That last more than 5 years before the gap in the socket pin opens up enough
to break contact on the grid pin?
octal EL34 type valves seem to have pins about 2.2/2.3 mm diameter. Failing
socket pins , measured cold , a gap in the Y as large as 2.1mm.
Luckily I've found a NOS McMurdo , British made socket that I will rob 4 of
the pins from, for the 4 grids, as physically compatible in the base matrix.
These unused ones measure 1.7/1.8mm in the active part of the Y gap.
The failed ones from 2007 have reduced metal in the region where its
required , the 2 prongs , except for a swelling at the contact point ,
measure in cross-section .7x.9mm down to the 2to1 middle of the pin . The
older ones measure .55 x 1.4mm , the 1.4mm dimension in the sense that you
want it , for long-term/hot-cold cycling strength.
Any modern makes have engineering drawings disclosing these pin dimensions ?
has the metal composition changed/ trade secret formulation lost?