Thought I'd check in one more time before I take my vacation from the hobby...
James, I agree with Ron that the spindle or spindle/shaft appears to be slightly bent.
Since this is a portable, the turntable was likely secured to prevent it from popping off the spindle in transport.
The most COMMON way to do this was to use a retainer ring at the base of the spindle where it comes into contact with the top of the turntable. To see if there was once one in place, check the spindle carefully to see if there's a slight groove. If there is, apply some penetrating lubricant at the base of the spindle and rock the turntable gently until you start to feel some give.
If there is no evidence that a retaining ring was used, look carefully to see if there is a hole drilled through the spindle, itself. If there is, then the spindle will unscrew. Insert a nail or rod through the hole and, holding the turntable by the ridge, try turning the rod counter-clockwise, or clockwise if it won't budge.
If there is no hole in the spindle, then it may be attached with a set screw under the turntable. (Hopefully, this isn't the case, because you'll need a very long & thin screwdriver to get at it.)
If you still can't remove the turntable, it might be best to contact one of the shops specializing in antique phonograph repair. Great Lakes Antique Phonograph is a good starting place --
http://www.victroladoctor.com/Hope this helps.
Joe
(Now, I'm outta' here..)