Review of Lange Datograph

By Peter Chong

November 1999

Driving in the rain…watercolor by Photoshop. Inspiration by Boon

The Lange Datograph. Here it lies on my wrist as I drove to work in the rain. The foul weather, and the resulting traffic jam, promised the drive to be bore. But the glint of the platinum catches my eye. It is
marvelous. It bekons, and persuades…ah…staring at the watch, I am almost thankful of the traffic…allowing me to share an intimate moment with this watch.

Immediately after Sincere’s Watch Show in Kuala Lumpur Oct 21 1999…the first public showing of the Datograph in the world, the kind folks at Lange Uhren extended me a loan of the Datograph, and the 1815 Moonphase in Rose gold for a week.

So here is the first review in the world, a Timezone exclusive, of this
magnificent watch, after a week of living with it.

I am jumping the gun, by saying that this is one of the nicest watches I have worn in a while. But it is indeed a marvel. The first new chronograph movement designed from ground up for nearly 20 years.

The Case

This is not a small watch. Measuring some 40mm diameter and 11mm in thickness, it is a large watch. The platinum case is very heavy, and the finish is very high. Polished areas achieve a high lustre and shine. The case side is decorated with a band of brushed finish which runs across the “barrel” of the case.

For such a large and heavy watch, it sits very nicely on the wrist, and is very comfortable on my 7.5″ wrists. The heft of the watch gives one the impression that it is hewn out of a block of platinum…a characteristic of Lange watches, but more so with the Datograph. The chronograph buttons are bright finished, as is the massive platinum buckle. As is typical of Lange buckles, this is made of a solid block of case metal (in this case, platinum) and the shape is designed in such a way that there is minimal deformation of the strap when buckled up.

Crown up. Camera: Samsung 145S with Schneider Variogon lens, scanned, and image sharpened and color balanced with Photoshop

Datograph, resting on the First Edition (2500 examples limited edition) Catalog, signed by Gunter Blumlein and Walter Lange.

The Movement – Lange Caliber L951.1

The Dial and Hands

The dial is machined from a piece of solid silver, and is black, with the constant seconds subdial and the minute recorder subdial in white. I don’t know if this will be changed when the first production examples hit the market sometime in December this year, but prototype examples, like the subject of this review came with either a plain sapphire glass crystal, or a coated, anti-reflective crystal. My review sample had the anti-reflective crystal, which at certain angles (see pictures taken by me at the end of the review) made the dial look blue. However, the promotion picture (original I have is 40MB tiff file made from a 4×5 camera) clearly shows the dial is black.

Lancet hands for the hours and minutes in rhodiumed white gold, with luminous sliver in the middle, and a very fine, needle like silver chrono seconds hands complete the picture. The constant seconds hand and the minute recorder is in blued steel.

Hour markers are
appliqué in rhodium plated white gold.

The crown is made from solid platinum, and embossed with the logo. The pushers are massive square blocks of platinum. The feel of pushers in operation gives the impression of a heavy piston moving smoothly through a pot of thick,
viscous oil. The amount of effort for each of the operation is exactly the same as the next, unlike many cheap navette type chronographs, where the effort to start the chrono is significantly larger than the effort to stop, which is again different from the effort required to reset. The way the Datograph pushers work gives evidence to the attention to detail common to Langes.

Also the feel of the crown, as one winds the watch is one which gives me extreme satisfaction.

As is typical of Lange movements, the caliber number indicates the year in which development work began. The L951.1 thus represents a movement in which work began in 1995, and was the first movement to be developed in that year.

The movement is in the classical Glashutte style, complete with 3/4 plate partially hidden below the chronograph work complete with gold chatons held by blued screws, and engraved balance cock with swan-neck micro adjustment system (shown as 3). It features a screw compensation balance with a Breguet overcoil hairspring, beating at 18,000 bph.

The movement allows the folks at Lange Uhren to show off finishing in two metals…the traditional Glashutte German silver used in the base plate, the 3/4 plate and the chronograph bridges
(exemplified by the cock holding the main chrono wheel indicated as 2), and high polish steel for the chronograph work.

The movement also features a jump minute recorder, which moves in 1 minute jumps, each time the chrono seconds hand completes one revolution.

The classical column wheel (shown as 1) is made in the traditional Lange style, sans polished steel cap, allowing full view of the turrets, and the star wheel activation mechanism below the column wheel proper.

Seen below is the detail of the column wheel, showing the high precision finishing work in the turrets. Note also the jagged teeth of the star wheel below the turrets, where a hook shaped pawl
(labeled 4) engages, and moves the column wheel one position, each time one of the two chronograph button is pressed. The spring loaded lever 5, prevents the column wheel from moving, without any instruction from the pushers.

Depending on the state in which the chronograph mechanism is in at that moment, the column wheel will coordinate the

  1. start of the chronograph
  2. stop of the chronograph
  3. reset of the chronograph
  4. retour en voul, or flyback without stopping.

