Joseph

[Joseph]

I had the same thought, but I have no problems going from 1000 diamond to Micro Fine Ceramic. The 1.4 micron stone seems more aggressive than the number would indicate. I personally use 800, 1000, Micro Fine Ceramic, then (sometimes) 5 micron and 3.5 micron diamond paste on balsa or leather strops.

I also have an older set of Super Fine Ceramic Stones, and have tried mixing those in. If those are used the progression might be 800, 1000, Micro Fine 1.4 micron, 1200 ceramic, 1600 ceramic, then Micro Fine 0.6 micron. I arrived at that just by tactile feel of the stones, don’t know if it’s optimal.

However it’s not clear to me whether the Super Fine stones are needed before the Micro Fine stones.

[Joseph]

Not only do I believe that the stones are mislabled, but if you look at this image (below), how COULD they be correct? The same side of one of the plates on one end says 800 and the other says 1000…

That is definitive. A side can only be one grit level. My 800/1000 stones are not split labeled like that, but the fact yours are indicates a possible wider problem. Maybe some are split labeled and some are just labeled wrong.

I’m OK with just using my 800/1000 stones in reverse order — provided it’s only a labeling issue. But if it’s a QC issue and the 1000-labeled stone is really not 800 grit but something else, then that requires different action.

[Joseph]

…Did you give what Tom suggested a try? As I mentioned, my 1000 grit stones “feel” coarser moving over the blade, but I think I have proved to myself that the scratch pattern is finer than the ones labled 800…

I first made a highly finished, mirror edge using 5 and 3.5 micron diamond paste and balsa strops. Sequence: 100, 200, 400, 600, 1000 (labeled), 800 (labeled), micro-fine ceramic 1.4 micron, micro-fine ceramic 0.6 micron, 5 micron diamond paste & balsa strops, 3.5 micron diamond paste & balsa strops.

I then went straight to 1000 grit diamond plates:

I then went to 800 grit diamond plates:

It still appears the 1000 grit plates are more coarse than the 800 grit plates. It can’t be the 1000 grit plates are *uncovering* prior scratches from previous coarser plates. I started with a highly finished bevel. Rather it appears the 1000 grit plates are simply more coarse than the 800 grit plates.

This is only logical: in every other grit sequence, the finer plate is smoother to touch *and* produces a smoother bevel than the coarser plate. But in this case the 1000 grit plate is coarser to touch than the 800 plate and produces a less finished bevel — even if starting from a mirror-finish bevel.

I guess it’s conceivable there’s some other explanation; if so I’d like to hear it.

[Joseph]

How did you hold it steady…it frustrates the hell out of me when trying to hold it in focus and steady while telling the PC to take a picture. I have tried a couple different kinds of stand, but no joy…

With the knife in the WE vise, I hold the microscope by hand and rest the transparent collar on the knife edge. The edge slightly bites into the collar, stabilizing it in two dimensions. Thus the only adjustments are tilt left/right and focus. As you tilt the microscope left and right, the lighting angle changes. At some point you observe the angle is optimum. This also reduces shaking and makes getting an in-focus shot easier.

My Dino-Lite microscope has a soft-touch “shutter” button on the microscope wand itself. I barely touch it to take a photo. If yours has a physical switch or requires pressing a keyboard button or on-screen button, that will be harder.

Of course you must be careful when doing this; you are looking at the screen while holding the microscope wand on the knife edge. However I think most WE users realize there are many ways to cut themselves. You naturally learn to stay alert and focused. E.g, you don’t rest a lot of pressure on the microscope, in case it slips off the edge.

[Joseph]

Yes,
Great photos..
…what you used to take them and especially what you did for lighting.
Phil

They were taken with a Dino-Lite AM411T USB microscope. It just plugs into a PC USB port and has its own software for image and video capture. There are many different models, some not very expensive. http://www.dino-lite.com/products_list_minute.php?product_number=AM411T%20Dino-Lite%20Pro

It has a ring of LEDs that surround the lens which provide primary illumination. Background illumination is just room lighting. The depth of field is very shallow, so anything in the background will be out of focus.

[Joseph]

OK I did photomicrographs of an S30V Ritter Mini-Griptilian after 100 strokes of new 800 grit and 1000 grit diamond stones; see below. It apparently confirms the previous photos, also the tactile feeling of the stones. 1000 grit is significantly more coarse than the 800 grit. There are several possible explanations, but the most obvious is the stones are mislabeled.

The stones are relatively new but not pristine — I’ve previously done about 10 knives on them. I don’t think continued break-in will alter the current behavior.

Progression (all mostly-new diamond stones): 100, 200, 400, 600, 800, 1000. After that I went back to 800. Whether stepping up from 800->1000 (as labeled) or down from 1000->800, the behavior is the same: 1000 is more coarse and produces a less finished bevel.

For now I’ll just use the 800/1000 diamond stones in reverse sequence.

1000 grit diamond:

800 grit diamond:

[Joseph]

Joema – can you get a microscope picture of your edge from the 800 and 1K diamonds? That would be more tangible proof to see if the numbers on the stone are consistent with the results.

That’s a great idea; unfortunately it will be a day or so before I can do that.

[Joseph]

Assuming this is a real problem and not a wild goose chase, I can just flip the stones over and use 1000 for 800 and vice versa. I have no problem with that. However this raises two scenarios about how it happened:

(1) It’s just a labeling problem and 800 and 1000 are actually at the expected grit but mislabeled.

(2) It’s labeled correctly but due to a QC problem what should be 800 and 1000 are not. IOW the unit-to-unit variation exceeds the labeled spec to such a degree it appears they are mislabeled.

Either way customers who have these might not know it, thus end up sharpening with the wrong grit.

Again, this assumes it’s a real problem, which is not yet determined.

[Joseph]

New 800 grit diamond stone, about 200x:

New 1000 grit diamond stone, about 200x:

New 800 grit diamond stone, about 200x, corner:

New 1000 grit diamond stone, about 200x, corner:

[Joseph]

Clay, I have a Dino-Lite AM-411T, unfortunately it doesn’t have a measurement feature.

The magnification of the first two photos is about 200x at the plane of the transparent nozzle, according to the mfg. The second two were slightly inside the microscope nozzle, so it’s probably a little higher, say 250x.

The new stones cut more aggressively, but I wasn’t comparing new vs old, but new 800 grit vs new 1000 grit.

If you look at my second two photos (the oblique angle shots) the 800 side looks smoother than the 1000 side. This corresponds with the tactile feel — the 800 side feels smoother than the 1000 side of the same brand new stone.

I realize this isn’t definitive, just wanted to see if anyone besides me and ThomasMeeks had observed it. I’ll try to get some better photos.

[Joseph]

Added oblique angle shots:

Label=800, color=light blue:

Label=1000, color=violet:

[Author]

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