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    Rory formerly worked as Curator of Horology at the Royal Observatory, Greenwich, where his role included day-to-day management of research and digitization projects, writing, public speaking, conservation, convening conferences, exhibition work, and development of acquisition/disposal and collection care policies. In addition, he has worked as a horological specialist at Bonhams in London, where he cataloged and handled many rare timepieces and built important relationships with collectors, buyers, and sellers. Most recently, Rory has used his talents to share his love of horology at the university level by teaching horological theory, history, and the practical repair and making of clocks and watches at Birmingham City University.

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Gents Pulsynetic Pendulum

spudfer

Registered User
Oct 17, 2013
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I have recently purchased a 1938 Pulsynetic master clock that sadly is incomplete because it is minus it's pendulum suspension spring and trunnion. Can anyone help me with any info on these missing parts such as sizes as I cannot find any details anywhere. The only thing I really know is the pendulum is made of Invar. I would be really grateful for any advice which will help me to reconstruct these parts.

Thank you
 

eskmill

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Aug 24, 2000
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Welcome to the Message Board spudfer.

Sadly, many master clocks are found without the pendulum because the unmanageable long pendulum rod and the heavy bob were usually removed and stored separately. Never to be rejoined as the whole clock.

You don't state exactly if the timepiece is badged as a Pulsynetic or as a Gent's of Leicester. And which model? Most of the commonly available are Gents C-7 type.

Unused pendulums are rarely found in the US but some can be obtained in England where they were more commonly used.

Making a usable substitute is difficult because the invar metal rod for the Gent is a flat shape. The proper size flat invar is difficult to locate in the US but round 5/16" diameter rod is available in 12 foot long pieces from at least two suppliers.

Occasionally, a four-foot long scrap can be found but without certification. A Gent's master clock doesn't look right with a round pendulum rod.

I would frankly advise fabricating a substitute flat rod using ordinary steel and learn to live with seasonal variations in rate and keep the clock in a temperature controlled environment.
 

John Hubby

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I have recently purchased a 1938 Pulsynetic master clock that sadly is incomplete because it is minus it's pendulum suspension spring and trunnion. Can anyone help me with any info on these missing parts such as sizes as I cannot find any details anywhere. The only thing I really know is the pendulum is made of Invar. I would be really grateful for any advice which will help me to reconstruct these parts.

Thank you
Spudfer, from your message it appears to me you have the pendulum but are missing the upper suspension and cross-bar trunnion that holds all this is place. Is this correct? If so it will be much easier to make a workable replacement than to construct a pendulum. If you could post photos of what you have it will help a lot.
 

eskmill

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Mea culpa. In my haste I misunderstood your need for the suspension trunnion and spring and instead replied as if the entire pendulum assembly was missing from your Pulsynetic master clock.

I thank John Hubby for his response.

Further, I understand that although the Pulsynetic master clocks were produced by Gent, the dimensions of and details of the pendulum suspension assembly or trunnion may be quite different as needed by the Pulsynetic clock when compared with the trunnion and suspension spring assembly used with the Gent C-7 master clock.

I believe that the services of a machinist may be required to fabricate a suitable trunnion assembly and suggest that Meadows and Passmore in England may be able to supply a compatible suspension spring.
 

spudfer

Registered User
Oct 17, 2013
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Many thanks for your reply just to to clear things up it is a Gents C7 Pulsynetic
master clock.It is missing the whole pendulum assembly including the suspension spring and trunnion.The Invar rod is not such a problem, it is what size the parts are so I can remanufacture them as to be as close to original as possible, that's the problem. Any ideas?

Regards,

Mike
 

eskmill

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I can only offer hope that a Message Board subscriber who has a dis-assembled or parts of a Gent's of Leicester C-7 master clock responds to your need for critical dimensions of the trunnion and the suspension spring attachment.

I don't have a Gent they're more popular with "sparkies" in England and its former colonies. Perhaps POM in Mumbai can provide a clear photo and enough measurements so that a drawing could be produced for fabrication. Suspension springs are available in England.

Ask POM for a photo and dimensions.
https://mb.nawcc.org/showthread.php?106455-Gents-Co-Leicester-Pulsynetic-Time-Worth-Acquiring
 
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prideofmatchingham

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Dec 13, 2011
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HI, Saw this thread now as my Gents was completing its restoration. I will provide whatever info is needed. Just let me know what is a trunnion!!! I can even ask my guy if he can make one trunnion and suspension spring attachment.

As of now, I dont have any slaves, so what voltage and current would be needed?
 

Dick C

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Oct 14, 2009
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You may have thought of this; however, a suggestion.

Go to the e...bay international sites such as www.ebay.co.uk and do a search for GENT CLOCK .... then if you find a part being offered contact the seller to see if they have anything else that may solve your problem.
 

eskmill

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POM asks, "As of now, I dont have any slaves, so what voltage and current would be needed?"

Generally the Gents master-slave system is not voltage rated. Instead the master-slave circuit has a current (ampere) requirement of 220 Milliamperes because the master and attached slave dials are connected in series. (daisy-chained)

On most Gent master clocks, there is a large movable tap wire wound resistance included in the circuit. The usual practice is to employ either 12 or 24 Volts DC then adjust the variable resistance while measuring the source current with the circuit manually closed to the required current.

Gent master pendulum fabrication could be made without using the required invar flat metal rod using plain steel stock if the master is used in a relatively constant temperature environment.

Locating a convenient length of the proper dimensioned flat invar alloy stock will likely be very difficult. The Gent master just doesn't look right with a round pendulum rod.

It is generous that POM has offered to provide the dimensions needed to fabricate the Gent pendulum assembly and the mounting bar or trunnion. The trunnion allows for lateral postion adjustment of the suspension assembly.
 
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jcosta-co

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Apr 4, 2011
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As of now, I dont have any slaves, so what voltage and current would be needed?
With no slaves connected to your master clock there is no need to supply power the to master-slave circuit. Leave it open circuited. Only the master clock would require power.
If and when you are ready to operate a slave with the master clock then you should power this master-slave circuit and adjust the current for approximately 220 ma.

Simply stated, right now you do not need to be concerned with the master-slave circuit.

Regards,
John
 
Last edited:

itspcb

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Aug 6, 2006
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Incidently my C7 is from 1934 S/N LA 3578
(Anyone know what the 'LA' means?)
Peter
 

spudfer

Registered User
Oct 17, 2013
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Hi

Many thanks for your kind offer. I have now managed to sort out the sizes. FYI the trunnion is the threaded bar with the two nuts and two large washers which holds the suspension spring at the very top of the pendulum.
as for your question on slaves it is normally 24volts .22 ma

Regards

Mike
 

spudfer

Registered User
Oct 17, 2013
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0
Hi Peter

Many thanks for the offer but I believe I now have everything sorted

Regards

Mike
 

paulb939

Registered User
Feb 11, 2014
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Boulder, CO
Incidently my C7 is from 1934 S/N LA 3578
(Anyone know what the 'LA' means?)
Peter
Mine is dated 18/6/'28 on the paper label inside the top of the clock, and is numbered just 2716 - no "LA"! However it does appear to have been initialed nearby - maybe that's what you are seeing. Is yours handwritten on the label?

IMG_0076.jpg
 

prideofmatchingham

Registered User
Dec 13, 2011
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Mine is 8656 dated 28-4-53. No LA here too!

DSC07576 (1024x768).jpg
 

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