Automatic club-tooth lever centre-seconds wrist-watch with gold case and brown leather strap

Description — British Museum

Automatic club-tooth lever centre-seconds wrist-watch with gold case and brown leather strap. Movement with club-tooth lever escapement and rotary automatic winding. Silvered-metal dial with raised gold Arabic hour numerals for even numbers 2-12 and triangular hour markers for the odd numbers between. Gold minute and centre-seconds hands; hours shown by rotating disc with gold triangular indicator. 14ct. gold case with snap-on back. Brown lizard-skin wrist-strap.

Curator's comments — British Museum

Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript) Made by Bulova Watch Company USA, c. 1960 Gold cased self winding wrist watch with a club tooth lever escapement. Signature: On the dial 'BULOVA SELFWINDING 30 Jewels'. On the self winding weight is 'BULOVA - U.S.A. 30 JEWELS 6 ADJUSTMENTS HEAT COLD ISOCHRONISM 3 POSITIONS', in rectangular cartouche the calibre number 10BZAC. Case: A 14 ct. two piece case with on the back 'BULOVA SELF WINDING 14KT.GOLD WATER PROOF L9 SHOCK RESISTANT ANTI MAGNETIC'. The watch with a strap marked in gold 'GENUINE LIZARD' and a cross and 'KREIZLER'. A gilt buckle so the strap probably not original. Dial & Hands: A silvered dial with the centre removed. The chapter ring with a matt finish. Raised numerals and batons finished gilt with the Arabic numerals 2, 4, 6, 8, 10 and 12, with batons between for the other hours. No hour hand instead a disc with a gilt baton, this disc with a circular grain. The minute hand is skeletonised and filled luminous. A gilt centre seconds hand. Movement: Ebauche Marks: In a rectangular cartouche on the self winding weight is the calibre number 10BZAC. Frame: A nickel silver frame with the self winding work mounted on top of a conventional movement. This self winding work can be removed in its entirety by releasing two screws. The basic movement has a bridge for the barrel and keyless work one for the train and cocks for the pallets and balance. Barrel and Mainspring: The barrel carries the message 'SEALED LIFETIME POWER - BULOVA - DO NOT OPEN'. Barrel: External diameter 10.0 mm., height 1.61 mm. Hooking: A slipping mainspring. Train: All the wheels gilded, except for the centre seconds pinion driving wheel which is nickel plated. The centre wheel, third and fourth wheels with five crossings. The steel escape wheel with four. Jewelling: Jewelled bearings for the entire train including the barrel arbor bearings, all the jewels pressed in. Ruby endstones to the fourth and escape wheels in the train bridge and an endstone for the escape wheel in the front plate. The balance with shock protected bearings. The entire self winding train is also jewelled. Escapement: A straight line layout club tooth lever escapement with short lever, double roller and D-shaped impulse pin. The exposed pallet stones have flat acting faces. A steel escape wheel with four crossings. An equidistant locking escapement. No. of teeth embraced 3½. Balance & Spring: a monometallic balance with gold screws. Balance diameter 9.93 mm, thickness 0.56 mm. A 'self compensating' flat spiral spring with 12 turns. Means of Regulation: An index on the balance cock registers against three divisions with '+' and '-' engraved on the balance cock table. Beat setting facility Train Counts and Beat Rate: Great wheel 72 (barrel) Centre wheel 64 pinion 10 Third wheel 60 pinion 8 Wheel on the third pinion of 60 driving the centre seconds pinion of 8. The backlash taken up by a drag spring. Fourth wheel 70 pinion 8 Escape wheel 15 pinion 7 Beat rate 18,000 Motion work: cannon pinion 10 minute wheel 30, minute pinion 8 hour wheel 32 Winding System: Conventional positive stem set keyless work. Self winding work: The weight pivots on a post and carries a pinion which is in permanent mesh with two reversing pinions. Each of these pinions is furnished with a face ratchet that also carries a pinion. These latter pinions are in mesh with the first of two wheel in the self winding train. This wheel carries a pinion which is in turn driving the second gear in the self winding train. The pinion carried by this wheel meshes with the barrel ratchet wheel. Dimensions: Case: Diameter 33.0 mm., height 11.3 mm. Movement: diameter 28.6 mm., (within its adaptor ring) 23.7 mm., out of the ring, height 7.2 mm. Provenance: Purchased in 1988 with the aid of funds from the Dingwall Bequest.