After watching this I have a new appreciation of my old vintage radio xtals. Quartz Radio xtals were also made in Australia during WW2.

I have tried the carborundum powder and plate glass grinding myself ... didn't have much success.

By the 1970s Phase Lock Loop technology had reduced the use of xtals in radio sets but xtals still have many applications to this day.

https://m.youtube.com/watch?v=duZlWWwxIPQ


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