a place to show or discuss your experimentation with sharpening devices, or techniques https://www.beyondt01micron.com/list.php?9 Sat, 15 Aug 2026 03:33:16 +0000 Phorum 5.2.23 https://www.beyondt01micron.com/read.php?9,1813,1813#msg-1813 https://www.beyondt01micron.com/read.php?9,1813,1813#msg-1813
Slicing is aggressive with a cool ripping sound.

I have long wondered what the edges look like...

Edge damage in the belly area from contact with dishes: [i.imgur.com]

The damaged area still slice-cuts (draw or push but mostly draw) food like meat, tomato skins, vegetables, pretty well at the table. They are now the first knives reached for during food prep unless long blades are needed.

Undamaged (lol) : [i.imgur.com]

The edge bevel is quite rough to touch, like a nail-file perhaps.

I might try a loaded leather belt on the grinder next, or maybe a finer grit for the edge bevel then the 36 grit for micro then strop.

For context, we have some very worn Cutco table knives and wood handled Henkels that still have serrations but are very thick at the edge. All our knives are piled in a drawer for dulling, and typically I have a bit of trouble figuring out which is the cutting edge on the small knives. I grind a thin edge on most of the chefs' knives at aroun 120 grit and steel them occasionally, and nightly use them as card scrapers on the cutting boards. In other words, our knives have rough lives!

My wife enjoys using a properly sharpened, thin-edge kitchen knife but says if we have to baby it then it's not worth it.]]> William Experiments Fri, 28 Feb 2025 16:07:21 +0000 https://www.beyondt01micron.com/read.php?9,1812,1812#msg-1812 https://www.beyondt01micron.com/read.php?9,1812,1812#msg-1812
Destressed edge: [i.imgur.com]

After 140 passes 22dps: [i.imgur.com]

Started shaving leg hair about 150 passes: [i.imgur.com]

Giving up at around 200 passes, alternating and crossing scratch pattern. I started adding force towards the end because I couldn't detect any changes on the last six sets and photos. Shaves leg hair well but will not catch anything above skin : [i.imgur.com]

I have had more aggressive edges from the Atoma 140 I think, but maybe there was more burr on the edge.]]> William Experiments Tue, 01 Jul 2025 18:16:17 +0000 https://www.beyondt01micron.com/read.php?9,1460,1460#msg-1460 https://www.beyondt01micron.com/read.php?9,1460,1460#msg-1460

Properties of the rock:

- Roughly 120mm by 90mm by 25mm. Slablike.

- Very hard.

- Waxy luster. The more rounded and worn parts of the surface look a bit like cold animal fat.

- Devoid of visible porosity/voids.

- Streaky and slightly translucent.

- Microcrystalline/cryptocrystalline (individual crystals are too small to be seen by eye).

- Based on observations above, principal mineral appears to be quartz. (See [www.quartzpage.de] to dive into a rabbit hole about quartz and its behavior.)

- Rock is presumably some kind of quartzite, though I am not certain.


Grinding:

- Done by hand.

- The substrate for grinding was a roughly 12 by 12 by 1.5 inch concrete paver tile (this cost about US$2 at a hardware store) resting on rubber coasters in a steel kitchen sink.

- The abrasive used was 80 grit loose SiC because it was what I had around. This breaks down into bluish toothpaste-like slurry very quickly, and cutting presumably slows down as it does so. I used a small spoonful at a time, rinsing the plate each time before replacing the grit. (This was based on speculation that mixing fresh grit with broken-down grit might cause the fresh grit to break down even faster, but it was only speculation. I don't know if rinsing made a difference.)

- Only one face was ground. The other face was left as found, smooth and flattish but uneven. Side surfaces were ground in places, and not in others, to clean the rock up a bit. Sharp edges of the ground face were chamfered.

- After grinding the rock is about 23mm thick. The usable sharpening area is about 80mm by 85mm.

- Weight of rock before grinding was 596g.

- Weight of rock after grinding is 580g.

- 16g of rock was ground away, consuming 62g of SiC abrasive grit.
(Note: I also used a SiC scythe stone to lightly chamfer the edges of the rock. The small amount of abrasive lost from the scythe stone is not included here, though any rock removed is included.)
(See Stamp's mention of "G ratio" here: [oldforum.beyondt01micron.com] . )


The ground face looks a lot like the rock in this image:
[en.wikipedia.org]
(Neither the image linked above nor the rock in the image are mine.)


Thoughts after the grinding process:

- This was even more work than it looked like ahead of time.

- Coarser grit would have been helpful.

