The Naked Watchmaker

The Reason

The Speedmaster is an example of an iconic design from one of the most well known of the established watch brands.

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Year manufactured 2004 (Limited Edition of 2004 pieces). Stainless steel case. Dimensions: 42mm diameter; 13mm thick. Perspex glass. Luminova on hands and indexes. Caliber: Manual wound chronograph caliber 1861. Original Omega bracelet. Lug width: 20mm.

The case back is secured using a key with 6 fingers to screw onto the case centre.

Made exclusively for the Japanese market in 2004. 2004 pieces were made and delivered, but not individually numbered. They differ from the regular 3570.50 reference in that they have the special grey matte dial with red/orange accents as well as orange hands for the chrono function. This watch is inspired from a very rare grey Racing dial model delivered from 1969-1971 as well as the Speedmaster Mark II.

Screwed on case back with machine engraved then blackened text.

The movement assembly is secured in the case by the outer anti-magnetic iron cover pushing down on the calibre when the case back is screwed in place

Inner case back with references

Centre of the anti-magnetic cap which hold the mvt in place. The raised button pushes directly on the inner case back.

Diverse views of the movement from the open case back

With the case back removed you can see the black rubber seal sitting in the case which is sandwiched between the case centre and case back, rendering this union resistant.

The Speedmaster's history goes back to 1957 when it was introduced as a sports and racing chronograph, complementing Omega's position as the official timekeeper for the Olympic Games.

The "Speedmaster" name was chosen for its tachymeter scale bezel and following the Omega convention used for other models like the Seamaster - initially the Speedmaster was part of the Seamaster line - and the Railmaster.

This first Speedmaster model - reference CK 2915 also known as the "Broad Arrow"- was designed by the Swiss Claude Baillod and was already featuring some of the hallmarks of the model: the triple-register chronograph layout, the high-contrast index markers, and the domed Plexiglas crystal. The dial was an example of perfect balance and proportions. The model had straight lugs, broad arrow hands and the bezel was in steel with engraved black print. The case diameter was 39 mm. (http://www.timeandwatches.com/p/history-of-omega-speedmaster.html)

The watch removed from its case

Around the movement is the movement ring which slides into the case

Profile view showing the wheels driving the chronograph

A tachymeter scale around the rim of the watchwatch can be used to compute a speed based on travel time or measure distance based on speed. The spacings between the marks on the tachymeter dial are therefore proportional to 1/t where t is the elapsed time.

The complete case bezel with Tachymetric scale

Inside view of the case showing the screw held pushers tightened from the inside of the bezel

The movement ring, set between the calibre and the bezel

Profile of the mvt showing the screw which holds in place the dial foot

Dial recto-verso

The dial washer holding the hour wheel securely in place.

The calibre Omega 1861, below the balance wheel

The flat side head is an eccentric which allows the coupling clutch to be adjusted altering the penetration of gears

The engraved bridge holding in place the chronograph and minute recording wheels

The central screw holds in placethe friction spring for the chronograph wheel, removing any slack between meshed teeth gears

The controling cam, replacing the traditional pillar wheel system

The Incabloc shock protection system protecting the balance pivots

The mvt serial number

The pin hooking onto the hammers which when moved releases the hammers to return the chronograph seconds and minute recorder wheel to zero

The flat sided screw is adjusted to assure a specific penetration between the coupling clutch and the chronograph seconds wheel

The -m- shaped section on the cam assembly secures the cam system is two specific locations as the cam is adjusted between -start- and -stop- of the chronograph

Below, the first wheel on the left is the driving wheel (or upper fourth wheel) of the chronograph, in the centre is the chronograph seconds wheel which is driven by the coupling clutch (here not shown). To the right is the intermediate wheel which is indexed every minute turning the minute recorder wheel on the far right.

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The balance and escapement is removed

Escapement, Swiss anchor and cock

Balance wheel and balance cock

Coupling clutch removed

Coupling clutch

The central lever touching the chronograph seconds wheel is a type of plastic which acts a break when the chronograph has been manual stopped.

The lower lever slides on the two shoulder screws holding it in place pushing the cam system

The assembly under the chronograph seconds wheel on the left meshes and indexes the intermediate pinion in the centre which then turns the minute recorder wheel on the right

The remaining wheel in place on the chronograph is the upper fourth wheel which drives the chronograph.

The lever in the centre of the image holds down the piece underneath it which in-turn pushes against the cam system. The central lever pushes this pieces to the left to reset each time the pusher on the outside of the case is manually activated.

The screwhead set into the centre of the index sits on an eccentric post which allows the index to be moved by small increments to regulate the length of the balance spring

The balance spring sits between a regulating pin and the boot which has a small cap preventing it from jumping out in case of shocks

The balance spring is held into the stud using resin to avoid any deformation of the spring

The small slot on the underside of the balance is the result of the poising of the balance

The pivots for the Swiss lever are never lubricated only the pallet jewels

The jewels are friction fitted into the lever and locked with shellac

Return to zero hammers

Underside of the return to zero hammers and the post they pivot on plus the pin which is spring loaded when assembled

The hour recorder operating lever

Profile of the hour recorder operating lever

Minute recorder wheel with its heart shaped cam for returning to zero though application of the hammers

Minute recorder wheel, showing the length of its axel which traverse the movement finishing flush with the dial

Underside of the chronograph seconds wheel showing the assembly that turns the intermediate pinion indexing the minute recorder

The triangular teeth profile of the chronograph wheel

The seconds chronograph wheel, the skeletonized section of the wheel allows visibility when the watch is being set up and adjusted

The spring which pushes against the hammers

The coupling clutch linking the movement to the chronograph wheels when the chrono is activated

Underside of the coupling clutch showing the excentric

The coupling clutch spring underside view

The chronograph wheel bridge

Underside of the chronograph wheel bridge with the indexing pawl and spring assembled

Diverse views of the assembled watch

The partially exploded watch

To learn more about Omega: www.omegawatches.com

Watch lent for deconstruction by

Roy & Sacha Davidoff.

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