jrwong23 (aka watchthebin)
Montblanc Timewalker 100: The Calibre MB M66.25 explained
To recap, the Timewalker Chronograph 100... a superwatch (like a supercar) mechanically in my books.
Not the most handsome watch at first glance. Not easy to appreciate in terms of its looks, especially for lovers of classical watches (like me).
A busy dial when you first look at it. It was not a watch I spent more time with when I first saw Montblanc's SIHH 2014 offerings. The new Heritage collection's Perpetual Calendar and Pulsograph, being classically designed and finished, naturally caught my attention more.
When Montblanc HQ shared more details of this Timewalker 100 with Mike and me, I learned and appreciated more about this watch. On a high level, I already knew the movement is superbly finished by Montblanc Villeret and it is a mechanical marvel being able to mechanically time up to 1/100th of a second.
Of course, we know the Montblanc Villeret TimeWriter II Chronographe Bi-Fréquence 1000 could measure time up to 1/1000th of a second and it's even a greater mechanical marvel but that is of a different price league and is constructed much more traditionally, according to the traditions of their Villeret manufacture (case, dial and movement). This Timewalker Chronograph 100 on the other hand, has a very nice blend of modern vs tradition. Mike and I have already covered the construction of the composite watch case and how the dial is designed and constructed in a very modern fashion, in our previous posts.
The movement, the MB M66.25 calibre, is however, very traditional in construction and finishing, to the highest of standards in the Montblanc Villeret manufacture.
First of all, let me state that I'm a big fan of traditionally crafted and very finely finished manual chronographs movements. I can stare at movements from Montblanc Villeret chronographs such as the calibres 16.29 and 13.21 as well as Lange's Datographs' movements or any highly finished VC/PP/JLC Duometre Chronos, etc for a long time, especially with a loupe. I just love all the details on a traditional chronograph from the column wheel, to the large balance wheels (slow oscillators are typical for such traditional chronos) to the chrono levers, etc, especially when they are very well finished by hand.
This calibre M66.25 is no exception. I saw the movement in person some months back and wish I could see it again soon in the metal. For now, thanks to Montblanc HQ, I have access to some pictures of the movement's assembly in their Villeret manufacture, which I will share soon
The calibre is essentially a movement with two hearts: One for the time and the other, for the chronograph function.
Like all other Montblanc Villeret movements, a manually regulated screwed balance wheel (visually very nice as it's a large balance wheel) beating at 18,000 semi-oscillations per hour, governs the time function. Here, I would like to emphasize all Montblanc Villeret's balance wheels and balance springs are completely manufactured in-house in the Montblanc Villeret manufacture. This is no simple feat and could explain why Montblanc Villeret produces so few watches and movements per year (around 200 to 250).
This watch has a second balance wheel for the chronograph function, which needs to measure time up to 1/100th of a second mechanically! Hence a super fast 360,000 semi-oscillations per hour is needed for this. The movement hence has separate escapements and transmission systems. Thus, the chronograph function can be carried out without interfering with the time function.
There are also two barrels to power separately the time and chronograph function, hence with the chronograph running (fast like a supercar!), the time function's power reserve will not be affected.
The winding system is a bi-directional one - clockwise to wind the time and anti-clockwise for the chronograph. See illustration below provided by Montblanc HQ with the 2 barrels shown on the picture.
The 1/100th of a second chronograph mechanism is a patented one by Montblanc. A two-level column-wheel separates the functional level for starting and stopping the chronograph from the zero-return level for the elapsed-time counters. The higher level controls the chronograph rocker: its arrowhead carries the slender steel lamella that starts and stops the 50-Hz balance. The lower level of the column-wheel is the switching plane for the beak of the heart-lever. This lever returns to zero the 60 elapsed-seconds hand, which is connected to the heart-lever of the 15 elapsed-minutes counter.
There are essentially two different reset mechanisms found on this movement. 1) A classical one with hammers for minutes and seconds. 2) a central reset mechanism with a catch instead of a whip for the 1/100th of a second measurement. Impressive! I hope the picture below explains this better? with some graphical illustrations.
Hope you enjoyed this series of technical write-ups from Mike and I on the Timewalker Chronograph 100 (itself a very technical watch from the case to the dial to the movement!). This is the second watch in 2014, with a LeLocle case and a Villeret movement (the other being the Heritage Pulsograph). I believe Montblanc will make their 2 watch manufactures collaborate even more in 2015, joining the expertise of both manufactures.
We have some nice pics of the movement assembly of this calibre M66.25 (thanks to our friends in the Montblanc Villeret manufacture!) and will share them soon
This message has been edited by jrwong23 on 2014-12-28 06:44:04