Tool options for tension-ring crystals?

MrRoundel

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Greetings,
Can I expect total failure if I try to use my cheap Harbor Freight case press to attempt to install a tension-ring crystal in a two-piece Perregaux wristy? I also have a regular GS crystal lever tool that I can use. Maybe that will work, as the dies are harder plastic than the HF cheapie? What I don't have is the special tool with the aluminum dies, which seems to be the best tool for the job. Any tips, suggestions, warnings, good-natured ribbings, etc. are appreciated. Thanks.
 

Chris Radek

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I have the big Bergeon set with really excellent aluminum dies (the set was $600ish) and installing these crystals on some cases is still finicky. I think you'll probably not succeed, but the harm is just breaking a crystal. Order two! I'm not sure which GS tool you're talking about, but if it's the one that deforms the crystal by pressing the center, that won't help you, because a tension ring crystal just has to be pressed straight in as-is because the ring doesn't compress.

(Make sure you have the right crystal. It should be 0.1 mm bigger than the bezel measurement.)
 
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MrRoundel

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Thanks, Chris. Yes, the GS case tool I have is the "distorter" that pushes out the center to pull in the sides. It's a nice 14K case and I don't want to distort it by applying too much pressure. It seems like this could happen. I did end up removing the old crystal with the above-mentioned press, but in two pieces. Three if you count the ring.
The first crystal I ordered was the wrong size for the amount the bezel grew since measuring the first time. :whistle: I was more careful the second time and I believe ordered the right one. Yes, it is about .1mm larger than the bezel opening.
I guess you have the 5500 Bergeon. That does look like the right set to have. My best bet will probably be to pay a local pro to do it, if they'll accommodate for a bit of cash money. I'll probably give the cheap HF press a chance but don't hold out much hope. But I'm sure not spending what I'd have to for that Bergeon for one crystal, obviously. Thanks for answering my question. Cheers.
 

MrRoundel

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Follow-up question:

Can anyone tell me the approximate year that Swiss watch manufacturers started using tension-ring crystals? I'm wondering if the tension-ring crystal that I broke out of the watch was not the original intended type, and that perhaps a regular round acrylic GS PA crystal would have been used originally.

The watch in question contains an GP Gyromatic auto from around 1954. Were tension-ring crystals being used for such a watch in '54? Thanks ahead of time. Cheers.
 

MrRoundel

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Thanks for your responses, roughbarked and Chris Radek! The walls appear to have straight walls, so tension-ring it is.

And great read, roughbarked. Thanks for including link. There's what I think is the identical 39J watch for sale on a big auction website out there. The one I'm working on is of more of a classic, Calatrava, style.

There's another on the same site that is more modern than mine but has really interesting lugs. It just had the basic 47 model automatic rather than the 39J. It was an oil company presentation watch. Cheers.
 

Paul_S

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Thanks, Chris. Yes, the GS case tool I have is the "distorter" that pushes out the center to pull in the sides. It's a nice 14K case and I don't want to distort it by applying too much pressure. It seems like this could happen. I did end up removing the old crystal with the above-mentioned press, but in two pieces. Three if you count the ring.
The first crystal I ordered was the wrong size for the amount the bezel grew since measuring the first time. :whistle: I was more careful the second time and I believe ordered the right one. Yes, it is about .1mm larger than the bezel opening.
I guess you have the 5500 Bergeon. That does look like the right set to have. My best bet will probably be to pay a local pro to do it, if they'll accommodate for a bit of cash money. I'll probably give the cheap HF press a chance but don't hold out much hope. But I'm sure not spending what I'd have to for that Bergeon for one crystal, obviously. Thanks for answering my question. Cheers.
For what it's worth, I have good success with a set of nylon Horotec tension ring crystal dies, which are (relatively) less expensive than the Bergeon option and work with a standard crystal press. The dies have slanted walls that compress the crystal wall.

I'll second buying 2 crystals. 1 mm larger than the bezel opening is usually perfect, but it's one of those things.

