Joe Gwinn
Stainless
- Joined
- Nov 22, 2009
- Location
- Boston, MA area
I always wondered how one sharpens diamond microtome knives, which are used to shave biological samples off into slices maybe 100 nanometers in thickness (about 4 microinches), for examination with an electron microscope. For the record, the wavelength of green light is about 530 nanometers.
This is well finer than any diamond polishing grit, so how is this done? It turned out to be a bit of a surprise.
The polisher is a very well balanced small flat-faced iron disk charged with very fine diamond paste, spinning at 50,000 to 100,000 rpm. At this speed, any bit of diamond blade sticking up is burned away. The principle is like a surface grinder sparking out.
So, the inventor inverted our usual observation that there should be no sparks with diamond, because the diamond will be destroyed.
The inventor is from Venezuela.
Diamond knives are also used in such things as eye surgery.
Diamond knife - Wikipedia
See reference [1] for the patent, which is in English. British patent 799,498 published in 1958.
This is well finer than any diamond polishing grit, so how is this done? It turned out to be a bit of a surprise.
The polisher is a very well balanced small flat-faced iron disk charged with very fine diamond paste, spinning at 50,000 to 100,000 rpm. At this speed, any bit of diamond blade sticking up is burned away. The principle is like a surface grinder sparking out.
So, the inventor inverted our usual observation that there should be no sparks with diamond, because the diamond will be destroyed.
The inventor is from Venezuela.
Diamond knives are also used in such things as eye surgery.
Diamond knife - Wikipedia
See reference [1] for the patent, which is in English. British patent 799,498 published in 1958.