I may need all of them when I invite people in, but most days I only need 4 cups or so. Still the 12 cups take up space, so I came up with this simple solution : store 12 cups within a footprint of only 6, hence the name Coffee Cup Doubler :-)
This shape of the Coffee Cup Doubler is such that it stays nice on top of the bottom row of cups and the top row of cups won't slide off either : there is a border on either sides for that purpose.
This project doensn't require much materials or tools, but you will need to work with high precision : the final piece is only few millimeters thick, so your routing will need to be accurate. This instructible is also a lesson in routing : how to make the best use of this versatile tool. As always, patience and practice make perfection.
Step 1: Materials & Tools
* Piece of wood : 30 x 16 cm (12" x 6"), thickness ~10 mm (3/8")
I decided to make this from some leftover Oak* : the resulting piece will be quite thin (4 mm - 1/8") so solid wood is needed for strength.
Caliper, for accurate measurements down to a millimeter.
Router, with a straightforward routing bit. I used my 12mm, I guess in the US that would be 1/2"
Sander, I used my orbital sander
Clamps, to keep the piece fixed while routing
Wood oil, I used Skydd from Ikea
* : I actually glued some boards together, but this is not essential, It's actually easier to use one solid piece of wood.
Step 2: SketchUp model
This way you can easily adjust any dimensions and experiment with the object, before actually starting to cut wood.