Question about Cousins Sapphire Domed Crystal

[SBree]

Hey everyone,

I'm struggling to get information; so any help would be appreciated.

I have a Seiko watch which needed a new movement; I changed the movement and also decided to upgrade the crystal to a domed sapphire from Cousing.

The original crystal was a flat 1.6mm crystal (dia. 29mm); however, the thickness of the crystal from Cousins is 1.0mm. I've installed this crystal and it's sitting sub-flush to the metal rim of the case. Is it possible to use one of the "L - Form" (e.g. L Gasket 30.0x28.9mm - LG300289) gaskets to move the crystal closer to being flush with the case? Or do I need to find a crystal that is 1.6mm thick at the edges? 

[tomh207]

You really need to replace crystals very close to like-for-like.

Tom

[RichardHarris123]

Hello and welcome from Leeds, England. As Tom said, you need a crystal as  close as possible to the original. 

[AndyGSi]

Welcome to the forum.

The Gaskets you refer too are for sealing the glass to the case.

You should have just gone for a 1.5mm Flat

[SBree]

Thanks for the replies; I’ll get the 1.5mm flat and change it out again. 

[AndyGSi]

1 hour ago, SBree said:

Thanks for the replies; I’ll get the 1.5mm flat and change it out again. 

What Seiko is it and does it have an I-Ring already fitted?

[clockboy]

Welcome to,the forum, enjoy. It’s always best I have found to replace like for like if possible when changing crystals.. also why high dombed 

[SBree]

12 hours ago, AndyGSi said:

What Seiko is it and does it have an I-Ring already fitted?

It’s a Seiko 7N42-7C00 from about 2002. 

[oldhippy]

Thank you for your introduction and welcome to this friendly forum.

We all look forward to your contributions and continued involvement. 

If there is anything we can help you with don’t be afraid to ask. Nice clear photos can help a lot.

[AndyGSi]

17 minutes ago, SBree said:

It’s a Seiko 7N42-7C00 from about 2002. 

You may want to consider getting a replacement gasket for the crystal too 8656.5320

[SBree]

18 minutes ago, AndyGSi said:

You may want to consider getting a replacement gasket for the crystal too 8656.5320

What’s the difference between this gasket and the cheaper Cousins versions?

[oldhippy]

So the movement is different but it’s the original case. So you need the numbers on the back of the case for the correct glass. if the original glass will not fit the original case because you have changed the movement then the movement is not suitable for the case.   

[AndyGSi]

35 minutes ago, SBree said:

What’s the difference between this gasket and the cheaper Cousins versions?

It all depends what the actual OD of the opening is compared to the Cousins generic ones.

[SBree]

On 7/31/2024 at 9:05 PM, oldhippy said:

So the movement is different but it’s the original case. So you need the numbers on the back of the case for the correct glass. if the original glass will not fit the original case because you have changed the movement then the movement is not suitable for the case.   

I changed out the movement with a like-for-like part; I wanted to upgrade the appearance by adding a domed sapphire crystal.

I have ordered a new gasket and a 1.5mm crystal to put into it instead.