We turners don't even know what sharp is *LINK*

Re: We turners don't even know what sharp is

John K Jordan

8 microns! Yikes.

I'll bet they don't grind those tools with an 80 grit Norton wheel.

It's amazing to me the long "shavings" don't come apart when the guy stops and starts.

JKJ

Re: We turners don't even know what sharp is

Don Orr

Wow! Incredibly sharp with extremely fine setup and perfect wood with the skill to put it all together.

Re: We turners don't even know what sharp is

Bob Macgregor

I think 8 microns is about red blood cell size, if memory serves. So, is this just a demonstration of skill or is there some use for those thin strips?

Re: We turners don't even know what sharp is

robo hippy

I have a friend who carves wood spoons and other kitchen ware. All of his work is 'off the tool' finish. I was feeling the edges of one of his knives, and he was complaining about the burr on it. I couldn't even feel the burr....

robo hippy

Re: We turners don't even know what sharp is

mikeee12345

Many of the stones they use for sharpening and honing an edge are 10K plus.

This turns into a competition as to who can create the sharpest edge derived from

the Samurai sword makers over the centuries. Most of their high end woodworking is

all hand crafted. This discipline is ingrained in their culture and shows in the arts and

crafts they are involved in.

Re: We turners don't even know what sharp is

philip f Duffy

OK, but will it burn? Or, does it just go up in Smoke? P.

Re: We turners don't even know what sharp is

Brad Vietje

That's pretty impressive. If we were to fully impregnate a piece of wood with a resin or epoxy, we should, in theory, be able to go thinner than that. BUT -- wood has physical properties that may set the limit regardless of the tools used. You may find that with resin-impregnated (stabilized) pen or project blanks that you can get a thinner cut than with bare wood.

Just for comparison's sake, when I worked in the Neurosciences, I did a lot of histology and electron microscopy. For the light microscope, tissues are infiltrated with (embedded in) a hard form of parafin wax, and typical sections are 3 to 4 microns.

"Hard sections" for the light microscope are embedded in (fully impregnated with) an epoxy resin, and sectioned at 0.5 microns (500 nm). These are used for very high-resolution imaging with oil-immersion objective lenses. Sections are handled with a very fine paint brush.

"Thin sections" for transmission electron microscopy are also embedded in epoxy (typically some form of Epon-Araldite), and sectioned at 300-500 Angstroms, or 30-50 nanometers. Those sections are so thin they can't easily be seen unless floating on the surface of water, where they create an interference pattern in which the color indicates the thickness -- exactly like the tiny film of oil on a puddle. Grey is about 35 nm, silver about 42 nm, and purple is about 50 nm. These are handled with a tiny, single-bristle glued to the end of a toothpick or similar tiny wood shaft, and can only be pushed around while floating on a pool of water.

The same color/thickness rules apply to the oily film behind a motor boat -- the colors tell you the thickness of the film, just like the thin sections.

Anyhow, it's pretty impressive to see a shaving come off a plane that you could read through.

Safe spinning,

Brad Vietje

Newbury, VT

Way OT:  Ultramicrotomy Pic

Brad Vietje

Sorry for the waaaay OT post, but this is something you may have never seen.

Here's a photo of a ribbon of silver-grey sections floating on the water trough behind a diamond knife -- made from the absolute highest-quality flawless diamonds, carefully oriented and polished to an edge that is in theory only 1 molecule thick at the edge when new.

This image shows 3 trapezoid-shaped sections, plus a little bit of a 4th. Sections are around 1 mm wide.

While these super-expensive diamond knives last a long time if lovingly babied (they are about $15,000 each), the very sharpest edge comes from a freshly-broken piece of high-density glass. Glass knives do not last long, but can cut even thinner sections.

Well... that was a fun little diversion! If you want to know about the smallest of the small, or the largest of the large, let me know -- I'm your guy.

Safe spinning,

Brad Vietje

Newbury, VT

Way OT:  OT happens

John K Jordan

>>>Well... that was a fun little diversion! If you want to know about the smallest of the small, or the largest of the large, let me know -- I'm your guy.

Ooo, now I want to come visit and hear all your stories!! I have a friend who uses an SEM, experimenting with carbon nanotubes and interesting ceramic applications. Another buddy spent years machining with a single-point diamond turning machine, playing and perfecting and making things like special mirrors that went into space. So many interesting things out there. Sounds like you would fit nicely into the club of people who can easily spend hours in fascinating discussion!

I have a question for you about small, concerning thin films and color. We have peacocks here and some feathers, of course, are brilliant with a variety of colors. With the microscope I see a feather is consists of a number of individual strands, each made of what looks a lot like a long stack of tiny donuts. (These are easily visible with the low-power stereo microscope I keep on my desk.)

With reflected light from above I can clearly see the various brilliant colors. With transmitted light from below all of these donuts appear a uniform dull translucent red. I have not yet tried looking with a higher power - it would be fun to look at a slice through the middle of a strand to see if these donuts are hollow or solid - I have a microtome. Viewing with polarized light and cross-polarized filters is another thing I want to try.

I speculated that thin surface layers might produce these colors but they are so brilliant I wondered if that could be - I've never seen color so bright from thin films. Perhaps films grown a molecule at a time can be brighter. I have not yet tried asking Sir Google.

Thoughts on this?

And speaking of large, excitement is growing around here about the total solar eclipse next year. I haven't checked - will it be visible in your area?

JKJ