Landeron 248 chronograph work

[Jon]

Hi guys,

I wrote a set of five lessons regarding the Landeron 248 chronograph, which I'm presently taking my second year students through. The lesson I'm posting here is the second of the five. It looks at disassembly of the chronograph mechanism focussing on the chronograph tension spring setting and understanding its importance. The first lesson explained how to set all the seven eccentric studs correctly, so the chronograph operates to its optimum. If someone can service a vintage chronograph such as this and set the eccentric studs properly, especially the minute register mechanism, then an ETA/Valjoux 7750 is child's play.

I have posted this lesson as a PDF, but unfortunately the videos in the lessons don't play, as it was written in PowerPoint

Here's a link to my cloud where you'll find the PowerPoint lesson. You'll need quite a new version of Microsoft Office to get the videos to play, otherwise they won't.

https://docs.google.com/presentation/d/12gb3BRu0smAGK634YC1ZtZZ5XH-OtzlU/edit?usp=sharing&ouid=107902587627140904870&rtpof=true&sd=true

Enjoy

Lesson 23. Landeron 248 Chronograph.pdf

[RichardHarris123]

Excellent, as usual. 

[Klassiker]

Jon, as you know, this has appeared at exactly the right time for me, so thank you! It never ceases to amaze me how generous the members of this forum are with their time and energy, especially the pros.