Fundamentals of Crystal fitting questions

[watchenthusiast101]

Hello,

After shattering five watch crystals today, I seek your counsel. I want to better understand the principles surrounding watch crystal replacement. More specifically, I am confused when one needs to use glue, a crystal lift, or a crystal press. It is my understanding that crystal lifts can be used well on acrylic crystals as these are more malleable and less likely to shatter. However, I do not understand when I am supposed to use a press vs glue. Especially when there is no tension ring and I am attempting to replace it with a flat mineral glass or a domed glass. If someone could loop me in on the fundamentals, or perhaps even link information, that would be fantastic. I have searched a fair bit online and there doesn't seem to be a whole lot of consistency.

Thank you

[HectorLooi]

Are you referring to acylic crystal or mineral glass?

A crystal lift is good only if the dome is high enough for it to grip and there is no tension ring. It's probably the only way to install the crystals of front loading movements. (Unless you have the proper size ring clamp type crystal tool)

There are some good videos on YouTube showing the correct way of installing crystals. You may wish to check them out first.

[HectorLooi]

Watch some of the videos from Esslinger. They expain the basics quite well.

You can also check out the videos in the resource section of this forum. 

But anyway, breaking things is all part of the learning process. We learn from our mistakes. Whenever you break something, find out what went wrong and don't do it again.  (Yeah! Right!)

I just broke a mineral glass crystal moments ago. 

[watchweasol]

 Hi Hector is spot on Esslingers have tutorials regarding crystal fitting, Basics are that if its a domed acrylic use a crystal lift,  If its flat mineral glass use a press. Some of the flat ones have a gasket in the bezel and the glass is pressed in straight,  some have no gasket and are glued in using a varaity of substaces (ie) hypo cement and UV setting cemento, so as you see there are variations and even these differ. One might have had a gasket at one time but an over size was glued in so as you see there are rules but not always followed.

[jdm]

3 minutes ago, watchweasol said:

Basics are that if its a domed acrylic use a crystal lift.

I don't agree with that, crystal lifts have their cons, and the good Swiss or American ones are expensive. My recommendation is to use a a press with proper dies. Attached the relevant section from a STK catalog, note they recommend using a claw type tool in order to save time and labor, but that's not an issue for the hobbyist. There is another section which details their very complete line of presses and dies, I'm not including that as they are very expensive and hard to find.

 

8836_Sternkreuz R19 Snap In Glasses Pages 12 to 29.pdf

[VWatchie]

Armored acrylic crystals have a chamfer enabling them to simply be pressed into the case as shown in my YT-video here.

However, I suspect that non-armored acrylic crystals lack a chamfer, and if someone can confirm or deny this it would be appreciated. In those cases either a crystal lift or a press with a die on the underside of the crystal being domed (convex) and a regular die on the topside I assume should be used. The idea is to press the crystal between the dies and thereby bend the crystal into a smaller diameter and then slide the case into the compressed crystal. If I recollect correctly watchfix.com has a bonus video demonstrating exactly this.

So, here's my question. I have a Bergeon 5500 crystal press, but I do not have any domed dies. The only domed dies I've seen are those for the Robur press. Any tip about where I could get a set of those domed dies for my Bergeon press? I suppose, although I could be wrong, it would be a bad idea to try this technique using a non-domed die?

[watchenthusiast101]

Thank you for all your responses! It seems that crystal lifts are useful when it is a domed acrylic and when there isn't a tension ring. Seems like a press is the way to go with flat mineral glass/acrylics with tension ring. What about domed mineral glass? Is a press always the way to go with this? Also, I have watched the esslinger videos etc. but they don't seem to do a good job spelling out exactly when to use which method. They are helpful for technique though.

[watchenthusiast101]

Also, as far as fitting, it seems like slightly bigger than space is good for acrylic/crystal lift. But, what about domed and flat mineral crystal?

[watchweasol]

It has been my experience that most mineral crystals are fitted with a press and usually a gasket.

What was meant in my previous statement was that in the simple element it is prety usual but not in every case , you have to judge each one as you find it as you never know its history, some one might have done it differntly so its somthing you need to be aware of.. 

[GuyMontag]

On 2/5/2022 at 10:49 PM, watchenthusiast101 said:

Hello,

After shattering five watch crystals today, I seek your counsel. I want to better understand the principles surrounding watch crystal replacement. More specifically, I am confused when one needs to use glue, a crystal lift, or a crystal press. It is my understanding that crystal lifts can be used well on acrylic crystals as these are more malleable and less likely to shatter. However, I do not understand when I am supposed to use a press vs glue. Especially when there is no tension ring and I am attempting to replace it with a flat mineral glass or a domed glass. If someone could loop me in on the fundamentals, or perhaps even link information, that would be fantastic. I have searched a fair bit online and there doesn't seem to be a whole lot of consistency.

