On Tue, 18 Feb 2020 17:48:38 -0700, Bob La Londe
wrote:


On 2/17/2020 9:23 PM, James Waldby wrote:
I noticed some annoying bait-and-switch in the article https://

http://www.popularmechanics.com/scie...object-vacuum-
friction/.

The first paragraph talks about balls of silicon dioxide that rotate
300 billion times per second, which would be 1.8 trillion RPM.
Imagine my dismay at finding out, a couple of paragraphs later,
that the author had mixed up RPS and RPM; the particles actually
are spinning at only 5 GHz (5 billion RPS), or 300 billion RPM.

Dang-it... and I was fantasizing about swapping out the 24K Spindle on
the machine I primarily use for engraving to a measly 60K spindle. Now
my plan is all shot to heck. My brains is going 1.8 trillion miles a
second dreaming about a 300 billion RPM spindle. 4 minute engraving
jobs could be done in a .0001 seconds. Hmmm.... I guess I'd have to
upgrade the lead screws and ways too.

I sure wouldn't want to be around the day that little mill bit gave up
the fight against centripetal force. Perhaps it would vaporize at
that speed, though. Much safer than grenading @3BRPM.

--
There is nothing more frightening than ignorance in action.

--Johann Wolfgang von Goethe