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Bifora 910/1

Bifora 910/1Bifora 910/1

Description

Bidlingmaier in Schwäbisch Gmünd in Germany was one of the first manufacturers of selfwinding wristwatches after WW II. The caliber Bifora 910/1 shown here was launched in 1964 and already belonged to the last but one series of selfwindig movements and shows clear sign of cost-cutting fabrication.

With a diameter of 11 1/2 lignes this movement has got the "full" size, the base movement, the Bifora 91, only uses 9 3/4 lignes, the rest is used by the oscillating weight.

 main platemain plate

At the main plate, you can see two things: First, that this movement uses plenty of bearing jewels, including the minute wheel, and second, that it is a pillar construction, which was cheaper to produce.

Detail: Minute wheel cockDetail: Minute wheel cock

The minute wheel cock of course houses the minute wheel. On top of it, there's the friction spring for the indirect center second.

gear traingear train

The gear train is common for most Bifora movements with the indirectly driven cender second hand and the two leg annular balance, which beats slowly with 18000 A/h and is beared in two inhouse Bishock shock protection bearings.

side view of the gear trainside view of the gear train

The mainspring barrel with open top side is odd, but often seen on Bifora movements. Even more unusual is the fact, that all gears, including the mainspring barrel(!) are housed under one single plate. But it seems, that there exists a second version of this movement, where the mainspring barrel is located under an own bridge.

base movement without selfwinding mechanismbase movement without selfwinding mechanism

Without the selfwinding mechanism, the Bifora 910/1 would be more or less a Bifora 91.

selfwinding mechanismselfwinding mechanism

The selfwindig mechanism with two ratchet wheel changers (at 6 and 7 o'clock) allows a bidirectional winding and decouples the oscillating weight on manual winding.

Detail ratchet wheel changerDetail ratchet wheel changer

The ratchet wheel changer is equipped with a kind of seesaw, which enables free spinning in one direction. 

movement without oscillating weightmovement without oscillating weight

Not only the base movement, but also the selfwinding mechanism is equipped with lots of jewels.

inner side of the oscillating weightinner side of the oscillating weight

The oscillating weight is axle beared.

Bifora 910/1 dial sideBifora 910/1 dial side

The dial side is identical to the Bifora 91. With a yoke winding system, this movements is one of the best Bifora movements, despite the pillar construction.

 Technical data

ManufacturerBifora
Caliber910/1
Number of jewels23
EscapementAnchor with pallets
BalanceNickel
Shock protection(s)Bidlingmaier (Bifora)
Balance cock directionclockwise
Hairspring studmoveable
Regulator typeHairspring key
Movement constructionFork. Escapement wheel, Fourth wheel, Third wheel, Fourth wheel, Mainspring barrel
Center wheel
Construction typepillar construction
Winding mechanismyoke
Setting lever spring3 holes
FeaturesSCI,AUT
FunctionsHour, minute, second, selfwinding
Beats per hour18000
Size111/2''' (measured: 25,6 mm)
Image in Flume Werksucher K3 207
Bifora 910/1BiforaBifora910/111 1/2'''Bifora 910/123 Jewels, 11 1/2''', 18000 A/h, SCI,AUT
Factsheet

 

In the lab

The movement came into a watch with missing back in very bad and dirty condition and got a full service treatmement. And although the rates are pretty poor (see below), the movement was at least brought back to life.

 

Timegrapher result

crown rightcrown right crown topcrown top crown leftcrown left crown bottomcrown bottom 
dial topdial top dial bottomdial bottom 

vertical positions
12 up  -105 seconds/day
3 up  -120 seconds/day
6 up  -140 seconds/day
9 up  -? seconds/day
horizontal positions
dial down  +30 seconds/day
dial up  -30 seconds/day
timegrapher measurings

As you can see, even a full service cannot do miracles to a heavily (mis-)used movement, but at least it works...

 

Usage gallery

Bifora mens' watchBifora mens' watch