Double Marble Puzzle





Introduction: Double Marble Puzzle

About: My name is Troy. I'm a Mechatronics graduate studying Mechanical Engineering. I like to make things and spend time outdoors (especially SCUBA diving). I am a Community Manager for Instructables.

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

Step 1:

Step 2: Tools and Materials

You will need a few things to make this puzzle.



  • Drill
  • Saw
  • Clamps

Step 3: Prepare Wood Blank

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.

Step 4: Rip Faces

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.

Step 5: Cut Template

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.

Step 6: Glue Together

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.

Step 7: Trim and Square Puzzle

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

Step 8: Drill Slanted Holes

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.

Step 9: Plug the Holes

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

Step 10: Glue Dowels

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.

Step 11: Cut Plugs

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.

Step 12: Drill Pilot Holes

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

Step 13: Apply Finish

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

Step 14: Clean Polycarbonate

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

Step 15: Attach 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.

Step 16: How Does It Work?

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.

3 People Made This Project!


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21 Discussions


1 year ago

Great little project, will have to make a few before Christmas. Nice job and they look great.

Cool! Definitely going to make this. Thank you for posting!

This is going on "the list". I've never seen anything like this before.

Awesome project, write-up, photo's and puzzle.

Nice! I really like has the same principle as my trick opening box. Well done and great job! #ilovepuzzles!


1 year ago

very cool

I love puzzles that make you think outside the box.

Polycarbonate can be found at most hardware / home improvement stores. You can ask for it by it's more common names of Plexi-Glass or Lexan.

It doesn't really matter for this application, but Polycarbonate, which is also sold under the brand names Lexan and Makrolon is a different material than PMMA (Polymethylmethacrylate), sold under the names Plexiglas, Acrylite, Perspex, etc. aren't the same material.

If you're going to drill it, polycarbonate is much less likely to crack.

Maybe this happens with Plexiglas as well, but if you're cutting Lexan with a bandsaw, go slowly. If you go too fast, you may melt it a little, and then it grabs the blade, possibly breaking it. Not a problem if you're patient.


1 year ago

Good one tomatoskins, I like everything except hammering nails on to the plastic. Given that we use what we have lying about some folk will use plastic that can't take the knocks and may have edges that are a lot of work to get nice - imagine I use he strip of rough sawn Perspex I have lying about? May I suggest making the sides a little higher to take a rebate that the plastic could sit in, a lot nicer and safer finish imho?

2 replies

You can definitely make yours like that. Keep in mind that I only hammered the nails till the touched the cover. I'm sure that hammering any further into the block would have split the plastic.

Polycarbonate is amazingly tough. I'm sure that it wouldn't split unless you hit it REALLY hard. On the other hand, the hammer could scratch it up.


1 year ago

My grandparents had a pressed metal one, 2" square with diagonal grooves and an end stop in the middle to keep 4 balls in their own tracks. The top cover was celluloid. Polycarbonate was not around in 1950. Spinning the toy briefly would bring the balls to the corners. I could do it in a second (behind my back, which mystified my school mates).

thanks for updating the template. Just to clairify, the two holes are pretty much drilled ninety degree,and you achieve the angle primarily with the angle that you position the dowels in the holes?

You put in two marbles, only two marbles are required, or, is there another way to do this with the extra marbles shown? You dont actually show adding the marbles as a step. Your finished piece is really sharp looking.

1 reply

yes only two marbles are required but (1) good luck trying to find a package of just one or two marbles for sale... and (2) just like Lays Patato Chips, good luck on being satisified with just one

I think you could make the marble holes more easily by cutting notches in the center piece of wood before gluing. Getting the lip angle just right would be a bit tricky, but you could clamp the three pieces together to test and tweak with a rasp accordingly.

1 reply

That's a great idea! If I make another I'll see what I can do!

You forgot step 13.5 where you put the marbles into the puzzle just before nailing the polycarbonate into place. :)

Good job on everything else though. I will make a few for presents.

I made a similar one few years back by taking two transparent plastic disposable cups, putting 2 table tennis balls in them and joining their open ends with clear plastic tape. The goal was to get a table tennis ball on each side of the cups and this was achieved by spinning the contraption. Remarkably Same, But cheaper and with less hard work ;)