Quote Originally Posted by JAZZCNC View Post
I could get into this deeper and tell you why you are wrong but I won't other than to say the water in the spindle is minimal, less than a cup full, so water weight isn't an issue.
The cooling comes from continuous recirculation of the water and provided the water container is large enough the spindle doesn't need a large volume of water around it.

Also, the 1.5Kw WC spindles are around 3Kg, not 5kg which is roughly the same weight as the Air-cooled. Cabling doesn't come into it because the Air-cooled still needs cable.
I expected there should be more water, at least around one litre, but if you say no, then I believe you. Yes, a 1.5kW water cooled and a 1.5kW air cooled has the same weight, but the discussion earlier was about a 2.2kW spindle, which is around 5kg.

You are right that the cable and the motor holder is the same, which is why I left that out of my "weight saving calculation" but my point with that was that when he calculates the new total weight he can't just look at the weight of the spindle, he must think about the rest also. While the cable is the same in all cases and makes no difference if it is for water or air cooled, it adds some extra to the weight which must be handled. But sure, if there is only a cup of water then it makes no difference for the total weight.