the motor is not a servo, it is a Nema34 Stepper motor with a 3-1 ratio. It worked well. Originally though my Chester Super Lux, came with a geared motor that works off main voltage. I still have it along with all the hardware to mount it. You add a dog clutch arrangement to the top end of the screw and the motor fits to it.
Another option I saw on Mycncuk I think was to use a cordless drill with an adapter on the hand crank.