Synthetic polycrystalline diamond paste — cheap and otherwise

[Steve Friedman]

It's a cool product, Jim, but it's maybe more fun to look at than use, as the area that isomorphically fits any given tool cutting edge contour can in practice be a fairly small, short region, especially for fishtails and spoons. But maybe that's just my gouges or my sharpening style.

I am not sure I could have put is as eloquently, but I am not thrilled with the Diamond Wave either. I have several large out-cannel bowl carving gouges (bent and straight), and find that the gouges are too large to fit into the concave portion of the wave at all. For removing the burr from the inside of the gouges, I find the DMT honing cones (or just leather) to be much more useful - the wave is (INHO) too bulky for that task. I was hoping it would solve my bowl gouge sharpening issues, but no luck.

David, thanks for all the great information in this thread. I just received a set of EZE-Laps today and plan to try them tonight. We'll see how that goes. I wouldn't mind sticking with sandpaper and waterstones for the straight edges, but really want something for the curved edges. I'm keeping my fingers crossed.

Steve

Steve

[David Barnett]

I am not sure I could have put is as eloquently, but I am not thrilled with the Diamond Wave either.

David, thanks for all the great information in this thread. I just received a set of EZE-Laps today and plan to try them tonight. We'll see how that goes.

Sometimes what appears to be a really good idea, or at least an attractive one just isn't, sort of like an overly conforming chair design that feels great when you first sit in it but becomes fatiguing and restricting when needing to shift positions. I do know someone who likes theirs, though, but they mostly use it to scuff curved sheet metal prior to epoxying—doesn't leave dust like abrasive papers.

Remember the Eze-Lap comes into its own after a good break in and that polycrystalline break in is slower and far more linear than monocrystalline, which is really more of a break down.

New Eze-Laps are candidates for lapping hardened tool steels, chisel and plane blade backs, reshaping edges, truing things in my machinist's chest, and so on. I distribute initial wear as evenly across the plate as I can, but that's more about my idiosyncrasies than necessity. Mostly, I prefer to work away some of the aggressiveness (the lap's, not mine) before putting it to my better gouges.

My oldest and silkiest Eze-Lap 121F stays in the kitchen close to the vintage Henckels and more modern very hard knives. Eze-Lap to ceramic to strop and just watch those thin tissue sections fall away as from a glass ultramicrotome.

And you're welcome.

[Steve Friedman]

to its own after a good break in and that polycrystalline break in is slower and far more linear than monocrystalline, which is really more of a break down.

New Eze-Laps are candidates for lapping hardened tool steels, chisel and plane blade backs, reshaping edges, truing things in my machinist's chest, and so on. I distribute initial wear as evenly across the plate as I can, but that's more about my idiosyncrasies than necessity. Mostly, I prefer to work away some of the aggressiveness (the lap's, not mine) before putting it to my better gouges.

Appreciate the caution. I have some vintage axes, drawknives, and chisels that need some significant work, so I may use them for the "wearing in" stage before trying to reshape the edges of my Hans Karlssen gouges. I have already worn away more steel from them than I ever wanted to.

As for the diamond paste, how does one buy cast iron that is machines flat enough to use for this purpose? I have some Kanaban from Joel at TFWW but wish they were a bit wider. I know Japan Woodworker use to sell larger pieces of Kanaban, but they were very expensive. Any sources for flat cast iron?

Steve

[Shaun Mahood]

Just have to second the thanks on this - I wish I had known all of this information before I blew a pile of money on ways to be cheap.

As a bit of an aside, would there be an issue compiling some of this info into another form? I would love to have the info from a bunch of these threads compiled together in a form that makes it easier to get all the useful info in one place. I find going through the threads (even with stickies) quite awkward, and would love to have it in a form closer to things like Brent Beach's site or some of the sharpening books. Anyone know if there are any forum rules beyond getting permission from the individual posters?

[David Barnett]

Just have to second the thanks on this - I wish I had known all of this information before I blew a pile of money on ways to be cheap.

You're welcome, Shaun, and I think I can say most of us have been there, if not over sharpening then other tool purchases.

As a bit of an aside, would there be an issue compiling some of this info into another form? I would love to have the info from a bunch of these threads compiled together in a form that makes it easier to get all the useful info in one place.