- Less brittle grit would have been helpful. SiC grit breaks down very quickly.
(This has been noted by others.
Stefan Wolf mentions Soft Arkansas crushing SiC grit quickly here: [oldforum.beyondt01micron.com] .
Cliff Stamp mentions SiC grit being crushed quickly here: [oldforum.beyondt01micron.com] . )

- Rough-cutting the rock with a tile saw / rock saw ahead of time would have saved a great deal of grinding time and effort.

- An enterprising person could have salvaged the broken-down grit and saved it for other work. I did not.

- The concrete tile is slightly concave now. In the center, aggregate pieces are visible in cross-section. The aggregate pieces are very slightly proud of the surrounding cement surface, presumably due to their greater abrasion resistance.


The rock after grinding:

- The bottom (unground) surface is uneven, but is flat enough that if the rock is placed on a dishrag it is stable enough to be used as a small benchstone. I prefer to use it handheld.

- The surface texture is whatever was there at the end of the last round of grinding. I have not gone out of my way to condition it in any particular way. If my assumptions about the material (that it is low porosity cryptocrystalline quartz) are correct, then it should be possible to apply a variety of different finishes to the surface.

To the touch, the surface texture seems:

- much smoother than that of a piece of large-pored novaculite (sold as "soft" Arkansas) I have

- smoother than that of my Norton fine India (both the used side and the side I leave unused as a reference)

- just barely smoother than that of a piece of small-pored novaculite (also sold as "soft" Arkansas) I have

- similar to, or just barely coarser than, that of my DMT XF plate

But of course the superficial surface texture of a sharpening surface and the scratch pattern it produces on a given material are two different things.

At some point I should see what the scratch pattern created by this surface really is:

- Mirror polish a test blade edge bevel.

- Grind the edge bevel with the surface in question.

- Have a look at the scratch pattern under magnification.

- Repeat the process using other abrasive surfaces I have here.

I haven't done this, so I can't say much yet about the scratch pattern this rock produces.


Sharpening:

In both cases below, mineral oil was used as a lubricant.


Using this rock as a microbeveling surface, and after some screwing around, I was able to push-cut U-line catalog paper, which I had not been able to do before. So far so good.

- The knife was a Dexter Russell 5"x1" rectangular shop knife that I use for practice and experiments. Model X5X1S, SKU 60090, full-height flat grind, unknown steel.

- I do not remember the cutting direction or the distance from holding point.

- If having surfaces finer than Norton fine India around is going to make sharpening for push-cutting easier, I should probably obtain some commercial examples. (My DMT XF plate doesn't count, as there is just enough grit contamination that I avoid using it.)

- Yet I know that I should be able to use my usual microbeveling surface, a Norton fine India, to create push-cutting edges. I simply haven't yet. I should show some discipline and make it work.


I used this rock to apply a microbevel to a Benchmade Mini Griptilian (154CM).

- The edge bevel was prepared beforehand with a King 1000 (muddy waterstone). I forget what I used before that (for shaping), if anything.

- For utility purposes (mostly angled push-cutting of packaging) the resulting edge is at least as functional as the Norton fine India edge I have used in the past, and maybe better.

- How much of this is the rock and how much of this is simply me getting better at what I am doing is not clear. I suspect it is mostly the latter. I hope it is the latter.

- This rock will microbevel 154CM without any problem. Good to know.


Conclusions:

- It is possible to turn a rock found on the ground, if it is the right rock, into a usable sharpening surface using a minimal skillset and cheap equipment.

- It is possible for a person with moderate sharpening skill to use the above surface productively.

- This can be worthwhile for education and entertainment (and satisfaction). It is unlikely to save anyone money or time over a commercial product unless they happen to already have a suitable rock, a rock saw, and lapping materials on hand.]]> alkali Experiments Tue, 01 Jul 2025 18:23:54 +0000 https://www.beyondt01micron.com/read.php?9,1198,1198#msg-1198 https://www.beyondt01micron.com/read.php?9,1198,1198#msg-1198 jasonstone20 Experiments Sat, 03 Sep 2022 16:30:05 +0000 https://www.beyondt01micron.com/read.php?9,280,280#msg-280 https://www.beyondt01micron.com/read.php?9,280,280#msg-280




As a starting point on how to design an experiment that will yield statistically useful data and then how to do the analysis for that data..Primarily, what needs to be changed and done to convert AVE's experiment into something that could be published under peer review. This will be a series of posts, and the next one will come later in the week.]]> Older Spice Experiments Mon, 17 Feb 2025 15:04:40 +0000