Introduction: Eureka Puzzle
The challenge with this puzzle is to remove the ring from the post AND put it back. The puzzle is interesting because the solution is not quick and easy. Even after the solution is given it is still a challenge to solve it on your own.
This project provides the solution in video and step by step still photos. The project then provides step by step instructions on how to make your own version of the puzzle.
First, we’ll look at how to solve the puzzle. Please note that with my solution, all activity takes place all on one side with only one disk. The other disk is only there to add confusion. There probably are other methods to solve this puzzle but this is how I do it.
Step 1: Solution (video)
Step 2: Solution - Remove the Ring - Step by Step Photos
Please note: I am left handed so everything is focused on the left side.
1. Position the pole with the loop in the back. Pull all excess rope to the left side.
2. Insert disk through the slot, left to right.
3. Place ball on top of pole.
4. Bring the ring up over the top of the pole and the ball. The ring should end up on the right side.
5. Pass the ring through the slot left to right.
6. Pass the disk through the slot left to right.
7. Very important!!!! Rotate the ring so the rope exits out through the bottom.
8. Rotate the ring over the top of the pole.
9. Pull all the excess rope to the left. You are now half way to removing the ring.
10. Insert disk through slot left to right.
11. Place the ball on top of the post.
12. Bring the ring up over the top of the pole and the ball. The ring should end up on the right side.
13. Insert ring through slot left to right.
14. Remove the ring.
15. Insert the disk through the slot left to right.
16. Mission Accomplished!
Step 3: Solution - Install the Ring - Step by Step
Again, please note: I am left handed so everything is focused on the left side
1. Pull all excess rope to the left side.
2. Insert wood disk through wood slot left to right.
3. Insert the rope and the ball through the ring. The rope and ball must exit through the back of the ring on the left side. Look closely at the photo to make sure you have the correct ring placement.
4. Pass the ring left to right through the wood.
5. Place the ball on top of the pole.
6. Bring the ring up over the pole and ball to the left.
7. Insert the disk through the slot right to left.
8. Rotate the ring over the top to the left.
9. Very important!!! Rotate the ring so the rope exits out through the top on the left.
10. Insert the disk through the slot left to right.
11. Insert the ring through the slot left to right.
12. Place the ball on top of the pole.
13. Bring the ring up over the pole to the left side.
14. The ring should now fall to the bottom of the pole.
15. Insert the disk into the slot right to left.
16. You should now be back where you started !
Step 4: Materials Required to Make the Eureka Puzzle
1. Piece of 3/4" wood at least 4" x 4" for the base
2. Piece of 3/8" wood (Rip from 3/4"?), enough to make two 1 3/4" disks
3. 5/8" wood dowel for two balls
4. 1 1/4" wood dowel for main pole
5. 1/4" wood dowel for rounding the two balls
5. Paracord to tie everything together
6. 1 1/2" metal ring. I found it at Menard's home improvement center
7. Glue and or Epoxy
Step 5: Let's Make the Parts
1. Cut the base from 3/4" wood. The base is 4" x 4".
2. Mark the center of the base. An easy way to do it is draw diagonal lines from each corner.
3. Drill a 1 1/4" hole in the center of the base.
4. Round the edges of the base (if desired and you have the equipment).
5. Cut a piece of 1 1/4" wood dowel, 5" long.
6. Make a mark 1 1/2" from one end.
7. Draw a line, ¼” in, from the top down to the 1 ½” marks. An easy way to do this is place the dowel in a clamp in between two pieces of scrap wood to act as walls. Place the clamp on the bottom 1 ½” segment. Then set a piece of ¼” board on edge on top of the dowel on each side against the scrap piece of wood to make the mark. Keep the clamp in place until step #9.
8. Cut the 1/4" sides of the dowel down to the 1 1/2" mark. The top of the dowel should now be 3/4" thick.
9. Turn the dowel 90°on its side. Draw the slot as shown.
10. If you have the tools/skills to make the slot without the cutting the pole in half you can proceed to step #15.
To remove the wood from the slot, we’ll cut it in half and remove the wood. Then we’ll glue it back together.
Draw a line across the slot somewhere near the middle to mark where to make the cut. The placement of this line is not critical.
11. Cut the dowel on the line just drawn.
12. Use whatever tools you have to clean out the slot (Bandsaw, Scroll saw, etc.).
13. Now glue the slot back together.
14. Sand the glue joint and round off the top of the slot. Make the inside of the slot as smooth as you can make it.
15. We need a “Ball” in front of each disk to prevent the disk from passing through the slot at the wrong time. Cut two ¾” pieces of 5/8” dowel. Drill a ¼” hole through the center. The “Ball” can be made from any wood dowel size that won’t pass through the slot but 5/8” is close enough to look like it should pass through the slot which adds to the complexity of the puzzle.
Remember to make two of them.
16. Temporarily insert a piece of 1/4" dowel into one end of the ball.
17. Using the 1/4" dowel as a handle, round off the end of the ball. Then insert the 1/4" dowel into the other end of the ball and round off the opposite end. Round off both balls.
18. Draw two 1 ¾” disks on 3/8” stock or draw them on paper and glue them to the stock. Before you cut the disks, drill a 3/16” hole, ~3/8” deep, in the edge of each disk. This will be used to attach the rope to the disk.
When you cut the two disks, cut them slightly larger than required. That will allow you to sand them down to a smooth reasonable round surface.
Remove the paper (if used) and sand the outside perimeter on both sides of each disk.
You may want to consider painting each disk and ball set a different color to make it a little easier to keep track of the disk movements while solving the puzzle.
19. Cut a piece of paracord (or string of your choice) ~15” long. Melt the ends with a match to prevent unraveling.
Step 6: Let's Put It All Together
1. If you haven’t already done so, glue the pole into the base. The bottom of the pole should be flush with the bottom of the base. The flat side of the pole should be parallel to the front of the base.
2. Drop the metal ring over the pole.
3. Attach the paracord to a disk. I used epoxy.
4. Slide a ball on to the paracord.
5. Insert the paracord through the wood slot.
6. Wrap the paracord once around the back side of the pole.
7.Insert the paracord through the second ball.
8. Before you attach the second disk, I recommend what I call the “Training Wheels” option. Cut a 2” x 2” square or whatever you have from some thinner material. It must be able to pass through the slot and thin enough to allow a knot to be tied and still pass thru the slot. Tie theparacord to the piece. Now as you learn how to manage this puzzle, you have a plan “B” ready to go if you get all tangled up. Simply untie the paracord and re-thread the puzzle.
9. Once you are confident that you can remove the ring AND re-install the ring, remove the training wheels and attach the second disk.
10. You are done....finished....complete!