While I think a compilation of posts on diamond sharpening from Sawmill Creek, WoodCentral and other forum sources might well be useful, I'm not sure how the intellectual property issues could be resolved. Cataloging links would likely skirt proprietary and distribution issues, at least, and, of course, archiving for oneself presents no obstacles; over the years I've archived articles, papers, press releases, promotional literature, blog entries and forum posts from serious, systematic enquirers such as Brent Beach, Steve Eliot, Bill Tindall and others who've devoted considerable effort studying and sharpening harder, tougher steels for hand tool woodworking,

One worthwhile book from Popular Woodworking, The Perfect Edge, The Ultimate Guide to Sharpening for Woodworkers, covers some of this ground and was written by Ron Hock, no stranger to tool steels and practical sharpening issues. While he does address both polycrystalline and monocrystalline diamond, I disagree with his, to me, mostly right but somewhat simplistic distinction of which diamond is best for what and why.

Ron writes:

"Bottom line: polycrystalline diamonds are well-suited for loose-grain (or paste) lapping compounds. They'll crush as they wear and resharpen themselves. Monocrystalline diamonds are recommended for bench "stones" or hones where the diamond is fixed in place (usually in a layer of plated-on nickel). In that application you want the crystals to stay put, and not crush, so they will continue to cut efficiently as long as possible."

I say:

Problem is, monocrystalline diamonds in an electroplated matrix do crush and don't break down nearly so gracefully and advantageouly as polycrystalline. Mono loses its mojo far too quickly and rather than evolving a more uniform cutting character as does polycrystalline, devolves into scratch patterns of inconsistent depth, width and distribution between the remaining unfractured crystals. More to the point, though, plated microcrystalline diamond products are cheaper to produce than polycrystalline.

But that's really not what his book is about so does not detract*. At any rate, Ron provides useful discussions of superabrasives, lapping, other abrasive technologies, approaches and a whole lot more that is bread and butter to hand tools forum readers. Be sure to read the Chris Schwarz review.

Discrepancies among manufacturers and vendors abound, however, both as to cost and to which diamond crystal habit is superior. Examples.

From DMT vendor literature:

"Monocrystalline diamonds are diamonds of high quality that are not fractured. These diamonds are uniformly sized. DMT® bonds these to a nickel backing to provide a long lasting very flat surface. The alternative is to use polycrystalline diamonds. These diamonds are fractured and will not wear as long as the higher quality monocrystalline."

"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."

Contrastingly, a seller of both polycrystalline and monocrystalline diamond, Allied High Tech Products states:

"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."

And here's a worthwhile technical promotion from another producer of both polycrystalline and monocrystalline diamond products, Pace Technologies.

So which costs more?

1µ DIAMAT PC diamond paste (5 gm) $37
1µ DIAMAT MA diamond paste (5 gm) $25

So which costs more?

"MONO-ECO monocrystalline diamond is a low-cost, monocrystalline metal-bond type diamond. The product is used in cost-sensitive applications, where the diamond cost has a major impact on the overall process cost. MONO-ECO diamond is available as diamond powder or as ready-to-use diamond slurry."

Eze-Lap vendor literature states:

"EZE-LAP sharpeners use the rugged Du Pont polycrystalline industrial diamond. These diamonds are more costly, but are significantly more efficient for low-speed manual sharpening than less-costly GE diamond monocrystalline."

This is probably a good place to say that my opinions on sharpening, diamond and otherwise, are just that; opinions—I have no pecuniary skin in the game, no commercial interest or agendum—so others are welcome to differ. I am not an expert so much as a craftsman who appreciates diamond for lapping and sharpening tools, for carving, faceting and polishing gems, and for cold-working glass castings and surfacing metals and stone, someone who enjoys the subject and the technology.

And don't take me wrong—I use monocrystalline diamond wherever appropriate, more even than polycrystalline, and I do like some DMT products—their Hardcoat Dia-Flat™ Lapping Plate is nothing short of awesome. I just find the marketing claims of some diamond products to woodworkers... amusing. Still, I prefer polycrystalline bench stones for sharpening, if for no other reason than polycrystalline diamond has at least 300% more surface area than monocrystalline, resulting in plated bench hones with denser, smoother scratch patterns and superior longevity.

So, does writing help insomnia? Not yet.

*I also have minor quibbles about Ron's omission of explosive detonation formation of nanodiamond and his micron to grit equivalents chart. Nothing but praise for his blades and knives, of course.

[David Weaver]

I can't say it with any elegance, but I also much prefer polycrystalline on tools. I've been through three DMTs (two are still cutting, they are just in that very blah phase of dull DMT), have two atomas (which are nice and last forever, but they do become slow cutting on metal - I have one of them for stone flattening and I think the other is just waiting around now that it's broken in, because the EZE laps are better for steel), and two ezelaps and two chinese polycrystalline stones.

