I had the money to spend, I would buy the whole lot, as they are a very good price.
Using a ceramic hone and .25 diamond spray, I skip the bevel refresh. Two squirt of the spray on the hone, a little water and ~15-20 laps later I am done honing. I follow that with CrOx on balsa and strop on pressed felt.
I should mention that my DMT has seen a lot of use and doesn't cut as quickly as it once did. 10 laps isn't removing a lot of metal.
Las Mañanitas brotha?