Re: [time-nuts] Antique pendulum clocks
Thanks for these links. The Harrison clocks are amazing -- I saw them at Greenwich some years ago. The Trinity reference also amuses me as that was my college (quite a long time ago). Back in the 60s, my father and his cousin were competing to produce accurate pendulum clocks with accuracies of the order of a fraction of a second per day. Invar pendulums, temperature and pressure compensation and temperature controlled environments. Electromagnetic pulse drive. All built with transistors... I wish that I could talk to them now Philip On Fri, Nov 22, 2019 at 9:30 AM Tony Finch wrote: > Philip Gladstone wrote: > > > > The data that I get is surprising in that the pendulum swing varies > > according to the position of the hands on the clock. > > Clocks with large outdoor faces have extra problems along those lines... > > http://trin-hosts.trin.cam.ac.uk/clock/main.php?menu_option=pigeons > > Tony. > -- > f.anthony.n.finchhttp://dotat.at/ > Sole, Lundy, Fastnet: Variable 4 or less, becoming north or northwest 4 to > 6, > occasionally 7 in Sole. Slight or moderate, occasionally rough in Sole. > Rain > or showers. Good, occasionally poor. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
I have two pendulum clocks, one a 1930s-era torsional pendulum clock from Bavaria and the other a swinging pendulum clock built around 1990. I will follow this thread closely. Tom, you mentioned that there are lots of resources out there - can you elucidate? Thanks. DaveD Sent from a small flat thingy > On Nov 20, 2019, at 21:18, Adrian Godwin wrote: > >> On Thu, Nov 21, 2019 at 2:01 AM Bill Beam wrote: >> >> Most people interested in this problem have been dead for about 200 years. >> >> I knew there was a reason why I didn't feel so well lately .. > > > I have an electric pendulum clock by Bulle. A coil swings in a short arc, > following a curved magnetic polepiece. At some point, contacts close and > provide a timed sustaining impulse to the coil. > > Out of sheer pigheadedness, I am attempting to monitor the movement with > antique (perhaps not quite so antique) timing equipment. I have an HP456A > current probe to capture the impulse instance, an HP 5275A counter to > measure the period and an HP101A oscillator to provide a reference. ADEV > calculations might be done by an HP9815 calculator or perhaps an HP41 if I > can't find the 9815's parallel interface. Non-HP equipment is permitted but > nothing suitable has come up so far. > > A difficulty at the moment is that the contacts bounce somewhat, making > the impulse timing poorly defined. I haven't yet got as far as seeing any > mechanically caused pattern to the errors. > > Thanks to Tom for giving me more distractions to read :) > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
You may be interested in a thread here earlier this year titled "Absolute time accuracy pre-Cesium?" starting March 25. Also, look for references to John Harrison in the archives. There's a video showing several of his clocks running with the grasshopper escapement, and one of his long clocks being taken apart. http://lists.febo.com/pipermail/time-nuts_lists.febo.com/ On Wed, Nov 20, 2019 at 8:00 PM Philip Gladstone wrote: > > I've started to monitor the individual ticks on a grandfather clock from > the 1790s. Essentially I timestamp whenever the pendulum breaks/restores a > light beam. > > The data that I get is surprising in that the pendulum swing varies > according to the position of the hands on the clock. It appears that the > amplitude of the swing depends on the driving force imparted by the > escapement. Since the second hand is not counterweighted, there is slightly > more energy available to drive the escapement during the first half of each > minute and slightly less in the second half. There is much bigger effect at > the end of each hour when the mechanism has to move a lever to trigger the > strike mechanism. This 'end of hour' effect changes the pendulum swing > enough so that the period is noticeably affected (maybe by 300ppm) > > Anyway, my google-fu did not reveal anybody else interested in this > stuff... Anybody here interested? > > Philip > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
Philip Gladstone wrote: > > The data that I get is surprising in that the pendulum swing varies > according to the position of the hands on the clock. Clocks with large outdoor faces have extra problems along those lines... http://trin-hosts.trin.cam.ac.uk/clock/main.php?menu_option=pigeons Tony. -- f.anthony.n.finchhttp://dotat.at/ Sole, Lundy, Fastnet: Variable 4 or less, becoming north or northwest 4 to 6, occasionally 7 in Sole. Slight or moderate, occasionally rough in Sole. Rain or showers. Good, occasionally poor. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
