The coolant system is an optional item for the LeBlond RKL Series manual lathes. You would want to use a coolant pump to keep your part and tool cool, so you can cut better. Besides, you don’t want chips flying off the machine and burning your arms.
The system uses a standard 110v coolant pump that mounts on the rear leg of the machine. The pump has single-phase wiring and not the more expensive three-phase plug.
The system uses a water-soluble coolant. You could also substitute a synthetic coolant but this option is more expensive. Oil-based coolants are too heavy for the pump to handle.
With some materials such as cast iron or brass, you cannot use a coolant and you must machine these materials dry to prevent rust and other problems.
Below is a video for a LeBlond Super Heavy Duty Model NR 54×163 lathe for sale from a machine consulting company. Look for a shot of the coolant pump at around 3:58.