[ARC5] WHINK and crystals.

[Kenneth G. Gordon]

On 26 Jun 2013 at 23:00, Dennis Monticelli wrote:

> Ken,
> 
> The etch rate is faster at first and then reduces.  Crystals of
> pre-1944 and particularly of 1944 manufacture were simply washed after
> lapping.   This left many loose particles still weakly attached to the
> surface as well as a rough crystal surface in which the crystal bonds
> were partially broken.

I remember reading that somewhere. I have here a military book on crystal 
manufacturing. It has a long section on lapping crystals. I had not thought of 
that occurring in this case, but after closely examining the crystal I am 
working with, it is obvious now that this is one of the problematic ones.

I had thought that I had none of those. Apparently, I have a lot of those.

> bring it the final distance.  In the meantime the HF did a great job
> of "cleaning" the blank.  Drift problem solved.  The government forced
> Bliley to disclose their technique to all other US crystal makers.

One of the WW-II crystals I have examined recently was a Bliley. It was the 
best-looking one of the bunch.

One of the crystals I opened up, which looked from the outside like all the 
rest, contained a CB crystal for channel 19. I was quite surprised.

I used that case to mount one of the smaller crystals I have here for a 
ham-band frequency into. I think the small crystal was for 7122 KHz. After 
mounting inside the "CB crystal" case, and plugging it into the GRC-109 
transmitter, the frequency counter says it is 7125 KHz.

BTW, this is fun. :-)

Ken W7EKB