I have a few old floor lamps which use three-way mogul base bulbs. As these bulbs are becoming less commonly available and are rather expensive, I was wondering if there is made an adapter which allows the use of a standard three-way Edison base bulb? I have a couple of screw-in adapters but they are not for three-way bulbs.

I've never come across Mogul-to-standard reducers for three way bulbs. The only ones I've seen are just for standard bulbs.

I guess you just have to replace the lampholder? I never understood why some lamps came equipped with these humongous sockets anyway....