What could have caused this?
These Raytheons in my attached photo clearly show a bevy of Baldwin Beauties
sporting Nailer's so-called "identical burn through holes in the getter flashing".
gadget makes a pretty good observation sighting a possible "manufacturing feature".
(or cosmetic defect)
guitbanger tosses in the thermal card with horizontally mounted tubes and rising
heat. Except the possibility that heat dispersion or concentration might behave
differently inside of a vacuum environment.
They are both equally plausible scenarios and are probably close to the bull's eye.
However my thinking suggests that since the tube manufacturing process is not all
hand assembly work, an operator sitting at a machine that mounts the getter to
the element package, places the element package into a fixed jig on the machine,
then the getter with it's mounting stem is then mechanically lowered or hand
placed on top of the element package; next the operator engages a control that
welds the getter stem to the top of the element package, which is then disengaged
from the jig to be removed and passed along to the next stage. Most of us should
know that there's a floor machinist assigned to maintain and watch over this
manufacturing equipment, and one could surmise that sometimes the mechanic
could at times be unable to keep up with the work flow; thus allowing enough time
for adjustment controls to slip out of "True Alignment".
So! the flashing blotches might very well have been brought on by a mechanical
setup flaw that repeatedly tilted the getter causing similar type blotches until it
could be realigned and eventually stabilized?.
Tube manufacturing is a delicate mechanical process that needs plenty of TLC.
thmbsp