A table saw is the best tool for ripping wood. That said, your description of the task is not that of ripping but “re-sawing” and neither radial arm or table saw is the right tool for that job – only a band saw is up to the task. Resawing 4″ thick stock will require at least a 14″ model. Those bench top models you see on sale all the time ( Home Deport, Lowes, etc.) for $99.00 are 9″, 10″, 12″ and can only do 2 to 3-7/8″. A 14″ saw will do up to 6 inches. It is a sizeable investment however. Good saws in the in the $400-$600 range

A few recommendations:

  1. Grizzly G1019 14″
  2. Grizzly G0555 14″
  3. Grizzly G1148 Heavy-Duty 15″
  4. Craftsman 14″ Professional

To do the job safely, you may also want to consider reading ‘ The Bandsaw Book’ by Lonnie Bird.