I highly recommend the water-cooled spindle for a number of reasons.
It is quieter, more powerful, and I don’t have to worry about brushes wearing out, or vents that get clogged with sawdust. It is very heavy and I used a single-start leadscrew for the Z so it would not drop when the power to the stepper goes off.
Here are videos about my build:
and
Here is what I wrote to one query in the YouTube comments about the spindle:
This is the item I got from Daedalus Machine Tools Store on Aliexpress: YL620-A VFD and 8A 400Hz 3-phase water-cooled spindle 65mmX200mm Jhong Hua Jiang mark. [https://www.aliexpress.com/item/4000570392908.html (230V option with the collets). There are many other vendors of identical and similar spindles. Read reviews and descriptions carefully. I can say that this vendor packed it well and did help me with figuring out how to configure the braking resistor I later got. Value for money is excellent. I also got more flexible clear vinyl tubing, quick-disconnects, a flow indicator, 4-conductor shielded flex cable (16AWG), aircraft connectors, and I installed a ground (earthing) wire to be able to use a Z probe touchplate. You may wish to get a spindle with a larger chuck. This set can use up to 7mm diameter (0.3125 inches) bits.
Today I received a CPU water cooling system that runs on 12V, instead of the 230VAC immersion pump I got with the spindle. I think that will do fine.