phd is short for post hole diggers. A tool used to dig a small round hole straight down into earth. The hole would then be used to place a fence pole or a sign post. Since a working man will never likely have a real PhD, This tool is a working man's phd. Borrowed from a song by country artist Aaron Tippon "working man's phd" where he sings about having pride for working hard for a living.
Don't forget to bring the phd today we need to set up two signs. I have my working man's phd in the back of the truck if we need it.