Diamond sharpening media question

[Tony Wilkins]

Out of all the sharpening questions lately I have one more ;)

I'm thinking I need a diamond 'stone' to flatten my water stones (don't like the idea of sandpaper) - is there a recommendation? Also, would it be too much to ask that stone to serve as a coarse 'grinding' stone below my 1000 grit Hida stone.

[Winton Applegate]

Yah Dog !
I mean . . . Hi Tony,
This one works very well for me and I am glad I bought it.
Unfortunately back in the days of poorly flattened blade backs I half wore it out.
I will buy another exact same one one of these days and be good to it. No more blade back flattening.
I am not saying buy it from Amazon. In fact I would strongly recommend you support your local woodworking tool store even if it costs a bit more. Just look at it as paying for all that great free advice they have to offer and a warm place to go look at woodworking stuff on a cold day (or a cool place to go when it is too hot to work in the shop).
anyway this is a worth while stone for your purposes.
http://www.amazon.com/DMT-W250CXNB-10-Inch-DuoSharp-Extra-Coarse/dp/B00004WFUL/ref=sr_1_11?ie=UTF8&qid=1372129586&sr=8-11&keywords=dmt+diamond+sharpening+stone

[Hilton Ralphs]

This one works very well for me and I am glad I bought it.

http://www.amazon.com/DMT-W250CXNB-10-Inch-DuoSharp-Extra-Coarse/dp/B00004WFUL/ref=sr_1_11?ie=UTF8&qid=1372129586&sr=8-11&keywords=dmt+diamond+sharpening+stone

I bought the same stone but the eight inch version as this was the only one that Amazon would ship to South Africa. I've heard that you should reserve one side for flattening waterstones and never to use it for anything else. DMT recommend flattening with the 325 side (coarse) and therefore I use the other side (extra coarse) for hectic grinding.

Stu from toolsfromjapan.com sells the Atoma 400 which a lot of people seem to recommend.

[Jim Matthews]

I own both the Duo-sharp and Atoma stones.

The Duo-sharp is BIG. I don't feel it cuts very fast.
The Atoma cuts fast, but it isn't very big.

I like the way I can keep the Duo-sharp next to my strop, if I need a touch up
but it's not a substitute for a full sharpening session.

I will say this, it's nearly indestructible.
I've lost track of it in my dimly lit shop, dimly stepped on it, and it was fine.

You would think something so bilious would be easy to see, in the dark.

[David Weaver]

Mixing use of the stone as a coarse grinder and as a flattener/conditioner for waterstones is going to cause the stone to flatten waterstones more slowly, eventually to the point that you won't feel like it's fast enough to flatten stones.

I'd keep the two things separate.

I'm no great fan of DMT products, but you could get a duosharp that was coarse and x-coarse and use the coarse side to condition the stones and the x coarse to hone.

The atoma is the nicest i've used for stones, though. I've been through all of the brands. Used a duosharp and a "bench stone" DMT for a while and totally clapped it out, then used two chinese two sided hones from best sharpening stones (actually, they're not too bad, they have a polycrystalline diamond feel to them - meaning they're pleasant to sharpen with and very even even when broken way in - they're just not flat and they cost *more* than an ezelap). Then got a couple of atomas and two ezelaps.

There's no reason I couldn't have just one atoma right now, I was just curious.

The price is no object route would be a 400 grit atoma for all of your waterstones 800 and above and the coarsest ezelap you could find to do sub 1000 grit work if using a grinder is really out of the question.

[Tony Shea]

I've noticed of late that you are recommending and using the Eze-laps lately David. Is this a fair observation? If true, what is your reason behind the choice over DMT's line of stones. Is it mostly based on the price vs. quality? I haven't bought a DMT for a long time as my DMT has lasted for a while now (extra-coarse duo on my waterstones) so am not sure on their quality of late as far as flatness is concerned. But the duo I have is incredibly flat and is still flattening my stones ok. It def has worn down over time but I almost like where it is at now better than before, especially on my finer stones.

I will say that my next diamond stone purchase will probably be Atoma.

But I have been thinking about getting an extra-coarse or xx-coarse for some bevel grinding, not stone maintenance therefore the stone doesn't need to be a high end extremely flat stone. And lately you've been talking alot about eze-laps so just curious what you think about an eze-lap for grinding steel purpose.

[David Weaver]

My duo was flat, as was a friend of mine, but I wore it out fairly quickly. I also didn't like its broken in feel compared to a chinese iwood copy that was polycrystalline (i didn't know it was a copy of anything, we didn't know what iwood hones were until stu started to carry them).

At any rate, I noticed that the chinese hone got finer, but it still seemed to cut OK and the feel was a lot better.

