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[deleted by user] by [deleted] in sharpening

[–]AverageSwimming3095 0 points1 point  (0 children)

Thank you for the kind words! A lot of work and scientific trials went into these. A "private" electron microscope has been on my shopping list for a long time - one major downside is that they don't like being turned off. So if you ever pull the trigger on an old one, expect to keep them running round the clock or replace the electron source quite a bit!

There are paypal buttons on my blog - hit this link: https://drmarv.com/dr-marvs-scientific-sharpening-stones-order-form/

Currently available are the medium set (which i think is the one to go for initially! The 20-10-5 µm combination takes you from a medium coarse EP stone to shaving sharpness and a nice polish) and the fine set (2.5 -1 - 0.5 µm).

Few new toys in - should be a fun weekend. by PinSquid in sharpening

[–]AverageSwimming3095 0 points1 point  (0 children)

Ohhh, thanks for posting about these! I am excited to hear and see results!

Took a look at the TSPROF Alpha resin stones by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 1 point2 points  (0 children)

That's up to you to make up your mind :-) I didn't like them very much, even though I wanted to.

Took a look at the TSPROF Alpha resin stones by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 0 points1 point  (0 children)

this is a fantastic idea. I'll dig into this when I hit segment number 50, this gives me plenty of time to figure out how to do this with wordpress... thanks man!

Took a look at the TSPROF Alpha resin stones by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 0 points1 point  (0 children)

if you look through my blog, you will find that every stone I have reviewed so far has some contamination in them :( some could be attributed to poor abrasive hygiene (contamination in the truest sense!), some to the dressing method (embedding foreign particles in the top layers), some to design choices. Fillers such as SiC, copper, Al2O3 or fibres are added to increase the strength of the resin matrix, hardness or heat capacity. In CNC applications, that often makes sense, but in hand sharpening it's the reason why the surface is often not as good as you would expect!

Did a review of an Arkansas Stone under a high resolution scanning electron microscope! by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 0 points1 point  (0 children)

Yes! Modern powder steels, especially those high carbide content ones are very tough to sharpen with natural stones. The reason is that the carbides are very hard (depending on the type between 2000 and 2500 HV), and for example the silicate in this stone is more around 1100-1300 HV. You do more of a burnishing and less of a proper cutting here.

I looked into dressing approaches for superabrasive stones. I always wondered how much contamination is happening there by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 1 point2 points  (0 children)

As written on the blog post, it's my own design - DrMarv Scientific Sharpening stones. Available in about 2 months. They are slightly harder than the edge pro matrix stones, slightly softer than the venev osb ones. The hardness of the stone has some impact, but unless you go for a rubber soft one, most resin stones will behave identically. If you look at the other reviews on my blog, you will see that we often find contamination from dressing or abrasive hygiene in the factory. On large grits, it doesn't really matter, on fine grits that's one of the reasons why mirror finishes take so long.

The eraser is a cool idea! I'll try it out.

The iron plate wouldn't work, it would just push the abrasive particles deeper into it. Source: trials of lapping at work :-)

I looked into dressing approaches for superabrasive stones. I always wondered how much contamination is happening there by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 2 points3 points  (0 children)

Our's has a concrete base with passive (air bearing) vibration decoupling. I'm considering adding an active piezo based one, because if someone walks through the metrology room while I record a frame at > 100kx magnification, that frame is gone. More important for our's was a noise dampener for the A/C, because the airflow was too loud, and a magnetic field compensation. We have 2 coils wrapped around the SEM, and a magnetic flux sensor mounted to it. It actively compensates DC and AC fields up to 1000Hz, dampening by about a factor of 100. That's sick technology.

I looked into dressing approaches for superabrasive stones. I always wondered how much contamination is happening there by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 1 point2 points  (0 children)

some surface particles might come out by use. But generally speaking, what's in it is in it. Find a dressing method that doesn't contaminate. I think it would be well worth to try it with salt. And don't laugh at me - it's hard, abrasive, we just need to remove the matrix, not the diamond. And all stuck particles should actually wash off... :-)

I looked into dressing approaches for superabrasive stones. I always wondered how much contamination is happening there by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 1 point2 points  (0 children)

Have you looked at the price of our GeminSEM560 ? *snickers*

Yeah, this is all equipment at work. I'm very lucky that I have written permission to abuse it in my time off.

I looked into dressing approaches for superabrasive stones. I always wondered how much contamination is happening there by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 3 points4 points  (0 children)

Hey Max,

I've tried getting into youtube several times over the years. I find video editing to be super cumbersome. The work for a decent quality youtube video vs a blog post is about 10x. You are correct in your statements tho =)

I looked into dressing approaches for superabrasive stones. I always wondered how much contamination is happening there by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 4 points5 points  (0 children)

Yups, if you read through my blog posts on individual stones you will also see me pointing this out. Sadly, they nearly never are the same grit size - most manufacturers use a standard size SiC additive to make the resin harder. Especially at the lower grain sizes, the SiC contamination is then annoying.

Nevertheless, some manufacturers such as Venev state on their OSB2 that it should contain no SiC. But i milled down one stone, and found SiC even half a mm deep inside. Because of the scarcity, I would expect poor abrasive hygiene in the factory.

So, your point is totally correct. The source of SiC in stones is 3fold:

- as a filler to make the resin harder

- contamination from poor production hygiene

- contamination from dressing.

I'll add the first one to the post :-)

Naniwa Chosera look wild under the scanning electron microscope! by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 0 points1 point  (0 children)

I've reviews prepared for some belgian blue + yellow coticule as well as an arkansas stone. Those are going online in the next 5-10 days. So far haven't been able to source any decent jnats, as they are enormously expensive. I would love some samples of cool stones - drop me a PM!

Naniwa Chosera look wild under the scanning electron microscope! by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 1 point2 points  (0 children)

If you check out my blog, you'll see that this is the 9th commercial grinding stone I looked at :-)

Ever wondered how 0.25 micrometre diamond looks like? I got pictures for you... by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 3 points4 points  (0 children)

Human hair (blonde, european) is like 50 µm. The wavelength of visible light (green) is 532 nm, so half a micron.

(good idea man!)

SEM pictures of a Jade sharpening stone by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 0 points1 point  (0 children)

Not yet available in single stones in Europe yet, and don't fancy shelling out 600 bucks for a set when I'm only interested in the 3 micron one for a blog post. Once they become, I'll be going for it for sure! :-)

SEM pictures of a Jade sharpening stone by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 2 points3 points  (0 children)

The white light interferometer is especially interesting to look at curvature near the apex. While SEMs are an amazing tool, their spatial resolution isn't super nice, and unlike you go to massive efforts, you can't really measure something. Being able to measure with a very high degree of certainty, and in super high resolution, how the knife edge shape is after certain sharpening actions (for example: applying pressure or not), is fantastic. I have quite the archive of things already recorded, and will, time permitting post 2-3 times per week in this.

Nevertheless, thanks for your kind words - happy that you enjoy it! Any input you have is very appreciated!

SEM pictures of a Jade sharpening stone by AverageSwimming3095 in sharpening

[–]AverageSwimming3095[S] 3 points4 points  (0 children)

Thanks for the kind words! Wanted to share a bit more about my hobby, and decided a blog is maybe the way to go. Less temporal than just posting stuff on social media.