Diamond Plate Questions

[silverlifter]

When I purchased my first natural stone a couple of years ago, I picked up a diamond plate (800) to lap it with. The plate has been used heavily since, on both naturals (including an Ark and a Charnley) and synthetics, and so should be well mellowed, or broken in.

It does, however, still leave prominent scratches on the face of naturals (hopefully visible in the shot below). This may just be my OCD, but I find it annoying. My real issue is related to that. I used it this week to create a slurry on a new, very hard, JNat and it left a couple of small chips on the edge of the razor mid-honing.

My question is, could it be possible that the hard JNat managed to dislodge a rogue piece of diamond or two from the substrate of the plate and contaminate the slurry?

Relatedly: should this plate still leave prominent scratches on natural stones after this time? Is it too aggressive? And would I be better off picking up a DIASharp like this one, or will I just end up in the same place?

 

[sbogill]

That looks like one of those old school Chefs Knives to Go plates. Not a bad plate for the money.

 

[Legion]

I've had cheaper diamond plates that have had raised "chunks" of diamond, for want of a better word. Or maybe clumps, that have sat proud from the face of the plate and caused scratches. And yes, it is possible for diamonds to break away and contaminate slurry, which is why some people don't like using them to make it.

Never had it on a DMT or Atoma, which I guess is the QC you pay extra for.

 

[silverlifter]

And yes, it is possible for diamonds to break away and contaminate slurry, which is why some people don't like using them to make it.

Thanks David. I don't have many options for nagura, so was hoping to use a diamond slurry at least early. I'll look at picking up the DIA Sharp.

 

[JPO]

If you just want a diamond plate to raise slurry, these small DMT plates does a good job.
I have not had any issues with diamonds getting loose after I have broken them in.

 

[Christian1212]

I just avoid using diamond stone for slurry. I would look at finding a tomo (or some asano nagura). I also like my edges more when the surface has been smoothed a tad bit from a nagura.

I personally never liked diamond slurry as a final tomo. I think some like it as the start of a touch up but not sure. I do like lapping my jnat after every 2 or 3 uses though - could see using the diamond plate to build slurry help keep wear even.

 

[H Brad Boonshaft]

Is that a dual grit diamond plate?

Apparently cross grit common with dual grit plates is common, not so much with single grits.

Try cleaning the plate with Barkeepers Friend, Oxalic acid. Make a paste and leave on for 10-15 minutes, scrub with a stiff brush, (fingernail brush). It will make a tired plate cut again.

If you have a high clump of diamonds, run a large kitchen knife on the surface and see if you can knock the clump or schmutz loose, you should be able to feel the grit and identify the spot.

 

[silverlifter]

I personally never liked diamond slurry as a final tomo. I think some like it as the start of a touch up but not sure. I do like lapping my jnat after every 2 or 3 uses though - could see using the diamond plate to build slurry help keep wear even

I like to go to a diamond slurry from the bevel set, and then after that finish with a mikawa slurry. Sometimes with a tomo in between. But essentially, using just the one stone.

Is that a dual grit diamond plate?

No, it is a single. I have previously used an old chisel to try and create a more uniform surface, I'll give it another shot.

 

[Frank Shaves]

A few months back, I replaced by cheap 400/1000 diamond plate with Atoma plates. Atoma plates are fantastic.

I have had zero problems using the red one of these to raise JNAT slurry.

 

[silverlifter]

A few months back, I replaced by cheap 400/1000 diamond plate with Atoma plates. Atoma plates are fantastic.

Thanks Frank. I've already pulled the trigger on the 8" DMT Fine.

 

[blade08]

I don't use a straight so not much to say about stones and all. I do know DMT stones a very good. I use them to sharpen pocket knives.

 

[captaincaed]

Before this thread gets too old and dead, wanted to share by experience with an EEF DMT.

I picked up the EF and EEF (1.2 and 8k) for bevel resets and then jumping up to naturals. I heard it worked for some. The EF is a peach, quick bevel reset, don’t need to worry about constantly flattening a bevel setter I have a feeling it’ll stick around.

The EEF was a different story. I’ll let the pics to the talking. Two from each plate. To answer the original questions, the size distribution can be wide, and dislodging diamonds is definitely possible. Not sure what happened in your case. But I can imagine a large diamond could carve a groove with a harsh lip into the stone. Even if you’re not kicking diamonds free, might be worth chilling the freshly cut surface out some other way.

 

[SliceOfLife]

Oh Ok, yeah they are definitely NOT breaking these in before selling anymore.

I'd do a heavy break-in on both. EF looks just as bad (to me) as the EE... but the fact it's more aggressive in general would make the rogue diamonds less noticeable/problematic I would assume.

I'd recommend a lot of break in on both of these. I wouldn't use a stone or abuse them, but spend a good 30 minutes at least, on each, just running a chisel or other broad tool on them; then take these pictures again and hopefully those oversized bits are gone.

If not, I don't think they can blame you for a return. If your mag is correctly reflected on my monitor (200x)... That one on the first pic is damn near 100 microns. That's absurd. That belongs in jewelry, not on a 3 micron plate.



I might consider doing it in some kind of a tub or pan fully submerged even. I'd be worried about the damage that diamond might do to the plate if it got caught under your tool.

 

[LJS]

That belongs in jewelry, not on a 3 micron plate.

