Atum Backpage Rose GoldReference# MG-001396
- Case: 18-karat rose gold
- Size: 41mm
- Movement: hand-wound manufacture movement 107.0
- Function: stop seconds
- Power Reserve: approximately 42 hours
- Dial: gray
- Caseback: sapphire crystal
- Hands: steel, annealed to a brown-violet hue
- Strap/Bracelet: hand-stitched alligator leather
Until now, most of the highlights of a Moritz Grossmann caliber could only be admired on the caseback side of the watch. The development of the caliber 107.0, makes them visible on the dial side for the first time.
This new caliber is a mirror image of caliber 100.1 but has been redesigned for reverse rotation so that the movement can sit ‘upside down’ in the case. A generous aperture in the dial then exposes characteristic movement details such as the Grossmann balance, the hand-engraved balance cock and the three-band snailing on the ratchet wheel – all without taking the watch off the wrist.
The dial presents a full minute scale and an hour display from 11 to 5 o’clock to frame the glittering caliber presentation. The recessed small seconds ring has an extravagant bearing for the second hand featuring a gold chaton.
Caliber 107.0 is essentially a mirror image of the caliber 100.1, but with crucial new design elements. An additional wheel between the crown wheel and the ratchet wheel reverses the entire drive train with respect to the rotation of the mainspring barrel. The wheel train runs in the right direction thanks to the mirrored escapement and the mirrored oscillation system – also including the balance spring coiling direction.
The larger dimensions of the 2/3 plate necessitated design changes for the balance cock and the escape-wheel cock. The cantilevered geometry of the escape-wheel cock creates a balanced accent in the overall arrangement of the movement. The high-artistic finish showcases attractive hand engravings, bevels, and chamfers.
To achieve the desired presence of the winding wheels on the dial side, the dial train was reconfigured. The artistically finished train wheels were arranged beneath a lavishly polished minute-wheel bridge. Since in this case, the hand-setting mechanism is located on the opposite side of the movement, the setting wheel extends all the way through the caliber. The new arrangement created space for the optimized barrel bearing and the ratchet wheel, which was also shifted to the front side.
On the new rear side of the movement, the winding and hand-setting mechanism is now openly integrated in the train bridge, so its functionality can be fully observed for the first time. The stop-seconds and stop-balance functions have been redesigned as well. In the hand-setting mechanism, the brake position is sampled at the clutch lever and, via a push rod, transferred to the brake spring, which then stops the balance. After the pusher is activated and the movement starts, the brake spring returns the push rod to its rest position.