DMT extra-extra-fine grit stone scratch pattern

jackknifeh · #1

I recently got a 4.25" DMT extra-extra-fine (EE) stone meant for the aligner system. When I first used it it left a definate scratch pattern. This is normal for a diamond stone before it is broken in. I never could get it broken in so the results were "smoother" than my extra-fine (E) stone leaves. I contacted DMT about it and sent the stone to them along with a paring knife with opposite sides sharpened with my Ef stone and the other with the EEf stone. The bevel sharpened with the EEf stone is scratchier than the side sharpened with the Ef stone. I had spent more than 3 hours sharpening knives with the stone (unknown steel, S30V and ZDP). One knife was a 10" bread knife with a straight edge that contacts the entire surface of the stone. The E fine stone leaves a very nice polished finish. I was hoping the EE fine stone would be better.

Has anyone else had similar results as I have? DMT says this is not normal. I'd appreciate input on any of you who have used the EE fine stone and it's results. Thanks in advance.

Jack

Pockets · #2

I have DMT medium and coarse stones, but I've never had anything like that happen, though they do take a bit to break in. Interesting fluke.

GCG199 · #3

Yes, it does take some time for new diamond stones to smooth out.

I have the tan extra/extra fine/8,000 grit & green extra fine/1,200 grit DMT dia-fold.

jackknifeh · #4

GCG199 wrote:Yes, it does take some time for new diamond stones to smooth out.

I have the tan extra/extra fine/8,000 grit & green extra fine/1,200 grit DMT dia-fold.

When I used my tan stone the scratch pattern was worse than after the green stone. This was after more than 3 hours of steady sharpening with the tan stone. I'll be interested in what DMT says. I'm sure they will replace the stone but if my first one is working properly that means I'll have to spend all that time on a new one.
I was wondering if anyone else had to put this much time into breaking in a tan EEF stone.

Jack

xceptnl · #5

I have spent about 2 hours breaking in my EE stone and it still is not quite as smooth. I have noticed a change with each use, but it has been a slight one each time.

GCG199 · #6

I have had mine for over a year now. I didn't try to break it in all at once.

It has smoothed out very well. It feels almost the same to me as the green extra-fine/1,200 grit.

jackknifeh · #7

GCG199 wrote:I have had mine for over a year now. I didn't try to break it in all at once.

It has smoothed out very well. It feels almost the same to me as the green extra-fine/1,200 grit.

Do you feel it is as broken-in as it will get or do you think it will get smoother? Do you think by owning a tan EE fine stone you actually might as well have two green ones?

Jack

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Sequimite · #8

When I started using my 6000 grit DMT stone I was also surprised at the scratch pattern. I went to sanding belts after that. I'll have to try "breaking it in".

GCG199 · #9

As far as I know, there is only an 8,000 grit DMT diamond stone, no 6,000 grit.

(Unless this is really new and just became available. I wasn't able to find anything about this on their website either.)

They do have a ceramic 2,200 grit though.

Back to your question Jack:

I believe that it will get the 8,000 grit finer, the more I use it. I am pleased with the results so far.

I understand the concern about there being too much of a gap between the 1,200 extra fine and 8,000 extra-extra fine.

Sometimes I cheat with the 2,200 ceramic as mentioned above or the Spyderco white side of the Double Stuff hone.

(I know that there is a difference in the scratch patterns of ceramic and diamond too.)

I usually finish-off sharpening by using the suede leather Double Stuff storage pouch or a KnivesPlus.com strop block.

Fancier · #10

Jack, are the two DMT "stones" that you are comparing both the same general model? That is, are they both for the aligner, or is one a DuoSharp or something else?
Also, in my opinion the diamond stones are "scratchier" than the ceramics and once you get down to the XF you need to use a ceramic (less "scratchy") or a strop if you want a finer polish.

jackknifeh · #11

Fancier wrote:Jack, are the two DMT "stones" that you are comparing both the same general model? That is, are they both for the aligner, or is one a DuoSharp or something else?
Also, in my opinion the diamond stones are "scratchier" than the ceramics and once you get down to the XF you need to use a ceramic (less "scratchy") or a strop if you want a finer polish.

My extra fine stone is the aligner size with the holes but there is one inch of continuous surface at one end. These are called "machinist" stones. The extra-extra fine stone has the holes all over it like the other stones for the aligner. I agree than diamond stones will never leave close to a mirror finish. Or, they haven't for me anyway. My water stones, mold master and flex stones leave closer to mirror than the diamonds in my experience. Especially the FLEX stones from congresstools.com. I was hoping to get closer with the EE DMT stone but no luck so far. I sent it to DMT and am waiting for their opinion and probably a replacement stone.

Speaking of the other stones I foune the 8" corregated duo-stones with base on knifesupply.com for $58.??. I don't need them but that looks like a very good price to me. Two grits in the 8" size with a base for under $60. Pretty good from my experience. :)

Jack

Kev-Man · #12

When I my set of DMT DaiSharp I made mistake of trying it on a knife first, got some nasty scratches. I ended up using one of my water stones to lightly break them in. I never liked the feel of the DaiSharp so they pretty much sit mainly unused except for stone flatening.

