Apologies to those who follow these blogs often as finding the time to add content can be hard when there are many projects and jobs to be done. This past month a rather unusual chronograph had come in and one i think worth sharing.
Many readers may be aware of the infamous 7750 movement used by many watch brands in its various forms and styles, this Tiffany chrono however is a little different so let us take a look. Normally the 7750 movement features sub dials at 6/9 &12, but as we can see this model has the same layout as the 7753 with sub dials at 3/6&9. The date function is also omitted here to account for the change in format. Why Tiffany choose this design or different approach we can only speculate but it makes for an interesting alternative when compared to many of the samey style 7750's available. The movement arrived in non working order but with no signs of damage a service was hopefully all that was needed.
So lets break down the movement and see what differs from the standard....
Removing the rotor we can safely let the mainspring power down by first removing the main click ( lower left ) and then releasing power via the automatic click situated in the second left hole on the automatic plate assembly. The dial is held in place with two small hooks which hide inside the central mainplate at approx 6 & 12 o'clock .....
We can see from the above photo the date assembly is absent and has instead been replaced with a custom gear train to run the 30 min sub dial at 3 o'clock. The upper gear is secured by a small brass friction bearing, hand levers are used to remove this before stripping down the motion/keyless work.
With the gear above removed we can proceed to remove the motion/keyless works before turning over and disassembling the main movement......
Time to turn over and break down the other side, photos not necessarily in the right order ( my mistake )....
With the movement stripped down and a thorough clean in the machines it was time to reassemble and test the movement.....
With the movement assembled and running it was due for a good test and after a few minor issues the movement was finally ready to be cased up inside a new casing ( original gold casing melted for scrap sadly ). The dial and hands required some modification for the new home but this was overcome without needing any drastic measures, the final result may not be original but it's not too shabby for a watch that was heading for early retirement. The movement may not be a strict 7750 design layout but it is an interesting and unique approach and one that marks it out different to the normal range available.
The watch is now returned and ready for a new owner, hopefully someone who appreciates an alternative design to a already loved classic movement.
More blogs are planned so stay tuned ;)
Hertfordshire based watch restorer. Follow my blog for new watches under restoration/repair