Can't claim any experience of crystal regrinding as all my surplus
crystals that can easily be taken apart are above the nearest amateur
band to the frequency that the crystal is already on.
However, an old compilation of articles from SPRAT, circa 1983, has an
article by G. J. Bennett (G3DNF) in which he describes the techniques
of regrinding old crystals and suggests the use of carborundum powder.
G3DNF advises using two grades, Fine Grit (also known as carborundum
flower) and Medium Grit, with water to make a grinding paste. He also
suggests getting small amounts of these by buying a beginners' rock
polishing kit. By this I guess he means the ornamental and
educational rocks from caves and from cliffs etc., rather than the
slang use of the word "rock" to mean a crystal for use in an
oscillator circuit. (Sorry, a brief lapse into a previous thread!)
He also advises using care when disposing of the used carborundum, as
it can take the finish off the sink, in his day he said the glaze but
I would guess that streaks in the polish of a stainless sink would be
just as unwelcome and I wouldn't put it down the waste disposal unit
either!
Cheers de Dave (G0DJA)
"How far that little candle throws its beams!" Merchant of Venice
Act 5
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