DMT D8XX 120 micron stone!

I have had a Razor edge coarse stone for approx 2 years and it gets allot of use , mostly daily for thinning my work knives and it shows little dipping or cupping in the middle. I am always careful to use the whole stone to prevent this occurring.
I purchased the DMT XX coarse about 2 months ago and I think it removes metal much faster than the RE stone, the way it will rub the factory edge off a new knife is impressive (the way it can rub your finger tips off is even more impressive!), I have found it is important to keep it clean with a cream cleanser as traces of fat or oil will keep it from cutting effectively. I then use the RE stone to remove the heavy scratches. I used the xx coarse to rub the factory edge out of a F.Dick 10" steak knife on the weekend, these knives are very hard (I'm told about 62HRC). I rubbed a flat taper about 1" back from the edge until the factor edge was gone along the entire blade, took awhile but I would not have liked to have tried it with a lesser hone.
I'm very Happy with it so far, the RE is also a good hone and quite a bit cheaper.
 
It is rather interesting that there is so much variation from one user to the next. I have never been impressed with the speed of cutting action of diamonds for their grit and was certainly surprised by Thom comparison to waterstones. I would wonder if we all have the same grit on the stones.

-Cliff
 
Meatcutter--

Thanks for your post. I have wondered what others who have used both products have found. It's interesting our results are the opposite and that so many think the D8XX is the best. I'll play around with the D8XX some more when I have to take a lot of metal off again. I'm curious why my results aren't the same as those of others.

Cliff--

I have other diamond hones and haven't been particularly impressed with their speed, either, so am also a little surprised about the great reviews of the D8XX.

I've read many threads where there is a lot of disagreement about the effectiveness of different sharpening media and systems. There would be some user variables involved regarding technique, preference, etc., and of course the great number of different knife steels and manufacturing methods would have a lot to do with it, but I would still think there would be a lot more agreement than there is.
 
My experience with the DMT extra coarse stone is that the first one I purchased cut very well for about a half hour, then "broke in" to cut OK for about 6 to 8 hours and then there were no more diamonds left over most of the stone.

I sent it back to DMT, who replaced it with a brand new extra coarse stone. I have been very nervous about using it for sharpening or grinding steel and have probably used it less than a couple hours total over the past 3 years for that purpose.

However, I do use it for flattening other stones and it works OK for that. As nearly as I can tell about 30% of the replaced stone has been stripped of diamonds so far.

I have been told that normal steel tends to pull out the diamonds and this certainly has been my experience. This presumably is much more of a problem with very coarse grits than with finer grits. Again, this has been my experience in that I have had a couple of those cheap diamond paddles for many years in medium and fine, and they still work. I'm sure they have 50 to 100 hours each on them, at least.

Also agree that diamond does not cut as fast as good waterstones (especially green carbide ones) with the same grit.

Diamond paste or powder embedded in cast iron laps seems to me to be a much more economical way to utilize diamonds for sharpening since it is very cheap to keep replenishing the diamonds as needed. I just haven't found a good, flat piece of cast iron yet.

Don Clark
 
Mtn your probably on to something with the difference in steels. I haven't used my D8XX alot yet but I really noticed the difference with it on very hard m2, old power hacksaw blade, compared to my SC black coarse hone. I'm guessing that with softer steels or more easily grinding steels I'll see alot less of a difference between them. Not to compare but I can say I really didn't need or want anything faster when reprofiling a 1095 blade with my black SC hone, but when I reprofiled a full hard 1095 blade it was slow going with the same SC hone. I think I was doing more reshaping of the hone than I was of the hard 1095. :)
 
Mtn Hawk said:
I've read many threads where there is a lot of disagreement about the effectiveness of different sharpening media and systems. There would be some user variables involved regarding technique, preference, etc., and of course the great number of different knife steels and manufacturing methods would have a lot to do with it, but I would still think there would be a lot more agreement than there is.
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In many cases you are often comparing subjective measures of sharpness with other people talking about different things not to mention using different angles and often as you noted using different steels. Use waterstones on 52100 and then diamond stones on S30V and the difference in steels is much larger than the stone difference. It is pretty easy to measure grinding speed. Just take a simple razor/utility blade and grind right into the edge for a number of passes and compare. You can easily grind on a scale to constrain force, but generally this isn't an issue.

Ripantuck said:
As nearly as I can tell about 30% of the replaced stone has been stripped of diamonds so far.
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So are those sections compeltely smooth?

