Diamond sharpening plates

Re: Diamond sharpening plates

Patrick Chase

As one of the (only) advocates/practitioners of diamond sharpening on this forum, I'm curious to know why you're headed that direction, and why plates in particular?

I use compounds and lapping films for speed when doing major work such as back-flattening, and for when I want the sharpest possible edge in a steel with nontrivial carbides. I don't use plates to work steel, because IMO they don't offer a competitive speed-vs-refinement tradeoff for that (in other words you can get either higher speed, a smoother surface, or both from films/compounds). I do use plates quite a bit for flattening waterstones, though.

FWIW I've tried all of the plates you list, and landed solidly on Atoma. They're not perfect, but they're the flattest (at least until stuff gets in between the plate and the Aluminum blank) and most uniform-cutting of all of the metal-bonded plates. They're also as long-lasting as any of the others. The Shapton resin-bonded plates are better in both respects, but don't last very long when confronted with steel. The Shaptons basically built like a super-expensive sheet of lapping film.

Re: Diamond sharpening plates

Bridger

I use diamond plates extensively for sharpening steel. I don't generally finish on them unless it's an edge that doesn't need refinement or will just be abused anyway, but for bevel shaping and the like diamond works well for me.

Re: Diamond sharpening plates

david weaver

Bill, I think your money is better spent (if the issue is coarse work) on a piece of glass about three feet long and a roll of PSA paper ("porter cable" paper on amazon is a decent choice, in 80 or 100 grit).

Using diamonds to grind is like paying Mercedes price for a rebadged cavalier. There's certain things diamonds are good for (honing steel with hard carbides, etc), but grinding isn't really one of them. They are slow for the depth of groove that they leave, and their wear rate can be sensitive to things like laminated steel.

If you're just honing, Ezelap 8x3 600 grit and 1 micron loose diamonds. I love the atoma hones, but don't much love the way they feel honing.

Actually... *LINK*

Bill Houghton, Sebastopol, CA

There have been extensive discussions of sharpening with diamonds here in past years; not so much of late. Bill Tindall and Phil Smith summarized some of their research in an article some years back, see link.


In the articles section

Re: Actually... *LINK*

David Bassett

You triggered the memory of Joel @TFWW writing about diamond sharpening on his blog:


Sharpening with Diamonds

Atoma

Bill Houghton, Sebastopol, CA

Thanks for your recommendation. The photos of Atoma stones that I've seen appear to show spacing something like rasp teeth. How do you avoid an edge with a series of parallel scratches with an Atoma stone?

Re: Actually...

Patrick Chase

Yep, I actually tried Acrylic as a sacrificial/disposable substrate for coarse diamonds after reading their posts and articles. There's a wealth of knowledge here for anybody who takes the time to look.

I meant that I'm one of the few currently active diamond advocates :-)

Re: Atoma

david weaver

Bill - you won't be able to control the travel of the tool neatly enough for that to be an issue, but you will feel the rows. They're so neatly arranged that the effect of machine rasp vs. hand cut is sort of there - they feel like you're honing on a zipper.

That said, the Atomas are probably more uniform in their scratches (not just the arrangement of the diamonds, but the size of the scratches they leave) than any other reasonably priced hone, so that kind of thing might be attractive.

I've never used an atoma finer than 400, and can't comment on their fitness for honing.

I believe Bill Tindall's regimen was a 600 EZE lap broken in and 1 micron diamonds, and it is a good one. The EZE-laps have a few snaggletooth diamonds on them when you first get them, but they get pulled loose soon enough. The fact that you're using only one loose diamond grit in a setup like that eliminates contamination problems that you can have if you use multiple sizes of loose diamonds (which can be a real pain if you're not intent on being really fussy with your sharpening area).

600 EZE laps are a bit coarse at first, but the next step up (1200) is too fine and slow once it's broken in. A broken in 600 eze-lap will work speed-wise more like a 1000 grit waterstone (ballparking it), and 1 micron diamonds are really fast, and can pick up from that point very well, but still make a fine edge that doesn't have much of an organized wire edge unless a substrate is rough and is roughing up the edge (it won't be the diamonds doing it, but milled substrates can be harsh on an edge until they're broken in).

