I don't think the speed call has any effect when you are only stepping the motor by one step at a time. Try stepping it two and see if that makes the difference. But if the motor is skipping then you are asking it to go faster than it can.
digitalWrite(COIL1,LOW); digitalWrite(COIL2,LOW); digitalWrite(COIL3,LOW); digitalWrite(COIL4,LOW);
Are you powering down your stepper as soon as you think it is in the right place? Why are you doing that?
Thanks for the replies guys, I have been messing around with the speed and stepping, I also swapped the +5v and ground around to use the other end of the pot range. All that has helped a lot,
I was shutting it down as it was getting so hot, I couldnt touch it. Its rated up to 36v and 3 amp so I used a 12v 2 amp supply which was making things to hot. I have changed to a 5v 450mA now and its cool as ice. I was using laptop chargers that I have lying around the house.
Still interested if a rotary switch will work to control the stepper. My understanding is that the Arduino takes the different voltage readings from the pot and this determins the stepper motor opertaion. Would a rotary switch also put out different voltages as the switch is turned?
I also swapped the +5v and ground around to use the other end of the pot range.
That sounds like you have a log pot not a linear one.
Would a rotary switch also put out different voltages as the switch is turned?