Impossible Steel Ball in a Wooden Cage With a Laser Engraver

When I was growing up, I had an uncle who loved puzzles and games. He would bring them to our family gatherings, and one puzzle that always intrigued me was the golf ball in a cage. So, when I came across the Instructable “Steel Ball in Wooden Cage” by BevCanTech, I was inspired to try it myself.

Traditionally, this project would be made using a drill press, router, or hand carved but I wanted to see if it could be done with a laser engraver. I expected this method would result in a very clean final product and would look great with the steel ball with dark-stained wood.

- Square dowels (I used 1 ¼” poplar because that’s what I had on hand)

- Ball bearings (1” fit my dowels well)

- xTool S1 40W Laser Engraver

- Pot to boil water

- Sandpaper

- Stain

- Clearcoat

I cut my dowels in half, making two 6” long pieces. You won’t need it this long for the final product, but the additional bulk on the ends can help prevent splitting. You can trim the ends off during the finishing process if desired.

Since I can only cut about ¾” with my laser, I had to cut from both sides. It’s critical that the placement of the wood is exactly the same for each setup. I used a scrap piece of plywood as a jig and secured it in the bottom of my crumb tray.

After placing the dowel in the jig, I used the laser marking feature of the S1 to map out the extents of the wood block to determine our workspace. Next, I drew a rectangle with chamfered corners, 0.7” x 3.5”, and centered it inside the workspace. I used the outline tool to create a 1/64” inset of the chamfered rectangle. I will set both of rectangles to a cut function. The inset provides enough slack for removing the pieces once cut.

Cutting something thick usually requires a very low speed, but I was getting a lot of charring and frame-ups. I decided to try multiple passes at a higher speed, which worked much better.

- Sides 1 and 3: I set the laser for 3 passes at 25 mm/sec and 100% power, lowering the focus by 3 mm. After running this on both sides, the piece could be dislodged with a little persuasion, though you may need an additional pass.

- Sides 2 and 4: I used the same settings on sides 2 and 4, but only one pass at a time. It would cut through by the second pass.

I set up a pot for boiling water and placed the block inside. I let it soak while the water warmed up and then let it boil for approximately 20 minutes.

I removed the block from the water and placed it on a towel. Using a spoon, I spread the bars and gently pressed the ball bearing between them. Once the ball was completely inside, I pressed the bars back to their original position and let them cool and dry.

After the block dried, I sanded all sides thoroughly, stained the wood, and applied a clearcoat.