Re: Atoma

Patrick Chase

Those "teeth" are actually flat cylindrical projections, each with many individual diamonds lined up in the same plane. It's therefore an "interrupted flat" surface rather than a toothed" surface.

The theory is that the gaps between those cylinders channel away swarf and lubricant, which is a very common design approach in diamond abrasives. Because the edges of the cylinders don't "cut" they don't leave marks as a rasp would.

Some other examples of the same basic approach:

DMT DuoSharp: https://www.dmtsharp.com/sharpeners/bench-stones/duosharp/

3M Flexible Diamond Tape: https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Flexible-Diamond-Hand-File-6210J/?N=5002385+3293082566&rt=rud

Diaface Moonflex files (popular with ski tuners): https://www.amazon.com/Diaface-Moonflex-Diamond-Stone-70/dp/B01N8V1NGV

Re: Atoma

Bruce, a MN Galoot

Bill did start with a worn out Eze Lap plate but later moved to a surface-ground cast iron plate. I use the same thing, a chunk of cast iron from an access panel of a discarded 5,000 HP diesel engine.

Re: Atoma

Patrick Chase

That does the trick.

I went the expensive route and picked up a few made-for-purpose cast iron laps from McMaster. By the time you've lapped the lap a few times there's no practical difference.

Re: Diamond sharpening plates

John Walkowiak

Hello, for what it's worth, I have been using the large DMT diamond plates for over a decade for my (many) edge tools. I don't have room for a dedicated sharpening bench and really don't want to spend any more time than necessary to get the tools back to work. I use an 8" slow speed grinder when that is necessary and always use the 8,000 grit plate and strop to finish. Once you get past the initial price they work as well as anything I ever tried, don't need flattening, don't create much of a mess, are fast and last for years and years. As an endorsement from a professional, the carver Mary May uses the 8,000 grit before stropping on her carving chisels. When I read that after the 8,000 grit was introduced I stopped looking for something better. It seemed to me if the diamond plates get her carving chisels sharp enough to work for her, they are certainly sharp enough for me!

Re: Atoma

Bruce, a MN Galoot

I had access to a mill and a power hacksaw at work, and the local tech college has an excellent machinist program. They surface ground both sides at no cost. I also have one chunk of iron that started life as a cast iron bathtub. It works just as well, just 5/16” thick.

Re: Diamond sharpening plates

Bruce, a MN Galoot

Bill, I hone with 3 and 1 micron paste. For flattening stuff, I use 15. Bill T recommended 30 micron for flattening. But unless you’re going to dedicate a plate just for that purpose, I wouldn’t recommend that route. The chance of cross contamination is pretty high, and those big diamonds would be hard to get out. Having said that, you sure can tell when you’re working with a grit that coarse.

I’d suggest following David’s recommendation for s strip of sandpaper on glass. I just acquired a roll of PSA 120 paper. I’ll send you some.

Re: Diamond sharpening plates

roger lance

Bill....my sharpening approach has been evolving and I currently have three levels of working on an edge.....

1.) For really out of flat blades, I have a granite plate to which sandpaper can be

attached.....80 or 100 grit.....rough work but a lot of metal can be removed.

2.) For those minor nicks you mentioned, I have some DMT DiaSharp steel plates.

220, 325, and 600 grit diamond plates that seem to work well at this type of

task.

3.) Then, its on to water stones.....Stu's Sigmas.....1200, 6000, and 13000 grit.

Re: Diamond sharpening plates

david weaver

that sounds like a good setup as long as the hone that you get is flat (IIRC, only the plastic duos and the atomas have a relatively spotless history for flatness).

Of course, for carving tools, it doesn't really matter if the diamond hone is perfectly flat. For working the back of a double iron, it might.

I'm sure the sharpness level is good, though - the hasluck text suggests that washita followed by emery is fine, and one would expect that the 3 micron diamond hones are as fine as that and easily followed by compound.