On Jun 5, 10:00*pm, Joseph Gwinn wrote:

As for the grit getting into the bearings, that sounds like a machine
design issue either way. *The flow of air or fluid should be arranged to
move the grit away from critical areas.

Joe Gwinn

The machine designers didn't have synthetic rubber for seals in 1919.
Some of our old home machines may have the same concerns. My 1965
South Bend lathe is an update of a 1920's model.

I read their long discussions to mean that a little lubricant is
enough to improve surface finish and a flood of any cheap coolant
greatly improves high speed production. For intermediate amounts, "The
average small stream as usually provided, is by no means sufficient to
secure ample cooling."
The book contains many observations and test results but generally
expects the reader to decide how to apply them.

Jim Wilkins