Seiko crystal help

[Takeitapart]

I was hoping for some guidance for finding crystals.   I have a number of e-bay Seiko 6309-?   "Seiko 5"  watch cases and movements.  I have been able to refurbish the movements to working order.  I have dials and hands.   I am trying to coble together some watches using the cases.  Unfortunately the backs do not exactly match the case so I am not sure about the case #'s.  I there a secret way to measure and fit a functional crystal to the cases.  Does someone have "generic"  Seiko crystals?  When I look at the suppliers websites I get overwhelmed with choices.  I am not looking for OEM original crystals or restoring to original specs.  For some reason I am not sure where to start with crystals and crystal gaskets.   I just would like to make some functional watches from the "reject" parts.  Any help would be appreciated.

 

mark

[RichardHarris123]

As far as the crystals are concerned, measure the diameter of the bezel and add 0.1 to 0.2 mm. Seiko also has case numbers which will help us finding the correct crystal.  I'm a  bit confused about the case backs. 

[Takeitapart]

Some of the cases have a groove in the bezel some have a gasket.  The case number is imprinted on the case back and I am not sure the back is always a match.  For example one case was round.  When I looked up the parts for the case number on the back, it needed a square crystal.  When I am able to find the proper part number the crystal is rarely available or very expensive.  I was hoping to find some generic replacements.  Thank you.

 

mark

[RichardHarris123]

Totally confused, I can only assume you've got a frankenstein watch case. 

[rjenkinsgb]

Is this any help? A list of case number to crystal IDs:

https://gleave.london/seiko-glass-by-case-number/

 

[Takeitapart]

Exactly.  Now I want to put a crystal in it.  Not sure how to go about it.  So many choices.  Not sure how to size and fit gaskets if needed.

 

mark

[rjenkinsgb]

The Case service guide may also help with some of the variations in seals & fittings?

https://www.seikoserviceusa.com/uploads/datasheets/Servicing_Guide.pdf

 

[Takeitapart]

Thank you for the case number crystal list.  Unfortunately I don't have the correct case numbers.  I think I need to start experimenting with "L"  gaskets and crystals.  Does anyone have a reference to the size diameter and thickness to the various gaskets on the market?

 

mark

[AndyGSi]

You can also sort out the case number from the Dial Number which would be 6309-****

This example from my collection 6309-863M is from a 6309-8480 Case