Post by Houston on Nov 12, 2007 11:55:11 GMT -5
November 12 2007
OMEGA USINE DE GENEVA TOURBILLON
A rare and important find, this Tourbillon was the fourth of twelve movements made in 1947 for the Geneva Observatory Trials. In 1987, seven examples of the movement using a seven and a half minute Tourbillon regulator were encased and sold, thereby making this one of a very rare series of watches.
The case in polished sterling silver possesses a lapidated bezel, concave lugs and display back. A push button for setting the hands of the watch is located in the 4 o’clock position on the side of the case. The dial in a matte silver finish has painted black Dauphine numerals adjacent to an outer minute track and a subsidiary seconds dial is featured at 6 o’clock. This exclusive and rare timepiece which features blued steel baton hands is simply signed with the OMEGA name and Tourbillon legend along with the OMEGA symbol of the original style.
Power for the Omega Usine de Geneva Tourbillon is courtesy of the 25-jewel OMEGA calibre 30 movement which originates from 1947 and comprises a 2/3 plate, maillechort, the 7.5 minute Tourbillon regulator with a two-part rhodium-plated brass cage which is held by three screws. There is a Guilaume balance with a Breguet overcoil and index regulator. The case is 36mm in diameter with a depth of 11.5mm
Special Note - Guillaume Balance
In 1899, Dr. Charles Edouard Guillaume noticed that steel with an addition of 44.4% nickel had a negative square coefficient of thermal expansion. This alloy, combined with brass in bimetallic lamina, makes its expansion close to quadratic. Balances with bimetallic rims made of anibal (anibal, an alloy invented by Guillaume, stands for Acier au Nickel pour BaLanciers) and brass are usually called Guillaume balances, or, as their inventor called them, integral balances. When combined with special balance springs, they exhibit remarkable temperature stability, on occasion not exceeding 1/50 second per day at 1ºC.
Pictures and data – antiquorum.com
ZIN
Not usually shaken nor stirred ;D ;D ;D
Please Note that our Homage to Bienne Series was created to present the timeless beauty and desirability of rare and unique OMEGA watches. As such most of these items are discontinued though some may be replaced by newer models