This is my second Instructable on a buttonhole puzzle. My first version used copper tubing and para cord. This version uses ball chain and stainless steel round. The original puzzle was invented by Sam Loyd 1841-1911. The puzzle is placed on a buttonhole and seams impossible to remove. This is where the term buttonholed (to get someone's attention) came from.

Step 1: Safety

You should always use safety glasses when sawing and drilling. You may also want to wear some gloves.

Step 2: Tools

I used a drill with a 1/8" diameter drill bit. A hacksaw with a metal cutting blade. And I used my multitool for cutting the ball chain and the file on it to deburr the edges.

Step 3: Materials

I used some stainless steel round stock. https://amzn.to/2zfS8CW

I only needed the 8 mm and 6 mm but it was just as cheap to get the hole set and I will come up with something to use the other pieces for.

I also used ball chain keyrings https://amzn.to/2OT1GJ0

Same as the round stock, I only needed a couple and I got longer, just in case.

Step 4: Cut the Roundstock

My roundstock was 4 inches long, so I cut them in half to make two 2 inch long pieces. I made one of the 8 mm diameter and one of the 6 mm diameter. The 8 mm can be a little too big for smaller buttonholes, I found the 6 mm was the best size.

Step 5: Drill a Thru Hole

I drilled a 1/8" diameter hole thru the round stock about 1/4 inch from the end. The 1/8" diameter hole is the perfect size for the ball chain link.

Step 6: Deburr

I deburred the cut and the hole. You could also polish up the piece to make it really shine.

Step 7: Find the Right Length for the Ball Chain

Test the ball chain length. You want it to be not quite long enough for the loop to go over the long end of the round piece. If it does, you need to cut it shorter.

Step 8: Cut the Ball Chain

Once you have found the right length for your ball chain, cut it. I found that 4 inches (including the link) was good.

Step 9: Assemble

Pass the ball chain thru the hole, attach the ends of the ball chain together using the ball chain link, and then push the ball chain link into the hole.

Step 10: Setting and Solving the Puzzle

Make sure you know how to put on and remove the Buttonhole Puzzle BEFORE trying it on someone. Find someone in a shirt with buttons. Make sure that they want to try the puzzle. Warn them that they could be driven insane. Let them inspect the puzzle. Explain that you will place the puzzle on their buttonhole and that they will try and remove it without cutting the ball chain or their shirt.

The trick is that the loop of the ball chain is not long enough to go over the long end of the round stock. The fabric of the shirt has to be pulled thru the loop of the ball chain far enough to go over the long end of the round stock. On the first "setting" of the puzzle, do not let the person see you setting it. If they do not figure it out, you could show the setting and solving of the puzzle.