-Cliff
 
Has anyone done a comparison on average life of a waterstone and diamond plate of comparable grit? I know waterstones are suppsed to get consumed during use, that and the mess of the slurry are why I decided to go with the DMT. If I need to cut any faster than this, I have 120V outlets all over the place.
 
IIRC one of the diamond hone manufacturers (dmt I think) explained that softer steels can tend to deform instead of cut cleanly and if too much pressure is used yank the diamonds out of the nickel plate. The harder the steel the longer the stone should last.
 
The only waterstones I can see wearing out are the really coarse grit, and even then it takes a long time. My 200 is more than half way gone and it took many years of extremely frequent and heavy use. You are looking at literally thousands of edge angle adjustments and heavy damage removal.

-Cliff
 
hardheart said:
Has anyone done a comparison on average life of a waterstone and diamond plate of comparable grit?
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My 80 grit 'Golden Lobster' hone wore faster than it cut. Still has years of life in it as a barely effective coarse hone if I don't pulverize it and scatter its abrasives to the wind.

My 120 grit EdgePro hones, held in hand as a file (ala Cliff) may have cut a little faster than my D8XX (can't remember), but it was limited in its scope and quickly wore deep grooves.

I'd rather have a very fast hone that stays flat for several edge-changes and waterstone flattenings and may one day up and die than one that might be a little faster, but harder to keep flat.
 
If you are really frugal there is nothing stopping you from recycling the grit. Lee Valley sells a platform which holds the stones over a bucket so when you flush them the swarf goes into the bucket. You can use this as a lapping/honing abrasive. You could even make your own blend by sharpening a high carbide steel and thus sell silicon+vanadium carbide lapping compound, even promote it as "cryo" treated.

-Cliff
 
Thanks. Would rather put on my goggles and respirator and smack the stone into dust with a hammer. I mean push cut it with a very convex edge. :)
 
Cliff,

It doesn't feel completely smooth, but I can't feel any diamonds on the stripped areas. I also cleaned the stone and inspected it with a 40X scope and couldn't see any shiny diamonds- there seemed to be a few lumps in the area. However, it is obvious that the stone is partially stripped because, when flattening other stones, those areas don't cut.

It is difficult for me to use a light touch when I am sharpening or grinding with a coarse stone, so I assume maybe these stones will last a lot longer with a lighter touch. The interesting thing is that I purchased 3 diamond stones from Harbour Freight for about $12.00 and they seem to be holding up at least as well as the DMT stones, except that the glue came loose from the backings when I left them soaking in water. Just have to re-glue them with epoxy.

Don
 
That is a general warning about using diamond stones, light pressure. If you compare diamonds going light to waterstones pressing heavy then it isn't any contest at all.

-Cliff
 
thombrogan said:
Thanks. Would rather put on my goggles and respirator and smack the stone into dust with a hammer. I mean push cut it with a very convex edge. :)
Click to expand...

I gave up trying to keep them flat and now just consider the golden and green lobster stones to be loose grit in a handy "stick" form. Just rub a knife on it for a bit, gather the loose grit onto the blade and wipe onto a kanaban ( http://www.toolsforworkingwood.com/Merchant/merchant.mvc?Screen=PROD&Store_Code=toolshop&Product_Code=MS-SFP200&Category_Code=THW ) and continue grinding on the kanaban.
 
1. Cliff- Did you ever contact DMT and ask them how much pressure is advised for their product?

2. Couldn't I substitute a coarse bastard file for a XX coarse DMT?
 
yuzuha said:
I gave up trying to keep them flat
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I just cut my 200 into blocks and use them as files. I alternate contacts to smooth out the wear, they don't need to be flat for regrinding anyway. You just have to take the wear into account as it will thicken the angle towards the edge if you use it extensively during a single session unless you take care to use the full surface of the stone.

matt321 said:
1. Cliff- Did you ever contact DMT and ask them how much pressure is advised for their product?
Click to expand...

Yes, their advice was to go light.

2. Couldn't I substitute a coarse bastard file for a XX coarse DMT?
Click to expand...

Yes, if the steel is soft enough then a file is much faster than any stone.

-Cliff
 
yuzuha said:
I gave up trying to keep them flat and now just consider the golden and green lobster stones to be loose grit in a handy "stick" form. Just rub a knife on it for a bit, gather the loose grit onto the blade and wipe onto a kanaban ( http://www.toolsforworkingwood.com/Merchant/merchant.mvc?Screen=PROD&Store_Code=toolshop&Product_Code=MS-SFP200&Category_Code=THW ) and continue grinding on the kanaban.
Click to expand...

Yuzuha, have you tried a kanaban with fine diamond pastes on knives yet? If so, how did that work out for you?
 
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