There were a range of demo "extreme" quartz crystals at STC UK. The lowest frequency was 800Hz duplex flexure (straight bar) the lowest shear mode was a 1 MHz 5th overtone contoured lenticular bi convex gold plated in a vacuum envelope the Q should have been 10000000 but priorities prevented its completion.
In message , Spehro Pefhany writes
Sadly most euro manufacturers now buy in lapped blanks from the far east and only evaporate to frequency.
In message , Alt Beer writes
I recall that a flat was left on circular blanks to indicate the z axist and indicate the best spring mounting position.
In message , Alt Beer writes
Is this the same thread as last week or are 2 people setting up lapping facilities.
In message , snipped-for-privacy@yahoo.com writes
Interesting... Is that no bulk lapping and / or no final lapping ?
Do you happen to know names of any far east bulk lapped blank suppliers ?
This is out of curiosity.. I'm no longer in the crystal business.
Yes remember the flat on STC blanks.
I have in my hand an STC 600 kHz highly polished double convex crystal with gold electrodes (ATcut ?) in an evacuated glass holder. Someone at STC told me it was to be used in underwater transatlantic repeater cable. Date code
7/69
In message , Alt Beer writes
Nor me for 20 years though still maintain contacts Contact me on snipped-for-privacy@BLOODYhotmail.com
I would guess a shear mode AT cut fundamental made regardless of cost I can still see in my minds eye the gold plating over the epoxy attachment cement.
In message , Alt Beer writes
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