Only 5.3% of US welders are women. After years as a professor, I became one

> One man, watching me while I cut 8-foot lengths of tubing for him, told me that I could simply hook my tape measure over the saw blade and subtract ⅛-inch to find the correct length. Piqued after I explained why his method wouldn’t work for a precise measurement, he responded by quizzing me on something I wasn’t likely to know: the purpose of the black diamonds on my tape measure.

Perhaps I'm picturing the situation wrong, but why wouldn't it work on the precision levels of a tape measure?