Hi, I succeeded in this pendulum project quite well.
I bought a M5 tapset via Ebay Germany, and made some soft iron retapped nuts which i have hung underneath the pendulum of two different Bürk 3/4 seconds master clocks, which are hanging next to each other.
These have been running perfectly in synch via an external 4.19 MHz quartz oscillator.
I used for the coil an E shape from an old discarded contactor and rewound a new coil to run on about 8 volts, impulsed every 3 seconds, via an 1 second impulse into a 4017 divider, to keep the output pulse within the beat of the 3/4 seconds beat of the clock.
I posted some photo's on an other thread in this forum, of the current arrangement which works well, but as i am in the process of tyding matters up i will take step by step photo's and will add these in the next couple of week or so.
Regards and happy time keeping, Raymond