On 11/24/2013 12:00 AM, Gunner Asch wrote:
On Sat, 23 Nov 2013 23:33:15 -0500, "Mike Marlow"
wrote:

Gunner Asch wrote:


Ayup...aerospace requires 50 millions or half 10ths all the time.

Which is damned hard to do with machines that hold +/- 2 tenths


One might think it is impossible to do with repeatability and assurance.

Hardly impossible. It happens many thousands..hundreds of thousands
of parts a day.

So - I am curious - what is it that aerospace requires that is 50
"millions"? I worked in that space for a while and I never saw any
tolerances like that - but that does not say much. I believe that even the
space shuttle does not demand tolerances that close - but I really do not
know.

Jet engine parts, microwave wave guides, thousands of things. Most of
which I was not cleared to know what they were when I ran into them..
An awful lot of optical stuff is that or more.

Shrug. And a lot of that stuff I figured would be good at
+0/- .001...but..the specs...

As the truism goes...the more zeros you add to the right of the
decimal point...you multiply the cost by a factor of 5-10


Half a thou? (NOBODY says 50 millionths!)
Integrated circuit transistor sizes run less than 200 nanometers. (for
CAD tolerance, not wood working, ok? Sheesh!)


Mike, as to getting to orbit, the precision required is nowhere near
that tight. It's actually fairly sloppy for a successful orbit. SPEED
it the key player there, not trajectory. 20,000 MPH straight down the
east bound lane of I-30 will do just fine. It won't be a circular
orbit, but you won't be back any time soon.