Synthetic polycrystalline diamond paste — cheap and otherwise

[David Barnett]

A couple people have asked me where to find friable synthetic diamond paste. Although you can purchase highly graded polycrystalline diamond from metallographic suppliers such as Pace Technologies' Diamat PC paste (http://www.metallographic.com/Consumables/Diamond-paste.htm)—there is none better—though 5g of 1µ will set you back $37, whereas Professional Gem Tools, Inc. (http://www.palagems.com/pgt_contact_us.htm), through Pala International makes it easy and more affordable, offering both compound (paste) and powder (loose grit) for as low a price as you're likely to find for a premium product—$18 for a 5g syringe—and they'll gladly accept orders for just one syringe at a time.

LapidaryPro High Grade Friable Diamond Compound (http://www.palagems.com/pgt_diamond.htm)

0.125µ__200,000 grit
0.25µ___100,000 grit
0.5µ_____60,000 grit
1µ_______14,000 grit
3µ________8,000 grit
6µ________3,000 grit

Each 5g syringe is $18.00

So much for the higher priced spread. A still cheaper option may appeal to some. While I require painfully tight grading for polishing faceted gems, for sharpening I'm not so pernickety (that's right, not persnickety) and will accept a few outliers, especially when skewed to the smaller than nominal micron end of the curve, which brings me to THK diamond paste.

THK (Treasure Hong Kong) (http://www.thk.hk/) offers direct online sales (http://www.thk.hk/products.php?cid=4) through their website and through eBay (http://stores.ebay.com/THK-Diamond-Tools), as well. I had heard THK's pastes were polycrystalline, had seen a rather disquieting YouTube video (http://www.youtube.com/watch?v=RL35ozvtbqs) where this was stated in the comments* and so wrote to Teddy Lau of THK to confirm if this was so. Mr. Lau wrote back yesterday morning, assuring me that his pastes were indeed formulated with polycrystalline diamond sands while monocrystalline diamond was used for his vacuum brazed industrial products.

While I've not tried THK's diamond lapping compound—I do intend to, of course—I thought I'd pass it along to any adventurous and frugal souls who might wish to trailblaze while I endeavor to overcome my procrastinative sloth (a trait—not an unmotivated arboreal pet). Until I've actually tried the THK product I can't vouch for it, obviously, but there you have it. I can say I've found a kilo of remaindered coarser polycrystalline diamond grit for just over $100 recently, so I would suppose such pricing for PCD compound is imaginable.

What you get:

7 syringes, 5g each (http://www.thk.hk/onlinestore_details.php?id=409)

0.25 Micron - Final Polish (Light Grey)
0.5 Micron - Final Polish (Rose)
1.0 Micron - Mirror finish (Light yellow)
1.5 Micron - Mirror finish (Dark yellow)
2.5 Micron - Mirror finish (Pink)
3.5 Micron - Fine Polish (Red)
5.0 Micron - Fine Polish (Blue)

PRICE:
USD 10.00

SHIPPING:
USD 4.00

SHIPPING DETAILS:
Regular Air postage with handling from Hong Kong to worldwide is US$4.00 and takes 7-10 days delivery to your home.

13 syringes, 5g each (http://www.thk.hk/onlinestore_details.php?id=134)

0.25 Micron - Final Polish (Light Grey)
0.5 Micron - Final Polish (Rose)
1.0 Micron - Mirror finish (Light yellow)
1.5 Micron - Mirror finish (Dark yellow)
2.5 Micron - Mirror finish (Pink)
3.5 Micron - Fine Polish (Red)
5.0 Micron - Fine Polish (Blue)
7.0 Micron - Pre Polish, fine lapping (Purple)
10 Micron - Lapping metals (Grey)
14 Micron - Stock Removal or lapping metals (Brown)
20 Micron - Stock Removal or lapping metals (Rust)
28 Micron - Medium fast lapping (Green)
40 Micron - Fast lapping or stock removal carbide (Black)

PRICE:
USD 20.00

SHIPPING:
USD 5.00

SHIPPING DETAILS:
Regular Air postage with handling from Hong Kong to worldwide is US$5.00 and takes 7-10 days delivery to your home.

Personally, for sharpening chisels and plane blades I really only use 1µ paste, for carving tools I sometimes will use submicron pastes, so buying all the grits isn't my best option and I do find the micron increments too gradual and compressed for my use. However, Teddy Lau says you can choose any combination of grits to make up your 7 or 13 syringes—you can have 7 of 1µ if that's what you want**—so it'd be pretty hard to not to come out where you want to be.