Didn't know anything about ezelaps until David Barnett mentioned that the older ones at least were polycrystalline and had the same kind of smooth feel that the chinese hone I referenced did, vs. the plain dullish feeling that the DMTs give you. And in my opinion, the scratch pattern off of polycrystalline is a little better.

Ezelaps apparently aren't all polycrystalline any longer, but they do feel like the chinese hone felt when they're broken in and they leave a nice even scratch pattern. And an 8x3 is $35.

As far as grinding, I don't like any stone as much as a grinder, and the best working grinding stones I've used are really soft coarse stones and they're a mess. If the ezelap coarsest stone has a rating number on it, figure it will feel like a stone twice as fine after it's been used for a while, and cut like a stone twice as fine as its grit rating. That's just my opinion, subjective. Whether or not there are any diamond hones that will work well as a grinding stone for a long time, I don't know. They will all continue to cut even when they feel dull (just more slowly), but when they get so slow you can't take it any longer, I don't know. And unfortunately, the coarser stones cost more, maybe because there's more diamonds on them, maybe because the plating has to be thicker, I'm not sure of the reason but regardless of what it is, they always cost more.

Grinding aside, though, the atoma is a good choice for flattening things, it doesn't suck to the stone as much and it has a nice even pattern.

[David Barnett]

Grinding aside, though, the atoma is a good choice for flattening things, it doesn't suck to the stone as much and it has a nice even pattern.

A student doing independent study in book arts and restoration just bought an Eze-Lap 81F (http://www.amazon.com/EZE-LAP-81F-Fine-Diamond-Stone/dp/B002RL843U/ref=sr_1_1?s=hi&ie=UTF8&qid=1372204563&sr=1-1&keywords=eze-lap+81F) on my recommendation and it really couldn't be nicer—very close to the original feel and the scratch pattern's acceptable in spite of the somewhat adulterated blend. I ordered a couple more for myself at $33 each. While I'd prefer to pay more for a non-hybrid plain polycrystalline, these stones are still far better than their short-lived monocrystalline counterparts.

Those Atoma stones, while a bit overpriced perhaps, are flat and have a good feel and seem to cut more evenly and do hold up longer than I'd have expected for monocrystalline. I still much prefer contiguously spaced polycrystalline diamond rather than dots of monocrystalline.

[Steve Friedman]

Does anyone know if the iwood that Stu sells are polycrystalline - or at least close to the EZE-Laps? I want to add some low grit diamond plates dedicated just for steel and was going to try the EZE-Laps. But, if the iwood are similar, I would rather much rather buy from Stu than from Amazon.

Steve

[David Weaver]

Those Atoma stones, while a bit overpriced perhaps, are flat and have a good feel and seem to cut more evenly and do hold up longer than I'd have expected for monocrystalline. I still much prefer contiguously spaced polycrystalline diamond rather than dots of monocrystalline.

The mono seems to be OK for flattening stones and sometimes use. I like the ezelaps better than the atomas for actual honing, though, but I do like the atoma for stone flattening (can't feel those mono diamonds doing that). I was kind of surprised when you mentioned that the ezelaps had mono diamonds in them because of how they feel (very smooth and even vs. the dull feeling DMTs and even the atoma has that dull feeling). I wonder why they put mono diamonds into their blend, did they ever release info as to why they did that?

[David Barnett]

I was kind of surprised when you mentioned that the ezelaps had mono diamonds in them because of how they feel (very smooth and even vs. the dull feeling DMTs and even the atoma has that dull feeling). I wonder why they put mono diamonds into their blend, did they ever release info as to why they did that?

So long ago I hardly remember the details, back when I was living in MA, I was assured that all the Eze-Lap diamond laps were PCD and PCD alone. DMT went with monocrystalline, that being the sexy new thing. Much promise was held for monocrystalline diamond and it offered properties that made it attractive; crystal size uniformity being just one. Cost was higher then. Now that manufacturing costs have diverged—monocrystalline having become amazingly cheap compared to polycrystalline, which has risen in production cost comparatively—one can't swing a dead cat without hitting cheap monocrystalline product, especially from Asian sources.

Sintered HPHT PCD has become the standard for heavy industrial applications such as drilling and mining bits*, and PCD consumables—loose crystals, pastes, sprays, slurries—command higher prices where PCD is highly desirable, such as certain metallographic applications.

Monocrystalline diamond is mainly exploited for its crystal uniformity and low cost, which makes it the choice for nearly everything not requiring poly, and where disposability, rapid crystal attrition and less predictable, less continuous friability profiles matter less.

From Allied High Tech Products, Inc (http://www.alliedhightech.com/polishing/diapolishing/).

POLYCRYSTALLINE DIAMOND has many more cutting surfaces per particle, resulting in higher removal rates. As it cuts, it breaks down in its original shape, allowing for finer finishes in less time than when using monocrystalline diamond. Because polycrystalline has no cleavage planes, it cannot crack or splinter like monocrystalline diamond. It causes less sub-deformation, and is excellent when polishing samples composed of different materials/hardness.

