Similar to this one. I used standards certified by the NBS (Now NIST) for testing it.
Posted on 03/11/2015 2:02:44 PM PDT by Red Badger
I used to calibrate Rockwell Hardness Meters..................
Similar to this one. I used standards certified by the NBS (Now NIST) for testing it.
LOL, I guess you know a LOT about hardness scales. I cut stones so I guess I’m closer to Stone Age thinking than most. I got on my soap-box because most people I run into really don’t understand the vast differences in stone hardness.
I worked for an aircraft sheet metal manufacturer. They could take a piece of aluminum, soften it to work it into a complex curve shape, then harden it again back to where it was.......................
Turboprop engine with a spinner but no propellers! ;)
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