# How to replace a pocket watch crystal



## Tucson_Tom (Dec 3, 2012)

OK, I have a pocket watch without a crystal (a recent adventurous purchase, a Burlington size 16), and a likely replacement crystal (marked 18 11/16 17 3/8 7), and I am looking at the bezel wondering
if I have the right size crystal and how it is supposed to go in there. The replacement crystal I have looks like somewhat of a historical relic, and perhaps I would be better served tracking down a more
recently made replacement?? It does look the right size, being ever so slightly bigger than the bezel hole viewed from the front, but what do I know?

First off, I am an absolute novice, but determined to learn, and grateful for advice and information.

I would have guessed that the crystal was glued in, but the bezel shows not a trace of any cement or adhesive.
This leads me to believe there is some trick to snapping the crystal into place ??

Thanks!

Tom


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## Tucson_Tom (Dec 3, 2012)

Some more information -- I measure the narrow part of the bezel to be 1.649 inches. The crystal needs to "snap" past this to the slightly wider part of the
bezel, which is essentially impossible to measure. The crystal that I selected measures 1.662 inches (which is 42.21 mm), and based on some tables I
was lucky to find, it is a 18 11/16 crystal (I have no clue what the 17 3/8 marking is, or the 7). 

An 18 10/16 crystal would be 42.0 mm and 1.653 inches, still seems too big
An 18 9/16 crystal would be 41.9 mm and 1.6496 inches, might just work (or be a bit too sloppy.

All this is well and good, but the only crystal I have among these listed is the 18 11/16 (and I have several). Hmmm


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## pithy (Aug 22, 2010)

Put the bezel over a light bulb for a few minutes and then measure it. p


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## Tucson_Tom (Dec 3, 2012)

pithy said:


> Put the bezel over a light bulb for a few minutes and then measure it. p


OK, when it is too hot to handle, I measure 1.651 (but it cools rapidly), when warm maybe 1.650, and when room temperature 1.649
I should go look up the coefficient of thermal expansion for brass and see if theory and reality correspond (this is a gold filled bezel).
So if I had an 18 9/16 crystal and heated the bezel, it should just drop right in to a hot bezel (and might not just drop back out when
it cooled).

In the spirt of honesty and full confession: I got busy last night with one of my 18 11/16 ligne crystals and a 400 grid diamond hone.
Went round and round to do my best to keep it circular and when I got close enough smoothed the edge with my 600 hone.
Didn't take all that long. Problem is when it was close enough to tempt me, I cracked the crystal trying to snap it in. Bummer.

I do have two more 18 11/16 ligne crystals, so I could try again, but I have a question. The crystals I have are clearly relics with
round labels, pale blue lettering (VTF I think) and say "France". They are very thin - I measure 0.5 mm.

The pocket watches I have and carry and like have a different sort of crystal. The both look to be much thicker, and I can see the
edge is ground to a bevel. I would rather put a crystal like this on this watch. Where can I get them? Presumably a more modern
crystal. I was looking on the Esslinger site (but was hard pressed to decide which of the many styles of crystals they sell is
appropriate for a pocket watch).


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## pithy (Aug 22, 2010)

pictures p


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## Tucson_Tom (Dec 3, 2012)

pithy said:


> pictures p


Here is a picture, but it probably isn't much help, let me change lenses and get right back to you:









(This is from a Burlington movement I am fooling with at the moment).


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## Tucson_Tom (Dec 3, 2012)

OK, here is a photo of the crystal I have been fooling with. I have a collection of these.
They are 0.5 mm thick, with a very shallow dome:








And here is a picture of a Hamilton pocketwatch with a crystal I like. You can see the bevel on
the edge. I fiddled around and found a way to measure the thickness of this one, and one on another
watch, they were 1.0 mm and 1.16 mm in the two I measured:









I would much rather be installing a crystal like this, but am unsure of how to get my hands on one.

Thanks.


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## radger (Nov 18, 2007)

There must be stockists in the U.S who has the thicker bevel edged crystals I'd think.
If you can't find one I'd consider a plastic crystal, these are readily available.
Very thin glass crystals are unsuitable for an open face watch.


