Seiko bezel gasket

[Moose]

I have a problem fitting a bezel to a case.

the watch is a Seiko and as usual is has a separate bezel which holds the crystal. the crystal is held in place by a crystal gasket and I can get that fitted in place without difficulty. The bezel also uses another plastic gasket to secure it to the case. The original gasket was taken off prior to cleaning.

I have used a new(replacement) gasket for the bezel which seems in all respects to be the same as what was removed, but I just cannot seem to get the bezel fitted to the case. I cannot reuse the original gasket as now it seems way too big to fit into the case, without deforming itself

Does anyone have any tips? Does one fit the gasket to the bezel first, or fit the gasket into the case first? I have tried both ways without success as yet.

It seems like I am exerting an inordinate amount of pressure to the bezel to get it inserted and I am worried about causing damage should I apply even more pressure to get it fitted. I have already removed the new crystal to prevent inadvertently breaking it ( it goes in from the front anyway, so can wait).

i have been using a handheld crystal press up until now as I have no alternative.

many thanks in advance.

[jdm]

21 minutes ago, Moose said:

I have a problem fitting a bezel to a case. the watch is a Seiko and as usual is has a separate bezel which holds the crystal. the crystal is held in place by a crystal gasket and I can get that fitted in place without difficulty. The bezel also uses another plastic gasket to secure it to the case. 

Like an Alpinist, there many more like that surely. It is indeed difficult to fit the bezel without pinching the gasket. The gasket should go first in the mid-case. You may need a good screw press and place a lot of attention and caution. As soon you feel that more force is needed or the bezel is not perfectly level on all sides stop there.

[jguitron]

The order of elements may be wrong. Can you show us a pic to better understand? Typically the crystal sits on the gasket.




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[saswatch88]

1 hour ago, jguitron said:

The order of elements may be wrong. Can you show us a pic to better understand? Typically the crystal sits on the gasket.




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Not in most Seikos i have worked on. Which is mostly their divers and chronos using Hardlex crystal or tension ringed plastic crystals. With out bezels and inner bezels or chapter rings. Not sure what model OP has but from what i have seen. The gasket sits around the crystal not under. Typically it goes gasket, crystal, then bezel. When the crystal is pressed it forces the gasket outwards between the outside of the crystal and the case. I have seen some with another gasket that sits where the bezel goes which i think is what the  OP has but i would love to see a picture as well. If this is the case then extreme caution is needed and a hand held press is not gunna do the job. But what i do to help any kinks or pinching i put a light coat of silicone grease on the gasket.

Edited January 5, 2020 by saswatch88

[Moose]

I will get some photos up tomorrow when back in the “shop”. But for clarity :

there are two gaskets for sure. One for retaining the crystal, and the second which is to retain the bezel in the case. Without any bezel gasket, the bezel will simply fall out.

it is a model SND661 Honda F1. You can see the black crystal gasket on the outer of the crystal. But the bezel itself comes off and has its own gasket which provides the water resistant seal with the case.

i will post photos of the actual watch under repair tomorrow. But for now, I think JDM has the handle on it. I think I will have to get a proper screw press to fit it as it really needs more pressure than I can safely provide with my lever press.

[Moose]

43 minutes ago, saswatch88 said:

Not in most Seikos i have worked on. Which is mostly their divers and chronos using Hardlex crystal or tension ringed plastic crystals. With out bezels and inner bezels or chapter rings. Not sure what model OP has but from what i have seen. The gasket sits around the crystal not under. Typically it goes gasket, crystal, then bezel. When the crystal is pressed it forces the gasket outwards between the outside of the crystal and the case. I have seen some with another gasket that sits where the bezel goes which i think is what the  OP has but i would love to see a picture as well. If this is the case then extreme caution is needed and a hand held press is not gunna do the job. But what i do to help any kinks or pinching i put a light coat of silicone grease on the gasket.

I think this may also help, but I agree also that my hand press is not likely up to the job.  :-(

 

[Moose]

PS. Also looking for a recommendation for a screw case press... 

[saswatch88]

11 minutes ago, Moose said:

PS. Also looking for a recommendation for a screw case press... 

I know they have a nice one on eBay for about $120. It’s works best if bolted to a bench. I bought one a while ago was unsure about the quality but its actually an amazing tool. I have a Bergeron now, and honestly i feel like I didn’t need to spend the $400 but i always like to have the best money can buy.

