[Milsurplus] Type 180 crystals

[Hue Miller]

Mark, do these have any actual frequencies stamped on them?
I didn't see that in the photos i saw.
The crystals don't seem to be for mobile radio. The in-line
pins would have no stabilizing effect for vibration, compared
to say, the TCS crystals or some airborne 3 pin types.
The third pin wouldn't be connected to some shielding or the
metal plate side of the package, would it?

Someone's writing a book about crystals???
I would think that's been covered, with little audience, but maybe
there is still an engineering audience for that material outside the
already established quartz grinding companies.

BTW, i came across a military manual for a quartz lapping machine.
Don't have the manual before me, but it had a TL- nomenclature.
Why on earth would the US military have reason to grind crystals?
-Hue