Thank you

Mark has three "bonus" videos if you are doing his course where he goes over this.

[jdm]

 

On 2/6/2022 at 4:34 PM, watchenthusiast101 said:

What about domed mineral glass? Is a press always the way to go with this?

Yes. As you can read in the document I have attached before, there are shaped rubber dies that can compress an acrylic crystal to refit it. Of course if is domed glass it doesn't get compressed, and you can use a crown nylon die to press on the rim or edge.

[mikepilk]

On 2/6/2022 at 3:38 PM, watchenthusiast101 said:

Also, as far as fitting, it seems like slightly bigger than space is good for acrylic/crystal lift. But, what about domed and flat mineral crystal?

For domed acrylic, 0.2 tp 0.5 mm bigger than the bezel internal diameter (I usually get 0.2 to 0.3 mm)

For flat mineral 0 to 0.1 mm bigger than the inner diameter of the gasket.

[jdm]

8 minutes ago, mikepilk said:

For flat mineral 0 to 0.1 mm bigger than the inner diameter of the gasket.

Worth to remind however that 99% of current watches having a flat mineral crystal are sized in steps of 0.5mm not 0.1. If measuring the gasket tells otherwise be in doubt and measure again.

[mikepilk]

1 hour ago, jdm said:

Worth to remind however that 99% of current watches having a flat mineral crystal are sized in steps of 0.5mm not 0.1. If measuring the gasket tells otherwise be in doubt and measure again.

Good point. I've only changed a few mineral glasses in older watches and bought the crystals from Cousins, whose range does go up in 0.1 mm steps.

[GuyMontag]

On 2/6/2022 at 7:20 AM, VWatchie said:

So, here's my question. I have a Bergeon 5500 crystal press, but I do not have any domed dies. The only domed dies I've seen are those for the Robur press. Any tip about where I could get a set of those domed dies for my Bergeon press? I suppose, although I could be wrong, it would be a bad idea to try this technique using a non-domed die?

 

I also purchased a Bergeon press (the 8250) after finally deciding on not getting a Robur. The Robur was significantly less expensive, but the dies are significantly more expensive than M6 dies that can be found on ebay/Aliexpress. But then I also couldn't find any of the M6 domed dies, at least on ebay/Aliexpress where I was looking. But then I saw that Bergeon actually makes Bakelite domed dies, the Bergeon 5500-E. I didn't need the whole set and Ofrei sells them individually so I picked up the three that I thought I would use the most.  They have worked great so far.

[LittleWatchShop]

I have read this very interesting thread.  The experts have spoken.

It would have been helpful if @watchenthusiast101had posted a picture of the watch(s) he is dealing with.  As noted in this thread, there are a variety of possibilities.

While it may not address this specific question, I can say with absolute certainty that there is at least one watch model that is a front loader and is armored that requires a crystal lift to remove the crystal and associated bezel insert.  This may be rare, but it gets to the point that someone made...each case must be studied carefully.

I have replaced mineral glass crystals where they were pressed in (I think the more common) and a few that were glued in (mostly ladies watches in my limited experience).

Every crystal replacement I encounter is met with caution and a little fear (for a nice watch and/or expensive crystal).  Partly because I am an amateur, and partly healthy respect.

I just replaced a hunting case crystal that is glued on to a bezel and then snapped on to the watch case.  The domed glass crystal was 0.5mm thick!!!  Yes...I approached it with fear and trembling.  Happy to report success.

I use a BB crystal press and I regularly 3D print a fixture to precisely fit the watch I am servicing.  I have the full set of BB aluminum fixtures but do not use them.

[watchenthusiast101]

It is pretty much all seiko 7xxx's. I have been exclusively working on vintage/15+ year old seikos. Some of them appear to have tension rings/gaskets and some don't. Does anyone have experience changing crystals on these? 

[watchenthusiast101]

Also, thank you all for your help! This has been super helpful so far.

[jdm]

3 hours ago, watchenthusiast101 said:

It is pretty much all seiko 7xxx's. I have been exclusively working on vintage/15+ year old seikos. Some of them appear to have tension rings/gaskets and some don't. Does anyone have experience changing crystals on these? 

There is nothing special about them. Just press out and in with the correct dies. Attached some relevant info.

1982.03 Seiko Case Servicing Guide.pdfCrystal Codes.pdf

[VWatchie]

16 hours ago, GuyMontag said:

But then I saw that Bergeon actually makes Bakelite domed dies, the Bergeon 5500-E. I didn't need the whole set and Ofrei sells them individually so I picked up the three that I thought I would use the most.  They have worked great so far.

Thanks for your post and the links. Very much appreciated, especially as I've been looking for these. I didn't know they were called "Bakelite dies" but had been searching for "Domed dies" (with no success). Anyway, once I searched Cousins  (I live in Europe) for "bakelite dies", there they were!