Heck as much as I like clocks I just want to see Adrians working HP 9815 calculator. Other comment for me at least is a good clock is a marvel by itself. Adding electronics removes the amazing engineering that went into the clock. By good I mean clocks few of us can afford. Though on time-nuts I have seen from time to time lucky people have found these clocks at affordable prices. Regards Paul. On Thu, Nov 21, 2019 at 2:00 AM Matthew D'Asaro wrote: > You are not the first to try this. The usual method for timing mechanical > clocks is either acoustic (a microphone picks up the sound of the > escapement) or optical (a sensor is blocked from light by the pendulum). > The optical method is more accurate but more cumbersome to setup. > > Matthew > > Sent from Matthew D'Asaro's iPhone > > > On Nov 20, 2019, at 6:18 PM, Adrian Godwin wrote: > > > >> On Thu, Nov 21, 2019 at 2:01 AM Bill Beam wrote: > >> > >> Most people interested in this problem have been dead for about 200 > years. > >> > >> I knew there was a reason why I didn't feel so well lately .. > > > > > > I have an electric pendulum clock by Bulle. A coil swings in a short arc, > > following a curved magnetic polepiece. At some point, contacts close and > > provide a timed sustaining impulse to the coil. > > > > Out of sheer pigheadedness, I am attempting to monitor the movement with > > antique (perhaps not quite so antique) timing equipment. I have an HP456A > > current probe to capture the impulse instance, an HP 5275A counter to > > measure the period and an HP101A oscillator to provide a reference. ADEV > > calculations might be done by an HP9815 calculator or perhaps an HP41 if > I > > can't find the 9815's parallel interface. Non-HP equipment is permitted > but > > nothing suitable has come up so far. > > > > A difficulty at the moment is that the contacts bounce somewhat, making > > the impulse timing poorly defined. I haven't yet got as far as seeing any > > mechanically caused pattern to the errors. > > > > Thanks to Tom for giving me more distractions to read :) > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
You are not the first to try this. The usual method for timing mechanical clocks is either acoustic (a microphone picks up the sound of the escapement) or optical (a sensor is blocked from light by the pendulum). The optical method is more accurate but more cumbersome to setup. Matthew Sent from Matthew D'Asaro's iPhone > On Nov 20, 2019, at 6:18 PM, Adrian Godwin wrote: > >> On Thu, Nov 21, 2019 at 2:01 AM Bill Beam wrote: >> >> Most people interested in this problem have been dead for about 200 years. >> >> I knew there was a reason why I didn't feel so well lately .. > > > I have an electric pendulum clock by Bulle. A coil swings in a short arc, > following a curved magnetic polepiece. At some point, contacts close and > provide a timed sustaining impulse to the coil. > > Out of sheer pigheadedness, I am attempting to monitor the movement with > antique (perhaps not quite so antique) timing equipment. I have an HP456A > current probe to capture the impulse instance, an HP 5275A counter to > measure the period and an HP101A oscillator to provide a reference. ADEV > calculations might be done by an HP9815 calculator or perhaps an HP41 if I > can't find the 9815's parallel interface. Non-HP equipment is permitted but > nothing suitable has come up so far. > > A difficulty at the moment is that the contacts bounce somewhat, making > the impulse timing poorly defined. I haven't yet got as far as seeing any > mechanically caused pattern to the errors. > > Thanks to Tom for giving me more distractions to read :) > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
Somewhere, a few years ago, I saw a video in which a fairly large number of metronomes were mounted on a common base and exhibited some interesting injection locking behavior. Personally I keep thinking of phase locking a G'father clock to a Rb standard. The trick will be to do so in a manner that requires no modification to the clock proper. And remembering to wind it at appropriate intervals- I'm too spoiled by watches and clocks that run for years at a time off a battery. Dana On Wed, Nov 20, 2019 at 9:00 PM jimlux wrote: > On 11/20/19 5:51 PM, Bill Beam wrote: > > On Tue, 19 Nov 2019 20:10:14 -0500, Philip Gladstone wrote: > > > >> I've started to monitor the individual ticks on a grandfather clock from > >> the 1790s. Essentially I timestamp whenever the pendulum > breaks/restores a > >> light beam. > > > >> The data that I get is surprising in that the pendulum swing varies > >> according to the position of the hands on the clock. It appears that the > > > Most people interested in this problem have been dead for about 200 > years. > > Also note that as the clock gets old and dirty it will begin to stop at > 8:45. > > > > Now if you want to see another old interesting clock problem look up the > > 'Thursday afternoon effect'. > > > > Now this time-geek-y stuff is why this list is interesting. > > I'm waiting for someone to have hooked up a bunch of cheap metronomes on > a common base to an array of TICCs... > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
On Wed 2019-11-20T16:51:00-0900 Bill Beam hath writ: > Most people interested in this problem have been dead for about 200 years. Au contraire. The BIH started operations early in the 1920s and those volumes of BIH Bulletin Horaire are scanned online. The first 20 years relied largely on pendulum clocks, and there are lots of fun diagrams of early electronics and radio tech too. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
On 11/20/19 5:51 PM, Bill Beam wrote: On Tue, 19 Nov 2019 20:10:14 -0500, Philip Gladstone wrote: I've started to monitor the individual ticks on a grandfather clock from the 1790s. Essentially I timestamp whenever the pendulum breaks/restores a light beam. The data that I get is surprising in that the pendulum swing varies according to the position of the hands on the clock. It appears that the Most people interested in this problem have been dead for about 200 years. Also note that as the clock gets old and dirty it will begin to stop at 8:45. Now if you want to see another old interesting clock problem look up the 'Thursday afternoon effect'. Now this time-geek-y stuff is why this list is interesting. I'm waiting for someone to have hooked up a bunch of cheap metronomes on a common base to an array of TICCs... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
