Today's interiors are designed well enough, but are disposable and should not be repaired just replaced. The whole interior he held together with rivets. By drilling a few rivets, you can see the interior parts.
The aluminum bulb holder is separated from the plastic base with an insulator.
The key shaft rests in a slot and is attached with a notched round piece on the end. This piece has brass covered on 3/4 of it. Rotating the key will open and close the circuit by supplying power to the brass tongue at the bottom of the socket. This is why polarization is important. You wouldn't want the hot wire attached to the aluminum screw cap.
These sockets tend to fail when the key gets stripped either at the internal mechanism or the plastic or metal key on the outside of the shaft.
As you can see the socket interior is made to be a single piece and not designed to be repaired or maintained. It is always safer to replace the socket interior. Most often we can reuse the socket cap and shell so a repair is barely noticeable.