TheRE are usually two important functions for cutting oils, they must lubricate and they must cool. Very often the latter is of primary importance and it is difficult to obtain sufficient cooling of the right part of tool and workpiece since even the largest volume of liquid that can be projected on to the tool point will not prevent excessive temperatures from being generated at the tip. It has been known for years that in certain machining operations, tools would last longer if the cutting edge could be cooled sufficiently but the difficulties of doing this are not only concerned with securing adequate volume of liquid which is wasteful because insufficient temperature reduction may still be obtainable with conventional coolants.
Industrial Lubrication and Tribology – Emerald Publishing
Published: Jul 1, 1954