On Thu, Nov 21, 2019 at 2:01 AM Bill Beam wrote: > Most people interested in this problem have been dead for about 200 years. > > I knew there was a reason why I didn't feel so well lately .. I have an electric pendulum clock by Bulle. A coil swings in a short arc, following a curved magnetic polepiece. At some point, contacts close and provide a timed sustaining impulse to the coil. Out of sheer pigheadedness, I am attempting to monitor the movement with antique (perhaps not quite so antique) timing equipment. I have an HP456A current probe to capture the impulse instance, an HP 5275A counter to measure the period and an HP101A oscillator to provide a reference. ADEV calculations might be done by an HP9815 calculator or perhaps an HP41 if I can't find the 9815's parallel interface. Non-HP equipment is permitted but nothing suitable has come up so far. A difficulty at the moment is that the contacts bounce somewhat, making the impulse timing poorly defined. I haven't yet got as far as seeing any mechanically caused pattern to the errors. Thanks to Tom for giving me more distractions to read :) ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
On Tue, 19 Nov 2019 20:10:14 -0500, Philip Gladstone wrote: >I've started to monitor the individual ticks on a grandfather clock from >the 1790s. Essentially I timestamp whenever the pendulum breaks/restores a >light beam. >The data that I get is surprising in that the pendulum swing varies >according to the position of the hands on the clock. It appears that the >amplitude of the swing depends on the driving force imparted by the >escapement. Since the second hand is not counterweighted, there is slightly >more energy available to drive the escapement during the first half of each >minute and slightly less in the second half. There is much bigger effect at >the end of each hour when the mechanism has to move a lever to trigger the >strike mechanism. This 'end of hour' effect changes the pendulum swing >enough so that the period is noticeably affected (maybe by 300ppm) >Anyway, my google-fu did not reveal anybody else interested in this >stuff... Anybody here interested? Most people interested in this problem have been dead for about 200 years. Also note that as the clock gets old and dirty it will begin to stop at 8:45. Now if you want to see another old interesting clock problem look up the 'Thursday afternoon effect'. >Philip >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
Hi Philip, For low rate measurements like a pendulum clock the timestamping method works well. A number of us do it that way. The same method works for GPS/1PPS-like signals and also mains (raw 50/60, or divided down to 1) Hz. Correct, if your measurements are precise enough, you should see rate modulation due to uneven mechanical effects like slightly unbalanced hands or gears with uneven wear. You might also see the effects of winding. The more complicated the clock the more rich the spectral peaks. You might want to fix the seconds hand so that it's balanced. Most clock hands are long and thin on one side and short and fat on the other so that rotational balance is maintained. Note that both TimeLab and Stable32 work with pendulum data. In Stable32, you'll find both PSD (Power Spectral Density) and ACF (Autocorrelation function) very useful when analyzing data from mechanical clocks. You asked if anyone else is interested in this level of detail. Yes, you're not alone. There are active discussions like this right now on the Synchronome list: https://groups.io/g/synchronome1/ Also, check out 30 years of wonderful HSN (Horological Science Newsletter) articles: http://www.hsn161.com/ Bryan's Microset website is a great resource for clock data and analysis: https://www.bmumford.com/microset.html Some nice examples of my own analyzing pendulum data: http://leapsecond.com/pend/shortt/ http://leapsecond.com/pend/clockb/ http://leapsecond.com/hsn2006/ We tend not to discuss the subject of mechanical clocks and watches here on time-nuts; mostly because those topics are already well represented with magazines, journals, books, and multiple web forums or email lists. But if you have specific questions about performance or measurement technique that's probably ok. See also the picPET timer chip, which does sub-microsecond timestamping [1]. And the TAPR TICC, which does sub-nanosecond timestamping [2]. /tvb [1] http://leapsecond.com/pic/ and http://leapsecond.com/pic/pp06.htm [2] https://www.tapr.org/kits_ticc.html On 11/19/2019 5:10 PM, Philip Gladstone wrote: I've started to monitor the individual ticks on a grandfather clock from the 1790s. Essentially I timestamp whenever the pendulum breaks/restores a light beam. The data that I get is surprising in that the pendulum swing varies according to the position of the hands on the clock. It appears that the amplitude of the swing depends on the driving force imparted by the escapement. Since the second hand is not counterweighted, there is slightly more energy available to drive the escapement during the first half of each minute and slightly less in the second half. There is much bigger effect at the end of each hour when the mechanism has to move a lever to trigger the strike mechanism. This 'end of hour' effect changes the pendulum swing enough so that the period is noticeably affected (maybe by 300ppm) Anyway, my google-fu did not reveal anybody else interested in this stuff... Anybody here interested? Philip ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
