Longines Ernest Francillon 1867 Owner Review : Exceptional, elegant and refined

Longines Ernest Francillon 1867 The main and major interest here is its mechanism. Case in 18k yellow gold, water-resistant to 30m, this extra-flat Longines is equipped with a record-breaking extra-flat caliber of the time, a Jean Lassale 1200, 1.2mm thick. This caliber was then bought by Piaget and then abandoned because it was unreliable. Although qualified for high complications for several Swiss houses, 20 years of professional experience, I have never been able to make its operation reliable and apparently the problem of untimely stopping is known on this caliber. Between the absence of a dart at the anchor, some wheels mounted on bearings and a very relative thickness of the bridges, there is no shortage of reasons. Regardless, the result is unique in its kind due to daring technical choices, the industrial challenge that it represented and for me also in the re-dressing. This is perhaps the reason why it only worked for about 6 months, and why I bought it new from stock in 1992. A Longines with something other than an ETA engine, rare enough to be mentioned!