Green Eyed Monsty Posted January 6 Share Posted January 6 5 minutes ago, Pegazus said: Oh, for sure. Normal tolerance for my parts is around .007 to .030. This was for a test harness cable and I initially told them it needed to be 60” long. But they complained because they couldn’t sign off the paperwork unless a tolerance was given. So plus or minus an inch which they failed to meet. The harness was fine to use at that length but I had to write a quality report justifying the use of a part that did not meeting the engineering specifications. So they caused me extra work twice. Once to revise the drawing and again to write the report. My father was a Master Millwright as well as having multiple certifications for welding [which saved his employer many thousands of dollars when a machinist screwed up]. He started with a bare plot of ground and a concrete slab [with isolation pads for each machine] with a sheet metal building and when his work was finished there was a precision heavy duty machine shop on the premises. The pies-de-resistance was the temperature controlled precision machining room where the temperature was controlled to within two degrees of spec when production was underway. The room was capable of handling machining operations on parts weighing up to ten tons so you can imagine the size of the machinery involved and the massive amount of cooling capacity required to maintain the temps during the peak of Southern California's summers. When the main doors had to be opened to move large parts in and out it took two days for the temperature to be certified as stable, so most of that work happened on a Friday. I witnessed all of the main oxygen metering valves for the Apollo Rockets go from raw aluminum castings to finished parts ready for assembly. Saw a lot of DOD sub-contract work as well. Good times. Growing up at that time and place and having the ability to see up close and personal and on a regular basis things most kids could only imagine was something I grow to appreciate more and more as I get older. I got used to thinking in terms of tolerances running to 4 digits to the right of the decimal when most people my age were dealing in two digit fractions for "close work". 7 Quote Link to comment Share on other sites More sharing options...
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