IWC caliber 79420 movement – specifications and photo

IWC caliber 79420 is Swiss movement from 201X.

Functions: day and date display, chronograph, small hacking seconds, rattrapante (split seconds hand for intermediate timing).

Automatic movement with 29 jewels

f = 28800 A/h/4 HZ

Power reserve: 44 hours

Diameter: 30.0 mm

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Rolex Submariner 5508 1962 Automatic Movement

Dimensions: 38 mm x 12 mm x 42 mm

I bought this watch from my watchmaker, who bought it from the original owner. The military serial number on the case back is from the Royal Navy and signifies where the owner signed on: it was either Portsmouth or Plymouth, which was confirmed by the MOD when I called them. (They do not normally do that, but the person I was speaking with was archiving casualty reports from 1962 at the time and confirmed the military service number was correct for the time period.)

As with my father’s watch, which he wore in the Scots Guards, all personal items worn on duty, such as watches, had the owner’s service number engraved on them. This is the nicest Rolex Submariner “non-crown guards” watch and is in amazing condition. It has a gloss gilt original untouched dial with an exclamation mark at six p.m with “SWISS” marked below the six p.m marker.

There is minor blemish at five p.m, but apart from that a very nice specimen. The hands have been replaced during a service, as originals would be gilt like the dial; the bezel was possibly replaced, as originals are chromed brass. … Continue reading...

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The distinctly ‘70s chrono’s big cushion case houses the ETA Valjoux 7753 workhorse

Unfortunately, and unlike the 7750, this movement provides no rapid- reset function for the date display via the crown. Instead, the wearer must press a recessed button on the left side of the case to reset the date. This requires a correction stylus or a repurposed tool such as a ballpoint pen or toothpick.

On the other hand, the operation of the crown and push- pieces leaves nothing to be desired. Furthermore, the movement is attractively decorated. Unfortunately, our test watch gained more than 10 second per day, as proven both by the timing machine and the wearing test. Moreover, the small elapsed- minutes hand is not 100 percent vertical in its testing position, but leans a tiny bit toward the left. Fans of retro and sports watches will need to accept this imperfection if they opt for the Heritage 1973. But perhaps they’ll interpret this trivial shortcoming as a beauty mark that reminds them of daring exploits in the glory days of auto racing, when success depended less on technology and engineering and far more on a driver’s passion and charisma.

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Inside Zenith Defy Zero G

The object of this test bench incorporates the latest advances in Zenith’s research as part of its quest for chronometry. The track explored in recent years by the brand’s technical department is head- on response to one of the factors disrupting the movement of watches: gravity. The nature of the problem became apparent from the very beginning of Huygens’ work on the balance- spring and isochronism. In the 17th century, “marine” watchmakers took account of this by affixing their chronometers to gyroscopes in order to maintain them in a constant horizontal position whatever the state of the seas. With the advent of the pocket watch between the 17th and 18th centuries, this solution could not be adapted for obvious reasons of size. It was then that Abraham-Louis Breguet invented the tourbillon which mixes the vertical positions so as to derive an average rate. By successfully placing the escapement and balance- spring assembly on a gyroscopic system. Zenith addresses the source of the problem, and does so in a clearly successful manner as revealed by our tests.


One might be tempted to say the question of the exterior is secondary, given connoisseurs’ naturally strong interest in the mechanical characteristics of this … Continue reading...

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Bulova 12EBACD (Buren 1322) movement – specifications and photo

Bulova 12EBACD (Buren 1322) is Swiss movement from 1960’s.

Functions: sweep second, date – changing between 23 and 24 h

Automatic movement with 17 or 30 jewels

f = 19800 A/h

Power reserve: 54 hours

Diameter: 28.15 mm

More information:

Angle of lift: 48°, micro rotor, double jewel bearing if 30 jewels double excenter
regulator for curb pins and stud carrier
selfwinding gear with direction switching by a pinion floating between two huge jewels

Oscillating weight set in the movement. No additional height taken up by the self-winding mechanism. Oscillating
weight made of heavy antimagnetic alloy. Mechanical inverser on roller bearings: no wear. Automatic engaging and disengaging of manual and automatic winding. Thus only the operating gear turns, performance is improved and there is no wear. Sliding pinion set between large jewels.

Bulova 12EBACD (Buren 1322) – Technical Bulletin

Spare parts for Bulova 12EBACD (Buren 1322)

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