Geocaching Puzzle Cube Cache

Geocaching (geocaching.com) is an outdoor game that uses the Global Positioning System (GPS). It's similar to a high tech treasure hunt. You use GPS co-ordinates to find containers, or caches, that are hidden all over the world. Using a hand held GPS unit or the cell phone app, you find your way to the cache location to find the cache. Create a free account to see all the cache locations. The cache is typically not out in the open so you must hunt for it. Caches vary in size from pill bottles to ammo cans and other custom made caches such as described here. Inside the cache is a paper to log the date and your user name. Larger caches such as this one contain swag (stuff we all get) such as key chains, stickers, CD's, fast food kids meal toys, etc. Families go geocaching with the kids and let the kids find the cache to see what's inside. The rule is, if you take some swag you must put other swag back in so there will be swag for the next person to find.

1. four pieces of 1/2 inch thick plywood, 8-1/2" x 8-1/2" square
2. one piece of 1/2 inch thick plywood, 9" x 9" square
3. 1/8 inch thick Baltic Birch plywood
4. magnetic child resistant cabinet/drawer locks
5. four strong alnico magnets
6. small nails or screws
7. wood glue
8. table saw
9. laser cutter
10. masking tape
11. polyurethane

Use the 9" x 9" piece of 1/2 inch thick plywood as the base for the cube. Glue the 8-1/2" x 8-1/2" pieces to the base and each other to form the cube. Nail or screw the pieces together for additional strength. After the glue has dried, give the cube a couple of coats of polyurethane to help make it weather resistant.

Before gluing the frame to the lock mount plate, align the two pieces together and trace around the frame. These lines will be used to align the magnetic locks and support braces. Measure 2 inches in from each corner and center the magnetic locks at these positions. Cut some pieces of 1/2 inch thick plywood to the height of the magnetic locks for the braces. The length of the braces will depend on the width of the magnetic locks you have. These braces are needed to prevent the locks from being broken off if someone tries to open the cube like a book. This is why the borders of the frame are labeled "Lift Lid Straight Up". Glue the braces into position and use some small nails or screws to strengthen the braces. Give the cube lid a couple of coats of polyurethane.

You will need three sets of puzzle pieces. The top section will be covered with masking tape to allow for scoring a design through the tape. Sections of the masking tape can be removed and that area painted to better define the design. The middle section will need laser cut holes based on the size and shape of the magnets you are using. The bottom pieces hold the magnets in place when all three layer of a puzzle piece are glued together. Make sure you have the polarity of the magnets set correctly to open the magnetic locks.

Since this is a square and the magnetic locks are placed in a regular spacing, it doesn't matter what orientation the puzzle is done on the frame.

Put a paper logbook in the cube as well as some swag. Put the puzzle pieces in a plastic bag or container. Don't put the puzzle pieces in the cube! Close the lid. Hide the cube under a large upside down plastic flower pot or a fake landscape boulder and see how many geocachers find your cache.