Before taking a chance, I called Jet technical support and asked about it. The tech guy was less than stunning - atypical of my support experience for my table saw. After my explanation of what the worklight was, he firmly stated that the bulb would not have to be changed. I tried to argue and explain the wiring. What I really wanted was Jet's direction on what kind of replacement bulb I should use and where to get it. He told me the bulb was only on one leg of the 220 and it would not be a problem.
<sigh> Ok. So I powered up the drill and tested the motor. It ran just fine with no sign of distress running on 220 volt. I got that part right. Then I screwed in a light bulb. It went POW and tripped the circuit breaker, slightly melting the center contact on the bulb. I restored power and checked the voltage across the light bulb socket -- 240.1 volts.
After searching for three hours and consulting with my dealer, he helped me find bulbs at Grainger and let me purchase under his dealership name. Great. I picked up two 60 watt 230 volt bulbs which cost an arm and a leg, by the way. I was really unhappy when I got home and discovered these bulbs were "fatter" than their 110 volt counterpart. They would not fit in the Jet drll press. Finally, I got out the wiring diagram and studied it. I changed one connection to put 110 volt on the light, while leaving 220 volt on the motor. After testing everything with a meter, I powered up. The motor still ran just fine and a 110 volt standard bulb worked fine.
I had logged another call with jet support, leaving a message on their answering machine. Another tech rep called me and said the first rep was completely wrong when he told me I would not need to replace the bulb and he apologized. He told me I needed an appliance bulb like those used in electric ranges. Well, some more bad advice. I could not find a 220 volt appliance bulb anywhere.
So I guess I'll go with my unauthorized rewiring job and get along with standard bulbs. They are so much cheaper, anyway.