Kev.

chuck_roxas45 · #13

jackknifeh wrote:Do you feel it is as broken-in as it will get or do you think it will get smoother? Do you think by owning a tan EE fine stone you actually might as well have two green ones?

Jack

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I lapped my EEF on a piece of steel plate very gently. It resulted in a finer scratch pattern than my green EF after being lapped.

jackknifeh · #14

chuck_roxas45 wrote:I lapped my EEF on a piece of steel plate very gently. It resulted in a finer scratch pattern than my green EF after being lapped.

That sounds like what I wanted. I used a 10" PE bread knife with a straight edge (no belly) trying to break it in. I think DMT is going to replace my stone. If the new one doesn't work like I hoped I'll just forget it. The Moldmaster and Flex stones I got from Congresstools.com put a very nice bevel on an edge. Maybe there was something wrong with the stone I got or maybe I didn't break it in properly. I had an EF 6" stone once and DMT gave me some advise to break it in and it ruined the stone. They replaced it and spent some time breaking it in for me. I thought that was pretty good. Their customer support has always been very good in my experience.

Jack

chuck_roxas45 · #15

jackknifeh wrote:That sounds like what I wanted. I used a 10" PE bread knife with a straight edge (no belly) trying to break it in. I think DMT is going to replace my stone. If the new one doesn't work like I hoped I'll just forget it. The Moldmaster and Flex stones I got from Congresstools.com put a very nice bevel on an edge. Maybe there was something wrong with the stone I got or maybe I didn't break it in properly. I had an EF 6" stone once and DMT gave me some advise to break it in and it ruined the stone. They replaced it and spent some time breaking it in for me. I thought that was pretty good. Their customer support has always been very good in my experience.

Jack

Good luck then Jack. I do like the moldmasters and BTW, I'm not getting my desired results from the flex 600. I rather like the moldmaster 600 (used dry) better than the flex 600.

jackknifeh · #16

chuck_roxas45 wrote:Good luck then Jack. I do like the moldmasters and BTW, I'm not getting my desired results from the flex 600. I rather like the moldmaster 600 (used dry) better than the flex 600.

The more I have used these stones I've come to like the moldmasters more myself. One of these days I'm going to get one of every grit (6"x1"x1/4") to use with my EP. Being 1/4" thick they will probably last me the rest of my life (hopefully not :) ). They remove steel fast as well as leave a really nice almost scratchless finish. If you want mirror a little time on a strop and you're done. Can't beat the price either. I do like the 4.25" DMT stones when mounted in the EP. It's easy to get used to how short they are. You just need 3/4" wide aluminum blanks instead of 1" wide. The DMT stones are 7/8" wide. Lowe's has the blank material in 3' lengths for about $4. I'm sure the 3/4" wide stuff would work on 1" wide stones also but I think I'd rather have the 1" wide for $8.

Jack

jackknifeh · #17

I had sent my EE fine stone to DMT and they replaced it. I got it yesterday. I started breaking it in with a 3" $6 paring knife so the steel should be fairly soft. Good knife though. Wife made me get 6 of them. :) Anyway, this stone is looking completely different than the first one. The stone shows wear on 100% of the surface. The first stone showed wear in stripes. The stripes were either between the holes or across the top of the holes. I can't remember which and they kept the stone. I really wish I had a camera that would take pictures that would show details but I don't. The scratch pattern looked horrible at first, like a broken in coarse stone. After almost one hour of stroking while watching tv the stone "all of a sudden" changed. It was suddenly providing a survace on the bevel that was a lot smoother. It's not to the point it can be called extra-extra fine yet but I have hopes. All in all I'm not sure getting an extra-extra fine DMT stone is worth it. The extra-fine stone produces a VERY nice surface and edge. It's not mirror but then again no stone I've used produces a mirror finish. That requires stropping for me. I'm not saying it's impossible for a stone to produce mirror. I just haven't used the right stone. Even if I used a stone with the capability, my skills may not be. For thoroughness I'll update this thread to give my final results of how this stone breaks in. It may help others with decisions about getting EE fine DMT stones.

Additional thought: Does anyone have experience with different diamond stones (Atoma, Norton, etc.) in the real fine grits? When dealing with coarser grits in any type abrasive it seems not to really matter what you use. If a scratchy bevel is ok for the knive and a toothy edge about any coarser stone I've tried does the job. It's the fine grits that need more attention in material used and manufacturing.

Jack

y2kfathead · #18

I have the DMT diafold - green (1200 grit) on one side, tan (8000 grit) on the other. My initial use left me with a similar impression as jackknifeh; green seemed finer than tan. Maybe I didn't use the tan enough to break it in very well. I was sharpening a Swiss Army pocketknife, and got a nice edge from the 1200 grit, and very lighly used the 8000 grit. I have a couple of old abused pocket knives I can experiment with, and work the 8000 grit some more to see if I just need to break it in a bit better.