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How to Build a Secret-Code Wheel

SAFETY FIRST: Ask an adult to help with tools you haven't used before.

Writing secret messages is easy with this cipher wheel. It scrambles the alphabet so nobody can read your message except your buddy with an identical wheel. Armies once used similar devices because they could easily change the secret code.




  • 2 pieces of plywood, 1/2″ x 8″ x 8″
  • 1/4″ machine bolt, 1 1/2″ long
  • 4 1/4″ flat washers
  • 2 1/4″ nuts
  • Medium-grade sandpaper
  • Coping saw
  • Crosscut saw
  • Drill
  • 1/4″ drill bit
  • Drawing compass
  • Protractor
  • Straight edge
  • Dark pen


cipher-1Step 1: Use the compass to draw a 6″ circle on one piece of wood. Draw a 7″ circle on the second piece of wood.


cipher-2Step 2: With the coping saw, cut out both circles. Sand smooth.


cipher-3Step 3: Use the straight edge to draw one line all the way across each disc, making sure the line goes through the center of both plywood circles.


cipher-4Step 4: Center the protractor on the lines you just drew and make a mark every 12 degrees halfway around each disc.


cipher-5Step 5: Draw a line through each mark, across the center of both discs.


cipher-6Step 6: Staying within 1/2″ of the edge of the 7″ wheel, write this scrambled alphabet, one letter in each space: S P H I N X T O W E R C L A M J U G B D F K Q V Y Z. In the leftover spaces, write 5, 6, 7, 8. On the 6″ wheel, write the alphabet in regular order (A B C …). In the leftover spaces, write 1, 2, 3, 4.


cipher-7Step 7: Drill a 1/4″ hole through the center of each disc. Assemble the cipher wheel by putting one washer on the bolt. Put the bolt and washer through the bottom of the 7″ wheel. Turn the wheel over so the letters are facing up. Put two washers on the bolt, then add the 6″ wheel. Place another washer on the bolt and two nuts hand tightened so the wheels are snug and turn smoothly.




Pick any letter on the outer wheel as your key letter. Turn the inner wheel so A lines up with the key letter. Next, find the first letter of your message on the inner wheel. Look at the letter or number above it on the outer wheel. Write this down. Do the same for each letter of your message.

Example: Use the key letter R. Use the message SCOUT LAW. The enciphered message should be 7LYS8KRH. You can pick a different key letter for each message.

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18 Comments on How to Build a Secret-Code Wheel

  1. cat in the hat // December 13, 2023 at 8:58 pm // Reply

    this looks cool and fun to make. how do you make it out of paper?

  2. go – lol

  3. Hillary Clinton // March 21, 2016 at 7:32 pm // Reply

    Really cool! Used it on my sister and she couldn’t solve for 2 hours and then I had to help her. Really cool for tricking my annoying sister.

  4. I could make hundreds of these with paper.

  5. This is a neat project – but- I would have set the marks at 10 degrees each so that you could have had ALL of the numerals PLUS a blank space.

  6. I must make one of these. 🙂

  7. WOW! it looks very cool, I want to make it right now.

  8. super neat

  9. cool;)

  10. Awsome

  11. I’ve done this before, and it turned out pretty bad. I give this progect a B+.

  12. looks hard

  13. i dont get it??

  14. WOW:)

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