Service: King Seiko 4420-9990R AD


The King has entered the blog;) In the 1960’s Seiko wanted too show the world what they where capable of making. Seiko created two marques that would be produced at two different factories that could internaly compete to make the best watch. The Suwa factory produced the Grand Seiko and Daini facotry made the King Seiko. This internal rivalry lead to Seiko producing advanced Hi-beat monsters that were out-performing the top swiss brands when it came to accuracy. This lasted into the quarts revolution where both lines had King and Grand quartz, but after some time both lines where discontinued. In 1998 Seiko relaunched the Grand Seiko, but that’s a different story;)

I always liked the look of the Seiko calibre 44 with it’s micro regulator and balance bridge. So I could not resist when I found something that looked like a decent example. 


The movement is a little dirty but otherwise in good condition.


Performing okay, but a service is in order.


I have removed the dial and hands and you can see the setting/winding mechanism. The funny thing is someone replaced a broken setting lever spring, but did not notice the broken off piece from the old setting lever spring:P


A very cool detail is the jewelled barrel and barrel lid.


A close-up of the barrel jewels.


Lower barrel arbor hole is also jewelled, but not the upper. Notice the thin layer of oily substance all over the movement.


With the train bridge removed you can see the gear train layout.


Dirty mainspring.


Everything cleaned and ready to be put back together. No lack of cap jewels.


Balance moves freely after fitting the jewels.


Cleaned and oiled mainspring back in the barrel.


Movement coming back together.


Gear train back in place.


Setting/winding mechanism back in place.


Movement back together and ticking.


Preforming well.


I wanted to replace the crystal. I realised after removing the old crystal that I did not have a die that could press the bezel ring back onto the case when fitting the new crystal.


My problem was the old dies were too shallow and would hit the crystal before actually pressing the bezel ring down. The solution was to machine out an old die so it was deeper.


I see the crystal fits inside the die and I’m now able to press the bezel ring onto the case with the new crystal.


Dial and hands back on the movement looking good.


Movement back in the case looking very clean and nice.


I like the clean design of this watch.


It’s almost too large for my wrist;)

8 Responses to Service: King Seiko 4420-9990R AD

  1. Barry says:

    Ooo nice one and I’m so so glad it turned out to be real, despite the fact that it has obviously needed your magic touch to get it too the 100% level.
    Great beefy lugs and yes it’s too big for you !!!!!!!.
    Whatever ever fantastic job as usual

  2. Urfan Khaliq says:

    Hello Mitka,

    A wonderful blog and a stunning watch!

    I am interested in your comment – which may be an aside – that the relaunched Grand Seiko’s from 1998 onwards are a different story. I have owned vintage Grand Seiko’s from the early 1970s as well as owning several more recent Grand Seiko’s as well as some of the higher end Swiss, Omega, IWC, JLC and Zenith. My Grand Seiko’s are, in my view, at the least a match for the Swiss brands I have mentioned in terms of finish and workmanship. I cannot speak for other Swiss brands as I don’t own them. Having said that I have never opened a GS or any the others but I am interested in your view as to the movements. I do think GS are stunning and innovative (Spring Drive and Hi Beat for example) and make stunning classic looking watches which the likes of Rolex and Omega no longer produce with them going for more flash designs.

    • mitka88 says:

      I have not worked on a modern GS, but from images they look to be very well made and the finishes look to be top notch! I think the classic GS and KS did not focus so much on decoration, but more on performance and practicality.

  3. matabog says:

    Never seen jewels on barrel lid and bottom! Nice!

  4. Qayyum says:

    Hey Mitka

    Mind sharing where u source the Seiko parts from? Thnks


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