Impossible Bolt and Nut

**mklotz** · Dec 17, 2019, 11:28 AM

A recent photo by Crusty...

https://www.homemadetools.net/forum/...turecomment_30

showing his "impossible dangle" inspired me to document one of the same I made some years ago.

Many of these dangles are made with the aid of various adhesives and/or solder but there is a way to make one with nothing more than machining on the lathe.

The first photo shows the assembled "impossible" device.

The shaft is actually two pieces. One has a stud threaded 1/4-20 that screws into a hole in the other half threaded to match. Once the two halves are threaded together, the shaft is mounted between centers and the central section is single-point threaded 1/2-20.

Once the larger thread is cut, the joint between the two halves is virtually invisible.

The nut is threaded 1/2-20 and is made long enough to cover the joint when the nut is at either end of its travel. Assembly is easy. First thread the nut onto one of the halves, then thread the second half simultaneously into the hole and into the nut; this is possible because the pitch of the two threads is the same.