DMcG, I used 026 and 029 key punch machines but you're probably referring to those little punches that always sat on top of one of the machines that you could slide one card into and move a punch die across it to the column you wanted, choose either a numbered or lettered zone and create a new hole. Yup, I've used those too. They were sometimes useful during program debugging because the object program was punched into binary cards—no operating system or disks—and, if you could visually "read" the binary cards, you could make some types of program corrections without having to go back to correct the source code and recompile. Of course this meant you also had to be able to code in your head in machine code.

Those were(n't) the days. <g>

      - Mark