Bifora 691

Dugena 2001

Bifora 691 | - The Movement Archive

Bifora 691


The 6 3/4 ligne, tonneau-shaped Bifora 691 was also used by Dugena under their own caliber number “Dugena 2001”. Besides the golden-toned plates, there are minor difference on the balance cock: Hairspring key and stud are a little bigger and more rounded.

Bifora 691: Version "Dugena 2001"

Version "Dugena 2001"

It finishes the series of tonneau-shaped ladies' movements from Bifora and was made until 1980. Its modern, cost-efficient construction can be seen e.g. on the fact, that the gear train bridge also covers the mainspring barrel and carries the crown wheel, so no additional bridge is used.

Bifora 691: base plate

base plate

Of course, on this pallet lever movement, all bearings contain synthetic rubies, even the minute wheel bearing has got two of them. Hence, the marketing efficient number of “17 jewels” could be achieved without additional cap jewels.

Bifora 691: gear train

gear train

The gear train is the classical one with main spring barrel, directly driven center minute wheel, third wheel, seconds wheel and finally the steel escape wheel.

Due to the reduced space, which a tonneau-shaped movement offers, a two-storey construction is used, where the lower bearings of the two small third- and seconds wheels are located above the large escape wheel.

Bifora 691: side view of the gear train

side view of the gear train

With its 21600 A/h, adjustable at the hairspring key only, the Bifora 691 was contemporarily semi-fast. Its two-leg anular balance is beared in two inhouse “Bishock” bearings.

Bifora 691: Bifora 691: Dial side

Bifora 691: Dial side

On the dial side, you see the yoke winding system, and also the two lower bearings, which are located (movement-side wise) above the escape wheel.

Bifora 691: dial side of the "Dugena 2001" version

dial side of the "Dugena 2001" version

The Dugena 2001 version has got golden toned plates and bridges.

In the lab

The specimen shown here came in good condition into the archive and got a simple service.

Timegrapher result

For a movement of that small size (the native Bifora version was tested), the results are pretty impressive, only the big difference between vertical and horizontal positions is not optimal. If that difference was lower, the movement would be capable to run almost within the chronometer specs.

horizontal positions
dial up -4 s/d 316° 0.1ms
dial down +-0 s/d 289° 0.0ms
vertical positions
crown right (12 up) +4 s/d 252° 0.5ms
crown up (3 up) +8 s/d 245° 0.3ms
crown left (6 up) +19 s/d 253° 0.0ms
crown down (9 up) +12 s/d 253° 0.0ms

Technical data

Caliber base:Bifora 69
Size:6 3/4 x 8''' (measured: 15,2 x 18,0mm)
Number of jewels:17
Escapement:Pallet lever
Balance types: monometallic anular balance (two legs)
Shock protection(s): Bidlingmaier (Bifora)
Balance bearing / direction hairspring:Clockwise
Moveable stud:yes
Adjust mechanism:Hairspring key
  • lever
  • escape wheel, seconds wheel, third wheel, center minute wheel, mainspring barrel
Construction type:solid construction
Winding mechanism:yoke winding system
Setting lever spring:4 hole(s)
Production period:1968 - 1980
Production years:1968-1980
Inventory number:22058

Usage gallery

Bifora 691: Bifora ladies' watch

Bifora ladies' watch

Bifora 691: Dugena ladies' watch

Dugena ladies' watch

The movement and watch, branded “Bifora” are a kind donation from Lars Schröder, and the version, branded “Dugena” is a kind donation from Erwin. Thank you very much for your great support of the movement archive!