This was a project I worked on years ago, before Bre and co brought 3d printing to the masses. The idea was to create a number of parts that could be printed on cardstock using a typical inkjet printer and assembled into working mechanical systems. I created the models in 3d Studio and used Tenkai (which is now Pepakura) to generate the printable patterns. Cardstock is remarkably strong at small scales, and the results are pretty durable for being paper.
This particular item is a set of 45 degree bevel gears that can be used to change the direction of rotation of a shaft by 90 degrees.
1) print out the image onto cardstock. Most quality art supply stores stock a good variety of 8.5x11 inch sheets of cardstock. Bonus points for using a cool metallic ;)
2) cut out all the parts. If you have a craft robo, that will probably help, but I've never tried it
3) assemble. Each bevel gear is made of four parts- one small gear shape for the top, one larger gear shape for the base, and the two halves of the rinds around the edge. Experience with papercrafts will definitely help.
Sorry I don't have a more detailed set of instructions. If there's interest, maybe I'll make a youtube video.
If you want to use the gears as part of an assembly, I recommend using lollipop sticks as the shafts. They're great- tightly rolled paper, which makes them strong and straight, but also very capable of forming a good bond with cardstock using white glue.