The chinese stone and the ezelaps stand head and shoulders above in use for metal.

"imprecise sharpening and shorter life" for polycrystalline? Huh? Not in my experience. Even my chinese polycrystalline stones outlasted the DMTs and remain usable, and have been more pleasant to use the entire time.

[David Barnett]

I can't say it with any elegance, but I also much prefer polycrystalline on tools. I've been through three DMTs (two are still cutting, they are just in that very blah phase of dull DMT)...

Plain spoken truth is elegance enough.

I know exactly what you mean about that "blah phase", which, for money, came far too soon, while my Eze-Lap seemed to keep improving. The Eze-Lap's still cutting thirteen years after I retired the three DMT stones. It was cutting four years before I bought them, too. Besides still performing well, it just feels better than the DMT stones ever did. Those Atomas also don't have that cheap feel and they're nicely flat.

The chinese stone and the ezelaps stand head and shoulders above in use for metal.

I've been quite happy with the Chinese laps, although they're rotary for faceting rather than for hand sharpening—I do use them for gravers, though. As I recall, the only drawback you encountered was flatness. As I mount my laps onto my own flat substrates, I've not had this problem, either with PSA or without. These Chinese plated "toppers", both polycrystalline and monocrystalline, have performed admirably and cost a fraction of the American-made.

"imprecise sharpening and shorter life" for polycrystalline? Huh? Not in my experience. Even my chinese polycrystalline stones outlasted the DMTs and remain usable, and have been more pleasant to use the entire time.

This somehow disappoints me the most. There's really no need to advertise in this way. It's one thing to say "we make a great product and stand by it," and quite another to seed questionable or misleading claims about a competitor's product.

While such statements aren't on DMT's dmtsharp.com website, they are sprinkled on U.S. and U.K. DMT vendor sites*, intentionally nuanced as they are, and while not technically, wholly untrue, no matter how reputable the company is in other respects—in their products and customer service—I find trust issues stemming from such marketing practices. When a company makes a quality product such as the Dia-Flat™ Lapping Plate, such marketing is unbecoming. At the very least, it's a style I find discomforting.

*Two quotes:

U.S.

What separates DMT Diamond from other diamond surfaces?

DMT's competitors use a fragmented polycrystalline diamond structure that leads to imprecise sharpening and a shorter product life.

U.K.

Polycrystalline Diamond (Weak diamonds that easily fragment)

DMT competitors use Polycrystalline diamond; this fragmented compound easily breaks apart, quickly and easily wears away, and will, therefore, be easily ground down with minimal use. Some competitor’s claims of multiple layers of diamond only indicate poor quality diamonds that, again, will quickly wear out and need replacement.

[David Weaver]

DMT was quite successful pushing that line, though (the bit about the diamonds being superior) to the point that they showed up in just about every catalog and store. I bought three of them! If I knew what I know now after having various things, I'd have an atoma to flatten stones and ezelaps to hone tools, and none of the others. One each (400 grit atoma for medium and fine stones and a 600 grit ezelap) is pretty much an indefinite solution.

The chinese hones were about 4 thousandths out of flat along 8 inches of length. I didn't notice they were out of flat, concave on the 1000 grit side, until I lapped a new plane iron on one and couldn't make my normal enormous jump to a 1 micron shapton stone. They were certainly fine for honing bevels on tools, though, and they have that velvety zzzzzzzzzzzzzzzip that the eze lap does, even as they become very fine with a lot of use. I did manage to rip a diamond shape (they look like a copy of the stones with the diamond shape patterns on them) of the plating off of one after several years, though.

The only chinese item I haven't been super pleased with is the square nasty thing that harbor freight sells with four sides. I saw it on alibaba for $1-$2 depending on quantity, and got one on sale at HF for $9. It releases diamonds slowly into my finish stone, so that experiment ended quickly. How it would work as a small and very cheap hone is hard to tell because the shape makes it tip all over the place. I only wanted to try it as an option to refresh hard stones, as my need for a diamond lapping stone isn't so much a need for flattening as it is cleaning.

Ezelaps at $35 are a no brainer, though. That sort of killed the experimenting, which I was only curious about because people (rightly so) complain that the ideal solution for tools is a few expensive hard waterstones and a $80-$100 atoma to go along with them.