Metal cutting machines include the option of coolant through the main spindle.

The use is mainly for deep drilling applications.

The high-pressure emulsion helps to remove the metal chips from the drilled hole.


The SFI Toodle Spindles use the coolant through the main spindle in order to drive the turbine spindle.

The machine pump delivers output pressure and flow rate.

The product of pressure [bar] and flow rate [LPM] is power [W].



The power of the pump is constant.

It is a function of the electric motor power and system efficiency.

In case of high flow rate, there will be a linear reduction in output pressure.


The coolant flows through hydraulic pipe lines and through the rotary unit in the main spindle, which produce friction pressure losses.

In order to evaluate the operational pressure in the system, it must be measured in the right location under flow.

A good condition pump should have an efficiency higher than 85%.

Over time, the efficiency of the pump will be lower due to wear in pump internal parts.

The coolant filter might produce resistance to flow rate followed by a reduction in pressure and in rotation speeds.

The SFI pressure gauge will indicate low pressure when the filter is not clean.

It is recommended to clean the filter periodically.


The SFI pressure gauge measures the pressure under the same flow rate as the Toodle Blue models.

The higher the pressure, the higher the rotation speed.

It is essential to know the actual Toodle rotation speed in order to determine the proper feed rate.


The new SFI gauge displays the actual pressure and the estimated rotation speed under each pressure level.

The visual indication of rotation speed allows an easy operation of the Toodles.

We do recommend to use the pressure gauge often (every new SET-UP procedure) in order to evaluate the pump condition and filter status.

Toodle Blue - Flow Rate

Toodle Blue - Pump Power


SFI Technical Team