On Sat, 27 Feb 2021 00:18:02 +0000, Dudy
wrote:

replying to Randy, Dudy wrote:
Does anyone have a copy of the instructions for adjusting the Lufkin 680a?

I don't know that I do, but US Patent number 1,424,383 is the key.

Enter US1424383 to Google Patents to get a copy.

Joe Gwinn