Is it a puzzle? A rattle? A knick knack? Well yes it is any and all of these. It a block of wood with eight marbles trapped into it. With three different options it can be enjoyed by babies, children and adults alike. Between the marbles 12 trapped steel bearings makes it rattle quite loudly. When people (adults always, children sometimes, babies never) ask how I make them I tell them either:
-20 years ago I placed the marbles and steel bearings on a branch right next to a tree truck and the tree grew around them. I then whittled away the rest........
-I tell them the process as shown in the steps below.
Step 1: Mark and Drill Holes
First you will want to use hardwood. You will need to find a piece enough to make a 2-1/2" cube. Many wood stores sell small blocks of hardwood to bowl turners. Using a table saw, miter box saw, power miter saw, or band saw, cut out the cube. If you do not have access to one of these tools then find a friend that does. Tell them you will give them a finished project if they will cut your cubes. You may be able to find precut wood cubes at a local craft store. Here is a internet source of maple cubes.
Start by marking four holes on each face, 3/4" from the sides. Then drill the hole on each face a bit further than halfway through. (I prefer this to drilling half as many holes all the way through. This guarantees the holes are placed at the right place on each face. Any misalignment is in the middle of the cube where you don't see it.) Use a 1/2" or 13mm bit Then sand the holes with a piece of rolled up sandpaper to get rid of any splintering caused by the drilling.
Step 2: Soak the Cube
Soak the cube in water for 24 hours to soften the wood. I like to use a Styrofoam cups because the cube will wedge into place and stay submerged. (If you don't like the idea of using a non recyclable material then don't throw it away. It's not waste if you don't waste it. Think of it as soft ceramic.)
Step 3: Press Marbles Into Place
The marbles are 9/16" in diameter and are the size you'd find in a Chinese checkers set. You will need a press to push the marbles into the wood from one of the two end grain faces. You will install 8 marbles, one in each corner and twelve bearing in the tubes between the corners. You can use your drill press or an arbor press to push the marble into place.
Because some of the bearing will be placed in horizontal tubes, the press will have to be tilted to keep the bearing in the tube while until it is sealed with a marble. To tilt the drill press place a block of wood behind the back of the stand. Place a block under the back of the arbor press to obtain the required tilt.
With the end grain up, press a marble into place. For the drill press place in the chuck a ¼" socket extender with a socket on the end. For the arbor press just use the socket. In either case the outside diameter of the socket need to be less than ½". Keep pressing until you feel the marble lock into place.
Before pressing the second marble, insert a bearing into the tube that will be sealed with the marble placement. Use the tilt of align it so the bearing rests on the marble already installed. Install the third marble and second bearing in the same manner. Then install the fourth bearing and with two bearing. The top side is complete.
Flip the cube over and put a bearing in each of the four vertical tubes. Then install the remaining four marbles and four bearing the same way you did on the top side.
After all the marbles are pressed in, leave the cube to dry for a week.
Step 4: Option #1 Large Cube
This is the easiest and most likely will be the option for people who bought properly sized cubes because of a lack of a saw. Sand all six faces of the cube. Break the edges and corners.
Step 5: Option #2 Beveled Cube
Take the cube and cut a5/16", 45 degree bevels on all 12 edges. You will still have to break the corners.
Step 6: Option #3 Small Cube
Take the cube and trim ¼" from each face. It makes the cube a easier size to hold. Break all the edges and corners. (Aggressively if this is to be used as a child's toy.) The reason why a larger cube was cut down instead of just using a cube is that a cube with holes that close to the edges will split when the marbles are pressed in.
Step 7: Finishing
Take all the pieces and sand them with 120 grit sandpaper.
To finish I like to use butcher block finish. It is easy to apply and made from only food grade ingredients.
Just wipe on, wait 20 minutes. and wipe off.