Unless you have a taper attachment or you are setting up with the tail stock offset, you can not use power feed to make a taper.
You will have to set the cross slide angle and then hand feed the cross slide for the whole length of the taper cut. If your cross slide does not have that much travel then you will have to do it in steps and hand finish out the line between sections (unless you are REALLY good at picking up the cut).
A 9.5° angle at 0.500 deep will give you a taper that is 2.988 long, only 0.012 off, prolly close enough for an ice bat.
If you really need 0.500 deep and 3.000 long then the angle will be 9.4623222°