[jdm]

5 hours ago, Moose said:

PS. Also looking for a recommendation for a screw case press... 

Check the pinned topic on that subject 

 

[Moose]

For those requesting a photo of the arrangement of bezels and gaskets...

From left to right,

• Main Case
• Metal "shim-thing" (I guess for centering the gasket)
• bezel sealing gasket
• bezel (the black-rubber crystal gasket is in place at this time)

Just up at top left, is the internal tachymetre ring, which goes in prior to fitting the bezel

[Moose]

Ready for assembly... (but pending acquisition of a screw press.) 

 

[Moose]

Just looking at the gasket profile... (images from Cousins product page.)

The gasket does have a chamfer on one edge, this leads me to believe there is only one way it will fit easily. As shown in the first picture, if I fit this into the case this way up the chamfer is facing outwards. If I try to fit the bezel now, the chamfer is not positioned correctly to allow the bezel to centre itself and force the gasket outwards, which I guess is the intention. More likely, the bezel will rest on the flat and "nip" the gasket if any pressure is applied. Similarly, if I flip the gasket, the chamfer now faces the inside-lower case side, which again means the bezel cannot centre itself when trying to press it in.

The only way I can logically fit this, is represented by the second picture which is flipped, but instead of fitting into the case, the gasket is instead fitted to the bezel, prior to press fitting. Thereby the chamfer will be correctly located to allow for centering whilst pressing home.

I would appreciate a second opinion on this reasoning please...

[jdm]

3 hours ago, Moose said:

The only way I can logically fit this, is represented by the second picture which is flipped, but instead of fitting into the case, the gasket is instead fitted to the bezel, prior to press fitting. Thereby the chamfer will be correctly located to allow for centering whilst pressing home.

Yes. But, if the gasket fitted on the bezel is just 0.05mm larger than the original, it will not fit into case opening. Because it will not compress evenly, but distort and pinch. 

[Moose]

Therein lies the rub... I have looked high and low but having problems finding an original and one removed is already deformed when I took it out.

The red Cousins gasket seems to be accurate, dimensions-wise, as measured with my digital vernier. But of course, I could not swear with any certainty if it was exactly the same, or has a 0.05mm variation or not.

[jdm]

What are case opening and gasket size when fitted? Maybe you can try sanding the outer face of the gasket slightly. 

[Moose]

2 minutes ago, jdm said:

What are case opening and gasket size when fitted? Maybe you can try sanding the outer face of the gasket slightly. 

You know - I had the same idea myself, and now you have mentioned it as well - it does not sound so daft to me anymore. I'll recalibrate my vernier again and measure the old one on an undamaged section, then compare it to the replacement and form an option. As you suggest, it may be worth trying to take a few thou off the replacement if it measures slightly larger.

Good suggestion.

[Moose]

OK - spurred by JDM's (and others) hints, I have had a productive hour or so.

Firstly, measurement of the case diameter - the bezel recess - shows 36mm. The bezel ring which fits inside it is 35.25mm. This means the gasket is taking up a minimum radius of 0.375mm.

Measurement of the thickness of the original gasket showed it was 0.45mm, a difference of 0.075mm larger. So I'm guessing this is to allow for a bit of compression to ensure a water-resistant and secure fit of the bezel into the case.

[Moose]

So - measurement of the aftermarket replacement shows the problem (or at least the biggest issue). It measure at 0.55mm. So far I have been unable to source a genuine replacement gasket or identify a suitable generic replacement, so a bit of fettling is called for. Sod's law now dictates that I will either find the correct gasket somewhere, of have dozens of suggestions offered...

Time for a bit of fettling now. Thankfully (and extremely fortuitously), I had a small paint pot (for retouching clock and watch hands, etc) that magically had a cap diameter very similar to the internal diameter of the gasket. So - on with the gasket and I settled down for half and hour or so of patient sanding with some very fine wet and dry paper. The pictures show the before measurement - during sanding - and finally the after measurement of the gasket thickness.

I know this seems like a lot of work for a piddling little gasket, but I really can't find one and it's for my son's watch. Again - I know - it's only a Seiko, but it still holds a bit of sentimental value between us and it would be nice to fix it for him. And at the end of the day - I don't make money out of watch fettling, it's only my hobby - so time spent is really not the issue.

Now I just have to wait a day or two for my screw-down case press to arrive, then I'm sure it will refit just fine.

Thanks again to all here for your hints and support.

Edited January 6, 2020 by Moose

[Moose]

[Moose]