Fastwong
1658
Moment of inertia vs mass
I don't know which watch in particular you are talking about but most titanium rotors are paired with a heavier pm or tungsten outer mass on the rotor so it's really about maximizing moi and maybe saving a little $ by using less pm. It's the same principle as skeletonizing the rotor, the important thing for winding efficiency is not the mass of the rotor itself but the moment of inertia it can exert. For example, take a 1 pound metal rod vs an almost 1 pound metal ball at the end of a near weightless plastic (e.g. titanium) rod of the same length. The lightweight rod with the metal ball at the end can generate more rotational torque than the plain 1 lb rod even if total weight is the same.
All that said, I'm not sure it it desirable at the high end. At the high end I'm okay losing a little functionality/max winding performance in exchange for a beautifully done pm rotor.
Titanium
Specific gravity (SG) of 4.5, the metal is light and strong. Why am I seeing the metal used for the construction of rotors in automatic watches where high SG metal (gold pt, etc) is the desirable option at the high-end? Clive
Moment of inertia vs mass
I don't know which watch in particular you are talking about but most titanium rotors are paired with a heavier pm or tungsten outer mass on the rotor so it's really about maximizing moi and maybe saving a little $ by using less pm. It's the same principl...
New or exotic material is good.
But the watch companies should not go too far to use it as selling point and charge a premium unless they make it a generic feature on all their watches. I guess high end watch companies also want to max profit by replacing precious metals with titanium a...
