Hi, the lamp holder on an old lamp base needs to be replaced and while the wiring to a new lamp holder is straightforward I don't know how to attach it to the lamp base so it's solid and the lamp shade doesn't make it wobble off the base. The old one looks like it might have been attached with some kind of screw & nut that's long gone - the bottom of the lamp base is open & can get access that way. Appreciate any advice.