Lighting, Light Fixtures, Ceiling and Exhaust Fans - Blinking Bulbs

I have a chandelier with 3 - 40 watt bulbs with tiny sockets like Christmas tree lights. And when I turn the light on one of the bulbs will occasionally blink off and sometimes back on again at what seems like random intervals. I've changed the bulb and turning the socket does seem to have some effect but the problem still persists. Do you have any idea what might be the cause of this problem and how do I go about fixing it?
Thank you in advance for your reply.

Patrick: Welcome to the forums. Don't think I'm crazy (I am) but since the bulbs have the same base as a Christmas tree string, make sure you aren't actually using A Christmas tree signal bulb, which will blink. Also, are the bulbs covered or bare? If covered, the wattage may be too much and can trip an overload, but my bet is on the Christmas tree bulb thingy.

Chandler,
Thank you for your reply. These are clear, approx. 2" diameter bulbs... 40 watt as specified on the fixture, not Christmas bulbs... sorry, my title probably should have been 'blinking bulb' as there are three bulbs total in the fixture.

OK, with the power off, if you have a set of hemostats (and if you were a teenager in the 60's you have a set), reach into the socket and pry up on the center contact a little. It is possible the contact is just barely making contact with the bulb base and as it heats up, the contact pulls away. Let us know how it goes.