|Diameter:||31 mm (13.75 ligne)|
|Landeron Cal. 48||Complications:||2-Button, Cam Switching Chronograph, Chronograph, Oscillating Pinion Chronograph|
|Hands:||30 Minute Chronograph Hand at 3:00, Central 60 Second Chronograph Hand, Central Hour Hand, Central Minute Hand, Small Seconds Hand at 9:00|
|Distinguishing Technical Characteristics|
Clockwise Balance Cock
|Production: 1937 – 1970|
Cal. 48 is one of a family of chronograph movements produced by Landeron from 1937 through the 1970s. In all, over 3.5 million examples were produced.
Landeron Cal. 48 is a 13.75 ligne movement with a cam switching chronograph system. A variety of 14 ligne variants were produced, as well as complicated versions with calendars, moon phase, and hour counters. Like all movements in the family it uses Heuer-style oscillating pinion rather than a traditional horizontal clutch to activate the chronograph function.
The preceding Landeron 47 movement (the first cam-actuated chronograph) featured three buttons Start, stop, and reset. Cal. 48 switched to two-button operation.
Landeron Calibre 48 Chronograph Operation
Unlike many 2-button chronograph movements, the stop function shares the reset button rather than the start button. Therefore, on many Cal. 48 family movements from Landeron, the buttons function as follows:
- 2:00 – Start
- 4:00 – Stop/Reset
The original Landeron 48 featured a deep, curving hammer, a feature carried on to the 54, 56, and 58. The Landeron 51/151 features a conventional “boot” hammer, as does the 55, 57, 59/159, 80/180, and 81/181. The Landeron 148 moved to a distinct “JI” hammer shape, a feature shared by the 149/189/349, 154, 185, 186, and 187/248. Finally, the Landeron 152/352 moved to a deeply bowed hammer, a feature shared by the 153/353.