nickd
1591
Confusion from clocks :)
Oct 09, 2012,04:47 AM
Clock pendulums were traditionally referred to in terms of the time to make one half-swing (eg from left to right), probably because most of the escapements acted on both the L->R and R->L swings and you design the wheel train to count the "ticks".
A pendulum with a half-swing of one second and a classic escapement ticks every second, which is very convenient for all sorts of mechanical design aspects and has the advantage that a one second pendulum is roughly a meter long and so a good size for a long case clock. This is a very convenient length as the dial can be centered on the average eye height of about 1.6 m (one of those design considerations which is totally obvious once you know about it
), you've got a good drop for the weights so you can go for a long running time without rewinding, and you can increase the mass of the pendulum bob (eg 7 kg in a Synchronome, Pulsynetic) which is great for long term accuracy and stability.
A so-called "one second pendulum" makes a full oscillation (left to right to left) in two seconds, which means a period of 2 seconds and as f=1/T the frequency is 0.5 Hz.
3/4 second pendulums were also common as this gives an easy count for the wheel train and a case about a meter high for the pendulum of about 60 cm, just right as a wall clock. 1/2 second pendulums have a frequency of 1 Hz and a length of about 25 cm.
Alex
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7,200vph = 1Hz / 18,000vph = 2.5Hz / etc...
By: elliot55 : October 2nd, 2012-12:51
It is truly amazing that something so small and delicate can oscillate hundreds, if not thousands of times per hour. A vast majority of mechanical watches run at 28,800vph, or what is referred to as 4Hz. This means that the palette fork will go back and f...
Brilliant!
By: elliot55 : October 2nd, 2012-20:11
Thanks so much for the feedback. I am eager to learn more about how and why watchmakers choose the frequency to utilize in their watch. Much appreciated. - Scott
I think it's as much about what can be done as what should be done.
By: mkvc : October 2nd, 2012-21:34
For a long time, the 2.5 hz standard (18,000 vph) was state of the art. My guess is that below that rate there's a real drop-off in precision; I have never seen a watch, even a really old one, that used a slower rate. The first move was a small one, to 2....
Awesome Insight
By: elliot55 : October 3rd, 2012-04:45
MKVC - Thanks so much. Your informative post (which I've now read three times) only makes me want to delve that much deeper! - Scott
My Atmos Clock
By: elliot55 : October 8th, 2012-16:31
Hey, G - I think my ATMOS runs modestly, with the regulator making a full sweep every thirty seconds. So is this 1Hz? Are clock escapements measured the same way? I tried to pose this question to Martin Braun the other night and he just looked at me as if...
I forgot my atmos. A...
By: G99 : October 9th, 2012-00:32
I forgot my atmos. A beautiful slow rotation that mesmerises you, especially with a mirror behind it. G
Confusion from clocks :)
By: nickd : October 9th, 2012-04:47
Clock pendulums were traditionally referred to in terms of the time to make one half-swing (eg from left to right), probably because most of the escapements acted on both the L->R and R->L swings and you design the wheel train to count the "ticks". A pend...
AtmosI
By: nickd : October 9th, 2012-05:24
I just looked up Atmos. 2 oscillations per minute=1 oscillation in 30s (the period). f=1/T the frequency is 1/30s=0.033 Hz. Alex
Much obliged...
By: elliot55 : October 9th, 2012-07:20
Nick - Thank you for your post! Great explanation. Clears up many questions. Now I can't stop staring at my Atmos! - Scott
Yes, i must say a ...
By: G99 : October 9th, 2012-08:50
Yes, i must say a big thank you as well Nick. Clocks will never appear the same again. Best G On Oct 9, 2012 3:20 PM, "www watchprosite" *Alert from:* www:watchprosite > *Posted By:* elliot55 (registered) on October 9th, 2012 - 07:20 > > *Title: Much obli...