OK, I get the lipstick on the pig reference, but can you enlighten me on the sewer pipe one? I work for piping company and if there is a joke there, I need to know about it! :-)
I don't work for a piping company, but I'm pretty sure pipe comes in standard sizes. Thus, any measuring device that comes within the accuracy of those standard sizes would be acceptable for determining the difference between 2 inch and 3 inch standard pipe. (Or whatever the standards are, I drill oil wells not sewage lines.)
Anyway, calipers would be significanly more accurate than needed for the task. The joke was that only us obsessive compulsive types would bother using calipers to obtain the extra accuracy.
If I have followed it correctly...
Michael