What year for plastic crystals?

[vroc4507]

Hello.......I'm curious as to what year plastic crystals started to be used? I've just acquired a 1923 Hamilton 992 in a nice swing out case. The crystal however is plastic so I'm guessing that it's not original.

Could any of you suggest a place that I could pick up a nice glass crystal to replace the plastic one? The plastic crystal is in very nice condition, but it just doesn't "feel" right if you know what I mean.

Thank you,
Brett

[rrwatch]

The Germanow-Simon Machine Co., which is a major manufacturer of plastic crystals, started in 1916. There may be other makers who were earlier, but I am unaware of them.
So, your watch could have been originally fitted with a plastic crystal, but the older ones tended to turn to a yellow green color and start to rust the hands and the top of the cannon pinion. Any watch with one of these yellow green crystals should be removed from the watch to prevent further damage. The modern plastic crystals will NOT discolor and are safe to use.
Before WWII, most railroads specifications that we have seen require glass crystals, but some the of the newer requirements (at least for RR approved wrist watches) mandated plastic and would not allow glass. In general, pocket watches approved for service required glass crystals to be fitted.

[Rms5268]

Brett and Ed,
From my observations a Dollar Watch collector, I would agree with Ed that the advent of Plastic crystals coincided with the formation of the G&S Machine Company of Rochester, NY., who by the way are still in business today after over 90 years. Most Dollar Watch companies moved to Plastic Crystals in the 1920's with E. Ingraham Company Using the Trade Mark " The Watch with the Non- Breakable Crystal " in their advertising during the 1920's.
It is my understanding that it was the reaction of the Crystal to UV Rays which made it deteriorate and turn a shade of green which then began to deteriorate both the hands and metal dials. This formula was later changed, but possibly not until the 1950's. I would say that the reason the $ Watch companies switched from Glass to plastic was lower cost and ease of installation.
Rob Sherman Ch106,149

[Jon Hanson]

Brett and Ed,
From my observations a Dollar Watch collector, I would agree with Ed that the advent of Plastic crystals coincided with the formation of the G&S Machine Company of Rochester, NY., who by the way are still in business today after over 90 years. Most Dollar Watch companies moved to Plastic Crystals in the 1920's with E. Ingraham Company Using the Trade Mark " The Watch with the Non- Breakable Crystal " in their advertising during the 1920's.
It is my understanding that it was the reaction of the Crystal to UV Rays which made it deteriorate and turn a shade of green which then began to deteriorate both the hands and metal dials. This formula was later changed, but possibly not until the 1950's. I would say that the reason the $ Watch companies switched from Glass to plastic was lower cost and ease of installation.
Rob Sherman Ch106,149

...................and breakage!

[vroc4507]

Thanks, guys! My plastic crystal is in very nice shape. Not yellowed or scratched at all. Just seems that a glass crystal would be more appealing.

Brett

[lak611]

I replaced a plastic crystal in a Hamilton 992B. There was probably nothing wrong with it, but I just did not like it.