 

[captaincaed]

Oh Ok, yeah they are definitely NOT breaking these in before selling anymore.

I'd do a heavy break-in on both. EF looks just as bad (to me) as the EE... but the fact it's more aggressive in general would make the rogue diamonds less noticeable/problematic I would assume.

I'd recommend a lot of break in on both of these. I wouldn't use a stone or abuse them, but spend a good 30 minutes at least, on each, just running a chisel or other broad tool on them; then take these pictures again and hopefully those oversized bits are gone.

If not, I don't think they can blame you for a return. If your mag is correctly reflected on my monitor (200x)... That one on the first pic is damn near 100 microns. That's absurd. That belongs in jewelry, not on a 3 micron plate.



I might consider doing it in some kind of a tub or pan fully submerged even. I'd be worried about the damage that diamond might do to the plate if it got caught under your tool.

Thanks for the sanity check. It’s 200x. Cheapo scope but still.

This is after 5” very lightly rubbing a soft ark nagura, then 5-10” on a kiridashi. I’ll try a little more. Gotta give it the college try.

I have a little more context in the “how to break in a DMT 8k” thread.

edit:never mind you saw it

 

[psfred]

I would not use a finishing stone after flattening with an 800 grit diamond plate until I had smoothed it quite a bit with another stone. Those deep scratches are an indication -- the surface is rough, and you really need a very smooth surface to hone razors. You can also embed a diamond that fractures off the plate into the stone. Both are less than ideal, and the later can chip edges.

Same issue with using loose grit by the way, errant grit can get into the stones even with careful washing -- I've scratched a few. Rough surface is a problem, particularly on hard stones. There is also the posibility of small bits of the stone coming free from deep scratches, with the same result.

I've flattened many stones with 60 grit silicon carbide loose grit, but unless the stone is intended for coarse grinding (soft Ark, King Deluxe 300) it will get finished with something else to smooth it before use.

 

[SliceOfLife]

It is pretty telling with why so many folks have struggled with these plates. To my memory:

When I bought mine, over a decade ago... DMT claimed they were broken in @ the factory, but said something to the effect of (from memory): "While no breakin is needed, as it is done at the factory, new users may see the plate lose some aggressiveness over the first few uses and seemingly become finer... this is normal" ... Maybe I'm dreaming that up, but I remember that being roughly the old wording of the FAQ.

Some folks reported even back then that they definitely DID still need a breakin.

So on arrival, I started with knives/etc to try and break in... but quickly realized mine didn't need it. It was so smooth in fact, it was hard to tell the correct side to use. Both sides felt virtually identical under most tools. So definitely no sense of big diamonds or the tools catching.

It looks like now the wording of the FAQ indicates a breakin definitely IS necessary. So it would appear that the plates are shipping out with far less consistency across the surface... whether that's from a lack of break-in, general reduction in quality, or a change in process, or something else: I can't be sure.

Very curious how your plate comes out once you've finished breaking it in.

 

[Gamma]

When I purchased my first natural stone a couple of years ago, I picked up a diamond plate (800) to lap it with. The plate has been used heavily since, on both naturals (including an Ark and a Charnley) and synthetics, and so should be well mellowed, or broken in.

It does, however, still leave prominent scratches on the face of naturals (hopefully visible in the shot below). This may just be my OCD, but I find it annoying. My real issue is related to that. I used it this week to create a slurry on a new, very hard, JNat and it left a couple of small chips on the edge of the razor mid-honing.

Scratches seen at the ends of a stone often mean the ends of the stone are still not in line with the rest of the working surface. The diamonds will ride that area and leave marks always. When I lap stones I carefully loupe the end edges to look for those striations. Once I achieve better flat-ness those marks subside.

My question is, could it be possible that the hard JNat managed to dislodge a rogue piece of diamond or two from the substrate of the plate and contaminate the slurry?

Possible, yes. Does not look that way though, it's too even. But diamonds winding up in slurry will happen periodically with cheaper plates. More than likely that Jnat just needs more flattening.

Relatedly: should this plate still leave prominent scratches on natural stones after this time? Is it too aggressive? And would I be better off picking up a DIASharp like this one, or will I just end up in the same place?

Harder stones (jnats, Arks, some slates, etc) show fine scratches from diamond plates more easily. As long as the scratches aren't felt when dragging a pin over them they're fine. Visually annoying as they are, I sometimes dress the surface down with 600x w/d to make them go away. Sometimes a good slurry session clears it too.
I lap just about everything with a 400x Atoma and I'm always good to go off that plate. The 'grit rating' on cheaper plates usually doesn't correspond to the ratings of Atoma or DMT so if yours was sold as 800x it may be, actually, significantly less fine, comparitively. I use a 400x to finish lap, used to use a DMT 325x. I usually never polish lap past 600x.

 

[SliceOfLife]

I mainly use a cheap 160x these days. I'm more concerned with getting things flat without breaking my back than leaving a clean surface. Can always easily clean up the surface. The hard work is flattening.


If I was still collecting stones as fast as I used to... a giant 13x8 or whatever flattening plate might make sense... mainly because I'd rather not use SIC powder unless I have to. With how often I buy stones though; the 160 is fine.

 

[captaincaed]

Very curious how your plate comes out once you've finished breaking it in.

I wrote dmt with my pictures. I may try more break in or return if I don't hear. The edges of the plate were curled up too. I broke those down so it's better, but still not dead flat.