My stock screw stripped the hell out of the hole after only about 3 uses, I really thought I was fucked for a while because it wasn't letting the chip sit securely so it wasn't level at all. Wound up having to get a larger, longer screw and carefully widen the xbit's hole with a drilll. Stock screw was not good at all, but even if you replace it early, it's the same as if you wind up having to do it later, like I did.
Also, mine didn't come with a spacer, and I had to cut one out of brass piping, but that's a different story.