Am not working today so am writing a little project. Some friends, knowing my interest in mechanical watches and that I spend a lot of my working day explaining how structures and mechanisms work, asked if I would show them the parts in a watch and what they do. I am putting the first sections here to see if it is of interest. It is likely to take me some time to complete and is a far more difficult to explain than even the mechanism of an aircraft pressure door....

This is for a cal 561 (very similar to all cal 56x movements), which I took photos of during the rebuild and am trying to explain in a way that is not too technical. We leave the real watchmaking and technical questions for Al. This is not watchmaking anyway, just what the parts are there to do. There's no discussion of endshake, depthing or even wibble-wobble. Oil choices and wars thereof are also not included. It is simpler than that. Even some of the names have been simplified to, hopefully, make it clearer. This is also not exactly the order that I usually work but seemed best for the explanation and did involve some assembly/disassembly because of that. All corrections and clarifications are willingly received.

All photos are with 12 O'clock at the top so, when viewing the dial side, 3 O'clock is at the right and when viewing the back, 3 O'clock is on the left.

Firstly, the order of my explanation leaves the explanation of how the balance governs the release of energy until somewhat later so, clearly not the way a watch course would do it.

Fig. 1: This is a bare mainplate from the dial side. This is not a bad example although it is a bit marked in places. I seem to have a black mark on my camera as it is on every photo at about 11 O'clock and about a third out from the movement centre.


Fig 2: This is a bare mainplate from the rear side. You can see five purple coloured jewels here from the centre of the movement going down towards six O'clock and across to the right. These have a hole through the centre and are the bearings for the various wheels so that the shafts are not rotating directly in the mainplate.
I just know that if he sees this, Al will pick up on the staining at the third wheel jewel - I promise you, it has been cleaned three times (hand and ultrasonic) and that marking is part of the plate now!


Fig 3: The barrel parts: the barrel lower left; the barrel closing plate above: the arbor to right and below that in the light blue ring is the mainspring. The lower end of the arbor is a square section, required later:


Fig 3a: The spring goes in the barrel and grips against the outer wall. I know, this is very basic! It is not aimed at Stewart for example... There is a little more to the way a spring grips the wall in an automatic but this is too complicated for the moment..


Fig 3b: The arbor (square section away from us) goes into the spring. The arbor grips the centre area of the spring so it's now connected to the barrel wall via the spring. If we hold the barrel wall and turn the arbor then we can tighten the spring so it stores energy. Then we can hold the arbor and release the barrel wall and the barrel will turn as the spring unwinds. This is what we use to power the watch.


Fig 3c: Barrel closing plate added and turned over to show the square arbor section and the teeth on the barrel along the upper circumference.


Fig 4: The barrel mounted in the mainplate. It will turn when the watch runs and the teeth on it are very close to the centre jewel to mesh with the 2nd wheel (or centre wheel here as it is at the centre of the movement):


Fig 5: The centre wheel on the right and the cannon pinion on the left. The mainplate goes between these as the centre wheel shaft extends through the mainplate from the rear side. Note the centre wheel has a small steel gear underneath the large gear. The large gear controls the release of the spring energy but that is much later so, for the moment just assume that the balance will tell that gear when to move. The rest of the time it is locked and cannot rotate
The small gear will mesh with the barrel teeth as it is on the rear of the mainplate and the long hollow shaft goes through the plate to take the cannon pinion on the dial side of the plate. They are pressed together so, as the barrel rotates, the centre wheel and the cannon pinion rotate as well. This wheel turns once per hour.


Fig 6: The second wheel mounted on the rear of the plate (with cannon pinion pressed on the other side). The small steel gear has meshed with the barrel teeth.


Fig 7: The barrel plate attached by 3 screws is fitted which provides the support on this side for the barrel arbor (no jewel) and the jewelled support for the centre wheel.


Fig 8: The dial side showing the cannon pinion. Note that it also has a gear. The minute hand will be pressed onto the outside of the cannon pinion later. You can also see that the barrel has filled in the big hole at the upper.


Fig 9: The cannon pinion gear meshes with a wheel on the mainplate shown in this picture. It is a pair of gears staked together - the large copper coloured one and the small steel one.


Fig 10: That steel gear meshes with this sleeve part that fits loosely over the cannon pinion and on here we will press the hour hand so, this one rotates once every twelve hours. I have to remove this and the previous wheel as turning the movement back over will cause them to fall off.


Continued in a minute as there are too many pictures...

 

Fig 11: Comparing to Fig 7, the toothed wheel (ratchet wheel), which has a square centre hole, has been fitted onto the square section of the arbor. It has an inner set of teeth and an outer set. If we turn this while the barrel is held by the centre wheel large gear, then the spring will get wound. The outer teeth are contacting the small semicircular piece added at about 10:30 which is the click. When the ratchet wheel rotates clockwise, the click gets pushed out of the way as shown. We need the click to spring back clockwise when the wind is finished to lock this the ratchet wheel and that is done by the click spring.


