Double Marble Puzzle

The goal of this classic marble puzzle is to be able to rest the marbles in the holes on each side of the block. Upon first contact with this puzzle, many observers will try to tilt the block to deposit the marbles in the holes. Quickly they will discover that the slope of each hole will not allow this to happen.

Commonly this puzzle has a divider in the middle to keep the marbles from touching. I found that I enjoy the sound that the marbles make when clacking together and the absence of this divider makes the puzzle more difficult.

Please read on to discover how to make your own double marble puzzle

You will need a few things to make this puzzle.

Materials:

• Wood
• Finishing Nails
• Marbles
• Dowel
• Polycarbonate Sheet
• Wood Finish
• Template (attached to this step)

Tools:

• Drill
• Saw
• Clamps

I glued together two 3/4 inch pieces of oak that were just larger than my template. Once dry, square up the edges on a table saw or jointer.

Draw registration marks on your wood blank. This will help you line everything up when gluing back together in a later step. Using a table saw or band saw, cut the wood blank into three pieces. 1/4 inch, just over 5/8 inch (this size is based on 5/8 inch marbles), and 1/4 inch.

Glue the attached template from step 1 to the inside slice. Cut this curved section out.

Note: I've updated the template to show the extra 1/4 inch not removed here. Follow the template and yours will turn out like mine.

Sand the inner track. A spindle sander would have been great here, but since I don't own one I sanded it by hand.

Apply a light amount of glue to each face to avoid squeeze out into the track. If you see any, remove as much as possible.

Using a table saw or jointer, square each face and trim to final dimensions.

This is probably the most difficult step. I used a 5/8 inch spade drill bit to center the holes on each side of the puzzle. You want these holes to be drilled almost horizontal. When I measured and marked these holes in my puzzle, I made the inside hole 7/16 inch below the top of the puzzle and the outside hole 1/2 inch below the top. This should result in a roughly 4° angle from horizontal.

Once each hole has been started with your spade bit, connect the holes with a smaller drill bit drilling from the outside of the puzzle. Once this pilot hole is through, use the spade bit to connect the holes.

I cleaned up the holes using a small drum sander attachment for my Dremel tool.

Using 5/8 inch dowels, plug each hole. Test fit the depth of each plug so each marble just rests in each hole.

Once you know the necessary depth of each hole, glue the dowels in place. If your hole ended up slightly larger than 5/8 inch like mine, mix up some sawdust with your glue to fill in the hole.

Once the glue has dried, remove the remaining plug with a band saw or table saw. Using a sander, flatten each end of the puzzle. Round each edge of the block except the top. This is where the polycarbonate will be attached.

Once the final dimensions of the block is found, cut the polycarbonate sheet to fit.

Using the right size drill bit for your finishing nails, drill holes through your polycarbonate into your block.

Apply a few coats of lacquer. Use fine grit sand paper between coats for a shiny finish.

Using window cleaner, remove all dust and dirt from your polycarbonate.

Before attaching your polycarboante, make sure that all dust is removed from your puzzle. You can do this with an air compressor or simple can of air. Once cleaned out, insert your marbles and nail your polycarbonate in place.

If you haven't figured it out by now, all you need to do to solve the puzzle is to set it on a table top or floor and spin it. As you spin the block, the inertia of the marbles will cause them to rise up to each side of the block and rest in the holes.

Have you ever made a puzzle like this? I'd love to see it! Leave a comment and include a picture of a puzzle that you've made.