I just had three more balls converted to the IT and have 4 It slugs that I switch between balls 6 now). I've noticed an inconsistency in that several inner slugs fail to go in smoothly. Some will turn smoothly and include that satisfying click at the end that lets you know it's locked in. Some of them come up to the point where it is supposed to click and then must be forced hard into the final aligned position. Still others will stop just before clicking in. In other words, not all of the slugs will click into the insert. On first glance it appears that the centerpiece drilled in to the bottom is slightly off center and doesn't match up. Could there be something else going wrong? The issue seems to be on the insert side of the system rather than on the ball side of the system.

Surely this must be a common problem. What is the resolution?

Thanks

Thanks for the reply Snakster. That's an obvious option of course, but still would like to know the details.... This happens from time to time with IT system....

A couple of possiblities could have caused this:

1.  When drilling the bit may have hit the core and "shuttered" slightly causing it not to be perfectly straight

2.  The drill bits are too dull (which would cause the above) even if it didn't hit any core mass.

Couple things.  Like somebody said, a dull bit or going too fast can result in issues.  The innards of a ball are pretty hard, but heat and speed especially combined with a dull bit can result in a hole that's just a few hairs too small. 

Another thing, and the most common problem I ran into in the beginning.  When installing the lock piece in the ball, the "stem" that goes down into the 1/2 hole IS LOOSE, it is a separate piece from the upper piece that the bottom of the slug screws into.  If that center stem doesn't get seated all the way down as far as it can go, it will rub against the bottom of the safety molly on the slug when you go to screw the slug in.  How I avoid this is when I screw the ball-it onto the insertion tool, I leave the ram in the insertion tool.  I screw the ball-it on, and push on the ram to make sure the stem is fully seated into the lock piece.  Also, because the stem fits snugly into the 1/2 hole at the bottom of the drilled hole in the ball, even if it is fully seated, it can get pushed back up during insertion.  While inserting, I've got a firm grasp on the handles with my fingers, and my palm pushing down on the ram.  FURTHERMORE, while tapping on the end of the ram with the hammer once the piece has been inserted, hold down on the handles of the insertion tool while tapping on the end of the ram.  The stem can actually absorb and rebound the force applied by the hammer on the ram and unseat and slightly start popping the insertion tool up if you aren't holding the insertion tool in place. 

Sometimes, however, they can just need to get a little worn in.  They should never be hard to screw in, but some go in super easy, and others are a little tight the first couple times and loosen up just fine after that.  That's what she said anyway. 

Vises fix is to remove the upper sleeve and see where the binding is. Then, remove the sleeve from that area and reglue the rest of the sleeve in. In other words, shim it.....lol. It does look hokey but works. I have run into this problem mostly when converting and existing thumb to an IT thumb.