OldRider said:
If you took the nut off of the bottom, it should come right out.
Yup. But if it does not, then turn the screw back in and get some penetrating oil on it. Then, screw it in/out as far as it will go, and go back in. Do this until the screw is freed from the perch.
It's a steel screw so it would be tough to snap it. But, apply force slowly as you reach the limit each time. Then, back it in and then back out. Repeat until it comes free.