Coolant does more than cool. It carries chips away, reduces friction, and protects the finish. Use the coolant concentration and refractometer correction calculators to keep the mix at the strength the manufacturer recommends, since a mix that is too weak or too strong can cause rust, foaming, or poor tool life.

The flow rate, nozzle velocity, and minimum chip evacuation flow calculators help size the delivery for deep pockets and holes. Heat generation gives a feel for how much energy the cut produces, and the bar to PSI converter helps match pump readings to the units on tool specifications.

Coolant concentration is the share of concentrate in the finished mix. A 5 percent mix means 5 parts concentrate to 95 parts water, or roughly 1 part to 19. Always add the concentrate to the water while mixing, not the other way round, so it emulsifies properly.

Check the concentration regularly with a refractometer, because water evaporates faster than concentrate and the mix gets stronger over time. Hard water, bacteria, and tramp oil all shorten coolant life, so keep the sump clean and top it up with pre-mixed coolant rather than plain water.