MONOCRYSTALLINE DIAMOND provides a cost effective means for good stock removal and finish. It has a slightly irregular shape with multiple cutting edges, and is recommended for general applications where polycrystalline's features are not required.

For contrast (http://www.sharpeningsupplies.com/Why-Use-DMT-Diamond-Sharpeners-W15C117.aspx), spincraft appreciation or just laughs:

The monocrystalline diamond used in DMT Diamond Sharpeners, a high-quality micronized super abrasive, leads to a remarkable sharpening speed. Not only does the monocrystalline structure offer greater sharpening speed, but the uniformity of each diamond crystal prevents the diamond surface from breaking apart. DMT's competitors use a fragmented polycrystalline diamond structure that leads to imprecise sharpening and a shorter product life.

"Imprecise sharpening" indeed. :)

At any rate, given the durability of Eze-Lap's diamond plates and resulting lower repurchase rates, and given the higher cost for quality synthetic PCD, I'd conjecture Eze-Lap has sought a sweet spot for keeping their retail price highly competitive while still offering a longer-wearing and better-performing product. Industry's full of such examples. Incandescent light bulbs lasting for decades would've put any manufacture out of business, and it's not easy to coax consumers into higher front-loaded purchase prices.

All that said, a combination of sufficient PCD of a given mean particle size—how PCD is always gauged and graded—with a smaller or variably-sized monocrystallite—a "filler", so to speak, isn't really so bad if done right, which is to say, that the breakdown produces the fewest and shallowest sharp-bottomed troughs possible in the scratch profile.

While I like diamond plates for convenience—I ordered two more for touching up carbide-tipped chisels for lettercutting in granite—I now use even coarser grades of PCD than previously on various substrates and finer PCD on cast iron and other substrates for micron through submicron needs.

The beauty of PCD loose grit, compound and sprays on cast iron, copper, and so on, is the build-up over a fairly short time to reach that favorable balance where only the smallest amount of diamond need be added to refresh the lapping surface. Hell, multiple and incredibly cheap CI lapping substrates can be had from any thrift store that sells old griddles if one has the means to cut them to convenient sizes and doesn't mind putting in an hour or two with a scraper.

I should say here, that while I highly prefer polycrystalline diamond for most things I do, I use monocrystalline diamond; cheap electrobond carving points and laps for gem faceting (roughing) and carving and homemade compound for carving and polishing. My dislike for DMT and preference for Eze-Lap, therefore, isn't just about the type of diamond alone but other aspects of product design and marketing that I'll not here reiterate.

For most woodworkers, though, who don't have such biases, if for no other reason, $35 for an 8"x3" diamond plate with free shipping (http://www.amazon.com/EZE-LAP-81F-Fine-Diamond-Stone/dp/B002RL843U/ref=pd_sim_hi_1) is really hard to beat. I mean, we're just sharpening woodworking tools, flattening tool backs and water stones, right?

*The promise of CVD coatings has yet to take hold.

[David Weaver]

You make a good point about the mono sizes when they're in a blend. For some reason, I assumed that the mono diamonds would be similar in size to the poly diamonds, and had the expectation that I would get what I'd call the Dull DMT edge, which is a low quality edge off of a slow cutting worn out stone. That's not a very rewarding thing to get into....low cut rates and random deep scratches. But if the mono diamonds are chosen to be somewhere that PCD will end up, vs. where they start, then the feel can still be sneaky good with the broken in plate (as it is on the two eze laps that I ordered - there is nothing untoward going on with them).

I read that literature from DMT when I got into the hobby. I believed it, too, why wouldn't I? Didn't arrive at the forums yet and it's like an old wive's tale, just make some argument and make it sound logical and people will buy into it. When my first DMT duosharp was clapped out after not that heavy use within about a year and a half, I wondered if there was just an expectation that you'd have to buy one every couple of years. I don't like that. And as Ray Stevens says in the Pirate Song...."i don't like it .... I don't like it and I won't do it. it's tacky...tacky tacky."

And when the chinese plate seemed to outlast the DMT and continue to cut fine, albeit more finely, as it wore, that was pretty telling. I was harder on that one, too and at the time it was 2/3rds the cost of the DMT (not to be confused with the very cheap chinese stuff that's literally a dollar on alibaba if you're willing to order 500 of them, it was in fact a quality electroplate hone on a milled steel plate).

AT any rate, bottom line is I'm glad the ezelaps are still inexpensive and they have the same kind of feel as that chinese plate did (the chinese plate actually cost more than ezelap charges for a one-sized plate now, but it is two sided and not flat, not sure which is the better buy - easy decision when one is domestic origin, though).