Am Thu, 12 Nov 2015 18:14:57 -0800 schrieb "Richard (Rick) Karlquist" <[email protected]>:
> > > On 11/12/2015 1:01 PM, William Schrempp wrote: > > > > has failed. I hear old machinists complaining about new machinists > > who can't drill a hole if the drill-press isn't > > computer-controlled. And in my work, nurse education, I see > > students who can't be bothered to learn how to take a manual > > blood-pressure, because a machine can now do it (sort of). Much to > > ponder here. . . . > > > Bill Schrempp > > > > This reminds me of a summer job I had as a lab assistant between my > freshman and sophomore years at college. There were a couple of > journeyman machinists with Bridgeport mills. They didn't let me > use them, but they did patiently teach me how to use the drill > press, taps, hacksaw, etc to make simple parts that didn't require > their skills. They told me that, in Germany, a kid training to be > a machinist would start out by being given a file, a pair of calipers, > and a rough block of metal. His task was to make a perfect cube with > sides of exactly 1 cm by 1 cm. Only after mastering that, would > he be allowed to move onto more advanced equipment. And that's been actually quite true. Not too long ago - well, around year 2000 - when I was just about to finish high school in Germany, we had a class in a machine shop. We were literally given one single piece of steel of about 10x10x20cm, and were to make a pretty nice PCB holder out of it. The only tools allowed for most of it were a set of files and a saw. Only after we managed to get most of the parts done according to the drawing - and they were tested to be nicely rectangular, to size and pretty flat on all sides - we were allowed to drill the missing holes and tap a few threads. Only the most skilled were finally allowed to turn the screws for the class on a lathe... > Fortunately, the > machinists just told me this story to scare me, but they didn't make > me file a perfect cube. They did tell me I needed to learn to drill > holes with 0.005 inch accuracy using a machinist's scale and a center > punch to lay them out. > Well, 5 mil shouldn't be too difficult if some care is taken. Of course this also depends a lot on the material used, dull or mis-centered drill bits certaily can destroy alignment and hole sizes easily... Best regards, Florian _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