Each move of the column wheel causes the fingers of the chronograph to either fall within the space between two turrets or pushed out by the turret.
From the chronograph running position shown right, if the column wheel is moved one position (clockwise), the finger 1 will drop towards the center, whilst the the finger 2 will be lifted by and sits at the left edge of the turret 3. The action on 2 swings the secondary chrono wheel away from its contact with the main chrono wheel, stopping power from the movement to the chrono. This action on 1 causes the brake lever to clamp onto the chrono wheel, stopping it. Note that because of the relative positions of 1 and 2, the action on 2 happens sooner than the action on 1.

On the next move of the column wheel, 1 will be lifted by the next turret, and 2 move from the left edge of turret to the right edge, ready to drop for the next command. The action of 1 lifts the brake lever from the chrono wheel, freeing it, while the reset lever snaps over the heart cam, returning the chrono wheel to zero position. With the non-action of 1, the power from the train remains away from the chrono.

Hence, in a classical chronograph, the column wheel is essential to keep the coordination of all activities in order.

The chronograph works thus:

  1. when the start button is pressed, the column wheel rotates one position clockwise. As seen earlier, this causes the brake (the highly polished edge of the brake finger is seen
    labeled 4) moves towards the top of the picture and releases its grip on the main chrono wheel
    (labeled 3). Immediately upon release, the secondary seconds wheel (the wheel on the left marked 2), is moved clockwise and comes into contact with the the main chrono wheel (marked 3), transferring the power from the wheel train to the chrono hand which is mounted on the main chrono wheel. As the secondary chrono wheel (2) is in constant contact and turning in unison with the fourth wheel of the base train, it rotates at the rate of one revolution per minute. Hence, the main chrono wheel, which carries the chronograph seconds hand, moves at the rate of 1 revolution per minute.

    Note that the chrono wheel carries small teeth, and the secondary wheel carries much larger teeth. This is designed as such to improve the lag between contact and start of the hands, and also to reduce backlash.

    Tolerances for the amount of movement the secondary chrono wheel moves is critical, and is adjusted by a screw slot shown as 1.

  2. When the stop button is pressed, the column wheel coordinates the split seconds between each of the 2 steps required: 1. move the secondary chrono wheel counterclockwise out of the way, removing power to the chrono hand, 2. engaging the brake finger
    (labeled 4) to swing clockwise and coming into contact with the chrono wheel, braking it. This allows the chrono hands to be still, and the timing read.
  3. When the reset button is pressed, the column wheel coordinates the release of the brake, and the striking of the reset finger (shown partially hidden by the top edge of the 3, towards the top edge of the number). The flat edge of the reset finger comes into contact with the heart shaped cam (The bottom sharp part of the cam can be seen partially hidden under the chrono cock…direct at the point of the label 3’s arrow), forcing the cam to rotate until the top part of the heart comes to rest with the flat edge of the lever. This causes the seconds hand to reset to zero.
The flyback mechanism is shown right. For this function, the same column wheel is required to perform steps 2 and 3 combined, with just one push of the reset button, and restart the chronograph.

The diagram clearly illustrates that when you push the flyback button, the mechanism moves into the dotted line position. It also shows that as long as you keep holding the flyback button, the chrono will not restart, as the flat part of the reset finger rests firmly at the top edge of the cam’s heart.

Note also that the secondary chrono wheel (shown as the only wheel carried by in a chaton) moves out of the way during the reset, removing power from the chrono hand.

Movement finish

As is typical of Lange watches, the finish is impeccable. Shown left is the detail of the balance cock, showing the balance wheel, and the balance spring.

1, is the overcoil curve. Note that as the name implies, the hairspring coils over itself. Invented by Breguet, this allows the coil to breathe regularly. However, in small escapements, the overcoil has a tendency to catch itself, causing the watch to gain wildly (up to minutes within an hour). I understand from my discussion with the Watchmakers at the factory, the Breguet overcoil is more
difficult to regulate than a flat one.

Labeled 2 shows the anglage work. Note the even-ness of the anglage throughout the bridge’s edge.

3 is the hand engraved balance cock. Sitting on the cock is the stainless steel swan neck fine

Note also the position of the lever which is always centered on the balance cock. In order to achieve this, after full regulation and adjustment is made by moving the lever, miniscule washers are placed in pairs between the screws and the balance, so as to bring the lever back to the center. This makes the screw compensation balance essential for regulation. In a simpler laser poised smooth balance wheel, the screws are not essential, because regulation can always be corrected by moving the lever, which adjusts the length of the balance spring. In a typical watch, the position of the lever is of no consequence. In a Lange, tradition and
aesthetics demand that it remains centered.

Movement finish is one of the hallmarks of Lange watches, and a lot of time and energy is spent to ensure that a perfect finish is approached as closely as is possible. For a look at how this is done, take a
tour of the factory with me.

Concluding remarks

This is the most remarkable watch unveiled in the Basel 1999. It was the talk of the show. I think this watch makes another mark for Lange Uhren, as the most prominent watchmaker of the decade. The finish is absolutely without peer. The movement design shows complete mastery of the tradition and classical horology.

Definitely highly recommended! I leave you with some pictures of the Lange Datograph, together with its Basel 99 sister: the very beautiful 1815
Moonphase. Enjoy!

Datograph and 1815 Moonphase in rose gold. Photographed sitting on the trunk of my car.
The rear view of the same watches. Note the layering effect of the Datograph’s chronograph mechanism.

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