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Bifora 735

 

Bifora 735Bifora 735

Description

Like its twin movement Bifora 734, the Bifora 735 is also a very rare 7 3/4 manual wind movement from Schwäbisch Gmünd, Germany.

Due its small diameter  combined with the multi-storey construction, it is stocky and thus difficult to service. For example, the hairspring is located in the very small gap between two gears and the balance wheel.

The Bifora 735 was launched in the early 1950ies, probably a little bit later than the caliber 734, and was produced until 1958.

base platebase plate

The base plate shows, that all important gears, except the minute wheel, are ruby-beared. The only difference to the caliber 734 is, that the balance wheel is shock protected with two Incabloc bearings. With two additional cap jewels, that's a a total of 17 jewels.

Like the caliber 734, it has got a directly driven center minute wheel, beared below an own cock.

gear traingear train

The Bifora 735 uses a typical contenporary gear train with center minute wheel, thied wheel, large center second wheel and escapement wheel. Because of the large diameter of the gears, it has to use a multi-storey construction with enormous height.

The only difference to the caliber 734 is apart from the Incabloc shock protection, that the crown wheel of the winding system is a little bit different and the ratchet uses two instead of three teeth.

side view of the gear trainside view of the gear train

The screw balance is shock protected in two Incabloc shock protection bearings and bears slowly with 18000 A/h. It controls a conventional swiss pallet lever movement and its frequency can be adjusted with a long regulator arm.

One problem of that construction is, that the two center wheel, almost reach to the escapement wheel axle, so there's few space for fiddling in the balance, especially, since the hairspring has to be located in the small space below the two wheels above the balance wheel. Maybe that complicated and difficult to service construction was the reason, why that movement is not (more?) often to find.

Bifora 735: Dial sideBifora 735: Dial side

On the dial side you among the hallmark also the yoke winding system and the flat Incabloc bearing. In contrast to the Bifora 734, the beveled edge of the plate is about twice as large.

 

 

 

 Technical data

ManufacturerBifora
Caliber735
Number of jewels17
EscapementAnchor with pallets
BalanceNickel screw balance
Shock protection(s)Incabloc
Balance cock directioncounterclockwise
Hairspring studfixed
Regulator typeLong regulator arm
Movement constructionFork
Escapement wheel, Fourth wheel, Third wheel
Center wheel
Mainspring barrel
Construction typesolid construction
Winding mechanismyoke
Setting lever spring2 holes
FeaturesSCD
FunctionsHour, minute, second
Beats per hour18000
Size73/4''' (measured: 17,3 mm)
Production time1950? - 1958
Image in Flume Werksucher 1957 29
Inventory ID 17038
Bifora 735BiforaBifora7351950? - 19587 3/4'''Bifora 73517 Jewels, 7 3/4''', 18000 A/h, SCD
Factsheet

 

 

 

This movement is a kind donation from Götz Schweitzer to the movement archiv. Thank you very much for the great support!