Fig 12: This is the click spring which is slightly bent up at the left hand end to catch the click.


Fig 13: The spring fits in the barrel plate groove and is held by that.


Fig 14: This is the inner ratchet wheel and the small gear on this meshes with the inner set of teeth on the ratchet wheel from Fig 11. It is shown upside down. It is this wheel that gets turned by the crown via the crown wheel.


Fig 15: Inner ratchet wheel and crown wheel mounted. The click spring has been fitted so the click is shown in it's locked position and the arbor cannot rotate anticlockwise. The crown wheel is driven through the slot on the left which becomes clearer turning the movement over.


Fig 16: From the dial side, the crown wheel teeth can be seen through the vertical slot at 3 O'clock. This is where the keyless works will drive it. Note the wheels from Fig 9 and 10 are not shown for clarity (and I forgot to put them back on).


Fig 17: From the left: clutch wheel; winding pinion and stem attached to the crown. Whoever designed these crowns was a 'form over function' guy as I can hardly grip it when the movement is cased. The clutch wheel has a square hole through it to vfit with the square section of the stem so, it always turns when the crown is turned. The 'clutch' part from which it derives it's name are the saw teeth at the right hand end that mesh with equivalent teeth on the winding pinion. The winding pinion has a circular hole so does not rotate with the crown unless the clutch wheel is engaged with it.


Fig 18: To make this clearer, I am putting the keyless works in withot grease so, it will all come apart again at the end... Those 3 parts fitted and the winding pinion is meshed with the crown wheel on the other side of the mainplate. The clutch wheel is shown almost engaged with the winding pinion. At the moment, it is free to move along the square section of the stem so we need to keep it in it's default position hard up to the winding pinion.


Fig 19: This is done by the Yoke (the vertical steel lever) and the yoke spring which looks a bit like a click spring. The yoke sits in the groove of the clutch wheel and pushes it to the right so it engages with the winding pinion sawteeth. Now, turning the crown will cause the barrel arbor to turn but, the crown can still be pulled out if as there is nothing to retain it. To the right of the winding pinion is a groove in the stem and it will be retained by putting a pin in that groove.


Fig 20: This is the setting lever and it retains the stem and crown. It is shown flipped over about a vertical axis and, as I forgot to take a picture, it is one from the scrap pile. That's why it is dirty, I promise! The lower part has a pin to fit in the stem groove and the large upper pin (in the corner of the L) fits into the baseplate hole. This is the part to push to remove the crown and stem.


Fig 21: Here it is, flipped right to left and fitted. It needs to be held down and that is performed by the setting lever pressure spring. It is free to rotate about the corner of the L where the big pin is through the baseplate. There is a small pin towards us at the upper left which is needed later.




Fig 22: The setting lever pressure spring is a piece of spring steel curved in this view and held by the one screw. It sits on the corner of the setting lever and provides the resistance when the lever is pushed from behind to release the crown and stem. The setting lever is still free to rotate which is needed to set the hands.


Fig 23: Replacing the wheels from Figures 9 and 10 which connect the minute and hour hands, there is one additional gear added here which serves no function when the watch is running. It s the small steel gear close to the clutch wheel and meshes with the gear from Fig 9.


Fig 24: But, when the crown is pulled out, the setting lever rotates about it's corner and pushes the cluch wheel away from the winding pinion so that it engages with this small gear. In this configuration, the crown turns the minute and hour hands but is disengaged from the winding mechanism.


Fig 25: In fact this is more accurately controlled by the setting lever spring (not to be confused with the setting lever pressure spring above!) which is this plate held on with two screws. It also serves to hold all this in place. The leg running vertically is the spring part and has two notches (a 565 quick date will have three) to engage with the small vertical pin of the setting lever. Here it is in 'crown in, wind position'.


Fig 26: Here it is in 'crown out, time set position'.



Well, that's part one and two. Next will be the train (the part that tells the centre wheel when to move, then date mechanism, then auto winder.

Cheers, Chris

 

I have no idea why there is an extra picture at the end and cannot remive it by editing. Ho hum.

 

Excellent Chris, very clear.

 

This is so cool for someone like me who knows so little about the inside (or outside, for that matter) of the watches I love!

Thanks for putting this together, and I look forward to the rest of the story. Keep up the great work.

 

Chris

Why is the ratchet wheel "doubled-up" on these 5xx movements? There is the lower gear just for the click, it seems, and then an upper pinion which engages with the crown wheel. Whereas on my dear old bumpers one wheel serves for both

 

merken!

this is just a reminder for me to re-find this thread...

