2000x Microscope
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The new scope came in Wednesday and I’d hoped to kick off this category with some great hi-res pics, but then was out sick on Thursday and wrapped up in meetings on Friday so I didn’t get a really good chance to play with it. I also still need to get a NIST traceable micro-ruler to calibrate it. If anyone knows of one for under $1200, I’d love to hear about it. Even without calibration though, I should be able to start posting some of the pics. At first glance, it looks pretty exciting. I can see the tiniest of scratches from our micro-abrasives really clearly, so with some luck and work, we should be able to learn a whole lot about all the stones and strops.
Hi Clay,
I searched around and found a NIST-traceable stage micrometer for about $500, but I’m not sure it is good enough; I think it only goes down to 0.1mm (100 microns).
“Reticle Calibration Stage Micrometer, NIST traceable NT59-281 $495.00”
http://www.edmundoptics.com/microscopy/reticles-stage-micrometers/reticle-calibration-stage-micrometer/2826
Edmund Optics also has many other calibration targets, so you might also look around at:
http://www.edmundoptics.com/testing-targets/test-targets/image-analysis-test-targets/
http://www.edmundoptics.com/microscopy/reticles-stage-micrometers/I also found this company that sells stage micrometers with NIST-traceable certificates. It seems if you buy the stage-micrometer from them, they lower the price for NIST-traceable calibration.
http://www.aig-imaging.com/NIST-Traceable-Calibration.html
http://www.aig-imaging.com/Stage-Micrometer-Scales.htmlOther places I looked at had fancier stage micrometers, but were very expensive ($1200+ for NIST-traceable):
http://www.emsdiasum.com/microscopy/products/magnifier/stage.aspx
http://www.tedpella.com/calibrat_html/calib.htmSincerely,
–LagrangianP.S. Another possibility is to get a mechanical microscope stage with micrometers. That is, it is a stage that can move in the X, or X-and-Y directions where each direction is literally moved by a micrometer-head. Presumably, if the micrometer-heads are NIST certified, then the microscope stage is very accurate. It may be expensive, so don’t know if it would cost less. And I don’t know if they actually are avaiable as NIST-traceable.
http://www.edmundoptics.com/microscopy/microscopy-mechanics/linear-positioning-stages/30mm-single-axis-crossed-roller-translation-stages/3216
Hi Clay:
Thanks! 🙂
Hi BassLakeDan:
For a variety of reasons, visible wavelength is often discussed in terms of nanometers, and sometimes in angstroms. But it’s just all unit conversions by factors of ten.
Visible light is approximately in the range of 0.4 to 0.7 microns (okay, if you are really picky, the 0.38 to 0.74 microns). If you want, that’s 400 to 700 nanometers, or 4000 to 7000 angstroms.
https://en.wikipedia.org/wiki/Visible_lightOptical microscopes use visible light to image stuff, so they’re pretty good until you start getting down to sub-wavelength features. Below about half a wavelength, you will probably not see anything. Current high-end optical microscopes have a resolution of about 0.2 microns. You can get better than this optically, but doing so requires extremely fancy and high-tech methods. So it’s only in a research lab that you would be likely to see an optical microscope with better than 0.2 micron resolution.
A ton of really good microscope information can be found here, on Nikon’s microscope web page:
http://microscopyu.com/To get to higher resolutions, one can use non-optical methods, such as using light outside of the visibel spectrum, or things like electron-microscopes, atomic-force microscopes, and scanning-tunnelling-electron micrscopes.
Sincerely,
–LagrangianP.S. btw, as a knife and sharpening enthusiast, I’m conceptually anchored at 0.5 microns because the sharpness of a modern razor is about 0.4 microns (according to Prof. John D. Verhoeven), and visible light is around 0.4 to 0.7 microns. So whenever I think about knife edges, microscope pictures, and the size of abrasive particles, I’m thinking in terms of 0.5 microns. This is why I think it’s cool that Clay got a stage micrometer… because in any photos he shows, we will be able to have some idea of the width of scratches in comparison to edge sharpness and abrasive grits.
P.P.S. I’ve only been a knife enthusiast for about a year, but over that time I’ve collected a short list of “length-scales” related to knives. It is kind of like a time-line, but instead of time, the axis is length (microns). Here’s a partial list:
50-100 microns = Approximate diameter of human hair (varies hugely; this is only part of the range)
25.4 microns = 0.001 inches (1 mil). Standard resolution for an imperial caliper
2.54 microns = 0.0001 inches (0.1 mil). Standard resolution for an imperial micrometer.
0.36-0.74 microns = Wavelength of visible light
0.4 microns = Sharpness of a modern razor blade.
0.2 microns = resolution limit of optical microscopes
0.05 microns = Sharpness of diamond coated razors.
0.005 microns = Sharpness of a diamond microtome knife.
0.003 microns = Sharpness of concoidally fractured obsidian.
0.00034 microns = van der Waals diameter of a carbon atom.Atomic-force microscopes (AFM) and scanning-tunneling-electron-microscopes (STEM) use needles which are atomically sharp; they literally have a single atom at the tip.
Sources:
https://en.wikipedia.org/wiki/Hair#Description
https://en.wikipedia.org/wiki/Visible_light
http://www-archive.mse.iastate.edu/fileadmin/www.mse.iastate.edu/static/files/verhoeven/KnifeShExps.pdf
http://microscopyu.com/articles/optics/index.html
http://www.technologyreview.com/computing/25988/
http://www.tedpella.com/diamond_html/diamondk.htm
http://en.wikipedia.org/wiki/Obsidian
https://en.wikipedia.org/wiki/Van_der_Waals_radiusP.P.P.S. If you are interested in the conversion between grit numbers and microns, then have a look at Komitadjie’s Grand Unified Grit Chart. Here are some plots by Mr. Wizard using the data that Komitadjie has compiled:
http://www.knifeforums.com/forums/showpost.php?post/2387907/
I just saw this post from Magnaminous_G on BladeForums.com:
http://www.bladeforums.com/forums/showthread.php/975577-This-might-interest-serious-sharpeners-free-SEM-imagingThis might interest serious sharpeners – free SEM imaging
It looks like ASPEX is now offering free SEM imagery of whatever you send to them (limit of 2 samples). It might be really cool to see a very refined edge under a SEM.
http://www.aspexcorp.com/Resources/SendUsYourSample.aspx%5B/quote%5D
If they are able to take SEM pictures looking directly into the edge (the same as Prof. John D. Verhoeven), then they may be able to measure the actual sharpness of your knife edge. That would be amazingly cool… With modern ultra-fine abrasives, do you think your edge is sharper than 0.4 microns? Now you can find out!
http://www-archive.mse.iastate.edu/fileadmin/www.mse.iastate.edu/static/files/verhoeven/KnifeShExps.pdfSincerely,
–Lagrangian
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