Water Cooled Spindles.
We have installed 2 of the water cooled spindles, 1 on my Joe's CNC which uses Mach3 and 1 on my brother's Shark. Both have been operational for a number of months with no issues but they are NOT used continuously such as in a commercial shop so I am not sure about the life. Below is some basic information about what we did. Be glad to try and answer any specific questions.
We used 220 volt 1.5KW WATER-COOLED SPINDLE MOTOR & VFD DRIVE INVERTER such as found here: http://www.ebay.com/itm/1-5KW-WATER-COO ... 0676620657
There are a number of sellers of these units and most are priced around $320 - $360 for both the spindle motor and the VFD drive inverter.
We used PC cooling systems to cool them. These are closed loop and typically include a small radiator, 12 volt fan, and 12 volt pump, with some hose. Examples are: http://www.ebay.com/itm/NZXT-Kraken-X31 ... 43cd31eee4
. These are very common and come in many configurations.
Total cost will be about $500-$600 depending on how much it costs you to set up a 220 volt circuit. We did not try to make use of the Shark's control system or Mach3 to operate the units. They are switched independently. Make sure your switch is DPDT so that both 110 feed circuits are switched simultaneously. The wiring from the controller to the spindle will need to be rated for the volts and amps of the unit and probably shielded if run parallel with other wiring through the CNC.
You will need to get longer tubing and different size fittings to adapt the cooling systems - Lowes had most of what we needed.
The VFD controler does have to be set up and programmed initially - it is easy to have the spindle run backwards!
It is very quiet and hardly gets warm even during a 14 hour carving. Since most of the noise comes from the bit cutting the material there still will be noise!
You will need a 12 volt power supply and switch to run the cooling system. Amperage depends on configuration.