Introduction: 8-Ball in Solid Wood Cube
There is something magical about wood puzzles. This mystery leaves the mind searching for any rationalization, any form of understanding that will answer the question of "How did that happen?" In this instructable, I will show you how to put an 8-ball into a block of wood so you can leave others searching for an answer themselves.
Step 1: Parts
You will need:
- 8-Ball
- Scrap Wood (I used a 4x4 made of cedar)
- 1-7/8-inch Forstner Bit or Hole Saw
- Wood finish
Step 2: Joint and Plane 4x4
Using a joiner and planer, take the overall size of the 4x4 down to 3" x 3" and cut into a 3" x 3" x 3" cube.
Step 3: Mark the Center of the Cube
Using a straight edge, mark the center of the cube so you know where to drill the holes.
Step 4: Router Edges
Using a 1/4" roundover bit, router the cube starting with the end grain using a push block to prevent tear out.
Step 5: Drill Holes
Using a 1-7/8" hole saw or forstner bit, drill out the center. Drill one side of the end grain then the other. Slowly work your way around the cube removing the wood plugs as you go.
Step 6: Sand Cube
Using sandpaper, smooth the cube and remove all sharp edges from the drilled holes. This will help later when the 8-ball is placed inside the cube.
Step 7: Soak and Boil the Cube
Using enough water to cover the cube, soak it for at least 24 hours. I soaked this cube for 36 hours just to be safe. After soaking, boil it for an hour to ensure proper saturation. Since wood floats, place something on top of the cube to hold it underwater. I used a glass vase I had nearby.
Step 8: Lubricate the 8-Ball
I covered the 8-ball with paste wax to act as lubricant for the next step.
Step 9: Press 8-Ball in Place
After the cube is finished boiling, use a bench vise to press the 8-ball inside the cube through the end grain. Do this slowly to prevent the wood from cracking. If you push cross grain you will split your cube. I used a cut off piece of PVC to press against the 8-ball to protect it from the vice.
-------SCIENCE-------
The reason this step works, is because of how trees are formed. Pretend that the bundle of matches in the photos above are the straw-like fibers of a tree (xylem). When the fibers of the wood get heated and saturated with water, they become flexible and stretchy. This allows you press the ball through the end grain of the wood. If you try to press the ball through the side grain, the wood doesn't move as easily, and in our project you risk possibly breaking the cube.
Step 10: Final Sanding
The cube will no longer be smooth because it soaked in water for so long. Once the cube dries overnight, sand it smooth. Be sure to sand the inside of the cube as well. I found the best method was to do it by hand to prevent scratching the 8-ball.
Step 11: Apply Finish
I finished my cube with a beeswax oil mixture found online. Apply liberally with a rag. I used this finish for two reasons. If there was still water inside the wood I didn't want to trap it there and risk the finish bubbling, and I didn't want any finish to change the look and smoothness of the 8-ball.
Step 12: How to Remove the 8-Ball
Other than potentially boiling the cube and 8-ball again and repeating the process done before, the only way to get the ball out is to break the cube around it. Using a chisel, this test cube was no match and the 8-ball was easily removed.

Participated in the
Full Spectrum Laser Contest 2016

Participated in the
Before and After Contest 2016
6 People Made This Project!
- colasam made it!
- monkeyknuckle made it!
- jstock4 made it!
- sankaraishaya made it!
See 2 More
84 Comments
7 years ago
Wonderful.
Fun.
Funny.
Well-explained.
Beautiful.
I love it.
Please do more.
Reply 7 years ago
ditto! x^D
7 years ago
I can tell you that from all the ideas that came to my mind on how to do this, your solution didn't even surface. And I must admit I don't think any of the solutions I thought of would have worked. Quite enlightening, so thanks for taking the time to illustrate!
7 years ago
I like it! The science lesson is good, too!
7 years ago
Looks pretty and it's also a cool way to tease your friends! They will probably have no idea how you put the ball inside the cube :)
7 years ago
Good job.
Thanks for the matches & science lesson, for us slower persons.
7 years ago
Nice Job! I did a smaller one in response to "Impossible marble in Truncated Cube" and I found I didn't need to soak the wood, I just used a vegetable steamer, and it didn't take long, I think it just needed the heat to soak through. I think it is probably better for the wood if water doesn't soak in too much.
7 years ago
Interesting project and very nice instructions and pictures!
7 years ago
to prevent cracking, did you. push against the grain?
Reply 7 years ago
I can't believe that I forgot that important bit of information! Make sure to press it through the end grain of the cube. I have edited the instructable to make that step easier to understand.
Tip 1 year ago on Step 12
I found that drilling out only one of the end grain ends (i.e only five holes) gave the ball a more centered seating
Question 2 years ago on Step 1
If the diameter of a regulation billiard ball is 2 1/4” inches then is the 1 7/8 inch Forster bit a misprint?
Answer 1 year ago
American cue ball is 2.25 ins. UK ball is 2 ins.
Answer 2 years ago
Nope. The holes are smaller than the billiard ball. That is the best part of this puzzle.
2 years ago
I just saw this today and it is awesome! I would never have figured out how you did it. But why would you want to remove the ball? Wouldn’t it be more fun to keep it on display to boggle everyone’s minds?
Question 3 years ago on Introduction
Hi, I found Balls with a dia of 6,2cm which is 2,44 Inches. Which hole dia do you suggest? Have a nice day. Joe
Question 3 years ago on Introduction
I've tried 7 times to make this and every time my block splits. I've used a pine 4 x 4 four time and a cedar 4 x 4 3 times. I soaked and boiled the pieces as instructed. I even increase the size of the hole saw to 2". The only thing I didn't do is to cut the block down to 3 x 3. Would that make a difference? I always used the end grain.
Answer 3 years ago
Bringing down the size may make the difference. As 4x4's are actually 3 1/2 x 3 1/2 the extra wood around the hole may not stretch as much as a thinner section of wood. Make sure that you don't have any knots close to the section of wood you are using as that could cause a section of weakness in the wood that you are stressing.
3 years ago
dude nice project im making this in my wood making class at the junior high thanks for your great instructions
4 years ago
I used this for a different purpose - see step 6.
https://www.instructables.com/id/Air-Plant-Holders...