Did the cut sound OK? I've had tool holders pull out when the cut was producing a lot of vibration.

Also, another thing to consider is that torque doesn't necessarily translate to holding force. An example: say you left a spindle with a draw-bar attached to a collet outside for a few years and the two pieces rusted together. It would take a LOT of torque to turn THAT draw-bar. 25 ft. lbs. probably wouldn't translate into any additional holding force. That's an extreme, but it's just an example to show that this fact is not debatable (as has occurred many times on this forum).

Are the threads of the TTS collet or draw-bar buggered up in any way?