I am upgrading my Techno Isel 4896 Servo powered CNC Router to a full ATC Spindle. I am ready to make my spindle purchase very, very soon and have narrowed it down to either an HSD or Colombo 5hp unit.

I would like input from those with experience with either spindle. Both use either ISO or HSK tool holders... with HSK supposedly having greater accuracy. I would like comments on either type.

I will be using an ER32 collet set with the tool holders. I have heard both good and bad comments about collet nuts with bearings vs. those without. What are your experiences?

I will be using an external mounted fan for cooling.

lastly, as I understand it, the only difference in the ISO 30 tool holders, is with the pull-stud configuration, so I should be able to purchase the tool holders from any supplier so long as the pull-stud is the correct one for the spindle. Correct me if I am in error.

Thanks in advance,

DNH