Anyway, these approximate diamond micron to grit equivalents give a sense of the range.

0.25µ_100,000 grit
0.5µ___50,000 to 60,000 grit
1µ_____14,000 grit
3µ______8,000 grit
6µ______3,000 grit
15µ_____1,200 grit
30µ_______600 grit
40µ_______400 grit

So, while I mix my own high-concentration diamond compound and really don't need any, I'll have to try these THK compounds just to see if they're the ultimate bargain in diamond pastes, even should they turn out not to be polycrystalline. I will say I've been terribly happy with my remarkably inexpensive Asian faceting laps and gem saw blades, and quite satisfied with the Asian monocrystalline products. If anyone beats me to the punch on this, do let us know what you think.


*"There had been a number of complaints/concerns brought up by users who purchased the THK branded polycrystalline diamond compound from Hong Kong regarding it being too viscous, waxy, clingy, etc." which turned out not to be the case for the YouTube reviewer, by the way, subjective though it is.

**From the THK website: "Please let us know if you are looking for any combination." From eBay: "We are pleasure to send different assortment. For examples, you can choose 7 pieces of 0.25 micron. Please remind us when you settle the payment by Paypal (write PAYPAL message)." The same goes for the set of 13.

[Dave Cav]

At these prices I may have to give diamond paste a try. Would MDF be an appropriate substrate, or something harder?

OK, I just read a few old threads and it looks like most folks are using MDF or hardwood plywood.

[Kurt Cady]

About How long would one 5g syringe last?

[David Barnett]

At these prices I may have to give diamond paste a try. Would MDF be an appropriate substrate, or something harder?

While MDF will work it was mostly used because it was for the most part already flat, as was plywood with smooth birch or maple outer veneers. An article in FWW years ago declared solid hard maple a better substrate than MDF whereas these days balsa is favored by both the straight razor and food prep communities.

As far as hardwoods go, the substrate considered the best diamond carrier among gem carvers is pink ivory, I kid you not*, but really, I'd say for the 1µ to submicron diamond I favor for woodworking tools, carving gouges and gravers, any flat hard surface will serve. While I mostly use cast iron, others use acrylic, Corian, paper phenolic, copper, certain ceramics, horse butt and so on. If I ever met a hard cheese I didn't like, I'd likely try that, too.

But yes, MDF will get you started. Takes a bit more paste to initially charge and bring it to equilibrium, but it'll get you through 1µ.

____________________________

*In a 2004 issue of Lapidary Journal, Derek Levin rates woods (http://gemmaker.com/extras/WoodenCarvingTools.html) suitable for charging with diamond for rotary handpiece or fixed arbor gem carving and polishing points (burrs), and has this to say:

"Pink Ivory — a wood from Africa, is Henry Hunt’s #1 choice. It’s a beautiful dark pink wood with many worthy characteristics which I’ve enjoyed having, although it is quite hard, rare and expensive. It shapes easily and holds diamond compound very well, whether the diamond is in an oil or a wax base. It also holds its shape well, and is especially useful with sharp edges for those straight line indentations."

Other worthwhile hardwoods include boxwood, ivorywood, briar and holly. There are others, of course, and I've tried quite a few. I make my points from buxus and pink ivory, mostly, and I have two excellent PI strops.

[David Barnett]

About How long would one 5g syringe last?

Years for woodworking tools. especially on cast iron. Once a lap is well charged, the amount needed to refresh it is downright picayune. I have a syringe of ½µ (60,000 grit) diamond in my woodshop that I bought in 2000. There's at least a couple more years left in it. People have a tendency to use way too much and it can be hard to disabuse them of the habit. Coarser grits do go faster than finer, but for anything 3µ (8,000 grit) and smaller, it's trivial. That said, at $2 and less per 5g syringe, it's about the cheapest sharpening consumable going, so feel entirely free to slather it on.

[David Weaver]

Another excellent line of posts, David, with satisfying detail and delivery. It should be archived. Thorough answers to any of the sharpening questions should be, as we seem to get the same ones over and over.

[Chris Hachet]

Another excellent line of posts, David, with satisfying detail and delivery. It should be archived. Thorough answers to any of the sharpening questions should be, as we seem to get the same ones over and over.
Yes, please archive this. I am not ready to buy this yet, I have been using Diamond stones and Oil stones and just bought my first water stones yesterday. I want to get used to trying water stones before I try diamond. And thanks to David B for the link...I am learning more here at the creek every day!

[Jessica Pierce-LaRose]

Any comments on diamond for sharpening profiled edge tools? I'm thinking gouges and molding plane irons (particularly hollows), and more curious about slight restoring over final honing.

