No Need for a press for the disc/hub studs. Support the disc well on a few wide pieces of wood. (4x4 is ideal but 2x4 is fine)
PUT ON SAFETY GLASSES!!!! If your hammer is made of crappy metal you could get metal shards flying around. If you know your hammers suck, get better ones...
Use a ball peen hammer and rest the ball on the curved top of the stud. (Put a regular nut on the stud for added protection if you want)
Take a second hammer and give the ball peen hammer a good solid whack and the stud should pop right out.
To get them back in, same process in reverse- just line the splines up if you can, before the hammer blow...