Following on form Nugs method, i did a similar thing.

I got an old bar of steel, and drilled just a small indent into it
Using just the drilltip was enough depth to cutout a small countersunk notch.

Holding the lamp base down onto the metal bar so the rear tip sits into the notch, i then used a nail and held in place inside the lamp holder, and tapped a few times with a hammer which basically re-tensioned the connection, much like the way they were pressed together in factory. (it's almost a rivet method).
Depending on the socket style, you could use the sharp end of the nail, or the bullet head end, or even grind off the tip to have a flat end.

I now don't have any rear solder tags that spin around in circles etc, and ALL my lamps are constantly bright.

I got to a point where i'd clip on (aligator clipleads) onto the socket being modified and put a globe in and test/shake/hit/flex to make sure it wasn't intermittent any more.
Each time a globe still flickered, i'd pull it out, whack the nail into the socket again, and try the globe again.

Didn't take long to have 50 STABLE sockets.

Good Luck,
Marty.