Changing crystal on 7A28-7040

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kerochan
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Changing crystal on 7A28-7040

Post by kerochan »

Will I need to remove the bezel before changing? I have a generic flat crystal from Cousins UK, 32mm 1.5mm thickness. Will it fit?

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Seiko7A38
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Re: Changing crystal on 7A28-7040

Post by Seiko7A38 »

You will indeed need to remove the bezel from your 7A28-7040 to replace the crystal, Dave. The bezel insert overlaps the crystal's beveled edge. If you rotate the bezel, looking sideways on at its mating flange with the case, you'll find a shallow fingernail shaped indentation on the underside of the bezel track, where you can insert a case knife. Here's an old photo (not mine) showing the equivalent blade insertion point on a 7A38-7070 case:

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Assuming you haven't made a typo, your 32.0 Ø x 1.5mm thick Cousins UK generic crystal won't fit. The original Seiko crystal p/n 310W64GN00 measures 31.0mm Ø x 1.95mm thick, with a polished beveled edge. Remaining supplies of these are all but exhausted and when opportunistic eBay sellers do occasionally list them, their asking prices are ridiculous - I've seen them as high as $85. :o

The solution to your problem is to be found on page 7 of the old forum’s Crystals and Gaskets thread, in my sequence of posts starting 27th June 2020.

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Bryan was keen to draw attention to his eBay listings and at times included the words: SEIKO, 310W64GN00 and OEM in his titles, at which point I got very annoyed with him, hence the comment at the bottom of my last post. His latest listing title is in no way misleading. His custom aftermarket crystals are a very good reproduction of the original.

https://www.ebay.co.uk/itm/Seiko-7A28-7 ... 4638989761

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kerochan
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Re: Changing crystal on 7A28-7040

Post by kerochan »

As I thought, there is never an easy way when you can make it complicated!

It was indeed a typo regarding the size of my crystal, it is 31 mm. But since it is only 1.5mm thick, I assume there will be a large gap between it and the bezel?

I just got the watch and everything is perfect - except for one big gash on the crystal which I know will never leave my mind at peace...

Thanks for the tip about the AM crystal. I don't mind using AM parts but the price is a little steep. And accounting for you guys not being in the EU anymore and my government loving taxes, the import charges are going to be about the same cost as the crystal. Perhaps I'll just have to learn to live with that blemish.

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Re: Changing crystal on 7A28-7040

Post by Seiko7A38 »

kerochan wrote: Fri Jul 23, 2021 9:54 pmAs I thought, there is never an easy way when you can make it complicated!
It's not complicated, Dave. All you need to remove the bezel from your 7A28-7040 is one of these - and a bit of courage.

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Some Seiko 7Axx rotating bezels, like that of the 7A38-6020 are a bit tougher to remove than others (understatement). I've just invested in one of these Horotec Bezel Removal Tools. (For the reasons why, see this thread on the old forum).

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Re: Changing crystal on 7A28-7040

Post by Seiko7A38 »

kerochan wrote: Fri Jul 23, 2021 9:54 pmI just got the watch and everything is perfect - except for one big gash on the crystal which I know will never leave my mind at peace...
I don't quite understand. :| So is the 7A28-7040 you've just bought, not the same as the watch in your original post ?

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kerochan wrote: Fri Jul 23, 2021 9:54 pmPerhaps I'll just have to learn to live with that blemish.
Could you post a photo of the actual watch showing the big gash / blemish please. :P

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Re: Changing crystal on 7A28-7040

Post by Seiko7A38 »

kerochan wrote: Fri Jul 23, 2021 9:54 pm It was indeed a typo regarding the size of my crystal, it is 31 mm. But since it is only 1.5mm thick, I assume there will be a large gap between it and the bezel?
There certainly will be a bigger gap, which apart from likely being unsightly, will allow dirt and dust to accumulate easier. Also, the top surface of the crystal won't be nearly as flush with the bezel insert as it should be (by 0.5mm).
kerochan wrote: Fri Jul 23, 2021 9:54 pm Thanks for the tip about the AM crystal. I don't mind using AM parts but the price is a little steep.
You may consider it expensive, Dave, but it's a much lower price than you're likely to have to pay for a genuine Seiko p/n 310W64GN00 crystal nowadays - that is IF you can find one.

Incidentally, there are a couple of slightly cheaper alternative options offered by other UK eBay sellers, which I would strongly recommend against buying. They're likely to be exactly the came Cousins UK cheap generic you already have.

https://www.ebay.co.uk/itm/113653412710

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https://www.ebay.co.uk/itm/274405519139 and https://www.ebay.co.uk/itm/283923642523

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