While on the few profiled tools I have I keep the edge working order with a strop, I feel like eventually it's goings to need something more. I can probably rig together something for grinding with the tools that I have, if I pick up something used that needs a lot of attention, but part of what's held me back from getting more tools of this sort has been not having any slip stones, and not being terribly thrilled with using sandpaper on shaped substrates - it seems to me that shaping something and applying diamond seems less expensive than picking up slip stones for those medium steps between grinding and stropping.

It makes me wonder though about how to choose something that's easily shaped for use a substrate yet would hold it's shape enough in use.

[David Weaver]

Hard maple is cheap and makes decent shaped slips with compound, etc.

one or two pieces of profiled hard leather wheels work well, too, and you can make those or buy them (feeding something to them always has the chance of launching, though).

[David Barnett]

Hard maple is cheap and makes decent shaped slips with compound, etc.

I have so many carving tools and so many shaped strops I've started storing them with the tool/gouge for which they're intended. I have trays instead of racks so this is doable and often the tool rests on its dedicated strop. Miniature chisels, gouges, and knives I store in smaller boxes with their strops. It's the only way I can keep up with all the blocks, half-cones, sanding sticks, dowels and whatever else I once made and forgot about. Not every tool has its own strop of course.

Anyway, I now only have two tool rolls and those hold stonecarving and lettercutting chisels apt to get used on the lanai. I leave a box of honing materials in one of the lanai closets.

While maple's my mainstay for hand carving tools, the larger gouges and allongees get horse butt for both diamond and oxides. So many substrates work for diamond paste, loose grit, sprays, though—wood, acrylic, polycarb, nylatron, vinyls, leathers, felts, fibers, woven goods, hard machinable microcrystalline waxes, zinc, copper, cast iron, thermoplastic resins, ceramics—just to name a few. And for metals, they can be scraped, frosted, smooth, roll printed, scored, mezzotint rocked, sanded and so on. There's even clay—or rather plastiline, if you don't want to shape all those slips and strops.

Take a slice of firm plastiline (I like the sulphur-bearing extra-hard Roma Plastilina (http://www.sculpturehouse.com/p-58-roma-plastilina-white-no-4-extra-hard-2-lbs.aspx)), work in a whole lot of loose diamond grit, press it to fit a particular gouge's sweep and it will work very nicely until pressed to fit another tool or an otherwise contoured metal for cleaning or polishing. Tweak it with oils and waxes to soften its consistency or add kaolin to stiffen. It's great for cleaning and polishing metals and other hard surfaces, too. Years ago I actually thought about selling the stuff. Turns black really fast.


One or two pieces of profiled hard leather wheels work well, too, and you can make those or buy them (feeding something to them always has the chance of launching, though).

Wheels—felt, paper, other fibers, leather, wood, whatever—and ensuing excitement is another post altogether.

[David Barnett]

It makes me wonder though about how to choose something that's easily shaped for use a substrate yet would hold it's shape enough in use.

Joshua, I've made shaped diamond-carrying substrates of various kinds, such as thin copper over wood, machinable and castable microcrystalline waxes, other casting RT resins and thermosetting resins, such as Jett-Set (http://www.contenti.com/products/stone-setting/510-620.html). All work, of course, so it comes down to practice and preference. The resins generally work better with a layer of loose diamond affixed by the setting resin or other coatings, whereas the wood, metal or fiber products perform better with pastes.

[Jim Koepke]

Yes, please archive this.

At the bottom of the page is a very useful tool:

266033

This allows people to insert search terms to find a thread in the future.

I find it quite handy.

jtk

[Jim Neeley]

Has any one tried the DMT Wave diamond sharpeners for profiled tools? The widly ranging radii available looked like it might be a good tool.


If nothing else, perhaps a choice to re-charge with diamond paste?

I have yet to venture far down the path of sharpening profiled tools (or own that many either) for this very reason.

Advice and experience appreciated.

Jim in Anchorage

[David Barnett]

Another excellent line of posts, David, with satisfying detail and delivery. It should be archived. Thorough answers to any of the sharpening questions should be, as we seem to get the same ones over and over.

Of course, as I was simply offering sources for friable diamond paste, I didn't state my reasons for preferring friable and polycrystalline synthetic diamond over monocrystalline for most sharpening in the woodshop. My main reasons, as you know, are twofold:

Firstly, each polycrystalline diamond particle has many more cutting points than monocrystalline diamond, leaving shallower troughs in the metal being sharpened, cutting faster, embedding securely in substrates and presenting fresh cutting points, as, unlike monocrystalline diamond's adverse cracking and splintering, polycrystalline diamond, having no cleavage planes, fractures far more advantageously.

