Arthur,
The spring ball oil fitting is installed only in the saddle casting , never in the ways. A small pilot hole for the oil port is drilled through the casting and then tapped the appropriate size. The ways get oiled when the pump oil can is seated squarely on the fitting and a squirt of oil is shot into the fitting.
The fittings can also be on bushings that require oiling.
Indispensable on many applications.
Dick
OldToolmaker