I have now serviced 10 861/1861 movements. This will be my first time with an 1866. I recently had 4 days of training on the El Primero have serviced 4 of them. It will be nice to go back to something a little simpler. I will post some stuff on the El Primero down the road, it is crazy how that thing is set up inside. Onto the 1866:

This in one of my personal and favorite watches. It has an hour counter issue. If the chrono is on while winding the watch the counter advances. It also doesn’t count hours accurately while the chrono is running. Some close checking of the hour counter wheel, stop lever and hour driving pinion on top of the barrel will be needed. First the back has to come off. I recently got this Bergeon case back opener to replace my Horotec one. So far it works much better. The back came off with a suction die.
The movement has been de-cased.

The movement ring has two push pieces in it for the date and moon phase quick change buttons.

Supplies ready for hand removal. I removed the 3 subdial hands first.


next the chrono seconds hand is removed.

now the hour and minute hands come of together.

I advanced the date counter to a safe position and it was removed next. All the hands safely tucked away.
the two dial screws are loosened, one can be seen in the center slot of the movement holder.

dial is off and safely stored. The dial screws were tightened back down. If this step is missed they will likely fall out while in the cleaning machine.
the upper dial support plate is absent and in its placed the components for the moon phase and date are in its place.
This is what the dial side of an 1861 looks like for comparison.

The dial washer, moon phase disc and date wheel are removed.

the movement is flipped and the hour recorder yoke is removed. This is needed to access the click to let the mainspring down
the click is accessed down through this opening.

the stem is removed and the movement goes in for pre-cleaning.

 

A little on the cleaning machine. I choose this machine as it allows for ultrasonic to be used if desired along with agitation and is completely programmable for cleaning time, spin off time, drying time, etc. I have an extra set of jars with separate solution for pre-cleaning and final cleaning.
I pre-clean as I check endshakes and all parts for wear/damage under the microscope during disassembly. This also could be down later during movement assembly, but I have had better results doing it this way. Most of my training has been by someone that worked for Rolex and pre-cleaning is what they do. It also is what WOSTEP teaches.

 

Moon phase/date platform removed. The components on the left are for the date and moon correctors. On the middle is the moon phase driving wheel and finger. On the right are the date and moon jumpers and springs.

 

Before removing the balance, I checked for proper endshake. I also add a few clicks of mainspring tension and performed some escapement checks, verifying proper/equal fork horn and guard pin clearance as well as the concentricity of the roller table. It’s rare to find an issue in a modern watch during these checks. As I am preparing to take the CW21 exam once the AWCI reopens, the 7750 practice test watches the instructor sends me often has these errors added in to see if I’m making the checks. No issues were found on this 1866


chrono bridge removed.

The jumper for the minute counter is under the chrono bridge.

One of the controls is adjusting the block that holds the jumper spring. The spring needs to have the correct bow and tension for the jumper to work correctly.

The hammer spring can be carefully flexed out of the way and then the hammer is lifted off its post.

The seconds and minute runners removed along with the intermediate minute counter wheel. The hammer, and up top the brake for the chrono seconds runner.

for comparison, the 1866 hammer and brake are on the left. On the right is a hammer and brake from an 1861. The finishing is much nicer on the 1866, even though this watch has a solid caseback. The derlin brake used in the 1861 is often seen as a downgrade. From a functional standpoint the derlin one is probably better. Another movement that uses a derlin brake is the 7750 for its hour counter wheel.

 

The hammer spring is removed, along with the operating lever and the stem-bolt and spring for the stem-bolt. The stem bolt holds the hammer up when the chrono is stopped. When the reset button is pressed, the stem bolt is moved out of the way allowing the hammer to fall and reset the minute counter and center chrono runner. Up top in the picture are the connector lever, operating lever and its spring, which is the fish hook looking thing.


Next the coupling clutch is removed along with its spring.

the upper and lower cam and its jumper.
That leaves just the driving wheel for the chronograph to be removed.

There are different ways to remove this wheel. The goal it to remove it without distorting it or scratching anything.

This one came off cleanly. Sometimes they can be pretty tight and other methods of removal have to be employed.

 

Complicated stuff, nicely done.

 

Nice work. What's the reference of this model?

 

Very good thread! Thanks for taking the time, @Deafcon

 

Thank you for this! This movement was on my fav watch, the 3876.50.31. It's wonderful the see the level of finishing on all the parts even if they can't be seen.

 

3575.30.00

 

Congratulations and good luck with the test. Is this your first career path or did you shift gears in your life with a new venture?

