i typically rock iprt, iam, and idw
pshhht
.prt (unigraphics) FTW 
oh, and to answer your original question… here ya go
http://www.freebyte.com/cad/cad.htm
bunch of free/open source cad software
^^^^^^ WORD to Newman
ask a professor that may have it, he may let you borrow it…i’ve done that before
CARDBOARD AND SCISSORS!!!
Edit: Maybe even fancy wrapping paper tubes!
exactly, a fabricators best friends right there…