Pressing in fancy shaped crystals?

[GuyMontag]

I have a crystal that is supposed to be the correct crystal for this case. However, it is a little long (~0.4mm) and it has a tiny bit of flash around the crystal. The packaging for the crystal (GS PMY311) says that when fitted tightly it require no cementing and to "file lightly".

What is the proper technique to get these to fit? If I file the crystal until it fits, it won't have tension to stay in place without glue. So how much does one file "lightly" and do you just try and press it in with finger pressure?

Edited April 6, 2023 by GuyMontag

[Neverenoughwatches]

6 minutes ago, GuyMontag said:

I have a crystal that is supposed to be the correct crystal for this case. However, it is a little long (~0.4mm) and it has a tiny bit of flash around the crystal. The packaging for the crystal (GS PMY311) says that when fitted tightly it require no cementing and to "file lightly".

What is the proper technique to get these to fit? If I file the crystal until it fits, it won't have tension to stay in place without glue. So how much does one file "lightly" and do you just try and press it in with finger pressure?

Maybe its like the chinese destructions you get for flat pack furniture. Everybody ignores them and makes up the assembly as they go along. Personally i would have a reasonably tight fit but still have some glue on there as a back up. Can you be fully sure that the crystal is tight enough not to be affected by temperature changes ? Is there much of a bevel on the case front to hold it in place ? Are you able to bend and manipulate the crystal enough to fully utilise the bevel edge ? Plus you have to file the crystal's bevel accurately. I would say a touch of glue.

[tomh207]

Probably better more experienced folks than me can answer. However if the instructions say to file it down I would first remove any flash on there. After that I would gently use high grit sticks to get it to the point it would just push in and hold. Lots of skill there to not screw it up

just take it a tiny bit at a time when you get to the adjustment stage, maybe one stroke each side with something like 2000 grit.

 

Tom

[Neverenoughwatches]

3 minutes ago, tomh207 said:

Probably better more experienced folks than me can answer. However if the instructions say to file it down I would first remove any flash on there. After that I would gently use high grit sticks to get it to the point it would just push in and hold. Lots of skill there to not screw it up

just take it a tiny bit at a time when you get to the adjustment stage, maybe one stroke each side with something like 2000 grit.

 

Tom

Fine emery grip paper double sided taped on to lollipop sticks, come in handy for allsorts of jobs like this.

2 minutes ago, Neverenoughwatches said:

Fine emery grip paper double sided taped on to lollipop sticks, come in handy for allsorts of jobs like this.

All done under a scope i would add to get the best fit possible. 

[tomh207]

5 minutes ago, Neverenoughwatches said:

Fine emery grip paper double sided taped on to lollipop sticks, come in handy for allsorts of jobs like this.

Sure does, I have this as well.

Tom

[Neverenoughwatches]

1 hour ago, tomh207 said:

Sure does, I have this as well.

Tom

Nice idea. Wrap the emery paper around the outside cover, the handle shaft holds the cover and paper in place. I like it , might make something. 

[GuyMontag]

The crystal isn't beveled at all. I lightly sanded it and was able to get it to close to fitting, but it changed the profile of the corners and I'm not really happy with how it looks. I think maybe I'll try the CMY311 if I can source one, maybe that one will work better.

[oldhippy]

You should first use a very fine emery stick, then crystal cement. That will prevent dust getting in under the glass or the glass falling out. 

[LittleWatchShop]

3 hours ago, GuyMontag said:

The crystal isn't beveled at all. I lightly sanded it and was able to get it to close to fitting, but it changed the profile of the corners and I'm not really happy with how it looks. I think maybe I'll try the CMY311 if I can source one, maybe that one will work better.

I am away from home right now, so cannot check. Reasonable likelihood I have that crystal.

[GuyMontag]

1 hour ago, oldhippy said:

You should first use a very fine emery stick, then crystal cement. That will prevent dust getting in under the glass or the glass falling out. 

Unfortunately, when I sanded the top/bottom of the crystal it changed the curve of the corner and I tried to smooth it out but now there is a bit of a gap in a couple of the corners between the crystal and the case. Bummer.

 

1 hour ago, LittleWatchShop said:

I am away from home right now, so cannot check. Reasonable likelihood I have that crystal.

[oldhippy]

To change the curve you must have sanded a lot away. If it still has a snap in fit the crystal cement will still do the trick. 

[GuyMontag]

Yeah, I was going slow and constantly checking the fit but by the time the length was to the point where it fit the case, the corners were affected. I *could* use it, I'm just worried that dust can get in in the small corner areas where the fit isn't 100%.

[oldhippy]

The cement will prevent dust getting under the glass. Watch cases that are not round are more likely to let dirt and dust in. 

[tomh207]

Not an expert like OldHippy but my understanding is in general rectangular shape crystals are glued.

 

Tom

[oldhippy]

1 hour ago, tomh207 said:

Not an expert like OldHippy but my understanding is in general rectangular shape crystals are glued.

 

Tom

Yes you are right. 

[RichardHarris123]

Which glue is recommended? 

[LittleWatchShop]

1 hour ago, RichardHarris123 said:

Which glue is recommended? 

GS Hypo is what I would use

[oldhippy]

Any of the ones that you find on the watch material suppliers sites.