Intresting machine work on this page

[wierdscience]

http://www.noao.edu/ets/gnirs/FabArchive.htm

Optics,big chunks of expensive metal and machines

[Evan]

Crap! You don't want to hear "Uh oh" when you are working on stuff like that. I wonder what the volume of swarf they generated was?

[Swarf&Sparks]

I wonder how the "uh-oh" for the Hubble mirror sounded?

[dan s]

First thing that comes to my mind is why didn’t they have custom castings done. Like Evan said it looks like 80% ended up as chips.

[Dawai]

<quote>I wonder how the "uh-oh" for the Hubble mirror sounded?</quote>

Probably about the same as the software glitch of "programmed in meter's and entered in feet" Mars lander software UHHH OOOOOHHHHH

[Rusty Marlin]

First thing that comes to my mind is why didn’t they have custom castings done. Like Evan said it looks like 80% ended up as chips.

Becuase you can't use castings in aerospace applications. Its forgings or nothing. It has to do with voids, grainstructure, and process control.

[YankeeMetallic]

Suddenly I feel very small in the world of all things.
Can you imagine their tolerances!?
If I could have that giant CNC that does that work, I would sell it & retire completely!

[Evan]

When I worked at Northwest Industries in Edmonton in the 70's they had a big gantry mill with an envelope of about 30 feet x 12' by 4'. It was an NC paper tape machine and when I was there they used it to machine fighter jet wing panels from solid. Huge quantities of swarf. Dumpster loads full. They didn't clamp down the stock, just placed it on the table. They ran it three shifts and it would take days to do one part.

[BillH]

I wonder how the "uh-oh" for the Hubble mirror sounded?

Well based upon the looks on the engineers faces when my friend asked them, "So how did the Hubble Lens get messed up?" Over at Hughes Aerospace in Danbury, CT... I guestimate the Uh Oh was more like an Oh **** on epic proportions.

Back in High School, our engineering club went on a field trip over there. We got to talk to the head engineer on the Hubble, and toured the manufacturing plant where they grind million dollar lenses. Yeh, he asked them that, the Irate looks of wanting to kill you with their bare hands and then the scolding remarks of, "WE MADE THAT LENS PERFECT TO THE JIG, IT WAS AN AMAZING ACCOMPLISHMENT, the jig was off...

[wierdscience]

I remember seeing a write up on the aft cockpit bulkhead for the F-22.IIRC it started out as a 400lb billet of titainium and finished at 22lbs,the rest was in chips.I figure those chips cost what I make in a year after making many times more chips.

Hummmm....I see a pattern forming here,life is measured in piles of swarf

[Evan]

The Hubble mirror uck up was Perkin Elmer's fault.

[japcas]

Sure makes me feel better about the 6.5 pound piece of brass stock I was machining the other day that finished up at 1 pound 4 ounces. Nice looking work for sure on that site.

[A.K. Boomer]

"WE MADE THAT LENS PERFECT TO THE JIG, IT WAS AN AMAZING ACCOMPLISHMENT, the jig was off...

Boy i gotta remember that line The Jig was off!!!......... that could keep me out of allot of trouble...

[Wirecutter]

Hey now! What? No remarks on how cool the GNIRS is because it's made out of so much BILLET? (Or as Forrest once said, "Bulls**t") Oh, wait - there's actually a good reason for that this time...

Sorry. I just couldn't resist pointing that out. That one's right up there with flux capacitors and jigawatts for me.

-Mark

[Evan]

That isn't billet, it's plate.