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Handwind Seiko Cronos cal.54

anilv
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anilv Distinguished Member

anilv

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Seiko watches have been a personal favorite of mine because of the quality of the materials used and also the quality of the design.

I recently purchased a hand-wind Seiko Cronos which was advertised as non-running and I thought I'd share my experience with it.

As received, the watch was in decent cosmetic condition but not running.

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Caseback is in decent shape and the case itself seems to be pretty much unworn. Its Gold-plated but no indication of the thickness. Serial is the 7 digit type used in the 60s so this would be April '61?

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I popped the front bezel off as the movement comes out the front, you can see some damage to the dial where the hands have grazed the dial.

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Another pic of the damaged area. Its a shame as the dial is in good condition otherwise.

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The Seiko calibre 54. These came in 54A, 54B and 54C.. not to sure which one this is as there's not much info about these movements. Decent looking and 23 jewels for a handwind is pretty awesome. A full bridge for the balance-wheel no less...just like Rolex! One of the case screws is missing.

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The dial side of the movement with the dial removed... not as pretty as the other side, cap jewels present but in a simpler design.

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With the ratchet-wheel, balance-wheel and pallet-fork removed.. here we see the first sign of a problem. The barrel arbor hole has been 'massaged' to reduce barrel endshake.

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The underside of the barrel-bridge.. negligible end-shake on the barrel so it will go back in as it is.

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Some wheels...pretty similar to a lot of other Seiko movements.

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Dial-side dismantled.. It is at this point I realised that Seiko was not above playing the 'jewel' game.

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In the picture below, you can see that the jewel for the pallet fork has an oil 'sink' . In these jewels the endshake is controlled by the inner flat surface, rather than cap jewel which makes the cap jewel superflous. Compare this to the escape wheel jewel where the jewel is domed on the outside and the oil sits in the gap between the curved jewel and the cap jewel. Here the cap jewel serves to ensure minimal friction as the point of the pivot rides on the cap-jewel whereas in normal uncapped settings the pivot's 'shoulder' hits the flat inner surface of the jewel. I'm not sure if Seiko did this to raise the jewel count, pallet-fork pivots are not usually oiled so it could be that having cap jewels here MAY reduce friction in this case as endshake is more controlled.

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Below we see the other side of these jewels, the escape wheel jewel is the one with a flat side.

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Mainspring looks good.

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Ditto the barrel

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The cap jewels have been cleaned, The double jewelled one goes back in one position only as the cutouts match the holes in the dial where you check the pallet/escape-wheel engagement.

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Diafix settings with the spring in the open position and cap-jewels about to be removed...

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Dirty jewels..

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And here we see the bottom of the train bridge. again we see another jewel which does not require a 'cap'. The fourth-wheel (seconds) jewel is flat on this side and has the oil-sink on the other. This wheel needs to be oiled and hence the cap-jewel is just a 'dustcap'.

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view of the oil-sink and 'proper' capped jewels for the escape and third wheel.

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All cleaned up and oiled. Fitting the diafix jewels went smoothly enough.. sometimes they cause problems but not today!

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Train bridge installed and checked for smooth runnig.. all good but.........

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The diafix springs were all over the place so I adjusted how they were aligned.. I think it looks a bit better now! (the upper left spring looks like it has one leg out of the groove but its actually OK).

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Everything running smoothly.

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Overall it was a nice movement to work on but the most difficult part about working on these watches is getting the clearance of the hands correct. I had to remove the bezel twice before it ran without hands snagging on each other and I believe that it wouldn't take much to get them out of alignment.

This movement was used as the basis for some early Grand Seiko watches and while I haven't timed it, it has been running well for the last few days. I really think that the 2 cap jewels I mentioned above are unnecessary and it would have been better to jewel the barrel arbor but even with 21 functional jewels it still is a nice running watch!

Hope you enjoyed reading about this as much as I enjoyed working on it!

 

Anilv

 

Ps.. while outwardly clean, the initial rinse in lighter fluid showed how much of dirt was in the movement. Here the balance and pallet fork was removed, the mainspring given a few turns and it was left to unwind in the fluid. I find that this helps clean the pivots but you have to prevent the wheels from turning (I used a sliver of pegwood) until the movement is submerged in the lighter fluid otherwise the wheels spin too fast and could wear the pivots unnecessarily.

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Edited by anilv
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RyMoeller Super WRT Addict

RyMoeller

Posted
Posted

Nice write-up for an interesting movement.

Even though those Diafix springs can be a real headache (it gave me shivers just seeing them in the pictures), that appears to be a high quality Seiko movement.  I especially like Seiko's use of balance bridges in their better movements; they fly a bit under the radar but put together a solid watch.

Great tip regarding unwinding the watch in fluid.  I can see how that would be helpful in both cleaning the pivots and jewel bearings. :)

Nice work and thanks for sharing!

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Sven New Member

Sven

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Posted

I have one with a broken Setting lever spring (I used your picture below to indicate the part) and would like to look up the part number and see I can find a new one, so looking for the parts list. Any suggestions welcome!

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