Bob,

Wire twisters are used in the aviation industry to twist safety wires on various fasteners. They are very easy to use and produce very even twists. The amount of tension and number of twists per unit length of wire is determined by the user. Try Aircraft Spruce and Specialty or other aviation maintenance supply houses and search for "Safety wire twisters". For occasional use with wire .035" and smaller consider the 6" model. You should pay $50-60 for the tool.

Thanks for the tip. I found them here at the site you suggested for $50. Note that they also have an economy version for $20.