My grandfather only finished the 8th grade but went on to be an engineer for Packard Motors.
And how did that work out???? (Couldn't resist) :-)
I have a degree in mechanical engineering, and am regularly embarrassed by auto mechanics.
Maybe that's why I never worked as an engineer...
My late father also was an 8th grade graduate. I always point out, however, that it was 8 years with nuns. In his job as a welder, he would often complain about college grad engineers who couldn't read a blueprint. My Dad could read a blueprint easily.