What school do u go to? Because one of our assignments in physics was to build a simple DC motor.. if u have any Q about it feel free to PM me, i got 67/67 (100%) for it, mine was prob one the most innovative designs. I also helped my friend build one with a three phase armature , i do not suggest this ( it took 30 hours to file back metal for the armature and also runs massive risk of eddy currents if not done correctly) lol its very very hard. If u need ideas or wana know what material to use just let me know...
P.S i have a shitload of pics of it etc and a VERY detailed method of how i done it. If u need. PM me ur MSN