a lot of the "OLD" type knobs were made of Bakelite. New knobs are molded in: Styrene,lexan which is Polycarbonate, acrylic,butyrate and other various plastics. Without seeing I cannot advise on the plastic in question.What part of the country are you in ? I might be able to direct you to someone. Metal to Metal "LOCTITE" for sure. If you go to a Home Depot, Lowes, Hardware Store and just ask them which Loctite they would recommend. It is a ONE componet adhesive.
Graingers is another source.
I have not used it but you can go on line to Loctite and check out all the various adhesives.
If you like e-mail me with other questions on your projects and if I can help you I will. I have been in the "PLASTIC"
Industry for over 35 years.