Recent content by John UK

  1. J

    Synchronome Slave - gravity problems!

    The minute hand on a Synchronome should be 'balanced'. Normally on a standard factory pattern hand, there is a small counterweight made of lead riveted to the hand. See attached pic (and I apologise for the poor quality!). Sometimes the 120 tooth driving wheel is counterbalanced instead - and...
  2. J

    Synchronous clock lubrication

    OK Mike, I stand corrected on the oil for the motor and completely agree re WD 40!. I am on the Gloucestershire/Worcestershire border area.
  3. J

    Synchronous clock lubrication

    Clock oils are good because they are formulated not to dry out or go 'gummy'. As a general 'rule of thumb', pivots (i.e. where a shaft rotates in a bearing/plate/support/tube) should be oiled - very sparingly. Gear trains (i.e. the gear teeth themselves) should usually be clean and dry. Being...
  4. J

    syncronome tower clock

    C421 dates to either late 1931 or early 1932, so about 90 years old. It is one of the "Coventry" series, made for Synchronome under contract in Coventry (UK) - designated by the C prefix. A distinguishing feature is a smooth inside radius to the bend of the gravity arm. Normal (i.e...
  5. J

    my Synchronome set

    Thank you for the pictures. The 3 slave dials with the convex glass and 'fancy' hands are unusual. I have not seen that pattern before. The copper cased one and the two wooden based ones are well known types. The master having green coil wire dates to pre about 1953.
  6. J

    syncronome tower clock

    A master and 5 slaves needs about 4.5 Volts (DC) for the master including it's inbuilt dial, and 1.5 Volts per external slave, so a 12 Volt supply should be absolutely fine. Current is 330 mA and the duty cycle is very low (roughly 100 milliseconds impulse every 30 seconds). This can be...
  7. J

    syncronome tower clock

    The larger Synchronome slave movements used two coils - running at a nominal 330 mA impulsed every 30 seconds (hence 120 teeth on the minute hand wheel). The two coil movements are most often seen on the Synchronome 'programme controllers' used to ring bells in schools, factories etc. but were...
  8. J

    syncronome tower clock

    You are quite right! It was my mistake to omit Gents (probably the most popular and well known of them all in the UK) from the group of "Synchronome, Lowne, Silent Electric, Gents". The Thornbridge, C6, C7 were all 30 second. Some of the later Gents (Chronopher) were 1 minute. Gents did some...
  9. J

    syncronome tower clock

    120 teeth on the wheel so half minute per pulse. Half minute impulses were standard (at that period) for most of the British master/slave clock systems (Synchronome, Lowne, Silent Electric) and the later Gillett & Johnston and English Clock Systems (ECS/Smiths). 1 minute impulse systems were...
  10. J

    syncronome tower clock

    If you could get a picture of the master clock - that would be great - if it is the original, the serial number on the bottom of the NRA plate (see attached) can give a good idea of the date for you. As a guide, serial number 100 was issued circa 1910 and by 1915 up to about 500. Early master...
  11. J

    syncronome tower clock

    The date given in the first post seems to tie in with the clock movement. The wooden former resistor (wired in parallel with the coils for spark suppression) was used up to around the mid 1920s. but the font and case used for the patented stamp was changed, probably around 1915, from the upper...
  12. J

    C7 Temperature stability

    Gent's own "see saw" mechanism can be seen on Clockdoc.org under Gents/Synchronisers/see saw
  13. J

    C7 Temperature stability

    The Gents pendulum rod should be Invar (unless it is a VERY early clock pre about 1910 which used a wooden rod). Invar should in itself give a good degree of temperature stability, but 25 degrees C is a wide range. I don't believe there is any 'compensation' as such used, but I may be wrong on...
  14. J

    Gents Gents leicester Hipp toggle master help required

    I can't give you a definitive answer and what follows is 'educated guesswork', but Gents C7 were designed for 220 mA series operation, but did come in different versions. I have one that was designed for use on 48V. Could it be a clue that your terminal board has a "50 Volt battery" set of...
  15. J

    Synchronome Minute Masters

    I am gathering data about Synchronome Minute Masters. These clocks, made between circa 1960 and 1970(ish) have a 3/4 second pendulum, Hipp toggle pendulum drive and a 1 minute single polarity impulse. My interest was triggered when a friend recently acquired a clock whose serial number was...

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