As for knowing if a watch was originally fitted with a tension ring, it's often apparent when the movement is cased up with a thin gap between the dial and the case.
 

roughbarked

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I've kept a full set of crystals since I was in the business of having to fit whatever crystal that came in on the day.
Have several presses and dies. Like the nylon ones and use them most of the time but do mix and match and there are of course some types that can only be fitted with the older dies.
 

MrRoundel

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... it's often apparent when the movement is cased up with a thin gap between the dial and the case.
Thanks, Paul_S. I think I see the tension ring in the image of the watch cased up. I didn't notice it before. Thanks for that tip. Makes sense that I'd be able to see it considering it sits within the crystal's ID. Cheers.

And yes, roughbarked, I realize that a set of crystals would be an absolute must if one was in the business of watch repair. It seems that I rarely get the right one on my first shot. This one was no exception. I swear that bezel size grew. :banghead:

IMG_2495.JPG
 
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karlmansson

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Any press that will press straight down and will take a decent die that is flat and only applies pressure to the periphery of the crystal will work fine. The cheaper ones are in general pretty loose and poorly fitted but will compress a standard, unbreakable crystal just fine. The issue with the tension ring Crystals is that they need to go in straight from the get go, and need even force around the rim as they do so.

I use an old Robur screw down type press for all acrylic Crystals. It has round, convex and concave, dies and for tension ring Crystals I use a modern nylon die that is flat to support a flat case back. I would venture that you could use a precise enough, small arbor press to accomplish the same thing if you find a good way to attach an appropriate die to the ram. Not that you need the force it can generate but the rigidity and precision is better than the cheap lever style presses.

Regards
Karl
 

roughbarked

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I've got the full Citizen screw down press. Have had it something like 30 years. Have only ever used it the once.
That's because I learned to use the lever presses and the are so much faster and easier to use. Some of them are better than others and maybe that does have something to do with price but mainly design.

Any good press lever or screw will press in an accurate straight line.
 

MrRoundel

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Thanks, gents. Yes, the Robur press looks like a pretty good one. I like the idea of the screw press because it seems less likely to get cocked as you work it. Of course a lever press that is sturdy and/or screwed to a sturdy base would probably be good as well.

I tried the cheap Harbor Freight press but it seems that the dies don't center like a well-machined aluminum one would. As I bring the die down onto the crystal, it slides around on the plastic. The slippery nature of these plastic dies, and the fact that it's hard to center things exactly, make it quite difficult. Probably not impossible for someone with greater skill than I, but certainly tough.

I got very close but one side was up a bit and the soft plastic die didn't have enough oomph or stiffness to reduce the OD by the slightest amount. I even tried tapping around the high spot with a nylon hammer. No help. I'm now pretty certain that the crystal is the right size for the case. It would be a shame to mess something up now.

If I can't get a local jeweler/watchmaker to press it in for me I'll probably end up buying the Chinese imitation of the Bergeon 5500 lever press. It looks like it will work OK. Otherwise I'll search for a used quality press. As an on-and-off hobbyist I don't need lifetime tools. In a perfect world I'd opt for the best tool, but I'm not living in that one. Thanks again. Cheers.
 

roughbarked

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This was the press I learned to use 50 years ago. I have adapted it several times, though still playing with the spring idea. It is so old now that there was a risk of the thing dropping down while putting the watch case under and with the super thin domed mineral crystals they are fitting to some these days, it could cost money. So was fiddling with a brake spring idea. I could have just wiped some dry lube on the shaft.

Retired now so I can perfect it.
This was originally made and came with the dies for fitting hunter real glass. I've used it with all sorts of dies since. The fact that I can hold it in my hand while fitting the crystal, is the best part.

I can probably count the number of people who have either used this tool correctly or abused it but I'd need at least both hands.

P2069064.JPG
 
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Paul Helmuth

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A case that takes a tension ring crystal will have straight walls for the crystal to press into. A case that takes a flex/snap crystal will have the groove slanted to match the lip on the crystal and make it seat fully.
What Chris said...
 

MrRoundel

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I just bought a press that is the same design as the BB crystal press, It is marked Fercal/Horofix. Next time I have to work with a tension-ring crystal I'll be able to get it done without subbing it out. Thanks to all who responded.
 

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