Quote:
Originally Posted by ODDJOB UNO
im not gonna argue usa vs jap precision tooling. i will argue chinese/korean/taiwan vs usa mfg'd.
99.8 % of all our tooling and precision tooling sold was MILITARY or NASA or DARPA contracts.
and the vast majority were STARRETT MADE IN ATHOL MASS USA precision tools. MANDATED BY CONTRACTS!
start putting alot of ZEROS after the decimal point like 78millionths. and it kind of gets INTENSE!
going into space? OH BOY yer tolerances better be dead nutz perfect. thread the shuttles exploding fuel cell bolts..............and tell me all about tolerances. if a Q-TIPS single strand of fiber grabbed a burr on a single thread under a magnifying glass, the entire lot was rejected until reworked and then NASA rechecked them. and yes they were starrett thread pitch gages used.
i still have some buddies at garrett/honeywell and by the time they get the part to machine................its already got $250K worth of machine work done to it already! before they even TOUCH IT!
if i remember the calibration room TEMP was set at a constant 72 degrees F with a certain number relative humidity CONSTANT! basically like an intel clean room for checking tolerances. mega filters on a/c units etc. everything lasered off. starrett surface plates cleaned every shift. and i mean BIG AZZD SURFACE PLATES THAT WOULD CRUSH A CAR IF DROPPED!
i made 16 ZILLION TRW airbag triggers out of 304 low leaded stainless. 37 QC checks on each one before sodium azide(EXTREMELY EXPLOSIVE) was installed and then shipped to auto mfg's. NOT a GUBBERMINT CONTRACT and ALL PRECISION TOOLING WAS MANDATED STARRETT USA! if that damn airbag trigger dont go off in a pico second, everybody from TRW all the way down to manufacture of that airbag trigger was SUED INTO THE STONE AGE!
it all depends on what yer making, if its aerospace, they kind of have it down to a science here in the usa. offshore.....................well its SCAREY!
|
Dude, I've worked in or ran precision machine shops for most of my adult life.
Millionths? You use starrett tools to measure to the millionths? You must be good.
My starrett mikes are only accurate to 5/100,000ths (half of the smallest graduation).
I have to use a precision ground quartz flat ( flat to 30 NANOMETERS PER CM)and a monocromatic helium light to measure to the millionths, (6 millionths is the width of a helium light band).
But that's OK, I gots two of them set-ups to measure the flatness of mechanical seal faces.
And starrett thread gauges are not capable of performing the task you described to the level of accuracy you described, but it sounded good.
I've got two granite inspection tables in my shop. The small one weights about a half ton. The big one needs special footings in the concrete under it to keep from crushing the 6" thick floor.
And this shop is 1/3 the size of the last shop I ran.
Here's an interesting tid-bit. We recently bought the BP refinery across the street and are in the process combining the two.
Their new maintenance building/machine shop cost $50 million to build 2 years ago.
And except for their larger overhead cranes and bigger VTL's (and more staffing) they don't have any capability my smaller shop doesn't have.
No big deal to overhaul/repair/modify/upgrade a $ multi-million machine in either shop. That's what we do.
And if ya wanna get into the shuttle's exploding fuel cell (and stage separation) bolts we can do that, if fact I can include the guy who came up with the design for most of em.
Did you know that back when they first started using exploding bolts on rockets (the bolts don't actually explode, duh, the shape charges are around them) they had shape charges 360 degrees around the bolts and broke the bolts through pure over-tensioning them. dumb de dumd dumb.
Dad said, that's dumb. Give me two hollowed out washers, I'll load the 'splosives in one side and index the charges 180 out and it'll shear the bolts just like using scissors. It was more reliable, accurate, and took 1/10th as much boom boom sauce.