A machinist shouldn't be seen using a commercially puchased plumb bob so I made this one. Actually, it was made when I was starting out in the hobby and was a test piece to develop my skills.
The body is solid brass and the replaceable tip (they often get damaged in use) is made of steel. The spherical end cap was made using my incremental technique of turning spheres (see the BALLCUT archive on my site).
I wanted to be sure that the line supporting the bob couldn't influence the way it hangs so the line is tied to a pierced ball that rides in a conical depression inside the spherical end cap. Thus the bob is always free to hang perfectly vertical. In retrospect, given the weight of the final form, this feature is probably unnecessary but I always like to add something special to my designs.