Flat Lapping.

So you make x-talls for radios?

"Pankaj Trivedi" skrev i melding news: snipped-for-privacy@posting.google.com...

Thats right mate.

Can you please help me out in reducing the frequency spread.

Thanks Pankaj.

Haaken Hveem (nospam) wrote:

Some general lapping information is available from lapping compound manufacturers such as:

Almost certainly your frequency spread is due to variations in the thichness of your quartz, due to out of flat or non-parallel surfaces.

The tolerances required for quartz crystal resonators is very similar to the tolerances required for gage blocks, and the lapping procedures are probably similar also. Some years ago I found a site that described the lapping procedures used in the manufacture of gage blocks, however I can't find it now in the few minutes I am willing to spend. I suggest you look for this, possibly someone on rec.crafts.metalworking can help.

The basic procedure is to lap a group of blocks (or crystals) in a holder between 2 lapping plates, with frequent swapping of positions of the blocks in the holder, such that the thickest blocks from one pass (Probably from one side or the other of the holder) wind up distributed around the holder on the next pass. Proper maintenance of flatness of the lapping plates is of course also critical, and requires being able to measure flatness fairly acurately.

Good luck, Glen

Thank You very much Glen

Still looking for some more information.....