Captive Nut Puzzle - Machined
This was a fun project for me to practice using the manual threading function on the lathe. I've always enjoyed lathe work a great deal, and making a puzzle was a fun challenge.
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I began this with one piece of brass hex rod, and cut it into three pieces, one for the "captive" nut, and two to make up the body of the piece. I drilled and tapped the ends of the body pieces and used Loc-tite to secure a smaller rod in place on one of the ends. I took extra care to make sure that the planes on the hex rod lined up after screwing them back together.
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I then turned down the middle section on the lathe and added the threads using a manual lathe. It was important to do this after separating the two pieces so that they would line up as much as possible to hide any seam that may have appeared from threading first and then cutting the puzzle in two. This was quite tricky, as I didn't have much space to start and stop the lathe before and after the threads began. Because the threads were in a section that was directly in the middle of two step-ups I had to slow down the lathe and be extra careful when turning the threads.
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The last step was simply to drill and tap the center of the nut. This was easy, and I made sure that the nut was a little bit looser than you would typically want so that it spun very freely.
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This was a fun project, making a convincing captive nut puzzle was a welcome challenge!
