Grönefeld caliber G-03
Bart and Tim Grönefeld use stainless steel bridges exclusively for their movements. As well as the superior hardness and durability of stainless steel compared to the more generally used steel and brass, the metal gleams when polished to a mirror finish. Achieving superlative finishes in stainless steel is no easy task: polishing the hard metal takes a master watchmaker up to four times longer than polishing more commonly used brass.
As with the immaculately finished movement bridges, the tourbillon cage is crafted in stainless steel. Three days are required just for the hand finishing of the tourbillon components. A highly-polished stainless steel sleeve around the tourbillon draws further attention to the beautiful escapement by reflecting the oscillating balance wheel and the rotations of the escape wheel and tourbillon cage.
Normally a central seconds hand requires a friction spring to prevent small fluttering caused by play in the gear train. But for the Parallax Tourbillon, the Grönefeld brothers developed the movement with an added pinion and wheel so that the energy-sapping friction spring is not required. The latter feature improves power transfer to the regulator, contributing to the impressive power-72-hour power reserve.