[AMRadio] Crystal Grinding

[russ dworakowski]

Tony and  the  group-  Acid  etching  process was  invented  by Bliley
Electric-  here  in  Erie,  They had  it  down to timing of dipping  the 
quartz wafers  in an acid  bath.  They knew  exactly  how  much  material  
would be  etched away,  and  as  a  result had  crystals
of  far greater  acuracy and  produced  in record  time and quantity.
During  WWII,  the  Army  paid  Blileys  a visit,  and  forced them  to  
reveal their  secret process to the  other manufacturers.  Blileys  never  
got patent rights  for  their  process.  I  contacted Charles Bliley on  the 
matter,  he  told  me it  didnot matter,  as they  got  their  share of  
military contracts.  Some  other  well known  publication  played  up James 
Knights Co.  as the  crystal gods-  sorry
not  so.          Russ.






>From: "Brian Carling" <bcarling at cfl.rr.com>
>Reply-To: amradio at mailman.qth.net
>To: amradio at mailman.qth.net
>Subject: Re: [AMRadio] Crystal Grinding
>Date: Fri, 13 Dec 2002 14:30:09 -0500
>
>On 12 Dec 2002 at 19:39, Barockteer at aol.com wrote:
>
> > Along the same lines, does anyone know about chemical etching of
> > crystals to shift frequency? I expect it requires some nasty hazmat
> > stuff to cut the quartz. I saw a reference in an old QST but didn't
> > have the issue mentioned.
> >
> > -Tony, K1KP
>
>I don't think chemical etching is recommended.
>
>The commercial boys do it with first a grinder to shape the crystal "bar" 
>and  then
>a SAW, to get the slices made aproximately right.
>Of course the wafers then are actually thicker than they will need to be in 
>the end.
>
>The final step is to put them in a lapping machine which rubs them down to 
>the
>required thickness, and up to the required frequency in a lubricative 
>cutting paste
>slurry which combines lubricants, cutting compounds and a means to conduct
>heat away into the lapping machine
>from the crystals so that they don't break.
>
>Of course radio amateurs have been known to use all kinds of unconventional
>methods and perhaps that could include chemical etching....
>
>
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