[8sigma]

Is there any reason the BT toolholders need to go in the spindle a certain way?
All our holders have a little hole in one key slot and we were told to ALWAYS put that toward the one key in the spindle.
The holder will go in either way, and when one holder got put in "backwards" by one of my students the boss was told I could have killed someone. The claim is the spindle and holder are only balanced if the hole matches the key.
Seems odd to me that Milltronics would ship spindles purposely unbalanced and all the BT holder makers in the world make their holders equally unbalanced, so the tool could "fly out" if you aren't careful.

[yugami]

Its my understanding that CAT the balance side (with the drill hole) should point away from the drive dog - Historically. Now days many people doing super high precision high speed work will tell you it doesn't matter.

I believe that BT did not require that ever but I could be wrong.

[Brian L]

It makes no never mind which way you put a holder in for balance. The spindle is balance separate of the holders and the holders are balanced (if they are balanced at all) outside of that spindle and are "neutral balance" if you will all on their own.

The practice of putting the holders in a specific way, and the different sized keys on some, come from that fact that you have canned cycles that will bore, orient the spindle to one spot, shift X over and then pull the boring head out of the hole without leaving drag marks on the finished bore. Imagine what would happen if you were to install the tool 180º off, oops, you'd get a major drag mark or bust your boring bar.

[sportybob]

On some tools, the side with the "hole" is a different "depth" " dog key slot" side to the hole side. and so may NOT make the connection to either the spindle dog or the "tool pot" on the tool changer.
odd but I have seen it.
Look at your tools and see if the "dog" cutout is the same on both sides. the "deep side" should go to the tool changer. the tool pocket "dog" is shorter then the spindle side.


sportytbob