Seiko 6105-8000 NOS build

Sometimes I get jobs in that I can’t wait to start and the watch featured today is no exception. I’ve been watching this one move up the work queue with eager anticipation as I literally couldn’t wait to get stuck into it! The watch in question is a 6105-8000 with a production date of January 1969 but what makes this special is that apart from the donor movement everything else has been collected over a period of years and is all new old stock parts. When I say everything I mean everything, the list reads as a NOS case and caseback, NOS chapter ring, NOS crystal gasket, NOS crystal retaining ring, NOS Crystal, NOS bezel assembly (including tension spring), NOS crown and stem, NOS movement ring and caseback seal, NOS dial and dial spacer and finally a NOS handset. It’s very rarely I get to tackle jobs like this but when they come along I love it! This watch belongs to the owner of the previously featured 6306-7001 – what a collection he has, there are still a few watches of his I’d like to feature in the future. The picture below shows how the watch arrived, in lots of carefully wrapped packets.

Seiko 6105-8000

Seiko 6105-8000

The first job with this was to build up the case and whilst I always take the greatest of care with watch work, when I get casebacks like the one below I have to approach it in a different manner so as not to damage that 46 year old protective coating and the labels.

Seiko 6105-8000

To fit the crystal the case is built up firstly with the chapter ring, then the crystal gasket is fitted, the crystal is then put in place and the crystal retaining ring is then pressed on to clip it all together. This is carried out in a press and you’d normally use a die to support the caseback and a die to fit the crystal ring, but of course with the factory protective coating still in place I didn’t want to undergo the slightest risk of marking it. I use a vintage Seiko S220 press for working on vintage Seikos, and fortunately a little while ago a well known vintage Seiko chap called John Bentley had made some nylon adapters for it. This adapter supports many of the common Seiko cases without the need to fit the caseback. I pressed it into service (geddit?!) to fit the crystal to this case, as you can see it has a cutout that allows the cases crown tube to fit without damage.

Seiko 6105-8000

The case slides over the die and is supported evenly all the way around the hole the movement normally occupies….

Seiko 6105-8000

….the die is then placed into the press and a suitable sized alloy die is selected to fit the crystal retaining ring….

Seiko 6105-8000

….and it’s pressed home until it clicks into place.

Seiko 6105-8000

This is the result.

Seiko 6105-8000

The bezel is the next component to be fitted, the 6105-8000s one is held in place with a wire retaining clip, much as the 62mas divers bezels are. The 62mas uses an octagonal clip that keeps the bezel located in eight places. When the 6105-8000 came along the design was changed to a ‘c’ type clip or spring if you prefer. This type locates the bezel in only three places and it’s always seemed a retrograde step to me, I think the 62mas clip is a better design with its eight points of contact. Anyway, as this is an exercise in NOS parts the correct clip is used!

Seiko 6105-8000

You can see the points at which the bezel is secured in this shot.

Seiko 6105-8000

Once the bezel was clipped on, the caseback was also screwed on and the crown was fitted. What a beauty this case is, to all intents and purposes a brand new 46 year old case!

Seiko 6105-8000

Seiko 6105-8000

The movement selected to grace the case is the correct 6105a variant with no hacking feature and its chamfered bridges. The movement was to undergo a full service.

Seiko 6105-8000

The stripdown revealed it was in a very healthy state with minimal wear and just dried oils to contend with.

Seiko 6105-8000

Seiko 6105-8000

The motion work side was just as good.

Seiko 6105-8000

Seiko 6105-8000

It was soon fully stripped and ready for the cleaning machine.

Seiko 6105-8000

Seiko 6105-8000

Nothing untoward was found during inspection so the rebuild started with the mainspring.

Seiko 6105-8000

Seiko 6105-8000

A Dainiseikosha produced movement no less!

Seiko 6105-8000

The calendar side was just as nice.

Seiko 6105-8000

Seiko 6105-8000

The dial and handset were next, so what’s in this little box? Ah, a NOS dial of course!

Seiko 6105-8000

And what’s in all the little waxed paper packets? Why it’s a NOS handset.

Seiko 6105-8000

The dial ring, dial and handset were fitted.

Seiko 6105-8000

The movement was cased with it’s NOS movement ring and the stem was trimmed to the correct length and fitted to the crown.

Seiko 6105-8000

The seals were silicone greased, and that caseback was finally tightened down!

Seiko 6105-8000

This meant it was finally finished, a brand new 46 year old 6105-8000. Sure it has a resist dial which technically isn’t correct for the year but that’s really a minor nitpicking point as later 8000’s came with resist dials anyway – how I wish this was mine!

Seiko 6105-8000

Seiko 6105-8000

Seiko 6105-8000

8 comments

  1. Beautiful build!
    How did Seiko install the bezel assy with the c-clip?
    I normally install the spring into the bezel groove and pop it on the case but recently had a difficult time installing one on a 6117-8000, just wouldn’t snap on!
    Finally had to install the spring onto the crystal ring groove as you have pictured, catch 2 of the protruding bends into the bezel groove and push the 3rd point in as I pushed the bezel down?
    Any tips?
    Love the watch!

    Like

    1. The way you did it is the way I do it, fit the c-clip to the case first, then fit the bezel and one by one push each of the protruding bends in as you push the bezel down. Works for me!

      Like

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