Secondly, due to its friability, it continues to cut longer and more consistently than fractured monocrystalline diamond*, progressively cutting ever more smoothly, linearly easing and blending the scratch pattern into a refined result or transitioning to subsequent abrasive media should that be required.

I like that I can get to a desired surface refinement endpoint, an optimal degree of polish on a tool edge, with fewer grits, hence fewer steps and do so with acceptable rapidity.

Although polycrystalline diamond is usually, initially more expensive than monocrystalline per weight—never mind what is erroneously stated in some woodworking product descriptions—it amortizes favorably in the amount required on a given substrate once charging has reached a point of sufficiency and equilibrium.

Compared with monocrystalline consumables, depending upon the application, substrates and amounts required to achieve a target surface refinement, polycrystalline may be more cost effective than monocrystalline, but not always, and must be determined through actual use.

For rapid and frequent refreshing of grit and very specific scratch pattern uniformities, monocrystalline diamond may be preferred. The exceptional crystal size and shape uniformities, highly-aligned distribution of monocrystalline 3M diamond lapping films, such as those sold by Lee Valley (http://www.leevalley.com/US/wood/page.aspx?p=68943&cat=1,43072), are an excellent example of how these features can be exploited.

So while I prefer friable polycrystalline diamond for many sharpening and polishing applications, monocrystalline diamond does much of the grunt work to get to the point where polycrystalline's best advantages are realized. For example, I'd generally choose monocrystalline diamond for rough lapping such as flattening chisel and plane blade backs on exceptionally tough, hard tool steels, as CBN is more expensive and silicon carbide would break down too quickly.

I'd likely lap backs to 30µ (600 grit), or maybe even 15µ (1,200 grit) or perhaps all the way to 6µ (3,000 grit), depending on the tool, before switching to polycrystalline for a bit of polish. For day-to-day chisel and plane sharpening, though, I mostly go from a 7" bench grinder to the 600 grit Eze-Lap, hopping to 1µ (14,000 grit) polycrystalline paste on cast iron, sometimes finishing with a ½µ diamond or oxide charged strop. Thing is, when the last charge of 1µ poly's settled in on the cast iron, I don't notice a lot of refinement beyond that unless I'm stropping carving tools with very low, thin bevels

Anyway, I guess I'm thinking my poly post isn't really robust enough to archive without mono content, but what do I know? At least those who want to try polycrystalline paste can get their hands on some (or vice versa) for not a lot of spondulicks.

*Why so many monocrystalline electroplated sharpening products give up the ghost fairly early and rapidly.

[David Barnett]

Has any one tried the DMT Wave diamond sharpeners for profiled tools? The widly ranging radii available looked like it might be a good tool.

Advice and experience appreciated.

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.

[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 (http://bladetest.infillplane.com/index.html), Bill Tindall (http://www.woodcentral.com/woodworking/forum/archives_handtools.pl/bid/3106/page/1/md/read/id/89166/sbj/status-of-loose-diamond-sharpening/) 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 (http://www.hocktools.com/perfectedge.htm), 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 (http://www.popularwoodworking.com/woodworking-blogs/chris-schwarz-blog/book-review-the-perfect-edge-by-ron-hock).

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




From DMT vendor literature (http://www.sharpeningsupplies.com/Why-Use-DMT-Diamond-Sharpeners-W15C117.aspx):

"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 (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."

And here's a worthwhile technical promotion from another producer of both polycrystalline and monocrystalline diamond products, Pace Technologies (http://www.metallographic.com/Newsletters/PC-diamond-newsletter3.PDF).

So which costs more? (http://www.metallographic.com/Consumables/Diamond-paste.htm)

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

So which costs more? (http://www.microdiamant.com/products/diamond-powder/monocrystalline-diamond-mono-eco/)

"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 (http://www.right-tool.com/ezcreatbeted.html):

"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 (http://www.dmtsharp.com/), 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 (http://www.popularwoodworking.com/woodworking-blogs/chris-schwarz-blog/dmts-dia-flat-takes-a-crazy-beating), such marketing is unbecoming. At the very least, it's a style I find discomforting.

*Two quotes:

U.S. (http://www.sharpeningsupplies.com/Why-Use-DMT-Diamond-Sharpeners-W15C117.aspx)

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. (http://www.sharkdesigns.co.uk/bushcraft/bushcraft_articles_and_advice/SHARPENING/dmt_sharpening_system.html)

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.