There, you have seen it. This is the last picture of the assembled Senator Chronograph Panorama Date that we are going to show because we are going to look inside at the chronograph movement. When we first reported on this Baselworld 2014 novelty (see here), we provided plenty of pictures and announced the inclusion of Glashütte Original’s in-house movement, its first conceived and built for a chronograph, the calibre 37-01. This integrated chronograph movement with flyback was also included in their seventies collection. As we peel away the layers to see and understand the chronograph function better, we get a glimpse at the workings of chronograph movements in general and at Glashütte Original’s timeless design in particular.
Glashütte-Original’s chronograph design takes an old school approach that celebrates the craft of watch making where other options exist to lower the price, simplify production and speed repair. It is their choice of a variable inertia, free sprung balance in the escapement, a column wheel and oscillating pinion for the chronograph complication that adds imperceptible value to the watch. This modern chronograph implementation reduces the parts in the movement to 450 with 65 jewels. They are careful to display the chronograph movement through the caseback, but we want to dissemble the movement for a better understanding. Let’s start with the escapement. (A detailed explanation on how escapements work can be found in our article on the GP Constant Escapement).
Calibre 37 with free sprung balance
The Calibre 37 escapement uses a variable inertia, free sprung balance. Four gold screws on the perimeter of the balance wheel adjust the inertia of the wheel while the length of the balance spring remains constant. The free sprung balance and its oscillation system allows for a reliable 70 hours of power reserve at a frequency of 4 Hz.
A regulated balance, the lower cost, ease of use, quick alternative, uses a regulator to adjust the balance spring, leaving those movements with a constant inertia, smooth balance wheel. Adjusting the balance spring as opposed to the balance wheel has a slightly more pronounced effect on the watch’s isochromism (accuracy over time). When a balance spring’s length remains constant as with a free sprung balance, it is able to oscillate freely, symmetrically and concentrically, providing a stability of rate. It is far easier to turn the screw of a regulator than to adjust the weights around a balance wheel, which is why the Glashütte Original’s free sprung balance adds old world craftsmanship to a modern chronograph re-design.
Some watches, and many older pocket watches, will incorporate both types of regulators, so that the primary, free sprung balance makes major changes and the secondary regulator, makes slight changes for fine tuning. The Calibre 37 might seem such a hybrid with its swan neck regulator, but this regulator adjusts the rate symmetry instead of the oscillation, meaning the pallet fork is positioned so that the impulse from the pallet fork to the escapement wheel is symmetrical in both directions. For those obsessed with accuracy, they might call this over-engineering, offering accurate recording up to 0.125 seconds, but we prefer the superlative, impeccable design.
Glashütte-Original Senator Chronograph – the chronograph function
Glashütte-Original Senator Chronograph’s movement, Calibre 37, utilization of a column wheel can also be contradistinguished from those chronographs run on cam actuated movements. The cam systems with their series of levers and cams have more play in their parts, a fact visibly noticeable in the jump of the seconds hand when pressing the start button.
The column wheel, reminiscent of a turret on a castle, turns with the push of the start and stop buttons and precisely engages or disengages the coupling (start) or the brake levers (stop). The video below shows the Calibre 37, and beginning at 0:22, you can get a quick glimpse of the column wheel in action.
Most chronographs feature either a horizontal or vertical clutch for transferring power from the watch movement to the chronograph function, but Glashütte Original has opted for a clutch with an oscillating pinion (composed of a moving rod and two pinions), which replaces the chronograph’s customary two large wheels. The efficacy of this coupling design is that it connects the chronograph directly to the watch movement, providing immediate starts and improved accuracy. The roots of the oscillating pinion go back to 1887 when Heuer invented the system; yet another reason why the Calibre 37 is steeped in the oldest watch making traditions.
(click on the images for larger versions)
Fortunately, we can imaginatively take apart Glashütte Originals Calibre 37 without having to put it back together again. The Glashütte-Original Senator Chronograph Panorama Date comes fully assembled, but to appreciate the magnitude of this watch, and its chronograph complication specifically, requires some deconstruction. Like an archeologist uncovering the past, we found the Calibre 37’s chronograph function comprised of highly skilled, labor intensive traditions. Finding such a love-of-craft in a watch adds an often overlooked category of owner luxury, the luxury of knowledge. Bravo G.O.