wickededge wrote:


While that would be interesting, I think you may get beyond what you're trying to "see" (from a practical stand point) Looking at the surface of polished steel where the grain structure looks like the surface of the moon may not actually be helpful in terms of sharpness. It would be interesting to figure out how much is enough, though.

For me, I find other elements like focus and depth of field to be more helpful than magnification.

Ken

Hey Ken,

My interest in the higher magnifications is to better understand what is happening with super fine polishing grits and substrates e.g. cow leather vs kangaroo vs horse vs nano-cloth etc... The studies I've already done have told me a lot, but I want to keep learning. I also want to be able to view and measure the edge end-on after it's been sharpened with various media.

KenBuzbee wrote:

Understood Clay, and I think that's a great thing. Just pointing out there may be (I don't really know) a point where more magnification isn't more helpful.

But you'll figure it out if true.

Ken

wickededge wrote:


I was going to say you're just a big tease... but in this case, I guess you're a little one!

Hi Clay,

Have you considered a contact profilometer at all? It's a device used to measure surface-roughness, and is typically used in some metal-working and/or machine-shops. It runs a tiny stylus over the surface and reports back a numerical measurement. The "advantage" is that while it is very expensive (thousands of dollars), it is not insanely expensive (like an scanning electron microscope). The downside is that it returns numbers, not an image. Or, I suppose, it may return a single line of data as a graph (ie: a 2d plot where x-axis is horizontal position of the stylus and y-axis is the stylus height). So it's not as simple to interpret the results. And if the surface is directional (like lots of parallel scratches), then the scanning direction will affect the results.

There are non-contact profilometers; they're typically based on light scanning. But non-contact profilometers are insanely expensive (at least from what little I've heard).

I know almost nothing about profilometers, except what I've read on wikipedia:
en.wikipedia.org/wiki/Profilometer
en.wikipedia.org/wiki/Surface_metrology

Example of a contact profilometer by Mitutoyo (high quality Japanese company):
www.amazon.com/Mitutoyo-178-561-02A-Surf...=pd_sim_sbs_indust_1

Probably not worth buying. But if you have any friends who work in a lab for manufacturing, machining, or metrology, it might be worth asking them for a favor?

I kind of got curious about metrology in general, and got sucked into browsing Wikipedia for hours and hours.

Sincerely,
--Lagrangian

This is fascinating. I'd never even heard of a contact profilometer before. It might be what CoorsTek uses for their stones since they measure in RA (roughness average). I'll definitely check them out. Thanks for the tip!

AnthonyYan wrote: