Question about hanging a manual wind pocket watch
Steve
hook inside a glass case) it rocks back and forth ever so slightly (I
assume from whatever gears are causing the watch to function). The
big problem is the time shifts slightly due to this movement. If I
lay the watch flat it keeps time perfectly.
I'm unfamiliar with pocket watches and this is my only one. Is this
normal?
John DeRosa
Sounds like angular momentum. The energy's going into moving the watch, instead
of moving the gears. Energy cannot be created or destroyed....
STDWATCH
While your watch is hanging unsupported, from its hook, the balance vibrations
cause the entire watch to act as a pendulum, transferring some of the
rotational energy of the balance wheel into making the entire watch rock back
nd forth. This will affect its rate, but will not damage the movement in any
way.
Carl West
Sounds like if he were to damp the swinging motion the watch would be more accurate.
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STDWATCH
vibrate back and forth the change in rate will not occur.
S Crowley
watch is in good order then all will be well. I don't notice any
serious rate changes but they are not running ALL of the time.
However, I do wonder if the LONG term running in JUST the one position
(under a dome) can have some specific wear problems. When I began at
the bench (just 50 years ago) I was told that hanging watches should
be run in other positions for a month or so every year. I have been
doing that ever since without any real scientific argument for or
against. I wonder if I am just perpetuating a myth...... Am very
open to advice on this......
Happy New Year everyone.......
Sylvester A Crowley, PO Box 93, Bridgend CF31 4YR, Wales, UK..
British Watch Clock Makers Guild - American Watchmaker Institute
Primary Web Site: http://www.silvabel.com
Does Ammonia Eat Clocks?: clocksammon...@yahoogroups.com
Fax : UK 020 77 48 31 77 International +44 20 77 48 31 77
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"STDWATCH" <stdw...@aol.com> wrote in message
news:20031230104847...@mb-m27.aol.com...
Stephen
"John DeRosa" <stu...@qwest.net> wrote in message
news:kl43vv8ttjtfku37g...@4ax.com...
And if the natural frequency of the watch as a pendulum is different from
the frequency of the balance (or a multiple thereof) it may tend to affect
the speed of vibration of the balance.
It is also possible that the watch will keep a slightly different rate when
'pendant up' than when laid 'face up', whether or not it is free to
oscillate. This is because there is slightly more friction in the bearings
in that position (I think).
Stephen Aleck
Kent Betts
I was told that hanging watches should
> be run in other positions for a month or so every year.
Stands to reason. A hanging watch would put all the wear on the jewels in
one spot. Since you have been at the bench 50 years, perhaps you could tell
me....do jewels wear, or are they so hard that they are not affected by it?
Do the jewels impart much wear on the pivots? What is the theory behind the
jewel useage? Is it primarily to reduce wear or to reduce friction? What
is the purpose of putting oil in a jewel?
S Crowley
learned anything other than there is always something new to
learn.....
As for those jewels...... I think you know the answers to all your
questions already.
SAC
Sylvester A Crowley, PO Box 93, Bridgend CF31 4YR, Wales, UK..
British Watch Clock Makers Guild - American Watchmaker Institute
Primary Web Site: http://www.silvabel.com
Does Ammonia Eat Clocks?: clocksammon...@yahoogroups.com
Fax : UK 020 77 48 31 77 International +44 20 77 48 31 77
======================================================================
============================================
"Kent Betts" <kentREb...@techispTHIS.com> wrote in message
news:vvnaohd...@corp.supernews.com...
SlamSpamThankYouMam
Hello, Ken.
Keeping the watch in a hanging position should put the weight of the
train on the bottom side of the jewels except that the torque imparted
by the mainspring tends to direct the pivots towards the same side of
the jewel that is 'resisting' the effect of the torque being applied
to that wheel. And the this force is far greater than the effect of
gravity; at least up to the escape wheel. Now when we get to the
lever and balance, gravity is a much larger influence thanks to the
diminuition of torque due to the gearing up effect of the train and
also due to change in function. Jewels are used to reduce friction
which, in turn, reduces wear. Using jewels allows pivots to be
much smaller and yet remain intact for many years when well
maintained. This reduces overall friction, and makes remaining
frictional forces more consistent during the run of the movement. An
escapement is most accurate when there is the least amount of
variation in the swing of the balance when exposed to changes in
temperature and position. Part of making an escapement accurate
involves paying attention to details such as pivot size and jewel
clearance, ensuring that fricional forces are consistent between
hanging positions and flat, proper gear and escapement engagements,
proper lubrication, and by having the mainspring run being as even in
power from beginning to end as is possible. This last is accomplished
by the use of longer, thinner mainsprings and fusees. In turn, this
is improved and made easier by jewelling all the way to the barrel
pivots.
I have seen balance cock cap jewels with pockets worn in by the end of
the balance staff when dirt got into the escapement. Dirt mixed with
oil makes a dandy cutting compound...
I've cleaned a few watches and put them together without any lube on
the bearing surfaces. I then observed their run. The low-grade
watches with brass escape wheels and only the basic seven jewels
mostly would not run with any kind of good swing; some not at all.
High grade watches often ran well, but with variations in
timekeeping. Oiling the low-grade watches while they were running
produced dramatic increases in amplitude and accuracy with the most
visible increase seen when the escape teeth were oiled. (Of course,
the balance had to be pulled to do the balance pivot jewels and caps.)
Oiling the high grade watches in the same way had much less visible
effect on amplitude, but good increase in timekeeping qualities. I
also found that I had to use an oil which 'stays put' in the
unjewelled pivots, but could use a mineral based oil in the jewelled
pivots. Mineral oils stay 'fresh' longer than the Moebius oil I
normally use, but unfortunately tends to dissipate from any but the
most highly polished surfaces.
Hope this is of interest
Regards,
Andy