A few weeks back, I had a fairly small crash on the Haas VF2 where the nut on the tool holder collided with my aluminum stock.
After inspecting the tool holder, it appeared to be functional. However, when putting a dial indicator on a gauge pin, there was nearly 2 thou (0.002") of run-out (when the tool doesn't spin concentric with the holder), which is not acceptable for machining. Thankfully after removing the nut and collet and checking the tool holder's inside taper, I found it to be within half a tenth (0.00005").
Unfortunately, after taking a closer look at the nut, my boss noticed two small cracks, which caused the crazy run-out. I mention this because after discussing my process for putting the tools together, he didn't realize how tight I was clamping down on the endmills. I had thought you really had to screw the nut on there when putting the tools together; however, after he showed the actual amount of force needed, I was amazed. He suspects that's why the nut cracked, and the crash was just the breaking point for the nut.
He had me check through all the other tooling run out, and to my dismay, I found several tools with up to a thou of wobble. I removed many of the tooling setups for the Rocket project, reset each one with the proper amount of force, and got them all within a tenth or two.
Thinking on it now, this may be apart of the reason I'm getting some odd finishes on my parts, and now that I know it doesn't require all that much force to put the tools together, I'm eager to test out some new finishing toolpaths.