Dan,
the heaters typically found in a motor starter type contactor are for overload protection, and won't be correct for 220. The coils on the contactor are what actually moves the armature by becoming an electromagnet when energized by the low voltage. If the control transformer has multiple taps for the primary, and you can set it to 220, then the coils will be fine. If not, you may have to do something different.
You say the starter are rated for 480, but is that what the machine was actually running on before you acquired it? What is the motor set up for?
You won't damage the motor, but David's point is well taken as far as safety goes. Less shock hazard at the control, and a no restart feature that won't be there on a drum switch. You could look at a low current (cheap) drum switch, and use it to control the contactors of the push button station wiring is a mess, but it's not that difficult to wire, normally.
edit: a 1 hp motor is not a problem finding a reversing drum switch for. If you don't mind the risks described so far, then go for it. Tons of them in use on BP type mills all over the world.