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Was wondering if this stepper motor would work. I have no experience with stepper motors but my thought was to remove the hand operated crank on the caster and install a sprocket with chain to a sprocket on the stepper motor as a method of revolving the main assembly. Program it to rotate after the lead was poured and solenoid for lead pour was off rotate about 30 degrees and pause followed by a revolution to TDC where lead pour would again start.
The stepper control would be tied into a computer.