I need a down and dirty 80mm fan hole/cutting guide. I know that there are guides out there that can be printed but my printer is down until someone decides to get me a new one. I cannot waste money on a printer when there are video cards, mobos and processors to be bought!!! So, how can I determine the size of an 80mm fan hole without a printable guide or a protractor? Any help would be much appreciated by me and my system.