Buren 481
Description
The Buren Watch Company from the swiss Büren an der Aare (hence the hallmark BAA) was always a producer of high quality pocket- and wristwatches, mainly labelled as “Grand Prix”.
This label carries also the 11 1/2 ligne caliber Buren 481 shown here, which has got a center seconds indication and very elaborated and simple mechanism to change the mainspring barrel.
base plate
The base plate already shows the high quality of this movement, even the minute wheel is ruby beared, and the recesses on the lower left are part of the genious mechanism, which allows the change of the mainspring barrel without tearing the whole movement apart.
Even more beautiful is the gear train bridge with its angled edges and the golden toned ruby settings.
base plate with minute wheel and open barrel bearing
While the barrel core is fix beared on the dial side, the barrel brigde, which also
bears the center minute wheel, has got no upper bearing for the barrel core, as you
can see on the picture.
That means, the barrel can simply slide out when you lift it a little bit.
closed barrel bearing
Only when the upper bearing is secured and screwed to the movement, the mainspring barrel is safely beared on both sides.
gear train
The gear train of this “Grand Prix” movement is the traditional one and builds pretty high: The mainspring barrel drives the center minute wheel, followed by third wheel, directly driven center seconds wheel and finally the escape wheel.
As escapement, a swiss pallet lever is used.
side view of the gear train
The Buren 481 uses a nice two leg screw balance, which is beared in a pair of Incabloc shock protections. It beats slowly with 18000 A/h and can be adjusted with the help of a long regulator arm.
Buren 481: Dial side
On the dial side, you see the yoke winding system and the slanted edge of the dial side plate. This saves a little height, especially when a curved dial is used, and this is not the worst idea for a movement with a large height of 4.8mm.
In the lab
Timegrapher result
Unfortunately, this movement is not in perfect condition and also shows signs of water damange. As to be expected, the timegrapher results, especially the low amplitude, are far below what you could expect from a specimen in good condition.| horizontal positions | |||
|---|---|---|---|
| dial up | -2 s/d | 194° | 0.1ms |
| dial down | +-0 s/d | 180° | 0.0ms |
| vertical positions | |||
| crown right (12 up) | -133 s/d | 162° | 1.2ms |
| crown up (3 up) | -40 s/d | 167° | 0.0ms |
| crown left (6 up) | +51 s/d | 162° | 0.0ms |
| crown down (9 up) | -6 s/d | 157° | 1.0ms |
Technical data
| Manufacturer: | Buren |
| Caliber: | 481 |
| Size: | 11 1/2''' (measured: 25,3mm) |
| Height: | 4,80mm |
| A/h: | 18000 |
| Number of jewels: | 17 |
| Escapement: | Pallet lever |
| Balance types: |
monometallic screw balance (two legs) |
| Shock protection(s): |
Incabloc |
| Balance bearing / direction hairspring: | Counterclockwise |
| Moveable stud: | no |
| Adjust mechanism: | Long regulator arm |
| Construction: |
|
| Construction type: | solid construction |
| Winding mechanism: | yoke winding system |
| Setting lever spring: | 5 hole(s) |
| Attachment of setting lever: | screwed |
| Features: |
|
| References: |
Ebauches: II 34/1 Flume: K2 - |
| Inventory number: | 23068 |
Usage gallery
Buren gents watch