On Wednesday, August 17, 2016 at 5:57:26 PM UTC-4, Ralph Mowery wrote:
In article ,
says...


Please explain how a tad more force on the base makes the tungsten
element burn out faster. Not that I doubt you but I don't see the
correlation.

The connection of the aluminum base to the glass is marginal. Any extra force twisting it deforms it enough to leak air in which fries the element eventually. Even a little bit is bad.

I have no evidence for this. It's what I've been told, and it may or may not be true. There does seem to be some experience with bulbs burning out faster when people screw them in tighter, hence the recommendation to screw them in until they just light, then only an additional 1/8th turn. That's for incandescents, CFLs or LEDs might need a different torque.


The alumminum base does not seal any vacuum in the glass. The glass is
totally sealed except where the wires come out of the glass.
You can take the base off and throw it away and connect to the wires and
it would not burn out any faster.


Huh. Never thought of that, but it makes sense. Then, I dunno, maybe you just shouldn't screw a bulb in too hard because it will get stuck.