[ARC5] Crystals and WWII

[hwhall at compuserve.com]

>
Hand grinding crystals to practically any frequency is not the problem: the  
BIG problem is maintaining the sides and ends of the crystal PARALLEL. 
>


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.

Wayne
WB4OGM