Something a Little Different

Just for fun, I thought I'd service something a little different - it is a Tissot but that's all I'll say for now.

To avoid giving the game away, I have obscured the calibre number and the pictures start with re-assembly.

Here is the gear train in place, waiting for the bridge:


Now with the train bridge and barrel in place


The barrel bridge, ratchet wheel, click and crown wheel back on. Before anybody says something, I haven't forgotten one of the crown wheel screws, as you'll see later.


Pallet and balance back in place and it is running again


The date change mechanism is where the big improvement over the 78x series lies. It actually works.



Now the auto winder goes back on (without the oscillating weight) as as you will see, the efficient bit of design here is that one of the screws for this is longer than the others and goes through the bridge and acts as the second screw for the crown wheel.


The clue to why this is different is in the first and fifth photos.

I saw this thread yesterday but it's taken me a whole day to make my mind up.

I'll be interested to see if I'm right. If so, I want one!

Cheers, Chris

Now that is a strange dial

Penultimate clue:

Jim, of course, was right - as you can see in this picture with the "hands" attached.


The clues were that there is a wheel to drive a second hand (in the first photo) but you can see in the fifth photo that the cannon pinion has a closed end and that the hour wheel is flat and has no way to attach an hour hand. The main plate is peculiar to this movement, as is the post on the second pinion (that has a rounded end and is shorter than the others in this series) because there is no second hand.

The 2581 is definitely a modified movement rather than a purpose made one but this series, the 24xx/25xx series are a very well designed series. They are so much better than the 78x series especially where the date change mechanism is concerned.

What I find interesting is the way the jump hour function works. That flat hour wheel only comes into play for setting the time, everything else works through the wheel that acts like a chronograph runner. It just presses onto the cannon pinion - in the same way that a minute hand would. This drives the minute disk directly and the finger flicks the hour disk round in the same way that the finger on a chronograph runner triggers the minute recorder. The spring at the top just ensures that the hour disk only jumps by one hour.

Whoever last serviced it put the enlargement ring on the wrong way round so the screws holding the disks ground through the "dial" that is printed on the back of the crystal. Luckily, I managed to pick up a replacement crystal on eBay, so what was a red dialed jump hour will now be a blue one and the replacement movement clamps turned up today, so I will re-case it at the weekend.

Watch this space and congratulations to @JimInOz .