Miele Man, that's nice work. For completeness sake, I'll (re)link Dave Moulton's similar solution, using scrap copper pipe.

Here's a cool one I found today: need to remove a freewheel (standard shimano/sunrace 12-spline) but don't have the freewheel removal tool? Any 13/16" hex shape should fit well into 6 of the 12 splines, so if you can grip it with vise grips or a pipe wrench, you can try to torque it out. One common example of a 13/16" hex? The back of a spark plug socket!