A little over a year ago, I posted directions on how to solve a snake puzzle. That puzzle was purchased from Amazon. This year, I decided to make my own. My design is significantly larger than anything you can purchase online and also makes a nice conversation piece for those awkward visits from the in-laws.

Although time-consuming and somewhat mind numbing, it wasn't very challenging to build. However, you will need to pay attention to the build and assembly instructions.

Step 1: Tools and Materials

Tools:

Table Saw
Router Table
45 Degree Chamfer Bit
Drill Press
1/4" Forstner Bit
Ruler / Straightedge
Pencil
Center Punch

Materials:

Wood: 2x2 x 6 feet long
Wood: 1/2" diameter by 1 inch long dowel
Bungee Cord, 3/16" Diameter by 4 feet long
Paint or Stain
Spray Polyurethane
Danish Oil

Step 2: Drawings

Drawings are provided at the appropriate steps. When you finish, your puzzle should look like this CAD rendered image.

Step 3: Blocks

I started with two 3' long poplar 2x2s. Each was slightly larger than 1.5" on each side. Since I wanted perfectly square blocks, I cut the boards down to 1.5" x 1.5". Next, I turned the board and starting cutting 1.5" long blocks. Note that you only need 27 blocks. However, this much wood should allow for a little over 40. If you are like me, you are sure to mess up along the way. Therefore, I suggest cutting all 40 blocks now.

Step 4: Holes - Style 1

You are going to be drilling three different hole styles. The first is straight forward - just a 1/4" hole straight through the block. Mark from corner to corner to find a center of the block. I used a 1/4" Forstner bit for the drill. Next, I drilled through the block. Even though my cheap drill press is level, it didn't hit the center on the other side which required me to scrap one of my extra blocks. See why I need 40 :)? For the next shot, I measured the center on both sides and drill half way through from each side. Although a little more time consuming, this worked perfectly. Make 9 of these blocks.

Step 5: Holes - Style 2

This block is similar to Style 1 except that a counterbore is used on one side. I started with a 1/2" Forstner bit and drilled the 1/4" hole from the other side. You will need 2 of these blocks for the end pieces.

Step 6: Holes - Style 3

This block was a little trickier to make and took a little trial and error. Although my table is adjustable (45 degrees), I found it tough to hold the blocks steady while drilling. Therefore, I made this quick fixture from a 4x4 that worked pretty well. I cut 45 degree cuts in the 4x4 to make a V-Shape notch. This captured the part while drilling and allowed me to easily drill the 45 degree hole. I drilled my first part and it worked as expected, but not perfectly, in the center at the drill exit. I refined the process by first drilling shallow straight holes on the two sides and then following it up with the 45 hole. Make 16 of these.

Step 7: Chamfers

This step is optional and time consuming but I thought it made for a nicer looking puzzle. I used a 45 degree bearing chamfer router bit and adjusted the router table height until I found something I liked...roughly 3/16 of an inch. I wasted a few more of my blocks playing around here.

After routing, I sanded each side of the blocks and smoothed the sharp edges - another tedious process.

Step 8: Plug

The plug is used to hide the bungee cord on the end (Style 2) blocks. Cut the 1/2" diameter dowel to the length shown. Make 2 of these.

Step 9: Paint or Stain

Refer to the tables in this step. To summarize, you should have:

9 of Style 1
2 of Style 2
16 of Style 3

Before painting, you might want to do a dry fit to make sure you built everything correctly.

Now it's time to paint or stain the blocks. I used my failed blocks to practice with different types of finish. I finally chose a watered down red paint with black added to make a dark red (maroon) color for 14 of the blocks. Paint the plugs at this point as well. After the painting, I used steel wool to smooth out the finish. I then coated them with spray polyurethane as an extra layer of protection. The other 13 blocks were left natural with only a Danish Oil finish.

Step 10: Assembly

Build as follows:

Cut the bungee cord to 48" long.
Tie knot(s) on one end of the bungee.
Feed the bungee through the counterbore block (Style 2).
String the blocks as shown in the table.
Feed the cord through the final counterbore block.
Remove any slack and stretch the cord slightly. I did this by hanging it vertically and shaking it.
Tie a knot in each end to secure the blocks.
Trim the excess bungee cord.
Add the plugs to the ends. I glued these into place. Touch up paint if required.

Step 11: Finished Puzzle

Although it was a lot of work, I'm very happy with how it turned out.

Step 12: Size Comparison

As mentioned in the intro, this puzzle is much larger than commercially available puzzles. These pictures show the size comparison between mine, a normal size and a small key chain version.

Step 13: Solution

The solution for the smaller version was previously shown here with pictures. This video shows the solution using my version. I'll admit, the larger size does make it more appropriate for Shaquille O'Neal but it is solvable if you place it on a table.