 

New venture. It’s more of a high end hobby and challenge. Maybe someday I’ll look at switching to watchmaking full time.

 

pallet bridge and fork removed.

Escape wheel bridge and escape wheel removed followed by the 3/4 plate, barrel and wheels.
There was some nasty grease inside of the barrel. There shouldn’t be anything, no breaking grease for a hand wind and the mainspring has dry lube on it from the factory. The grease was leaching out into the hour pinion that drives the hour recorder, likely causing the hour recorder issues this watch had.

A little extra cleaning of the barrel was needed before all the parts go in for final cleaning.

 

This is fascinating! All those little parts. My goodness, it's like brain surgery.

 

Thanks for taking the time to post this! I’ve had the 3576.50.00 for four years now. I really love the added visual interest of the moonphase and the functionality of the date. I’ve seen other disassemblies of a Speedmaster (1861 or 1863), but never one with my moonphase. It’s cool to see how that fits into the case without making it a thicker watch. (Here’s a shot with a new strap I just got for Christmas.) My 3576 is my only Omega and the main watch I usually wear in my two-watch collection. Mine has a sapphire caseback, and I really enjoy being able to see the movement. The finishing is really beautiful. Such a well-designed movement. I look forward to hearing your comments on the El Primero movement and how the design/construction differs.

 

This is one of the problems with pre-cleaning in my view. Since this movement has been through a cleaning cycle fully assembled, you really have no way of knowing what the inside of the barrel looked like originally. I know Rolex is a big advocate of this (as is Tom), but IMO it's simply not needed, and often washes away or disturbs evidence that is useful in diagnosing problems with the movement.

BTW, do you have the dial side movement holder also? It's very useful for hand installation and testing of all chronograph and date/moon phase functions. The moon phase has some very specific checks that need to be done on them BTW, so end shake checks and adjustments...something to look into before you get to that part of the assembly.

Cheers, Al

 

Ah the El Primero. I’ll get a write on it soon. It’s crazy how complicated the design is compared to other chronographs with the same functions, or in the case of the 7750, it has more functions but is much easier to work on.

 

I see both side of the pre-cleaning subject. In my current full time profession looking for the actual cause of failure is important, not just the other symptoms that may be present. The collection of debris and old lubrication could be good clues that do get washed away in pre-cleaning.
As Tom is my instructor, as long as I’m working with him I’m going to abide by his methods. Down the road as I gain more experience and receive training from other instructors I’m sure I’ll form my own process.
I do have a dial side movement holder, but it’s the AF one, not the Omega one. I’m currently waiting on some new hands as the minute counter is loose on its tube and the other hands don’t look as nice as they should for a watch that is this nice. “Patina” on these type of hands isn’t a good thing.

 

I understand - as Tom says you do what you are required to in the moment, so at any brand training, if they tell you to do X and you normally do Y, do X.

I think one of the reasons Rolex is so adamant about this, is that they generally don't do a great job of adjusting end shakes at the factory. Tom may have mentioned this, and Rolex pretty much expects you to adjust the end shakes at service. For Omega, I find this much less likely. But if I do have to adjust the end shakes, I just run the parts back through the cleaning machine - this was I get the best of both worlds - I see all the evidence at disassembly, and am able to adjust whatever needs it and wash again if required.

These hands are sometimes not fun - keeping them pristine is the key...note that you may have to do some fitting on these - same with the blued steel versions as they tend to be quite tight.

Cheers, Al

 

From top to bottom, the hour reset hammer spring, the switch which has an eccentric for adjustment of the interaction between the hour recorder stop lever and hour hammer, the spring for the hour recorder stop lever, and the hour recorder stop lever.

The hour recorder runner, and the hour reset hammer. The hour recorder runner is driven directly off the barrel via a pinion mounted on an extended barrel arbor. The teeth on the hour recorder runner can become worn, contributing to hour counter creep. Both the stop lever and runner were ok on this movement.

The pinion is held in place by a friction spring which is held to the barrel cover with two tiny little screws. I didn’t get a picture of the pinion or the assembled barrel. The screws and spring must be removed for proper cleaning and checks. One of the checks I was taught to make is how the pinion turns on the barrel arbor without the friction spring and before lubricating it after the parts are clean. This area can be a contributing factor to chrono hour creep. This area was the source of the hour counter issues this watch had.


All that’s left is the winding and timing setting works.

Under the 3/4 bridge the crown wheel is removed before final inspection and cleaning
All the parts are checked under the stereo microscope. I found both the crown wheel and winding pinion worn. They will be replaced with new parts. There was also another area of wear found which will be detailed in the next installment.