Diamond stones on things softer than metal

[Jamey Howard]

Hey all, so my brand new WE stuff arrived last week (huge thanks to Bob at Oldawan for the excellent customer service) and I’ve been having a lot of fun sharpening knives, everything works great.

I’ve got the 50/80 grit stones and I was watching them cut through metal thinking “I’d better be careful not to slip my finger down one by accident while applying pressure” when later on, while washing the stone I did just that by mistake.

It didn’t hurt much. So I did it again deliberately. Still nothing. I thought it might be because it was wet, so when it was dry I did it again. Same result.

So (and this is where I should say nobody should try this at home, I’m stupid and did this because I’m a curious idiot) I picked up the stone and scrubbed a bit of the skin on my hand with it. Still no real result. And remember this is the 50 grit stone, that shaves metal off a blade very fast.

So then I started applying what I would call medium pressure, about the same as I had been using on the knives. I scrubbed up and down on my skin at least twenty times, maybe more. thinking back to how the stone cuts through metal it ought to have left a red/raw patch on my skin, but it didn’t. Skin felt perfectly fine.

At this point I wondered if it’s because skin is soft and flows around the stone instead of resisting, so I tried to file one of my fingernails on the stone. It did file a bit, but no faster than a normal metal nail file.

So then I picked up an empty aluminium drink can and had a go on that. After about twenty medium-pressure strokes it was only just starting to scratch the paint off.

Now don’t get me wrong, I’m very happy with the stone, it does exactly what I want it to when it comes to knife sharpening. I just don’t understand how a diamond surface that cuts through metal so well can have such a seemingly reduced effect on other surfaces. What gives? Can anyone explain what’s going on here?

Sorry for the slightly leftfield, non-sharpening-related question, but I’m naturally curious and hope someone can shed some light on it.

[Nicholas Angeja]

you should try it on your knee and see if its dependent on the bone. Which can possibly translate into an answer to a question I asked recently “what are the benefits of aluminium or glass strop backings?”

[Jeremy Long]

I did the same thing out of curiosity when I got my first diamond bench stones

[Mark76]

Should we start a subforum on automutilation? B) :ohmy: 😉

Molecule Polishing: my blog about sharpening with the Wicked Edge

[cbwx34]

So then I picked up an empty aluminium drink can and had a go on that. After about twenty medium-pressure strokes it was only just starting to scratch the paint off.

This statement, and the one about “aluminum vs. glass backing” reminded me… A few years back I was going to flatten some aluminum blanks I had, and thought a DMT-XXC stone I had would make quick work of it. I got the same result… although it was (and still is) a stone that was great on knives, flattening waterstones, etc. It took what seemed like FOREVER to flatten the blanks… and they weren’t that bad.

So, there must be a reason for it… no idea what it is though. :blink:

[Jamey Howard]

This statement, and the one about “aluminum vs. glass backing” reminded me… A few years back I was going to flatten some aluminum blanks I had, and thought a DMT-XXC stone I had would make quick work of it. I got the same result… although it was (and still is) a stone that was great on knives, flattening waterstones, etc. It took what seemed like FOREVER to flatten the blanks… and they weren’t that bad.

So, there must be a reason for it… no idea what it is though. :blink:

Weird, thanks for sharing. Yeah there’s definitely something at play here, would love to know what it is. Like I said, I’m not complaining as the stones do the job they were designed for perfectly, I’m just curious. I don’t like not knowing things.

[Mark76]

I don’t quite grasp what is so weird here. The diamond stones scrape off or even knock out bits from a hard material like knife steel. Softer material has a give to it, so that this is less easy. The material may even clog the stone.

It similar to knife edges. When the steel is hard, it may chip. When the steel is soft, it may roll.

What am I missing?

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Jamey Howard]

What am I missing?

The aluminium drinks can?

[Author]

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