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Seiko caliber 6309

Seiko Caliber 6309

Seiko caliber 6309

Brand Seiko
Caliber Number 6309, 6309A
Movement Type Automatic
Jewels 17
Vibrations Per Hour
21,600 bph
Power Reserve 47 hours
Diameter 12”’ (27mm)
Thickness 5.3mm
Shock System Diashock
Rotor Ball bearing
Mainspring 401615
Balance Staff 311601
Hands 1.5 x .90 x .20
Hacking? No
Manual Winding? No
Crown Location 4:00
Functions Hours, minutes, central seconds, quickset bi-lingual day, quickset date
Country of Manufacture Japan
Known Models 6309 (add more in the comments below)

The Seiko caliber 6309 is a vintage automatic workhorse movement that was found in many Scuba Diver models, seiko 5, and dress watches in the 1980’s. There are different variations of this movement, including Seiko caliber 6308A (17J), 6319A (21J), 6347A (moonphase, 23J), 6349A (23J).

In old Seiko documentation, they refer to the 6309 as a Highly Reliable Movement:

The highly stabilized accuracy and high reliability established for the 61XX series has been incorporated into the movement.

Also mentioning easy servicing:

Please allow us to interrupt your gear turning and caliber learning to say thank you. Thank you for being here! Now, back to the movement..

Disassembling and reassembling procedures and serviceability have been improved largely by:

  • Employment of a new balance hairspring holding device (aka no stud for the hairspring since it clamps directly in the terminal)
  • Decrease in number of parts from the simplification of the movement structure.
  • Decrease in number of new parts resulting from interchangeability of some parts with Cal. 61XX series.

In an interesting thread on the Military Watch Resource forum comparing the Seiko caliber 6309 to the ETA caliber 2824, shortwave said:

I have a 25 year old 6309 7290. It hasn’t been cleaned in at least 10 years. It advances 1 to 2 seconds in 12 days. I’ve never seen such accuracy in any manual watch. The ETA in my Marathon, gains seconds a day.

 

Is the Seiko Caliber 6309 any good? Share your opinions, experiences and watches below... Keep comments respectful and follow our community guidelines.

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carls
carls

He tenido seikos con este calibre 6309 y son fabulosos van mas exactos y precisos que otros relojes que montan maquinas eta, sellita o unitas., son unos autenticos caballos de batalla sencillos, fiables, precisos y robustos.

Jonathan Shaw
Jonathan Shaw

I have just bought one of these movements in a bit of a frankenwatch, its got a really cool retro orange with green circle face, except I’m pretty sure its not the original case due to the way the case’s internal outer edge cuts off the numbers 2/4/8/9 and 10, I might even have a go at removing this part of the case to get the full face on show, it would make a desirable vintage 5 if I could sort that out, oh and sinceI got the watch it has been running fast, I’m trying to use the regulator… Read more »

schilviu
schilviu

I own this watch since August 1987. First time was cleaned after ten years of service. After few adjustments, accuracy reached a couple of seconds per week, amazing for an automatic, mid-to-low end, general purpose watch.

Andrew Barwell
Andrew Barwell

Mid-to-low end? Sorry, but you can’t judge the amazing qualities of the Seiko 6309 diver by using the obsolete method of trying to fit it somewhere along the very overpriced (and overhyped) Swiss watch lines. Seiko broke the mold and the Swiss have list their way regarding affordable quality (for most people.)

Vlad
Vlad

Can anyone tell me if someone has the correct Lift angle for this caliber or if there are any calibers similar to this one.

VDO
VDO

I have a Seiko 6309-729A 150M diver. I had got it in 1988 as a gift. As a young boy I used it a lot for many years. However, it was neglected and kept in a drawer for the last 20 years as I used various other watches. As part of house cleaning, just found it. Just washed it and cleaned it myself. And it is working fine. What a sturdy movement. It has been working fine. A question – should I get it serviced? Everything seems fine. I just don’t want some service shop to messup. Thanks for answer… Read more »

Andre
Andre

Yes. You should have someone perform a full service on that watch if you care about it to continue running well. After so many years, the oil dried up and actually became abrasive. So now, as the watch runs, the pivots and jewel bearings get damaged. This kind of damage cannot be repaired cheaply. There is also a possibility that the rubber gaskets (crown and back plate) will need to get replaced. There is a chance that an old leaky gasket may have caused some corrosion inside. A watchmaker should be able to check and advise in a case of… Read more »

Emrah
Emrah

I am 32 years old now and it is still on my father’s arm… I think i had opened my eyes to world with that machine… And now unfortunately, it needs a service… It is stopped in a sudden…

Andre
Andre

That’s expected on an old, never serviced watch. Just have a service performed on it by a watchmaker.

Matthew
Matthew

Reliability? 6309-8920 blue dial with dented crown and much scratches all over the watch. 35 years old. Stopped working for about than 10 years. Inherited it from my dad. No servicing was done since manufactured. Shake it hard for a couple of minutes. It’s running like usual again. Opened up the back case, no corrosion and very minor dirt deposit on the gears. A true power horse indeed.

trackback
Seiko 6309-7290 Review - A Classic Diver From The 80s - iknowwatches.com

[…] 6309 designation is for a Seiko automatic movement with 17 jewels and 47 hours of power reserve. It beats at 21,600 […]

Adam Gutterman
Adam Gutterman

I have one of these (6309-7159) that I’m about to reset the hands on. I was thinking I should replace the gasket as well. This is my first time doing this – how would I know what size gasket to get?

Andrew Barwell
Andrew Barwell

The crown is at 4:00 on the 6309 divers.

Placide
Placide

Hello
I have just bought an old Seiko 5 6309-8610 watch on eBay. i hope I will find some watch professional to repair it

Eddie M.
Eddie M.

What is wrong with it?

Auburn Senn
Auburn Senn

By far the best SEIKO movement I have ever come across. My 6309 watches are robust and accurate. I have over 50 pieces of the 6309-7040/49s and they all work perfect

Andrew Barwell
Andrew Barwell

Wow, how do you rotate your to-wear cycle with that amount of watches?

Terrell
Terrell

I have a Seiko 6309-7049. It needs an overhaul and service. My local jewelry tech was of no help. Any recommendations for a vendor to service it?

Tucker
Tucker

Even though sending Seikos to their repair center in NJ gets abysmal reviews on Yelp, I had a positive experience. They repaired the movement, replaced the crystal, and cleaned the whole watch for $170. Sure I could have replaced my old chronograph for that amount, but that wasn’t the point.