I have built an electromagnet in a shape that can be described as a gapped toroid.  The core is 1008 LCS of .070" diameter.  The diameter of the ring is 1.5" The gap is .200"  The coil was wound by hand so I am unsure of the number of turns however it is 36 gage at 10 ohms, one layer.  I believe there is approximately 800-1000 turns.  I apply a voltage of 5V.  The poles face each other and are ground flat.  I have noticed a problem where the South pole is orders of magnitude stronger than the north pole.  If the current is reversed through the coil, the opposite pole (now the south pole)is now much stronger.  I expected there to be fringing involved with the coil but assumed the poles would still be relatively close in magnetic strength.  My assumption is the magnetic flux is traveling through the coil, exiting the south pole but not making a connection to the opposite pole.  Is the gap too large?  Should the pole faces have a different shape? What other cause and solutions are there to this problem?  Thanks for any help!