[Milsurplus] Crystals new and old

[CL in NC]

When ICM went out of biz, I was pretty ticked, but I guess the technology evolved making the need for a lot of crystals and their sales fall off greatly.  But, what happened to all the equipment ICM used, did someone buy it to scrap it?  I had hoped a cottage industry would have opened up.  So, I decided to start figuring out what it would take to roll my own.  A couple 1934 QST's had articles showing how to make your own, even the design of a copper cutting wheel saw to make slices, one article had the only place I have ever seen the formula for how thick the first cut needed to be in order to get to a particular freq, plus also gave the angles of overtone crystals and how to sight through the Brazilian quartz(preferred) to see where to cut.  I bought a couple small pieces of surplus gear needed to check crystals, and in the manual of one of them was a typewritten set of instructions from within the Midland Company.  In it, it detailed a procedure for the night shift on how to make crystals, seal the metal cases, HC49's I think, offsets to compensate for freq changes between ground crystal and finished, all this was done in house by Midland, who at that time, was a big CB radio builder, making their own crystals.  The process must have evolved quite a bit in the early 60's such that even a CB maker had a line to make their rocks, just wished the machines had survived.

As a caveat, one fellow mentioned putting smaller crystals in FT243 holders.  AF4K did that, and had complaints about burned out crystals when they were used in a rig wanting high crystal current, like homebrew transmitters or the Conar 400.

Charlie, W4MEC in NC