[ARC5] Crystals and WWII

[Dennis Monticelli]

One also had to cut the natural crystal at exactly the proper angle.  I
have a couple of large crystal points that are cemented to metal
substrates, marked for cutting at precise angles, and having about half of
the point sliced away by an ultra-fine blade immersed in a slurry. These
came from a crystal maker that bought surplus equipment after the war and
put himself fin business.  I got the items from his estate.

BTW, twinning wreaks havoc with the piezoelectric properties of crystal
lattice.

Dennis AE6C

On Sat, Mar 16, 2013 at 7:43 PM, Kenneth G. Gordon <kgordon2006 at frontier.com
> wrote:

> On 16 Mar 2013 at 22:30, hwhall at compuserve.com wrote:
>
> > I recall reading an old QST article, from the 1930's I think, that
> > recommended grinding only on one side. A pencil mark was made on one
> > corner of the unground side as an index. Then frequent micrometer
> > readings were made and recorded as grinding progressed so one could
> > see when parallelism was being lost and where to increase or decrease
> > grinding to correct it. They seem to have put a lot of care into
> > homebrewing crystals back then.
>
> One of my favorites is the article that begins, "Take a block of quartz.
> Clamp
> it into your vise. Then get out your hacksaw...."
>
> From the description, it took at least a week of very hard work to obtain
> ONE
> crystal that worked.
>
> Ken W7EKB
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