I've been working on drawings since the mid 1980's and I haven't come
across this one yet...
Anyone ever see a call out on a print like the one below? This print is
from the '60 and it points to a few surfaces and a bore. I'm thinking
it might be some kind of burr call-out? The mating part calls out the
same symbol on the mating shaft and face. All the same surfaces
indicated by this also have the normal 32 surface finish call out, so
it's not that.
I tried searching the web, but came up short...any ideas?
Had to snip out comp.cad.pro-engineer because of a crosspost limit.
Well, even with the free pass I still wouldn't "just" ignore that
callout without thinking it through first. Look at the names in the
title box, and see if you can track down any of the original engineers
or designers of the device - ask them what the heck it means.
Get the details of what this part is supposed to do and how it goes
together, and have their engineers think it through as if they were
designing it new. If it makes sense to do a radius break on that
corner, you want to do it - AIUI, a knife-edge corner is a real good
place to start a crack, where a nice radius edge spreads the stresses
around _just_ enough to keep it from starting...
And if this is for aircraft or medical use, you'll be in BIG trouble
not following the print, especially when it fails and kills someone -
The FAA or the FDA is going to want to know the exact parentage of
that part that failed. And they'll be looking for blood.
Good theory, it's possible - but more likely that the origin of the
callout is simply lost in the mists of time.
"Never ascribe to Malice what can easily be written off as Stupidity."
If they walk in and see Brown M&M's in the bowl, that is a Red Flag
to make sure the promoter has the right risers on the stage, the right
microphones and band amps, the right mix board and house sound system,
and all the other myrtiad details are complete and correct.
And if they aren't, THEN they have an perfectly valid reason to
storm out and cancel the gig - The band usally arrives the morning of
the show or at best a day ahead, and there is simply no time to fix it
if the Promoter has deliberately not followed the contract.
There are many unscrupulous promoters out there who will cut corners
ruthlessly to make more money from staging the concert, to the point
where the band sounds like crap, looks like crap and the reviewers
can't help but notrice and tell the world that the band has "lost
their groove thang"... And guess whose reputation takes a hit? (Hint:
It 's the band, NOT the promoter.)
If the band contract calls out for specific models of Sennheiser or
Blue or other specialty vocal mikes that capture their voices best,
and they walk in and see the Promoter has rented them a row of beat-up
old Shure 57's for primary singers and a bunch of Shotguns for the
backup singers, that is going to be trouble. Yes, they will "work",
but they are not the best fit for many voices and will make you sound
horrid - they will amplify any faults in your voice.
In the same spirit, they will cut corners on the speaker stacks, the
amps, the mixing board (an old Nady instead of the big Yamaha the
specs called for) the lighting, the effects, the Stage Security and
controlling the Access Passes...
--<< Bruce >>--
Have to try the nursing home - lol...<joke> Some of the other
components calling out the same symbol have a 1953 dwn date...On the
basis that the engineer/designer/draftsman were around say 30 years old
around that time, that would put them in their late 70's or 80's, well
past retirement. I don't think there is anyone there from that era
anymore. Also, the prints were acquired by our customer in the 1980's
when the original company was acquired (I believe), so the paper trail
to find someone gets a little muddy..
The problem is that all the things you mention are all on the print too.
Radius, chamfers, surface finishes are all called out. (The leader is
not pointing to edges but to surfaces.)...and besides, come on - we
would never leave a knife edge (unless otherwise specified - and even
then the guys on the shop floor would be coming in giving me crap about
that! - lol)
(BTW - for the other poster - It's a moving part - no welds whatsoever)
yup - We've been mfg aircraft and medical parts for 30 years, so we kind
of know. We don't fool around. (www.precipart.com)
This is a long shot, but my first reaction was that it was a callout for the
lay and direction of the finish texture. I've seen those in mold work and
sometimes on bearing surfaces, but my books don't show that one. It's
So? Track a few bodies down, if they are retired from the client
company their Payroll Department had better know where they are
sending the retirement checks...
Call. Or if you are close, stop by, and bring their favorite
libation... You might be pleasantly surprised how much you get when
you pick their brains.
Including "Oh, THAT part! Did they give you the print for the A
revision, or the C Revision? We had a crash and traced the failure
back to the A Revision part, we totally redesigned it in 1960."
(And then you look, and you were indeed going to make a batch of a
known bad design off the A Revision print, because someone at the
office didn't dig into the old files deep enough...)
The joys of a lack of corporate continuity - having a few old farts
hang around who remember where all the bodies are buried, and can show
the young bucks that there are /far/ better ways to get things done
than a brute-force frontal assault.
But the Accountants can't let that happen - they hire for the
project and fire as soon as it's over.
I figured you knew, but it never hurts to restate the obvious - just
in case Transient CRS happened.
--<< Bruce >>--
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