 

Superb Thread Chris.
Thanks for enlighten us, the noobies in intricacy of mechanical watch movement with such simple step to step explanation. Couldn't wait for the next part.

Disimpan

 

You have a devious mind John! Have you thought about a new career in aerospace engineering? I completely missed this part of the explanation, so, addenda as follows:

Fig 11: Omega rightly call this the 'automatic ratchet wheel' (lets use ARW as it's a bit long to type) so, let's dispense with the term outer ratchet wheel. When (if) I get to the auto winder mechanism, which is a really clever part in itself, you would see that the output drive from the auto winder meshes with the ARW external teeth and turns this wheel clockwise mimicking the action of turning the crown. If this was directly connected to the crown wheel-winding pinion-clutch wheel-stem train, then the [edit - typed this a bit quickly] winding pinion would turn as the auto winder works. If you look at Fig 17, the sawteeth are actually a triangular section so turning the crown clockwise means the clutch wheel locks to the winding pinion and turns it. If the winding pinion is turned clockwise by the crown wheel, then the sawteeth slide up on the meshing clutch wheel teeth and push the clutch towards the centre of the movement against the yoke spring. This all takes force and would reduce the auto winder efficiency but, the clutch and crown do not rotate.

The parts are decoupled by the inner ratchet wheel.

Fig 14: The inner ratchet wheel (IRW) has that little star shaped gear which is held in by a screw shown in Fig 15. The screw is tight but this little gear is free to rotate. The teeth are asymmetric so, if you turn it anticlockwise in this view (clockwise in Fig 15) it locks into the corresponding ARW teeth and is not free to turn. So, rotating the IRW turns the ARW.
On the other hand, turning the IRW clockwise in this view (anticlockwise in Fig 15) just makes this little star shaped wheel turn and the ARW stays still. Following that logic, in Fig 15, if we turn the ARW by an external force (the auto winder) in a clockwise direction, the IRW stays still as the star gear just rotates.

I will get some pictures of this and add them in later thus week.

I have no idea how the bumpers do this (yet) but, I should service my 354 later this year so, will keep you posted! Why did they change the way if doing this? I don't believe the bumpers suffer from reliability/efficiency problems so, it is likely that the 565 is a cheaper way if doing things.

Cheers, Chris.

 

Chris

Thank you for the explanation. This made me look twice at the cal 351 I am stripping down for spares at this very moment, and it would seem that on these bumpers the auto-wind drives the crown wheel directly, so yes the crown does turn as the watch winds up. This happens so gradually that I suppose the wearer just does not notice it . . .

P.S. There must be something wrong with the 351 I tested, because on one of my other 351 bumpers the crown does not move so now I am thoroughly confused . . .

 

Unfortunately, you typed as I was correcting my text. Have another read now. Sorry! However, perhaps this was an efficiency improvement if that's the case?

 

Chris, thanks for your fuller explanation. Yes, I can see the point of taking out the normal crown wheel/clutch etc train from the auto-wind as that is just additional load on the rotor assembly. I think I need to study my auto-winder assembly a little more thoroughly! Up till now I just accepted the fact that it works without thinking too hard about exactly where the winding effort was introduced into the crown wheel/ratchet wheel assemblage. What you do have on these old bumpers is a very delicate and complex pawl arrangement to get around the problem that a small movement of the rotor will not produce enough movement on the ratchet wheel to get it past a whole tooth and hence one click. The extra pawl "saves" the energy produced by a partial rotation of the oscillating weight, and adds these movements together to move the ratchet wheel past the click.

 

My error, sorry. Don't type on the phone while watching the TV.. Luckily, we have the edit function. Those bumpers sound interesting and it seems like you are getting to know them well. I have looked at mine and I know the pawl you are speaking about. It is quite a delicate looking arrangement so they may have changed for robustness or possibly it wouldn't work with the full rotor movement? Interesting discussion, thanks!

 

Here is another part - slow going now...

Fig 27: In Figure 5, we left it that the large gear on the centre (2nd) wheel would be controlled to release the mainspring power and drive the watch. That large gear has 64 teeth and rotates once per hour (3600 seconds) so, if this gear was stopped/released on each tooth as appropriate, the minute hand would move in almost one minute jumps. The train wheels are there to control this more finely by working at faster rotational speeds. The picture shows, from left to right, the 3rd wheel, 4th wheel and the escape wheel.

The 3rd wheel has a small gear of 8 teeth which meshes with the large gear of the centre (2nd) wheel. So, for one rotation of the centre wheel, the 3rd wheel rotates 64/8 = 8 times. Therefore, it rotates once in 3600/8 = 450 seconds. It also has a large gear and that has 60 teeth.

That large gear meshes with the small gear on the 4th wheel which has 8 teeth as well. So, for one rotation of the 3rd wheel, the 4th wheel rotates 60/8 = 7.5 times. Therefore, it rotates once in 450/7.5 = 60 seconds. It also has a large gear and that has 77 teeth.

