Bifora 910/1

 
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Bifora 910/1

Description

Bidlingmaier in Schwäbisch Gmünd in Germany was one of the first manufacturers of selfwinding wristwatches after WW II. The caliber Bifora 9101 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.

Video on YouTube

With a diameter of 11 12 lignes this movement has got the “full” size, the base movement, the Bifora 91, only uses 9 34 lignes, the rest is used by the oscillating weight.

main plate

main 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 cock

Detail: 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 train

gear 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 train

side 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 mechanism

base movement without selfwinding mechanism

Without the selfwinding mechanism, the Bifora 9101 would be more or less a Bifora 91.

selfwinding mechanism

selfwinding 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 changer

Detail ratchet wheel changer

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

movement without oscillating weight

movement without oscillating weight

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

inner side of the oscillating weight

inner side of the oscillating weight

The oscillating weight is axle beared.

Bifora 910/1 dial side

Bifora 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.

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 right (12 up)

crown right (12 up)

crown up (3 up)

crown up (3 up)

crown left (6 up)

crown left (6 up)

crown down (9 up)

crown down (9 up)

dial up

dial up

dial down

dial down


horizontal positions
dial up-30 s/d
dial down+30 s/d
vertical positions
crown right (12 up)-105 s/d
crown up (3 up)-120 s/d
crown left (6 up)-140 s/d
crown down (9 up)-? s/d
Timegrapher output

Technical data

Manufacturer:Bifora
Caliber:910/1
Number of jewels:23
Escapement:Pallet lever
Balance types: Nickel anular balance
Shock protection(s): Bidlingmaier (Bifora)
Balance bearing / direction hairspring:Clockwise
Moveable stud:yes
Adjust mechanism:Hairspring key
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel, seconds wheel, mainspring barrel
  • center minute wheel
Construction type:pillar construction
Winding mechanism:yoke winding system
Setting lever spring:3 hole(s)
Features:SCI,AUT
Functions:hour, minute, second, selfwinding
A/h:18000
Size:11 1/2''' (measured: 25,6mm)
Literature: Flume: K3 207

Usage gallery

Bifora mens' watch

Bifora mens' watch