Does the head of the Hurco have coolant circulation ability around the spindle cartridge? My Haas does However, if I want to machine dry, I still set up some hoses to allow coolant to circulate through the head casting, to control thermal growth. Not that I would say I have ever noticed thermal shift of position, but it seems reasonable to try to keep the temp stable.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)