Spyderco 306UF vs DMT Extra Extra Fine?

V

vtvman

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Mar 14, 2012
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Im currently debating about the two and hear great things about both. I planned on going with the DMT plates all the way from coarse to xxfine but many people on the forums have noted that the xxfine has an extremely long break in time until it cuts like it should.

Ive also heard that diamonds leave a different edge compared to waterstones or ceramics which is why im also interested in a DMT stone as a finisher but the spyderco UFs have been nothing but great on the sharpmaker :confused:

I do own some super steels such as m390, m4, and 3v but thats about it. The rest of my knives are s30v and chinese steels. Dont know if that should influence my purchasing decision.

Which do you guys prefer? Also does anyone who owns both sizes of the DMT plates feel that the 3x6's size is more advantageous than the 2x6 to justify its costs? The longest knife I sharpen by "stone" is 10 inches with a 5 inch blade.
 
As for hone size I personally like 8x3 because it is the standard for full size stones.

A set of DMT hones would serve you well considering the steels you have to sharpen. Maybe a set of C/F/EF to start? The newer EEF hones I've seen have been pre-broke-in, I have not used them but seems as if it would help the time needed to get them working properly.

Remember, what you use before is as important as the stone you finish with.
 
I also prefer the 8x3 but I only have a well used extra coarse and coarse. The latter one is more a fine one now and I use it as the final stone actually until I can somewhat shave (a few hair anyway), then I strop with good quality green compound (recommended by knifenut1013 by the way some time ago!). That is more than I need (and I would not be able to archive more anyway) for my outdoors and kitchen tasks.
 
For knives with high Vanadium & Tungsten content (>1%), go with knifenut1013's recommendation. 306UF AlO/alumina infused ceramic is too soft for those knives. Sure, it can abrade away steel matrix, consequentially V&T carbides fall off, so DMT is a better tool for sharpen these high alloy knives. btw - avoid dmt duosharp metal grid stone (diasharp pocket type is ok), its surface has low/high bands.

8Cr* steel (the rest of others) knives - 306UF produces more polish bevel (almost mirror), while XXF dmt yields hazy finish. 306UF was the most PITA to flatten the first time - took me around 10hrs (doh reminding self -> use low grit SiC sandpaper next time!). Once flatten, my 306UF worth many times over the purchased price. Aslo, 306uf is really great for honing professional small cobalt steel tools.
 
bluntcut said:
For knives with high Vanadium & Tungsten content (>1%), go with knifenut1013's recommendation. 306UF AlO/alumina infused ceramic is too soft for those knives. Sure, it can abrade away steel matrix, consequentially V&T carbides fall off, so DMT is a better tool for sharpen these high alloy knives. btw - avoid dmt duosharp metal grid stone (diasharp pocket type is ok), its surface has low/high bands.

8Cr* steel (the rest of others) knives - 306UF produces more polish bevel (almost mirror), while XXF dmt yields hazy finish. 306UF was the most PITA to flatten the first time - took me around 10hrs (doh reminding self -> use low grit SiC sandpaper next time!). Once flatten, my 306UF worth many times over the purchased price. Aslo, 306uf is really great for honing professional small cobalt steel tools.
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That is incorrect,

Spyderco ceramics are more than hard enough to sharpen the hardest and most wear resistant of steels.

There is also no need to flatten them as they were already ground on a milling table using diamond abrasive. You might be able to improve on the finish the stone provides by lapping but it was already flat. FYI, sandpaper won't work you must use diamond to cut ceramic.
 
I read somewhere that the only difference between the fine and ultra fine stones was that they used a different surface finish on the uf stone. Wouldn't that change the micron size if you tried to flatten it with only low grit sandpaper?
 
knifenut1013 said:
That is incorrect,

Spyderco ceramics are more than hard enough to sharpen the hardest and most wear resistant of steels.

There is also no need to flatten them as they were already ground on a milling table using diamond abrasive. You might be able to improve on the finish the stone provides by lapping but it was already flat. FYI, sandpaper won't work you must use diamond to cut ceramic.
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Well, maybe your 306uf was flat but mine sure warped - over 1mm undulation surface. Even after 10hrs and 2 ruined dmt bench stones, 1 corner still low. I coated the entire 306uf with permanent sharpie, keep lapping with dmt until ink is gone. hmm - somehow, I thought SiC is harder than ceramic & alumina. As for sharpening my GB cpm-m4 with this, well, it felt like burnishing instead of honing and my edge wasn't that sharp. Perhaps in a better skill sharpeners, 306uf can be more effective.
 
knifenut1013 said:
FYI, sandpaper won't work you must use diamond to cut ceramic.
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Hmmm, I lapped my 302F using a Norton economy SiC stone from HD for a plate. Started with 120 grit SiC powder and worked my way up to 600 grit powder to finish it off. The ceramic is so tough that it reduced the larger grit slurry to a fine mud - had to keep using fresh grit. It took a long time, but I now have a fine ceramic with a UF mirror finish on one side. FWIW, both sides have some surface irregularities - a slight ripple on the fine side and the UF side had two low spots that became visible as the finish cleared up. I have to believe the Spyderco ceramics can work on anything, they are extremely tough - can pulverize SIC grains down with only the slightest hint of their passing.
 
