PeterH:
GoForSmoke:
You want to use electromagnet(s) to move something -through- a stainless steel vessel?What's the problem?
Stainless steel is a conductor. The moving field will make lots of eddy current in the conductor and that is where the power will go. Better to use a glass vessel.
I believe I saw the board is capable of 20 mA.
That's a safe value per pin but from: http://arduino.cc/en/Main/ArduinoBoardUno
This is for the UNO, other boards are listed on the Hardware page.
DC Current per I/O Pin 40 mA
DC Current for 3.3V Pin 50 mA
Those are maximums, it is better to run 20 mA or less on any one pin at 5V, but total, you don't want more than 200 mA through that poor little chip.
Can EM’s pull things?
Yes, very. Look up Nikola Tesla and the induction egg, or just induction motors.