How can I make my own perforated edge? I'd like to make my own perforated edges on paper, so I can tear certain designs instead. I don't like the odds of tears when I just fold back and forth, and I don't want to use cutting in this case. 

I'm making some small books and I want to take my printed pages and make them easy to tear out. But some pages might have tear-out shapes, as well. 

Is there a tool I can use to easily make perforations instead?
A sewing machine without thread does a great job at making a perforation in most paper. Depending on the settings it can be rather coarse, or quite fine. Much of this will depend on what stitch types your machine is capable of. I would not use your nicest needle however, as it will most likely wear prematurely.

Otherwise, there are purpose built perforators available for ordering online, that work much like a rotary paper cutter, with the obvious difference that they do not completely sever the paper.