The ceramic is so hard it will wear out the sandpaper before anything is done to the stone.

All spyderco ceramics are the same particle size with the only difference being firing and finishing processes.

UF ceramics are lapped Fine ceramics.
 
vtvman said:
I read somewhere that the only difference between the fine and ultra fine stones was that they used a different surface finish on the uf stone. Wouldn't that change the micron size if you tried to flatten it with only low grit sandpaper?
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For initial flattening, that wouldn't matter. I use dmt fine for subsequence truing/flattening. Yes, the AlO/alumina will be rounded top, so right after flattened, the stone doesn't cut aggressively. Can one dish this stone, sure you can, just rub a s30v knife spine to the edge of this stone, you will see the build up and wear on this stone.
 
I thought with the Spydie benchstones that they are so tough that they would wear for a very long time with alot of use! Is this true or not?
 
I have both and I would my choice would be the Spyderco Ultra fine stone especially the 306uf. It's a great finishing stone and yields a very fine edge. I agree with knifenut1013 there is no need to flatten it and it's more than hard enough to cut any steel. I have been really pleased with mine.
 
sir_mike said:
I thought with the Spydie benchstones that they are so tough that they would wear for a very long time with alot of use! Is this true or not?
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Yes, spydies and dmt stones would last a long long time for those with zen (master of patience) touches. Too much pressure will wear&tear them to ab early death.
 
Knifenut1013 & Heavyhanded - I agreed that ceramic is harder than vanadium carbide. Does ceramic binder/matrix or infused alumina do the cutting/abrading? or combination thereof?
 
bluntcut said:
Yes, spydies and dmt stones would last a long long time for those with zen (master of patience) touches. Too much pressure will wear&tear them to ab early death.
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Ahh, got it. Thanks!

I went alittle crazy and picked up alot of stones! The 302M, 302F, 302UF, 306UF, Doublestuff 303MF, Profile set 701MF, sharpmaker with UF set, and a Japanese whetstone at 400/1200.

Do I really need all of these??
 
You can wear out a diamond with too much pressure, yes. You cannot do the same to a ceramic, a ceramic hardly wears, doubt you could dish it, and if you can find stone build-up from a UF ceramic then I would love to see that picture.

No Zen mastery needed.
 
I've linked this in previous threads before, but here it is again. A very interesting discussion on Spyderco's own forum, on an almost identical topic (Spyderco ceramics compared to EF DMT). Lots of good input from Sal Glesser too. I think he also points out, diamond is about the only thing that'll lap/flatten the ceramics. For my two cents' worth, I've tried using wet/dry SiC sandpaper on my little ol' Spyderco DoubleStuff hones. Sandpaper wouldn't faze 'em; it was like rubbing smooth glass against smooth glass.

http://www.spyderco.com/forums/showthread.php?31188-Ceramic-benchstones-compared-to-DMT-extra-fine
 
knifenut1013 said:
You can wear out a diamond with too much pressure, yes. You cannot do the same to a ceramic, a ceramic hardly wears, doubt you could dish it, and if you can find stone build-up from a UF ceramic then I would love to see that picture.

No Zen mastery needed.
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I doubt if you gouged a Spyderco stone with an axe head it would show any wear. I still remember lapping mine down, the 120 grit would start out raspy and just get worked down to a thin paste. The only evidence of it doing anything was the mud had a slightly lighter shade from the white ceramics, and my Sharpie proof marks were slowly worn away. Had to wash and dry it and hold it steep to a good light source to see how well it was coming along. It did come along though, I even radiused one long edge so I could do recurves on it. I tried to "rough" up the fine side to make it a bit more aggressive - used 60 grit SiC and a lot of pressure, stopping and adding fresh grit before the SiC broke down to a smaller size. That stone didn't get one bit more textured and I couldn't see a single scratch either.
 
It makes it very hard to compare products with different companies when they dont standardize products like stones using grits. How can any new guy (like me) figure out which stones will work and keep my knives sharp and whether or not a medium stone will let you profile abit.

Very frustrating as I am trying to get some stones for freehanding...
 
sir_mike said:
I thought with the Spydie benchstones that they are so tough that they would wear for a very long time with alot of use! Is this true or not?
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This is a quote from Sal Glesser in the thread I linked earlier (post #20 in that thread):

"50,000 years from now when the Pyramids have crumbled and humans are but a memory, Spyderco ceramic stones will be seen sticking out of the earth, ready to work.

sal
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Assuming anybody is still around to find one then, this wouldn't surprise me at all.
 
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