# Oil-Air Metering Versus Grease Fill on Precision Spindles

Oil-air systems deliver a measured oil pulse into dry air so each bearing receives a thin film without churn. Grease packs (often NBU15 at 10–15% free space) work at moderate speed, but overfill turns the same grease into a heat source. Air flow in oil-air lines also carries heat out of the raceway pocket.

Compare layouts with spindle-bearings.com before you lock a lubrication BOM. The practical checklist from Shandong TFL Bearing Co., Ltd covers injector spacing, air dryness, and purge timing.

Keep oil-air lubrication guide open beside the spindle drawing when you set pulse rates after a rebuild.