Load the Easel cut file and cut the pieces out of MDF. (Photos represent hardwood cut on a lasercutter, but Easel file designed for a Carvey with an 1/8" bit.)
Apply a thin layer of glue to the circular recess in the center of the largest pieces. Put the medium-sized discs into the recess.
Estimated time: 2 minutes
Put a small amount of glue on the axle (the rectangular center piece) & then slide it through the square holes in the center of the discs to align them. Add glue to the center recession in the medium-sized discs, then slide the smallest disc onto the axle.
Estimated time: 2 minutes
Finally, add glue to the axle recession on the other half of the yo-yo, and then slide it onto the axle. Put a small book (or other weight) on top of the yo-yo to hold it in place while the glue dries, taking care to ensure that the weight is evenly distributed in order to avoid uneven yo-yo halves.
Estimated time: 25 minutes
After the glue has dried, slip on a cotton yo-yo string (beeswax on the string loop optional) & have fun! You can also assemble this model inside-out for a classic "looper" shape.
Check out http://yoyonews.com/ for the latest in yo-yo tricks & videos.