I own an SP-15, and it definitely comes off. It indeed has a taper, but it's very shallow. You don't want to rock it back and forth too much as you will damage the bearing. I'd suggest a bit of penetrating oil at the joint by the spindle. I've also heard of people using a 12" long by 1-2" wide steel bar or piece of hardwood, that you can lay across the point of the spindle and use to push down on the spindle while you pull up on the platter.
Mine took a bit of doing to get the platter off when I first got it, but eventually it came off. Good luck.
David
Mine took a bit of doing to get the platter off when I first got it, but eventually it came off. Good luck.
David