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G6Tanuki · 12th Oct 2020, 4:13 pm

The crystals I offered here a week or so back will be on their ways to two new owners shortly, but while packing them up I started wondering if anyone on the forum has experience in crystal-grinding?

All the 'classic' ham-radio handbooks talk about lapping crystals using a very fine abrasive (Jeweller's Rouge, Ajax) or etching them using Hydrofluoric Acid (oooer!) but that was back in the days of the olf FT241/FT243 crystals whose holders could be dismantled, the rock lapped, then refitted into its holder (which made contact with the rock at only a few points)

I've got a 5.something-MHZ crystal I would like to shift HF by a few hundred KHz but it's one of the HC6/U type in a solder-sealed can: last one of these I remember opening-up had the faces of the crystal silvered and suspended on very fine wires that were somehow affixed to the silvering.

Any ideas how I'd go about grinding it? I don't know what 'cut' it is, so not sure where I would want to remove material either!

12th Oct 2020, 4:13 pm	#1
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Grinding crystals The crystals I offered here a week or so back will be on their ways to two new owners shortly, but while packing them up I started wondering if anyone on the forum has experience in crystal-grinding? All the 'classic' ham-radio handbooks talk about lapping crystals using a very fine abrasive (Jeweller's Rouge, Ajax) or etching them using Hydrofluoric Acid (oooer!) but that was back in the days of the olf FT241/FT243 crystals whose holders could be dismantled, the rock lapped, then refitted into its holder (which made contact with the rock at only a few points) I've got a 5.something-MHZ crystal I would like to shift HF by a few hundred KHz but it's one of the HC6/U type in a solder-sealed can: last one of these I remember opening-up had the faces of the crystal silvered and suspended on very fine wires that were somehow affixed to the silvering. Any ideas how I'd go about grinding it? I don't know what 'cut' it is, so not sure where I would want to remove material either!