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First Chronograph Done & Dusted


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Eureka!

 

Just completed my first chronograph service, an ETA 7750. Leading up to this I watched Mark's videos quite a few times and went through the ETA Swisslab. I finally plucked up the courage, ordered some Molykote DX and begun the strip down while I waited.

I done the strip down without any instruction and was a little concerned that I had bit off more than I can chew.

 

There were a couple of springs that caught me unaware but nothing was lost or broken ;)

I labelled up several little storage tins so each section went into their own section with their screws as this is where I get caught out sometimes, using the wrong screw and having to backtrack later down the line.

 

Whilst I waited for the Molykote (from the USA) I took all the parts into class and put them through the cleaning machine.

As I didn't need the Molykote until the chrono module I built up the gear train and regulated it. The beat was out slightly, it was running +30 dial up but it had a healthy amplitude ~300

I soon had the beat error at 0 and soon after had it 0 secs per day dial up. in 4 positions it was not out anymore than 9 seconds (pendant down)

Impressive!

The Molykote arrived and I began the build up. I spent some time a few weeks back shaping the tips of my oilers and since then my oiling has improved significantly. This helped a lot building up the chrono module as it requires some very precise application.

Finishing off the chrono module with the installation of the chrono bridge whilst engaging the reversing wheel click spring...Yes!

Seeing the oscillating pinion happily turning away was a relief ;)

It was at this point I began to work out how it actually all worked.

The cam system with it's hammers and springs, the oscillating pinion with it's clutch & the hammer and the heart shape pieces, it's brilliant, so so clever. As you can probably guess I'm seriously impressed :)

The rest of the assembly went without incident except a tricky moment with the date jumper spring but a bit of peg wood in the right place had that secured ;)

 

It's all complete and I am looking forward to my next challenge (maybe a column wheel chrono)

The ETA 7750 is a great movement, I enjoyed working with it very much. I have an Asian copy here that will no doubt be a bit more of a challenge!

 

Cheers.

 

Installation of the Chronograph cam and Hammer Cam Jumper

cam1.jpg

 

Minute counting wheel, lock and operating lever installed.

cam2.jpg

 

Chrono module complete, ready for the chorine bridge to be installed.

chrono.jpg

 

Nearly there!

 

datewheel.jpg

 
Big spinny thing ;)
 
rotor.jpg
 
All done. I have to reset the 2 of the hands but apart from that, it's running very well.
 
dial.jpg
Edited by jaycey
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Thanks for the kind words guys.

Geo, you are spot on. I was on a whole new level of feeling awesome when I finished :D

 

Unfortunately, as nice as it looks I don't own the rest of the watch and I am dubious as to if the dial is genuine. I just do not know enough about the Breitling Chronomat Evolution that this belongs too?

No matter, I paid roughly half of what a 7750 is currently fetching so with the added enjoyment of servicing the movement...I'm quids in!

 

Just for added awesomeness, before I started this barely ran for more than 1-2 minutes with a really low amplitude, so I am definitely doing something right.

 

Cheers.

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