The Dale C. Maley Family Web Site

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Magnetic Marble Game

My grandkids love the marble maze games I built for them.

My wife saw another idea which uses magnetic balls.  You use a magnetic stylus to move painted steel balls from the bottom storage to the top semi-circle.  You have to have the right number and color for each semi-circle. 

Steel Ball Diameter

I went to Amazon, and they sell steel balls with diameters of 3/16, 5/16, and 3/8".   The 3/8" size is the most common, since they are used as ammo for sling shots.

The marbles I normally use are about 5/8" diameter, so I decided to design the game to use 3/8" diameter painted steel balls.

The clear plastic I have in inventory comes in 12x12 inch sheets, so I want to keep the over-all game size below 12x12 inches.

The back will be 3/16" Luan Plywood. The body will be common pine.

Magnetic Stylus

I checked at Ace hardware, and found a magnetic pick-up, that I think will work ok for this game......

Balls from McMaster-Carr

What Size should semi-circles be to hold steel balls?

The semi-circles need to hold 6 of the balls, I actually designed them to hold 7 balls by mistake versus 6, but that is ok.

Sketchup Design


I decided to glue up several standard 3/4" thick pine boards large enough to cut out the main body, then plane them down to 7/16" thick, or 1/16" thicker than the 3/8" steel bearings. I was going to plane down to 1/2" thick, but the magnetic stylus quickly loses it's strength as the air gap between the stylus and balls increases....hopefully this will work ok.

I scroll sawed out the main body, and the 6 semi-circles.  I had Elmer's glued the paper pattern to the blank, so I cleaned it off with a wet rag and water..........then dried the pieces in my oven at 120F for about 10 minutes to take the water back out.

Using scroll saw scrap to locate where 6 semicircles go

Flush router trimming Luan bottom

I used the pine main body as a template and pencil drew on the Luan.  I went to the scroll saw and tried to cut about 1/8" outside the pencil line, so I could trim it exactly flush with the router.  This worked great.  After flush trimming, I did an 1/8" roundover bit on the router on the bottom edges, so make it smoother to handle.

Plastic sheet for cover

I thought I had a 12x12 inch by 0.100 inch thick piece of acrylic in stock, but I did not I ordered 3 sheets to restock my inventory.


I used Anita's paint bottles, latex, so easy to clean brush with water......... I get them from Hobby Lobby.

Status on July 28, 2020

Waiting on steel bearings from mcmaster-carr..........and sheet of plastic or acrylic from Meisel.

Adding height block to back

After playing with game, I decided to add a height block on back, to keep the game at an angle where the marbles won't come out of the pockets.  I think it would be too hard for a small child to keep it tipped right the whole time, while dragging marbles up their spots.

Marking the plastic front to scroll saw

Brass Screws to attach plastic cover from McMaster-Carr

Hobby Lobby colored cord to attach magnetic pen to base

Sketchup Drawing

Finished Game

Closing Thoughts

This was a fun project.  The magnetic pick-up from Ace Hardware solved the problem of how to make or buy the you can attach it with string to the game so it does not get lost !!   The steel balls from mcmaster-carr served as the marbles for the game.  Hopefully the grandkids will enjoy it !!