[Milsurplus] Let's appreciate crystals

[hwhall@aol.com]

Back in the very early radio days, there were hams who were making their own crystals. How many? I don't know but the radio magazines of the time had articles on how to do it.

Speaking of crystals, it would also be a cottage industry if someone produced the crystals that were so common in microphones & record players.

Wayne
WB4OGM

On Tuesday, October 28, 2025 at 07:27:10 PM MDT, Bob Camp <kb8tq at n1k.org> wrote: 

Hi

The “big deal” with synthetic quartz was its lack of twinning. You need the entire blank to be left handed or right handed. If it’s “some of each” the piezo polarity will shift and cancel out. Natural quartz was not very consistent. The result there was that you lost a noticeable percentage of what you cut. 

During WWII something over a hundred small outfits made crystals. It was very much something a lot of folks got into. After the war, very few of them survived. 

Bob

> On Oct 28, 2025, at 7:09 PM, hwhall at aol.com <hwhall at compuserve.com> wrote:
> 
> I'd guess that the lab-grown crystals were a lot easier to orient for cutting & may not have needed to be x-rayed as much or at all. The natural position of the axes should be apparent & twinning not an issue (presumably controlled for). So, maybe folks like those who are intense enough to try to make vacuum tubes would think about making their own crystals...
> 
> Wayne
> WB4OGM
> 
> On Tuesday, October 28, 2025 at 09:56:09 AM MDT, Bob Camp <kb8tq at n1k.org> wrote: 
> 
> Hi
> 
> If you worked in a crystal plant 20 or 30 years later, you would see folks doing a lot of the same things. The methods they used had not changed as much as you might think. The big change was going to synthetic quartz rather than natural for the “feed” into the process. Yes, the crystal packages did change a bit over the years ….
> 
> Bob
> 
>> On Oct 28, 2025, at 11:18 AM, Ken Kinderman <scr274 at gmail.com> wrote:
>> 
>> Just watched "Crystals Go to War" on youtube.
>> https://www.youtube.com/watch?v=wHenisSTUQY
>> Never again will I take the humble FT-243, DC-10 and their cousins for granted. I suppose if we thought about it, we would appreciate the labor- and skill-intensive process, but this film drives it home. 
>> These guys and gals were heroes... 
>> - hand selecting and hand grading the quartz
>> - dipping the raw stone into oil to identify the axes, hours at a time: bare hands, no gloves
>> - further grading with the casual use of X-rays: I notice only one young lady with a bare minimum protective apron
>> - crystal dust
>> - bare hands in hot soapy water all day
>> - fingers inches away from razor thin, diamond edged, spinning saw blades 
>> - skillfully evaluating the quartz slices for imperfections and maximum yield
>> - acid fumes
>> - constant exposure to watery abrasive slurry
>> - only once did I see protective gloves: a young lady removing blanks from the "acid bath"
>> - coaxing the blanks, one by one, onto frequency.
>> - putting little metal labels on with tiny screws, no doubt "girls work"
>> I will think twice the next time I abandon an oddball frequency crystal as unusable. Each one is a gem.
>>  
>> 73,
>> Ken
>> W2EWL