The first time I bought a vintage watch (in Paris as it happens) the seller asked if I wanted to see the movement. Not wishing to appear a complete fool I said, "of course!"

I had no idea what I was looking at.

Now first I must say here I am not a watch maker and I am ready to be rebuked by someone so qualified, and I repeat, this is just what I do in the absence of a better knowledge - that I will always gratefully absorb.

Here is a newly arrived purchase. As a watch it is fabulous, but the movement has a few issues that will make me send it straight up to my Essex friends for a service.

This photo shows some important things.Here is what I am looking at, (and here the names are what I think they are called, please correct me!).

Top right is the column wheel, and I am looking to see all the "columns" are intact. I have seen broken ones. This one looks OK.

Then the large flat metal clutch bridge (with a single screw and a cog wheel at the other end). This is the correct early type. The asymmetrical one is fitted to later 321 movements.

Now I am looking at that cog wheel, and the way it meshes with its friend. (Third and fourth wheel?). Now just because I am not sure of the names, I don't like the way the wheels fit.

Lastly this movement shows signs of a lot of work. The screw heads, especially the one upper left in the photo, shows driver marks. This was not a surprise as the case back has more watchmakers marks than I have ever seen before.

So in summary, I am happy, but will be happier once it has been serviced.

 

I imagine the symmetrical clutch bridge aligns with the serial number too.

Here in your photo, the colours also look even for the parts shown. I'm told to look for this as well, for example the plate with the serial number having a different shade as compared to the other copper coloured parts.

Thanks Achim

 

Okay let's remove the nails from the blackboard and introduce some proper terms here...my comments inserted below in bold.

Personally I would look for signs of corrosion, and look for broken parts.

Cheers, Al

 

Thanks Al

 

I second that - Good to learn the technical terms and to get some insight into what to look for

 

Thanks Al.

Really appreciate your pointers.

The meshing thing......so I was looking at the teeth. some times I see them meshed in together, sometimes plenty of space between teeth, in this case I see different profiles on the teeth. I am just going on simple engineering experience and was thinking, ooh, that doesn't look right.

People like me must drive you and other watchmakers mad so I thank you for your patience and time to educate me, (us).

 

No not mad at all. I'm glad to help when people appreciate it and listen to it.

Yes the teeth will not always be "in mesh" as small imperfections in the bushings or pivots can cause slight sticking (sometimes dried oils too) so this is why the friction spring for the chronograph runner is needed - to take up backlash and smooth all that out.

If you understand how the horizontal coupling works, then your engineering experience will tell you that the teeth are this way for a reason - they are all like this so this one is not some exception to the shape of the teeth.

So the drive wheel for the chronograph (the one pressed onto the 4th wheel) is always turning when the watch is ticking. This is always in mesh with the coupling clutch wheel, so that wheel is also always turning - this is an important point. Look at this photo please:



It's of an 861 but the same thing applies with a 321. The coupling clutch (again with it's wheel always turning) swings in to the chronograph runner when the start button is pressed, as shown by the red arrow above. Now you are trying to engage one wheel that is turning, with a wheel that is stationary - at this point the chronograph runner has been held stationary. A closer look at the 2 wheels that now must mesh:



The reason the teeth are pointed is quite simple - this reduces the chance of "tip to tip" contact when the two wheels are coming together. If this were to happen it could damage the tips of the teeth, or cause the chronograph runner to jump backwards or forwards. Also you will note that the engagement shown here is quite shallow, again by design.

So they may look funny, but it's done this way for a reason.

Hope this helps.

Cheers, Al

 

Informative!