Side mount sockets are used for special applications where lamp sockets must be mounted from the side. Pull chain side mount sockets are frequently used on lamp clusters and are sometimes called angle lamp sockets. Standard side mount sockets have brass shells and caps with set screw. Tapped 1/8IP side mount sockets are used with standard lamp pipe.
Before making any changes to electrical fixtures and lamps:
Disconnect plug/wire from the electrical source.
Turning lamp off will not protect you from electric shock.
If you are unsure how to safely proceed contact a licensed electrician.