The Reason
The Cronometro Tipo chronograph houses the El Primero chronograph originally launched in 1969, the most historically famous calibre to be made by Zenith. It is an automatic chronograph with 30 minute recorder and frequency of 36,000 beats per hour.
Views of the watch with the strap and buckle removed.
The case back is held on by 4 stainless steel screws. Once loosened the case back can be removed revealing the calibre. The surface of the inner case around the case screws is polished to assure water resistance with the case back and seal when assembled.
When the movement is removed from the case it forms a solid block with the dial and movement ring surrounding the movement. The bottom, right image shows the dial in place with the hands removed.
The case with the movement removed, the glass is made from sapphire with an anti-reflective coating. The bezel can be manually adjusted in both directions. The seal for the crown tube often on the inside of the crown tube is on the outside in this design.
The polished minute and hour hands are filled with luminescent paint. The constant seconds hand plus chronograph minutes and seconds are laquered white.
The movement removed from the case but still inside of the movement ring which is held in place by two screws and clamps. The rotor held in place by 3 screws is now removed.
To the left is the movement ring with the paddles which transmit the pressure from the external pushers through to the movement. To the right images of the movement free from the movement ring.
The automatic/chronograph bridge removed
The Slick 13 1/4, is the reference for the movement holder for any calibre of the same diameter.
The automatic reverser wheel removed. The chronograph wheels in close up. The large lever in the foreground is the jumper spring for the minute recorder.
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