Thursday, July 1, 2010

Speaking of Diamonds

I don't know if you caught it, but after my last post, boasting of my brides' lack of care about diamonds, she mentioned that Joseph the goat could use a diamond collar, hrmmph...Well, have I got the diamonds for him. A while back, I was reading Ron Hocks Sharpening Blog about the role of diamonds in modern steel honing and saw the light, as they say.

Old school carbon steel has all the qualities that I want in a tool, save one. It's easy to sharpen because it's soft enough and it can get sharp as you could ever want, but it can rust (which I take to mean that you aren't in the shop enough) and it dulls relatively quickly.

So, with all our technology, we've added some elements such as chromium, to retard the rust process and also to prolong the durability of the edge. The main problem with this is that the edge that we get with traditional cutting honing stones doesn't get these particles properly sharp.

I've come to think of it, with Ron's help, as a chocolate chip cookie. We can sharpen the cookie, but the chips, they need something more.

This is where the diamonds come in. The diamonds can cut the chips and get these ultra durable particles sharp, so I've heard.

To test this myself, I went online (boy you can get anything there) and found some diamond paste for 3 bucks a tube (in China, diamonds must be a seasoning). After the wait for transit, I found that indeed, I was able to get all of my modern steels significantly sharper by simply honing them with the paste. For my plane type blades, I rubbed the paste on an old black Arkansas stone, honed as usual, and was thrilled to watch my spokeshave conquer curly cherry to a glistening finish. I did the same with my high speed steel turning tools.

For my concave spokeshave, I tried something a bit different. I turned a piece of beech that I culled from around my spring (now the spring doesn't dry up in summer) and applied the sequence of pastes down to the finest 1/2 micron, which equals a 30,000 grit stone. I kept the beech spinning in the lathe and carefully rubbed the edge on it. A real revelation, I'd never, in the 11 years that I've worked with this tool gotten it this sharp, with so little effort.

I was doing this during the down time while teaching a student, who couldn't help but tease me as I grabbed every tool in the shop and tuned it. So, I suppose there is a moral to this story, but who cares, my tools are sharper and it's easier to do, what more do you want??


jmk89 (Jeremy Kriewaldt) said...

Diamonds are a woodie's best friend - I put Chinese diamond paste (in oil ) and some baby oil on a leather hone and get that next level of sharpness.
No need to change from your existing sharpening regime, except to add diamond paste at the end!

Tico Vogt said...

Hi Peter,

You mentioned a sequence of pastes; what are they? You apply one onto the spinning beech block, hone, then the next, etc. Is that right? do you also work the flat backs with the paste/


John said...

Yes, Peter you have a sharpening junkys interest. Source of paste and sequence is something I would love to see. John

Anonymous said...

Hi Pete , thanks for sharing , I didnt think of sharpening my concave blade that way , so do you have a tricky way of sharpening a convex blade ? , MiM .

ss said...

'what more do you want??'

another goat.