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## dacattoo (Jan 9, 2011)

Let's back up. You may know some of this already. There are glass crystals and plastic crystals. They are installed differently. I install glass crystals with cement. Plastic crystals are installed by using a tool that distorts the crystal shape and therefore reducing the diameter. The crystal is inserted in the bezel and the distortion removed increasing the diameter and fitting the crystal in the bezel tightly. You need a couple of things to be successful with plastic. One is experience. Understanding GS tables, what size to order based on the bezel diameter, how much you can distort the crystal before it cracks and what the appropriated crystal for the watch actually is. We can actually start a lively debate amongst watchmakers by debating plastic versus glass. Later. Number two is a crystal press. There are varieties. I use an old Girard Perregaux press in a small valise. It fits in my bench vise, opened and closed with a screw. Others have a press mounted on top of a crystal cabinet operated by a foot pedal. There are several other varieties as well.

There are different dies to fit different crystals.


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## Ben_hutcherson (Aug 27, 2011)

No cement is necessary to install a correctly sized American glass crystal. 

The usual way to fit a crystal is to work through a well-stocked cabinet and find the largest size which will fit the bezel with no resistance. One then selects the next larger size. The crystal is then set down on the bezel and pushed in place with ones thumbs. It will fit into the bezel with an audible "snap" and remain in place with no cement. 

Absent a well-stocked crystal cabinet, it's usually best to send the bezel to someone to have it fitted. If I'm trying to fit it myself, I will usually measure the bezel as closely as possible with a pair of calipers(I usually take three measurements at three separate points and take the average of them), and then order this size as well as one size over and one size under. Generally one of these three will fit, and I keep the others for reference or eventual use. 

Glass crystals are available from Daves Watch Parts, Dashto, and White's Crystals. 

Plastic crystals are not desireable.


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## dacattoo (Jan 9, 2011)

Unless your watch is a Rolex and then they are mandatory. Or are the rules different in Kentucky? Or Omega or many other brands of watches that came with plastic crystals.


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## pithy (Aug 22, 2010)

Ben_hutcherson said:


> . . . . . . . Plastic crystals are not desireable.





dacattoo said:


> . . . . . Or are the rules different in Kentucky? . . . . . . .


Michael, you obviously aren't a serious collector of American pocket watches and Ben probably doesn't do a lot of rapelling or skydiving while carrying open faced pw's.

lol

p


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## dacattoo (Jan 9, 2011)

I said we could start a spirited discussion on plastic versus glass earlier. Ben threw down the gaunlet. 

I like glass if it is going to sit in a box. But we no longer have a pocket to carry an open face watch. I don't wear bib overalls every day and don't own a vest. If you want to carry a pocket watch in your jeans 'coin pocket' it should be plastic because it is the most practical. Plastic offers an inexpensive solution to scratches. They can be buffed out quite easily. Tried buffing a glass crystal lately? Glass shatters, shards bend hands and scratch dials. Often plastic cracks. Still provides a modicum of dirt, water and scratch protection. Plastics today are much improved over the plastics of old. They no longer discolor to yellow or green like the good old days and more than once I have been fooled in thinking a plastic crystal was glass. But that's in Montana, now in Kentucky that might be different. How about it Ben? ;-)


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## dacattoo (Jan 9, 2011)

Not really sure what a serious collector is. I don't aspire to be one though. I do work on quite a few as wristwatches still haven't made it to Montana yet ;-)


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## Tucson_Tom (Dec 3, 2012)

Ben_hutcherson said:


> Glass crystals are available from Daves Watch Parts, Dashto, and White's Crystals.
> 
> Plastic crystals are not desireable.


I heartily agree about plastic crystals -- I will do as you say and order the size I think I need, along perhaps with the next bigger and smaller.
Thanks!


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## Ben_hutcherson (Aug 27, 2011)

Many railroad time service standards up through the 1970s forbid the use of anything but glass for crystals. 

I don't spend my days shoveling coal into a firebox, and if glass is good enough for that it's good enough for me doing what little I do on a day to day basis  Plus, if you're wearing the watch correctly(crystal toward your body when in your pocket) the chances of the crystal breaking even if falling on the watch are small. 

I have broken exactly one glass crystal, and that was when I dropped a loose bezel while setting the time on a lever set watch. They're a lot more durable than many want to give them credit for, especially the old beveled edge Mi-Chevee railroad glass style. I've seen watches take falls crystal-down hard enough to break both staff pivots, yet the glass was fine. One old collector buddy of mine is fond of taking an old 18 size "turnip" with the 2mm beveled glass and stepping on it. The glass is fine, even supporting all of his(not insignificant) weight. 

