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My 2019 Watchmaking Goal.. Learn the 1970's Seiko 6139 Chronograph

  • by Darren Thomson
  • 05 Jan, 2019
If you suffer from 1970's sensibilties, then you probably love the watch pictured here. This is a 1971 Seiko 6139 Chronograph, sometimes referred to as the "Pogue" (for reasons that we'll discuss later). This model (discontinued in 1980) came with three dial options each over time having their own unique quirks and traits that are now sought after by collectors. The blue and silver dials are desirable in their own way but are never as eye-catching as the golden hues of the yellow dial, seen above. 

The movement used in this watch, the Caliber "6139", is important in watchmaking for a few reasons. Firstly, it may well have been the first automatic (self-winding) chronograph (watch with a "stop-watch" function) ever created. This is up for debate with some of the Swiss manufacturers maintaining that they got there before the Japanese (a story for another time). Secondly, this watch went to space for 84 days! Whilst the Omega Speedmaster was famously selected by NASA for their space missions, this Seiko model was smuggled aboard a "Skylab" mission in the 1970's by an astronaut named Col. William Pogue (hence the nickname). Pogue just happened to love his Seiko, had been using the watch during his training and decided that he didn't want to be without it on his mission (see here for more details). Lastly, this watch is just damn cool (don't you think?).

These three attributes have made this type of watch increasingly collectable in recent years and good examples are getting harder and harder to come by. This brings me to the point of this blog and a new watchmaking goal for me in 2019. My love of these pieces and the general trend of their "collectability" has led me to the conclusion that the ability to fully service the 6139 movement is going to become more and more important. As these watches (and parts for them) become rarer and more in demand, the current lack of watchmakers prepared to take service and repair jobs on is going to leave a gap in the market. So... I'm going to make this the first chronograph movement that I learn to service (chronographs are seen by many as the most complicated of the various features that can appear on a watch and I have yet to pluck up the courage to go through this particular learning curve).
So, here it is... A Seiko 6139 Chronograph movement, stripped down to its individual parts. My plan is to slowly put this back together, referencing some old Seiko Service Guides that I've managed to dig up from the internet. Once that's done and I've got this thing working, I'll take it part and start all over again. I'll keep doing that until I know every square mm of this movement and I'm confident in repairing and servicing these for paying customers. Along the way, things will go wrong. Parts will be damaged and will need replacing, some may get "pinged" across my workshop and lost forever. Parts won't seem to fit (but will, in good time, behave themselves, based on my slow increase in competence). This I just the nature course of things in watchmaking, I've found.

Eventually, though.. I'll be able add this movement to list the I am able to service and, in doing this, I'll be able to work with some historical watches from the era of my birth and I may be able to keep some of these beautiful watches running for their owners so that they are not simply consigned to the scrap heap when they stop working. Here goes....
by Darren Thomson 15 June 2020
As can be seen here, this old watch's case has seen better days. On the upside, it is made of solid Sterling silver and experience tells me that I might be surprised at how nice I can get this looking with a little time on the polishing machine.

... And, sure enough, 20 minutes of careful polishing accomplished this..
by Darren Thomson 8 June 2020
After some serious rooting about in my various parts drawers.. I found a bag..
by Darren Thomson 4 June 2020
We are almost ready to put the dial and hands onto the pocket watch but before that can happen we need to clean the dial and install the "Motion Works". 

Examining the back of the dial reminds us, once again, of the general quality of components used here.
by Darren Thomson 1 June 2020
All of the major functioning parts of this pocket watch's movement are now in place and functional. It's time to see if the old girl has life in her. The project pretty much ends here if there is a major issue with the balance or the mainspring (still un-inspected internally for reasons stated back in part 3). There is almost no chance of finding replacement parts for this piece so it could get consigned back to the spares drawer if this doesn't go well..

A careful wind of the mainspring (feels solid and free-moving - click is working well). And....
by Darren Thomson 28 May 2020
With the train of wheels now installed and working, we can turn our attention to the Pallet Fork and its bridge and screws. Here they are..
by Darren Thomson 24 May 2020
For me, this is the most interesting part of the build, certainly from a mechanical perspective. This is where we get to see how the power delivered from the mainspring travels through a train of wheels to deliver suitable energy to the balance.

Here are the components at play for this stage..
by Darren Thomson 23 May 2020
With the barrel and winding system now in place, we would normally secure them with a bridge. In this case, though, it looks like the main bridge has to go on after the rest of the gear train is assembled. So, for now will just make sure that the centre wheel is properly secured into the bridge and test fit the whole thing.

Having inspected the main bridge and centre wheel.. I've found out where that little pinion gear referenced in part 3 lives..
by Darren Thomson 20 May 2020
Now that we have everything clean and checked over, its time to starting putting the 130 year-old movement back together again. Honestly, anything could happen here and, on a job like this one, I won't even bother to start thinking about the watches' case, dial and so on until I know that I can get the movement ticking again. The good news is, it wont take long. An old pocket watch like this is quite a simple mechanism in comparison to modern wrist watches. For one thing, we have less parts to worry about (no calendar, no "keyless works", no automatic winding mechanism...).

We'll start, as with most watches, with the barrel which houses the mainspring and the associated "click" mechanism (the ratchet that stops the barrel and mainspring from un-winding under tension and the thing that you hear when you wind a watch). Here are the components for this part of the build..
by Darren Thomson 18 May 2020
One benefit of buying a "bag of bits" is that I can skip the initial strip down of the watch. Of course, the downside here is that I really don't know if anything is missing or broken. So, the first thing to do is clean everything up and get 100 years worth of grime off of the components and then inspect everything carefully.. In particular the hairspring, gear teeth, mainspring & jewel settings..

The hairspring is by far the most sensitive watch part. This one looks very dirty but it has a good spiral shape to it, with no parts of that spiral touching other parts of it (which is a common cause of "fast running"). The Waltham spring also has a "Breguet Overcoil" design. This is a specific hairspring design invented by Abraham-Louis Breguet (important watch dude) waaaaay back in the 1700's and, essentially, allows for better performance of the hairspring through varying mainspring tensions (watches tend to slow down as a mainspring loses power and go faster when it is fully wound).

I'm going to clean this movement using my ultra-sonic cleaner and, to do that, I like to mount the balance and hairspring in the main plate to keep it safe during cleaning..
by Darren Thomson 15 May 2020
Well, my last little side-project got completed and we are still in "semi" lockdown in the UK so I thought i'd turn my attention to something else that I've been meaning to get to in the workshop.

As a watchmaker, one thing that you will certainly accumulate in time is PARTS. They come from watches that never got repaired, over-ordering when you only need one of something and a seller will only sell you 10 and, frankly.....Well, I don't know where many of them come from... but come they do. Here's a sneaky peak at ONE of my many "parts drawers".. 
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