Sean,
You can try at http://www.antiqueradioknobs.com
Play things of the past has some knobs too. http://www.oldradiopparts.com (currently owner is recovering from surgery)
I cannot guarantee they have them and you will have to supply as much detail as possible per instructions on the sites, in order for them to know exactly what you need. Most of the trick to finding knobs is having an example scan/photo.
Jeff W
::Hello. does anybody know where to get detrola model 106 knobs. I am missing the two knobs that go to the tuner. I think there are supposed to be two of them since the hole in the case is larger than the others and there are two shafts. One shaft is the longest and the other one fits over the longer one and is half as long. So I would guess that it is supposed to have slow and fast tuning adjustment.