Thread: Bottle holder
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Old May 24th 19, 12:17 AM posted to rec.bicycles.tech
AMuzi
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Posts: 13,447
Default Bottle holder

On 5/23/2019 6:04 PM, John B. Slocomb wrote:
On Thu, 23 May 2019 06:56:28 -0700, sms
wrote:

On 5/23/2019 3:34 AM, John B. Slocomb wrote:

snip

No, sorry, they didn't teach us about stress concentrations when
drilling holes, primarily because any hole is a stress concentration,
at least to some extent. And it is illogical to think that one can
change "fatigue life" by drilling a hole in some special manner.


It is not illogical at all. It is a fact. There is just no way that any
course in machining would not teach about how to reduce stress
concentration of holes drilled into metal. You might want to ask for a
partial refund if that school is still in existence.

Well, I can only comment that in my career I drilled holes in just
about everything that flew and much of that was specified in either
manufacturer's designs and/or specifications from people who had been
assigned to design and document a modification and I cannot remember
ever seeing any specifications, or directions, or other data intended
to tell me how to change "fatigue life" by drilling a hole in some
specific manner.

So kindly teach me. But before you get off your podium please remember
that we are not talking about designing a hole, or placing a hole or
any other fuzzy example that you may care to elaborate on. We are
discussing the drilling, or boring of a cylindrical passageway through
a base material.

We just had a spectacular example of the result of improper drilling of
holes in steel beams in San Francisco, but these were not drilled by
journeyman machinists.


I assume that you are referring to the following
https://www.nbcbayarea.com/investiga...494862071.html

If so than once again you demonstrate that you simply do not know what
you are talking about and apparently haven't even bothered to take the
time to "read up" on what you are trying to say.

The "holes you are talking about aren't drilled, i.e. cylindrical,
holes but are , apparently, cut "holes" as described in the article,
that you obviously didn't read, which says, "It's not a good
structural element, says mechanical engineer Bernard Cuzzillo,
referring to rectangular notches clearly cut in the four-inch thick
steel at the bottom of the 85-foot long I-beam used to support the
terminal deck across Fremont Street.

Please note, "RECTANGULAR NOTCHES" not drilled holes.
Unless, of course, you anticipate cutting rectangular holes to install
the cylindrical revnuts.

For God's Sake! They even had a video that clearly showed the cut,
angular, holes... and you didn't even bother to watch the movie.



Square apertures like a DeHavilland Comet? What could go wrong?

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


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