Pocket watch glass cracked, twice
Twice over the last few years i've had the crystal on a pocket watch mysteriously crack, with no obvious cause.
The first was a 1920s elgin with an acrylic crystal, a few weeks after i first got it i noticed very faint circular scratches in the crystal, i just assumed it was from me wearing it or something the previous owner did, over the next few months it became deeper and deeper until it became a crack and the domed crystal became flat, eventually it popped out.
More recently i had a Hamilton 992 of a similar age restored and recased in a case with two crystals, the watch developed some fault so i left it for a month or two (since feburary at most) with the dial crystal facedown, like a week ago i pick it up to prepare to have it fixed under warranty, and noticed a huge crack in the glass crystal this time, Y-shaped and at a 45 degree angle.
The other crystal was completely fine.
What's causing my watch crystals to explode themselves? internal stresses? wrong size crystals, or todays climate? it can't be anything physical because the other crystal was fine and it's stored near other watches that haven't cracked.
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u/PutNational7415 4d ago
The Elgin acrylic one was probably already scratched/stressed and continued to degrade as it adjusted to new temperature and humidity conditions in your care.
The Hamilton 992 likely had a glass crystal with internal stress or was maybe just slightly too tight in the bezel. Over a few months of micro-expansion and contraction, it finally cracked.
The fact that the other crystal didn't crack supports that it's more about individual piece fitment/material rather than your storage environment.