The human body is amazing,Ford mechanics were taught 'feel',torque wrenches were not used. Skills were imparted,a journeyman would guide an apprentice,much as it is today.
The human body is amazing? yes sir,once a feel for the tension on an assembly is developed,its truly amazing how the brain and body work together to duplicate the same 'feel' I've actually seen the results against a torque wrench,once you have a feel for a value repeat it a few times and test it with a torque wrench,you'll be surprised.
I've also seen great consistency between a mechanic and his air operated impact wrench..know some cats who swore by a butterfly,they could nail an assembly.Flat rate specialists,real fast operators..