Re: [time-nuts] Three subjects.
Neat. Thanks.
I think we had one like that back in grade school. That was a long time ago.
There was an article in Scientific American 20 or 30 years ago. The idea was
to make an old grandfather clock keep very good time by adding a magnet to
the pendulum so you could gently push/pull it.
Anybody remember that one? Anybody build one?
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Yes, there were a similar product produced for schools and offices that
synchronized the clocks to a master kept in the office though it lacked
the function for bringing a generator output into line.
For a time, before quartz, the very best observatory clocks were a
pendulum variety with a 'master' pendulum in a vacuum case and a 'slave'
pendulum in a conventional clock. The slave was set very slightly slower
and pulled into line from a periodic pulse from the master (which was
kept running with electrical impulses). I would guess that there was a
Amateur Scientist article covering something like this, though with the
refinement of pendulum longcase (grandfather) clocks by that time in
history, I don't know as any amateur modifications would actually
improve timekeeping.
Hal Murray wrote:
Neat. Thanks.
I think we had one like that back in grade school. That was a long time ago.
There was an article in Scientific American 20 or 30 years ago. The idea was
to make an old grandfather clock keep very good time by adding a magnet to
the pendulum so you could gently push/pull it.
Anybody remember that one? Anybody build one?
Earlier this week I made a claim that I am a Time Nut from way back. In
further evidence of that, I report that I actually clipped and saved that
article.
Reference: Scientific American, September 1974, pages 192 - 198, in a section
called The Amateur Scientist.
The man made a quarts crystal oscillator that sent a pulse to an electromagnet
that was placed near a permanent magnet mounted on the pendulum of a wall (not
a grandfather) clock. The pendulum was set a bit slow for its 72 per minuet
beat and the electronics gave it a push each cycle to make it swing at the
correct rate.
He had faster and slower count settings to adjust its rate. The ultimate check
was still listening to WWV while looking at the clock.
-- Dennis O'Keefe
New Paltz, New York
On Wed, 04 Jan 2006 23:11:07 -0800
Hal Murray hmurray@suespammers.org wrote:
Neat. Thanks.
I think we had one like that back in grade school. That was a long time
ago.
There was an article in Scientific American 20 or 30 years ago. The idea
was to make an old grandfather clock keep very good time by adding a magnet to
the pendulum so you could gently push/pull it.
Anybody remember that one? Anybody build one?
--
Dennis O'Keefe wrote:
Earlier this week I made a claim that I am a Time Nut from way back. In
further evidence of that, I report that I actually clipped and saved that
article.
Reference: Scientific American, September 1974, pages 192 - 198, in a section
called The Amateur Scientist.
The man made a quarts crystal oscillator that sent a pulse to an electromagnet
that was placed near a permanent magnet mounted on the pendulum of a wall (not
a grandfather) clock. The pendulum was set a bit slow for its 72 per minuet
beat and the electronics gave it a push each cycle to make it swing at the
correct rate.
He had faster and slower count settings to adjust its rate. The ultimate check
was still listening to WWV while looking at the clock.
If you have an electronic copy of that I'd like to see it. I found a
text-only version, but would like to see the original.
I believe he used a TCXO. I have a small French clock that sits on a
mantelpiece, I'd like to do that too, but getting power to it is not too
easy. My wife is not keen on wires going to it.
I did think about solar power, or powering it from the pendulum itself,
but neither look too practical in my particular circumstances.
I did wonder if its possible to put the electromagnet under the clock,
rather than inside it, but that will probably put too much wear on the
clock.
You can probably cut down the power consumption by running the clock at
as accurate as possible (not slow) and using a bipolar pulse, rather
than a uni-polar one.
Certainly an interesting idea.
BTW, if you look at the sound produced by an old clock wth a microphone
and scope, it is far from regular. I suspect the pendulum is more so
though.
I don't have a electronic way to distribute this article, but will mail a
photocopy to the first ten people who request them directly to me at
There are several diagrams and tables that would make a text-only copy
useless.
Dennis O'Keefe
New Paltz, New York
If you have an electronic copy of that I'd like to see it. I found a
text-only version, but would like to see the original.
I believe he used a TCXO. I have a small French clock that sits on a
mantelpiece, I'd like to do that too, but getting power to it is not too
easy. My wife is not keen on wires going to it.
I did think about solar power, or powering it from the pendulum itself,
but neither look too practical in my particular circumstances.
I did wonder if its possible to put the electromagnet under the clock,
rather than inside it, but that will probably put too much wear on the
clock.
You can probably cut down the power consumption by running the clock at
as accurate as possible (not slow) and using a bipolar pulse, rather
than a uni-polar one.
Certainly an interesting idea.
BTW, if you look at the sound produced by an old clock with a microphone
and scope, it is far from regular. I suspect the pendulum is more so
though.
The man made a quarts crystal oscillator that sent a pulse to an
electromagnet
that was placed near a permanent magnet mounted on the pendulum of a wall
(not
a grandfather) clock. The pendulum was set a bit slow for its 72 per
minuet
beat and the electronics gave it a push each cycle to make it swing at the
correct rate.
For a modern treatment of this see Bryan Mumford's
excellent web site:
http://www.bmumford.com/clocks/index.html
Those of you time-nuts who also keep "real" clocks
in addition to atomic clocks you'll find his Microset
timer an excellent way to track the performance of
your chronometers and pendulum clocks:
http://www.bmumford.com/microset.html
One last thing I should point out is that for every
person on this "electronic timekeeping" time-nuts
list there are a hundred old guys out there who
collect old mechanical clocks and watches. They
are members of the NAWCC (National Association
of Watch and Clock Collectors).
A small subset are NAWCC Horological Science
Chapter #161. This is a group of modern pendulum
clock makers and are driven more by the amazingly
deep science and technology of vintage and modern
precision pendulum clocks than the art and fashion
of wristwatches. See also:
Horological Science Newsletter
http://www.ubr.com/clocks/nawcc/hsc/hsn.html
Horological Science Issue Index
http://www.iinet.com/~holmstro/hsnissueindex.php
Subject Index to Horological Science Newsletter
http://www.horology.com/hip-hsin.html
At 01:37 PM 1/5/2006 , Tom Van Baak wrote:
A small subset are NAWCC Horological Science
Chapter #161. This is a group of modern pendulum
clock makers and are driven more by the amazingly
deep science and technology of vintage and modern
precision pendulum clocks than the art and fashion
of wristwatches. See also:
Which reminds me...I once was told that some of the early IBM big iron used
a very refined mechanical (low tc pendulum?) clock for the time of day
ticker. Anyone know if this is true or not?
--
newell
"Tom Van Baak" tvb@leapsecond.com wrote:
One last thing I should point out is that for every
person on this "electronic timekeeping" time-nuts
list there are a hundred old guys out there who
collect old mechanical clocks and watches. They
are members of the NAWCC (National Association
of Watch and Clock Collectors).
And as proof that there's a genetic component to our affliction,
my father is a long-time member of the NAWCC, and my baby pictures
are mixed in with pictures of hundreds of railroad watches :-).
Tim.