Plastic crystals aren't a deal killer for many of the collectors I know, but they certainly are looked down on as they simply don't look right. I've yet to see good plastic with the desired beveled edge that we want to see. Most of the collectors that I know will replace plastic with glass as quickly as possible. None of the ones I talk to on a regular basis will say that they prefer plastic to glass.

By the way, I've never scratched a glass crystal wearing it the watch pocket of my jeans. I have a few which I installed new, and even after quite a bit of carry they still look as such. Plastic, on the other hand, often looks like it's been sandblasted after carrying for any amount of time


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## Tucson_Tom (Dec 3, 2012)

Wow - I guess I launched "crystal wars". Well I definitely agree with Ben (and am reassured to hear his comments about durability). I much much prefer the watches I have with glass crystals. The ones I have with plastic crystals are just waiting for the time and skill (and supply of crystals) to be replace with glass. Every glass crystal I have is spectacular. The plastic crystals are discolored, cloudy, scratched, or all of the above. I am talking pocket watches, and open faced watches at that. Too bad that Whites Crystals seems "off-line" right now -- I guess Mr. White is busy with other ventures, or that is what I found stated on another forum.

Thanks for all the advice and discussion.


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## Tucson_Tom (Dec 3, 2012)

Following up and getting back to the original topic (this thread comes up near the top on a Google search on replacing pocket watch crystals, which is scary).

I ordered a 1mm thick domed crystal (from the flat crystal selection at Esslingers), for a mere $4.00 or so. It arrived today and after screwing around attempting to snap it in place
and heating the bezel, I said the heck with it. Got my 600 grit diamond hone and carefully worked around the edge to reduce the diameter (I suppose 600 grit silicon carbide paper
would be fine). Checking frequently, I got it down to where it would be a snug fit in the bezel. Then cleaned everything with acetone and used GS Hypo cement to glue it in place.
It looks just great. Did not take long at all, even the patient shaving down of the crystal (I had to remove maybe .002 inches from the diameter, i.e .05 mm).

Doing some searching, I see that the famous William White of White's crystals says that he prefers to glue crystals in place, especially (he says) if the watch is going to be
carried regularly. He and others prefer to use UV curing epoxies rather than the GS Hypo, and after some things I read, I plan to switch to the UV epoxy also as soon as I get
some ordered up. There is certainly less fretting gluing a crystal in place, and if a novice like me can do a nice job on the first try, that is something to recommend it also.
They say the UV epoxy is easier to work with than the GS Hypo -- we shall see, I have some more crystals to do. The word is that the GS Hypo does not hold up long term
(there is a significant rate of failures within a years time).


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## pithy (Aug 22, 2010)

Any adhesive is subject to failure, hence the superiority of the interference fit whether accomplished via pressure or thermal expansion. Happy Holidays. p


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## Arlin (Sep 3, 2013)

Hello,
I have a hundred yr old Elgin, which is a family heirloom pocket watch. Pictures attached.
The crystal was recently smashed by careless workers in the house. It is not a carry watch, but rather a display watch.
What would you recommend regarding replacement crystals? I do not want plastic but since the watch is so dear to me and represents previous generations, I would like to replace the broken crystal with something appropriate.
I would appreciate any advice.
Thank you,
Stephen Arlin
619 287 2524


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## watchme2 (Feb 10, 2014)

Ben_hutcherson said:


> No cement is necessary to install a correctly sized American glass crystal.
> 
> The usual way to fit a crystal is to work through a well-stocked cabinet and find the largest size which will fit the bezel with no resistance. One then selects the next larger size. The crystal is then set down on the bezel and pushed in place with ones thumbs. It will fit into the bezel with an audible "snap" and remain in place with no cement.
> 
> ...


Thanks Ben for this info! So If I have a original glass crystal that need's replacing, the reverse is also true....two thumbs and the original crystal should remove from bezel?


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## Ben_hutcherson (Aug 27, 2011)

watchme2 said:


> Thanks Ben for this info! So If I have a original glass crystal that need's replacing, the reverse is also true....two thumbs and the original crystal should remove from bezel?


Yes, that's all that's required to remove one that hasn't been cemented. Even if it has been, if the "correct" type of glue was used, this will still remove the crystal.


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