Union Nuts, and How to Make Them

These are quite different from those commercially available and are made from copper

- Brian Baker

So, to make the olives. These are quite different from those commercially available and are made from copper. First, chuck a suitable piece of copper rod in the three-jaw chuck with enough material protruding to make three or four olives. I should mention that thick wall copper pipe is also suitable for use. Using one of the union nuts that you have previously made, turn the outside of the rod or pipe to be about 5 thousandths of an inch (0.1 mm) smaller than the diameter of the threaded portion of the nut (photo 18). This allows clearance for the olive to swell slightly when tightened.

Next centre drill and then drill about ¼ inch (6 mm) deep a hole, with a drill size about 4 thousandths of an inch (0.1 mm) larger than the pipe size you are using (photo 19). The ‘little extra’ allows a small gap for the silver solder to penetrate easily when we attach it to the pipe. Next part off about 1⁄16 inch (1.5 mm) long (photo 20). As the olive is parted off, it tends to distort and slightly close the hole previously drilled but this is just what we want since this reduction in diameter stops the olive sliding down the pipe when silver soldering takes place.