Servicing caliber 861
I approximately have this Omega Speedmaster since ten years, and its operation is irreproachable.
However, I noticed that for some time, the hand of the 12 hours counter of the chronograph shifts slightly, half an hour approximately.
This small problem which does not disturb me a lot made me become aware that my watch undoubtedly needed a revision. In fact, the shoe blocker of hours counter should not press any more suitably on the wheel, which releases the hand.
I thus decided to make a cleaning/complete oiling of my watch.
Disassembling.
First of all, I dismount the bracelet to be able to block the case correctly and to unscrew the back.
The tool Bergeon n°4077 maintains the watch firmly and makes it possible not to scrape on the bottom by making a beautiful stripe. In theory the tool is him even fixed at the vice for a maximum of effectiveness.
All is well, the bottom is released rather easily and dust cap appears. This last is also used to fix the movement in the case and advantageously replaces the legs and usual screws fastening.
The bottom of the dust cap gives information: the watch had its last revision on November 28, 1992: it was time!
The stem of winder is maintained by a screw, that it is advisable to unscrew slightly until the winder is released and can thus leave its housing.
At this stage, the movement is retained more in the box only by its ring of assembly. It is thus enough to make slip the ring out of the case, the movement is thus released.
I arrive now at a crucial moment, which I apprehend always a little. The disassembling of the hands of a watch is always delicate, because a wrong movement can be heavy consequences, both for the hands the dial. On Speedmaster, the central second hand is rather strongly riveted, of a blow of 5 kg (cf Omega Saga de Marco Richon). Using the tool Bergeon presto n° 30636
it is necessary to catch the needle closest to its gun under penalty of seeing this one breaking into two at the time of wrenching.
Ok, very occurred well,
I can pass at the following stage, i.e. remove hours and minutes hands always with the Presto tool.
Those do not raise a difficulty thanks to their greater solidity.
As regards the small remaining hands, an easy way consists to free the feet of the dial (Screws located on the section of the plate) and to make lever by raising this one gently (the dial). In theory the hands are detached without too much from problem.
Without problem? I realize that the small second hand does not have any more its gun, which remained on the second wheel axle ! No moment I forced and the break was done really too easily. Obviously, the needle had a problem with manufacture, and this one appeared with the first constraint.
My watch never would undoubtedly have arrived at the end of the tests of NASA...
The dial is removed, and arrives now the disassembling of the movement.
The complete désarmage of driving spring is not yet possible because the pawl which maintains it in tension is not accessible for the moment.
The technical review of caliber 861 recommends to start with the parts being under the dial, i.e. the mechanism of reseting the hours counter.
Warning: This caliber comprises 3 referred eccentrics 1779, 1701, 1702 not to confuse with screws, it thus should not be touched during disassembling under penalty of modifying the adjustments:
Disassembling of the chronograph part under the dial
the movement is then turned over to dismount all the remainder of the chronograph part.
The balance wheel is also deposited to avoid any accident.
There remains nothing any more but one wheel to be dismounted on the pic.
The driving wheel for chronograph is then removed by making lever as shown on the diagram
The driving spring can be expanded with this stage of disassembling.
There remains now only one traditional watch, the anchor bridge as well as the bridge of the train of wheel are unscrewed and removed.
It does not remain any more that one battle field
The watch is now entirely disassembled, the parts arranged in baskets passed to the "washing machine" with products envisaged for this purpose (Solution one dip at Bergeon)
(Photo washing machine to come)
the rinsed and dried parts are recovered and ready for the reassembly of the movement.
Reassembly
Employed oils:
For the overhauling of caliber 861, Omega recommends the use of 3 oils and 3 different greases:
fine oil : Moebius 9010
Average oil : Moebius 9020
Thick Oils : Moebius D5
Average grease : Jismaa 124 B-sp
Thick grease : Blasolube 316
Special grease for escapement: Moebius 9415
The points of greasing and oiling are given on the technical review which you can get on Chuck Maddox's website (see the links page).
I start with the hour setting mechanism
Then the hour counter mechanism comes
It east can be more advised to assemble this part at the end, but that does not pose a problem if one thinks of oiling the jewels on the basic movement berore.
The movement is turned over and the basic movement is assembled and oiled
Finally anchor and balance wheel find their place
The higher pivot is oiled by opening the incabloc and by removing the cap jewel.
There remains now only the assembly of the chronograph's mechanism
The chronograph part then reassembled with greasing oiling etc...
I exempt nth photograph of the movement to you.
It should all the same be specified that during the reassembly certain adjustments are to be checked and if required to correct with the famous above mentioned eccentrics. (cf Technical book)
The movement is reassembled ! and all functions correctly what is nothing...
It any more but does not remain to put back the dial and the needles. It is a little less difficult than with disassembling but attention should all the same be paid.
A precaution to be taken: To make sure well that the chronograph is to zero, before and after the installation of the hand, indeed a shift can occur at the time of the installation.
Are then posed the hand of minute
counter like that the hand of sec....
SH....!!! I forgot the second hand is broken!
Que c'est bon d'avoir des pièces en stock !
En fait j'avais commandé un jeu d'aiguilles et finalement je n'avais utilisé que la seconde centrale pour une autre montre.
L'aiguille des secondes est donc remplacée
Une fois tout en place, il faut s'assurer qu'aucune aiguille ne touche l'autre en faisant jouer la couronne de mise à l'heure
Dernière précaution, le chrono est lancé et remis à zéro plusieurs fois pour s'assurer qu'aucun décalage ne se produit.
Alors que le chrono tourne, on peut en profiter pour faire un petit nettoyage de la boîte et un polissage du plexi, ce n'est pas grand chose et l'effet est garanti !
Je ne parle pas de polissage de la boîte car celle-ci est en trés bon état et surtout je ne sais pas du tout comment faire. Je sais simplement que c'est difficile et que rare sont les amateurs qui obtiennent les effets escomptés.
Voilà, c'est reparti pour une dizaine (j'espère !) d'années de service...
