XY Plotter/CNC style interpolation project. Need great deal of help

No circuit diagram...

Hmm I haven't put in a resistor; is that my problem? I have these: http://www.electronicsurplus.com/Item/19781/MICRO%20SWITCH%20-%20Switch_%20micro_%20Contacts_%20SPDT_%20-%201052-7325/

with ground and NC (normally closed) wired. Input pin is directly into my arduino...