Seiko 6309-729B

Seikos 6309 divers watch comes in a number of variants ranging from the classic cushion cased 6309-7040/9 and the slim cased 6309-7290, to the blue and red bezel of the slim cased 6309-729A. The scarcest of all these is the slim cased orange dialled 6309-729B.


This example dates from August 1983 and came in for a service and a bit of a spruce up.


Overall the condition wasn’t too bad, with the caseback removed you can see there’s not too much out of place, a little corrosion but not bad at all.


The hands had degraded somewhat and were very scratched up. The seconds hand has been replaced with an aftermarket silver one but it should be gilt like the hour and minute hands. This will present a bit of a problem, whilst it’s still possible to come across gilt hour and minute hands occasionally due to the fact they were used in other models, the seconds hand is particular to the 6309-729B and the chances of finding a replacement is slim to non existent. There’s also a little flake of the dials finish missing and it’s a little stained in places.


The movement was stripped ready for cleaning and no surprises were found which was good, just the usual dried out lubricants.



The case was stripped to install a frosted bevel crystal and good job it was! Nothing seemed amiss as the bezel turned freely but once it and the crystal retaining ring was removed there was a lot of corrosion underneath. If left unchecked this would have done quite a bit of damage to the case and ring. It also rendered the crystal seal unusable so a NOS one was fitted.



With the corrosion cleaned off there was quite a pile of rot left behind!

P1010928aA trip through the ultrasonic bath soon had the case parts back up to scratch.


The crown was stripped for cleaning and to replace the o-ring and I noted that the retaining washer was missing, I reckon 50% of 6309 and 7548’s I see have this important component missing.


With the crown reassembled you can see where the washer fits, this securely holds the female part of the stem together.


This completed the case side of the job.


Now back to the hands. As gold replacements are just not available (especially the seconds hand) a bit of lateral thinking was needed. I found an original set of 6309 hands in the parts drawer that had rotten lume which had attacked the plating on the frames. These hands are plated over brass so I decided to polish the plating off completely and see what the result was like.


Not too shabby, especially when compared to the originals.

P1010920aSome lume was mixed up…


…the hands were turned over….


… three coats of lume were applied….


….which turned out very well I thought.


The movement was then inspected and reassembled starting with the mainspring as always with me!


The train coming together….


….and the motion work completed


The keyless work was assembled….


….adn the calendar side was completed. Another point was the calendar wheel was bent and had a chunk filed off it which meant it worked OK until the 16th got to the window, then it wouldn’t click into position until it reached the 21st.


Straightening calendar wheels is something I’ll do if I have no other choice as it’s very time consuming and isn’t guaranteed to work. A replacement was found in the parts drawer and was fitted.


The dial was gently cleaned with spit and a cotton bud (seriously), I’ve found if this method doesn’t shift any stains they aren’t going anywhere! The dial and handset was then re-installed.


The movement was recased and a new seal fitted.


And here she is, job done. It would have been nice if the dial could have been in slightly better condition but with the watch on the wrist the stains aren’t noticeable at all. Bearing in mind this is the first 6309-729B I’ve actually seen in the metal I think it’s a rare survivor indeed!





  1. Very nice job. I am looking for these gold hands, and can’t find them anywhere!!
    I’ve been looking for this 729B on eBay, to scavenge the hands.
    If I can’t find it, I might have a set of AM hands gold plated.


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