That large gear meshes with the small gear on the escape wheel which has 7 teeth (That wheel has some old oil staining but the teeth all look OK.) So, for one rotation of the 4th wheel, the escape wheel rotates 77/7 = 11 times. Therefore, it rotates once in 60/11 = 5.4545 seconds. It also has a large gear and that has 15 strangely shaped teeth. This is the one that meshes with the pallet fork and so, the teeth pass the fork every 5.45/15 = 0.3636 seconds. There has been a little rounding of numbers in this paragraph for simplicity.

This tells us that this watch beats at 2.75 Hz (watchmakers call this 19800 A/hour = 2.75*60*60*2) as 2.75 times per second means one beat is in 0.3636 seconds.



Fig 28: Here are the three wheels loosely mounted in the movement and the meshing is clear except that the 4th to escape wheels have slipped slightly apart for this picture.

Note the position of the 4th wheel which is on a vertical line between the centre of the movement and the 6 O'clock marker. If this was a sub second dial movement, by extending the 4th wheel shaft throuch the mainplate, a second hand could be directly mounted to that on the dial side as this wheel runs at 60 seconds per rotation. All that would be necessary is to extend the shaft and change the lowest jewel in Fig 2 to allow the shaft to go through the plate.


Fig 29: The train bridge is mounted by two screws and the three wheels are properly supported and meshed. Turning the barrel causes the escape wheel to move. I can't count the barrel and 2nd wheel small gear teeth properly now but, there are about 88 teeth on the barrel and, if I remember correctly, 12 on the small gear of the centre wheel. So, one tooth movement on the barrel gives:
0.08 rotations of the centre wheel
0.67 rotations of the 3rd wheel
5.00 rotations of the 4th wheel
55.00 rotations of the escape wheel or the equivalent of about 5 minutes running.

This is pretty impressive overall gearing for any system as one full barrel rotation causes nearly 5000 escape wheel rotations.

Cheers, Chris

 

merken

 

Quadrophenic-Schizophrenia

A marker also, many thanks for all your time, Chris!

 

Fig 30: The pallet fork goes in next. It is pivoted at the next jewel over in Fig 29 and 'meshes' with the escape wheel. The two long red jewels on the end of the fork contact the escape wheel teeth and control the release of the energy in the mainspring. I forgot this picture so, other things have changed as I took it much later. I got fed up with looking at the crown wheel and ratchet wheel which were quite marked so also changed them later on.


Fig 31: The pallet fork bridge (cock) goes on with two screws and supports this side of the fork pivot. It might just be clear that the escape wheel is giving an impulse to the pallet fork exit stone (the one on the outside of the movement) and turning the fork anticlockwise about it's pivot. The right hand end of the fork is very close to a hole in the baseplate and this is where the balance is mounted. Just above that hole is the end of a screw which is seen in the next figure.


Fig 32: On the lower left, I have refitted the red incabloc which protects the balance staff when the watch is subjected to a sudden shock, commonly known as being dropped....(if you want to know how this very clever jewel arrangement works, go to http://www.incabloc.ch/en/systeme_incabloc.php). This is a slightly earlier design and is retained by the screw directly above it.


Fig 33: The balance wheel with ruby pin, hairspring (balance spring) and balance cock assembly viewed from the dial side before mounting. The spring is attached to the balance wheel and spirals out to an attachment on the cock (the machined plate with single screw hole). The spring is at rest and by moving the end attachment of the spring on the cock,the ruby pin and balance wheel rest position will rotate. This is used to correct the 'beat error'.

The spring also goes through a guide in the cock, at about 10 O'clock, which also can be moved varying the effective length of the spring and adjusting the rate of the watch. I'm not that happy with the shape of this spring and will have a look at it later.


Fig 34: The balance cock assembly mounted with it's single screw. There is an incabloc on this side of the balance staff as well. The movement will now run. The big unknown here is how this swinging balance, ruby pin, fork and escape wheel control the power release and is too complex to explain here. For me, the best explanation is in Figure 48 of Practical Watch Repairing by Donald De Carle (available on Kindle for about $7 and well worth the expense if you have the interest).

 

Fig 35: In Fig 27, the 4th wheel has 8 teeth meshing with the third wheel and turned once per minute. This long spindle (centre second pinion) has eight teeth on the end and will also mesh with the third wheel. It goes through the 2nd wheel/cannon pinion and will take the second hand. The little V shaped plate is a spring to hold this in place. That spindle looks a little bent but it isn't at the end.


Fig 36: Here it is mounted in the centre of the movement. This completes everything on this side except for the auto winder which is added at the very end.

 

merken

 

Just to kick this to a second page as it is very heavy to load.