Pocket Watch Crystal Replacement

[gpraceman]

I was doing the final assembly on a 1937 Elgin Grade 315 pocket watch tonight and managed to shatter the crystal.  I cannot get a measurement on the crystal's diameter, since it is in too many pieces, but I measured the bezel at 38.5 mm.  So, when looking for a new mineral crystal, should I look for one that is that measurement, or go to one that is say 38.6 mm?  I have only dealt with acrylic crystals up to this point.

Edited September 11, 2023 by gpraceman

[gpraceman]

No responses.  Anyways, I figured it is best to get one matching the size of the bezel measurement.  If it doesn't friction fit, then I'll glue it in.

[RichardHarris123]

From what I have read, mineral glass is either fitted with a tension ring or glued in but I have only used acrylic. 

[mikepilk]

My understanding is that mineral glasses are usually 0.1mm larger than the inner diameter of the gasket they fit. As you have no gasket, I would go with 38.5mm and glue.

[JohnR725]

12 hours ago, mikepilk said:

My understanding is that mineral glasses are usually 0.1mm larger than the inner diameter of the gasket they fit. As you have no gasket, I would go with 38.5mm and glue.

Are we talking vintage glass or modern glass? The unfortunate reality of there are lots of different types of crystals. Typically modern crystals are held in with  a gasket and have to be pressed in. But what was the original question?

On 9/11/2023 at 1:45 AM, gpraceman said:

1937 Elgin Grade 315 pocket watch

Vintage definitely not pressed in as they never had a gasket. Either glass typically glued in or plastic which could either be glued in or if you can size it right? Plastic crystals are interesting in the case of a pocket watch crystal and some watch crystals you can hold the crystal near the edge and pushed dead center on the inside and the crystal itself will bow and become smaller in diameter and then the watch bezel itself can be pushed down on the bode crystal and then when you release friction will hold the whole thing in place. Which probably sounds that you're very poor description hopefully the second link explains it a little Better with pictures. The only catch is the crystal does have to be the right size of its too small it won't stay in place if it's too big Often times Poet enough to get the bezel to fit were to get really enthusiastic and push really hard you can shatter the crystal. But it is a really nice way to get a plastic crystal it without glue and will hold quite nicely

but oftentimes pocket watches were designed for a glass. If you're looking for glass crystals try the first link. He gives all ties the specifications of stuff on the website if you're not sure you can just send the watch and he'll fit the crystal for you.

http://whitescrystals.com/

https://blog.esslinger.com/how-to-press-a-compression-fit-watch-crystal-into-place-with-a-watch-crystal-press/

 

 

 

[gpraceman]

8 minutes ago, JohnR725 said:

Are we talking vintage glass or modern glass? The unfortunate reality of there are lots of different types of crystals. Typically modern crystals are held in with  a gasket and have to be pressed in. But what was the original question?

Vintage definitely not pressed in as they never had a gasket. Either glass typically glued in or plastic which could either be glued in or if you can size it right? Plastic crystals are interesting in the case of a pocket watch crystal and some watch crystals you can hold the crystal near the edge and pushed dead center on the inside and the crystal itself will bow and become smaller in diameter and then the watch bezel itself can be pushed down on the bode crystal and then when you release friction will hold the whole thing in place. Which probably sounds that you're very poor description hopefully the second link explains it a little Better with pictures. The only catch is the crystal does have to be the right size of its too small it won't stay in place if it's too big Often times Poet enough to get the bezel to fit were to get really enthusiastic and push really hard you can shatter the crystal. But it is a really nice way to get a plastic crystal it without glue and will hold quite nicely

but oftentimes pocket watches were designed for a glass. If you're looking for glass crystals try the first link. He gives all ties the specifications of stuff on the website if you're not sure you can just send the watch and he'll fit the crystal for you.

http://whitescrystals.com/

https://blog.esslinger.com/how-to-press-a-compression-fit-watch-crystal-into-place-with-a-watch-crystal-press/

 

 

 

The old glass crystal was press fit.  I shattered it trying to get it back in the bezel (face palm).

White's Crystals is where I ended up ordering the new crystal from.  Found them on eBay.  Hasn't shipped yet, but hopefully soon.  I do have some GS cement, if needed for the install.

My experience up to this point was with acrylic crystals.  I do have a crystal press when there is the need.

[JohnR725]

22 minutes ago, gpraceman said:

The old glass crystal was press fit.  I shattered it trying to get it back in the bezel (face palm).

Out of curiosity how did the crystal come out of the bezel in the first place?

As you discovered the crystal was not pressed in. This is much more common in clock repair where the bezels are bigger then In watch repair but I've heard that people supposedly do this and watch repair. If you get your glass sized exactly right and you can warm up the bezel so it expands just a little bit then the crystal can go in and When the bezel cools it shrinks and holds the crystal. 

Other thing is for gluing glass in UV glue I rather like that providing the glass crystal fits nice and tight. Because it glue doesn't start setting intellects exposed to UV it gives you working time. Epoxy is very popular and of course GS cement.

[gpraceman]

7 minutes ago, JohnR725 said:

Out of curiosity how did the crystal come out of the bezel in the first place?

As you discovered the crystal was not pressed in. This is much more common in clock repair where the bezels are bigger then In watch repair but I've heard that people supposedly do this and watch repair. If you get your glass sized exactly right and you can warm up the bezel so it expands just a little bit then the crystal can go in and When the bezel cools it shrinks and holds the crystal. 

Other thing is for gluing glass in UV glue I rather like that providing the glass crystal fits nice and tight. Because it glue doesn't start setting intellects exposed to UV it gives you working time. Epoxy is very popular and of course GS cement.

Well, I usually pop out the crystal on a watch before I put the case in the ultrasonic cleaner.  Wish I hadn't on this one.  There were no signs of glue, so the old crystal was a a pretty good fit to the bezel.

Edited September 13, 2023 by gpraceman

[JohnR725]

27 minutes ago, gpraceman said:

I usually pop out the crystal on a watch before I put the case in the ultrasonic cleaner.

Usually when I'm cleaning a pocket watch case I don't worry about the crystal sort of in other words I kinda hope it will stay in place and I don't have to glue it back in.

1 hour ago, gpraceman said:

Wish I hadn't on this one.  There were no signs of glue, so the old crystal was a a pretty good fit to the bezel.

This is why when I wash the case if the crystal stays in place I'm happy if it comes out than I have to deal with that. But I don't typically push them out ahead of time. Because a lot of crystals are were seem to be relatively permanent in their bezel and I would prefer they stay that way if I can.