This entry from www.watchtock.com/blog disappeared, so I dug it up from an archive service and reposted it. Quality info here that I haven't seen from any other source:
Watchmaking Innovation in the Rolex Yacht-Master II
It is not often that Rolex and innovation come together in the same sentence. They are a company well known for producing reliable mechanical watches using tried and true watchmaking methods and designs, not innovation. I will say that for the most part, that is true. However, one of the lesser talked about Rolex watches actually houses one of the most technically advanced and innovative movements ever produced by Rolex. Even more interesting than that is that Rolex does not make any mention of the innovative movement design to anyone outside of the watchmakers who work on these movements.
This chronograph was built to count down from 1 to 10 minute intervals and the user is able to set the number of minutes to be counted via the Ring Command bezel and Triplock crown. Once the countdown chronograph is started, the user can synchronize it with the official regatta timing signals with a simple push of the reset button while the chrono is running. This causes an instantaneous jump of the minute hand to the nearest minute and the second counter to zero while continuing to countdown. It is kind of like a fly-back action for the second hand to sync it while maintaining the proper minute countdown. When the hands jump to the synced position, it is essential that there is minimal play in the wheel/teeth meshing of the chronograph wheels in order to minimize or hopefully eliminate any backlash. Due to the nature of the interaction of wheel teeth, there must be some amount of play so that the teeth do not bind and cause an undesirable amount of friction.
This play (slack) between teeth is what causes backlash or lag when starting a chronograph or using a fly-back or synchronizing function.
Here is a normal tooth profile that works well for most watchmaking applications:
To eliminate this play between teeth, Rolex designed the wheels to have slightly larger tooth profiles which would normally cause the watch to lock up. Then, to keep wheels from locking up, they essentially cut the tooth down the middle and removed material so that the tooth is actually like prongs that can flex to eliminate tooth play and avoid binding.
These wheels are actually grown using a LIGA (a German acronym for Lithographie, Galvanoformung, Abformung, or Lithography, Electroplating, and Molding in English).
Rolex makes a negative blank and then basically builds up material in empty space that will become the wheel. This is opposed to the standard cutting process that would not allow for a wheel of this design to be manufactured.
Here is a basic drawing I made to show the “spring” like wheel that is in the Rolex 4160:
It amazes me that Rolex does not publicize this innovation, but I’m sure they have their reasons. For now, this very special and uniquely Rolex wheel will remain a secret to all but Rolex watchmakers and readers of WatchTock.
Watchmaking Innovation in the Rolex Yacht-Master II
It is not often that Rolex and innovation come together in the same sentence. They are a company well known for producing reliable mechanical watches using tried and true watchmaking methods and designs, not innovation. I will say that for the most part, that is true. However, one of the lesser talked about Rolex watches actually houses one of the most technically advanced and innovative movements ever produced by Rolex. Even more interesting than that is that Rolex does not make any mention of the innovative movement design to anyone outside of the watchmakers who work on these movements.
I’m talking about the Rolex Yacht-Master II with the completely in-house Rolex 4160 caliber. This watch has a countdown chronograph for timing regatta starting sequences. The complication itself is not what is innovative, it is actually the way they improved it that excites my watchmaker side. First I will explain the function of the chronograph, and then I will get into the innovative designs Rolex used to improve the chronograph.
This chronograph was built to count down from 1 to 10 minute intervals and the user is able to set the number of minutes to be counted via the Ring Command bezel and Triplock crown. Once the countdown chronograph is started, the user can synchronize it with the official regatta timing signals with a simple push of the reset button while the chrono is running. This causes an instantaneous jump of the minute hand to the nearest minute and the second counter to zero while continuing to countdown. It is kind of like a fly-back action for the second hand to sync it while maintaining the proper minute countdown. When the hands jump to the synced position, it is essential that there is minimal play in the wheel/teeth meshing of the chronograph wheels in order to minimize or hopefully eliminate any backlash. Due to the nature of the interaction of wheel teeth, there must be some amount of play so that the teeth do not bind and cause an undesirable amount of friction.
This play (slack) between teeth is what causes backlash or lag when starting a chronograph or using a fly-back or synchronizing function.
Here is a normal tooth profile that works well for most watchmaking applications:
To eliminate this play between teeth, Rolex designed the wheels to have slightly larger tooth profiles which would normally cause the watch to lock up. Then, to keep wheels from locking up, they essentially cut the tooth down the middle and removed material so that the tooth is actually like prongs that can flex to eliminate tooth play and avoid binding.
These wheels are actually grown using a LIGA (a German acronym for Lithographie, Galvanoformung, Abformung, or Lithography, Electroplating, and Molding in English).
Rolex makes a negative blank and then basically builds up material in empty space that will become the wheel. This is opposed to the standard cutting process that would not allow for a wheel of this design to be manufactured.
Here is a basic drawing I made to show the “spring” like wheel that is in the Rolex 4160:
It amazes me that Rolex does not publicize this innovation, but I’m sure they have their reasons. For now, this very special and uniquely Rolex wheel will remain a secret to all but Rolex watchmakers and readers of WatchTock.
