Got the toolchanger design mostly done, got the materials and equipment for it, have to print off the drawings and go machine it all. What I would need for the Basic, sequence possibly should go; Solenoid energises to draw lock pin, lock pin sensor sees pin unlocked, stepper motor accelerates then deaccelerates to stop at called out position, 200 step motor, 8 positions, so 25 steps per tool position, code would be better if it were bidirectional so some logic needed to decide which way to go for shortest change degrees. As lock pin solenoid denergises, stepper "vibrates" maybe one microstep either way until lock pin sensor sees pin fully locked. Pin locked signal determines program resume. I will try to get away with not using a home sensor on the turret and will make sure I set the turret in tool position 1 before shutdown each time, upon machine start it will assume it is in that place. If this is a problem I can add a turret home sensor eventually. The italian toolchanger I used in the Clausing lathe had a DC motor to turn it, and as the lock pin plunged back in it would reverse slightly to assist the pin to seat fully, this system worked well and never gave any trouble in years of operation. Using a stepper to do this is possibly easier to do. Thanks to all.